/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│ │vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│ ╞══════════════════════════════════════════════════════════════════════════════╡ │ Copyright 2020 Justine Alexandra Roberts Tunney │ │ │ │ This program is free software; you can redistribute it and/or modify │ │ it under the terms of the GNU General Public License as published by │ │ the Free Software Foundation; version 2 of the License. │ │ │ │ This program is distributed in the hope that it will be useful, but │ │ WITHOUT ANY WARRANTY; without even the implied warranty of │ │ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │ │ General Public License for more details. │ │ │ │ You should have received a copy of the GNU General Public License │ │ along with this program; if not, write to the Free Software │ │ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │ │ 02110-1301 USA │ ╚─────────────────────────────────────────────────────────────────────────────*/ #include "libc/assert.h" #include "libc/macros.h" #include "libc/math.h" #include "libc/mem/mem.h" #include "libc/str/str.h" #include "third_party/stb/stb_image_resize.h" asm(".ident\t\"\\n\\n\ stb_image_resize (Public Domain)\\n\ Credit: Jorge L Rodriguez (@VinoBS), Sean Barrett, et al.\\n\ http://nothings.org/stb\""); #define STBIR_ASSERT(x) assert(x) #define STBIR_MALLOC(size, c) ((void)(c), malloc(size)) #define STBIR_FREE(ptr, c) ((void)(c), free(ptr)) #define STBIR__UNUSED_PARAM(v) #define STBIR__NOTUSED(v) #define STBIR__ARRAY_SIZE(a) ARRAYLEN(a) #ifndef STBIR_DEFAULT_FILTER_UPSAMPLE #define STBIR_DEFAULT_FILTER_UPSAMPLE STBIR_FILTER_CATMULLROM #endif #ifndef STBIR_DEFAULT_FILTER_DOWNSAMPLE #define STBIR_DEFAULT_FILTER_DOWNSAMPLE STBIR_FILTER_MITCHELL #endif #ifndef STBIR_PROGRESS_REPORT #define STBIR_PROGRESS_REPORT(float_0_to_1) #endif #ifndef STBIR_MAX_CHANNELS #define STBIR_MAX_CHANNELS 64 #endif #if STBIR_MAX_CHANNELS > 65536 #error "Too many channels; STBIR_MAX_CHANNELS must be no more than 65536." // because we store the indices in 16-bit variables #endif // This value is added to alpha just before premultiplication to avoid // zeroing out color values. It is equivalent to 2^-80. If you don't want // that behavior (it may interfere if you have floating point images with // very small alpha values) then you can define STBIR_NO_ALPHA_EPSILON to // disable it. #ifndef STBIR_ALPHA_EPSILON #define STBIR_ALPHA_EPSILON \ ((float)1 / (1 << 20) / (1 << 20) / (1 << 20) / (1 << 20)) #endif // must match stbir_datatype static unsigned char stbir__type_size[] = { 1, // STBIR_TYPE_UINT8 2, // STBIR_TYPE_UINT16 4, // STBIR_TYPE_UINT32 4, // STBIR_TYPE_FLOAT }; // Kernel function centered at 0 typedef float(stbir__kernel_fn)(float x, float scale); typedef float(stbir__support_fn)(float scale); typedef struct { stbir__kernel_fn* kernel; stbir__support_fn* support; } stbir__filter_info; // When upsampling, the contributors are which source pixels contribute. // When downsampling, the contributors are which destination pixels are // contributed to. typedef struct { int n0; // First contributing pixel int n1; // Last contributing pixel } stbir__contributors; typedef struct { const void* input_data; int input_w; int input_h; int input_stride_bytes; void* output_data; int output_w; int output_h; int output_stride_bytes; float s0, t0, s1, t1; float horizontal_shift; // Units: output pixels float vertical_shift; // Units: output pixels float horizontal_scale; float vertical_scale; int channels; int alpha_channel; uint32_t flags; stbir_datatype type; stbir_filter horizontal_filter; stbir_filter vertical_filter; stbir_edge edge_horizontal; stbir_edge edge_vertical; stbir_colorspace colorspace; stbir__contributors* horizontal_contributors; float* horizontal_coefficients; stbir__contributors* vertical_contributors; float* vertical_coefficients; int decode_buffer_pixels; float* decode_buffer; float* horizontal_buffer; // cache these because ceil/floor are inexplicably showing up in profile int horizontal_coefficient_width; int vertical_coefficient_width; int horizontal_filter_pixel_width; int vertical_filter_pixel_width; int horizontal_filter_pixel_margin; int vertical_filter_pixel_margin; int horizontal_num_contributors; int vertical_num_contributors; int ring_buffer_length_bytes; // The length of an individual entry in the // ring buffer. The total number of ring // buffers is // stbir__get_filter_pixel_width(filter) int ring_buffer_num_entries; // Total number of entries in the ring buffer. int ring_buffer_first_scanline; int ring_buffer_last_scanline; int ring_buffer_begin_index; // first_scanline is at this index in the ring // buffer float* ring_buffer; float* encode_buffer; // A temporary buffer to store floats so we don't lose // precision while we do multiply-adds. int horizontal_contributors_size; int horizontal_coefficients_size; int vertical_contributors_size; int vertical_coefficients_size; int decode_buffer_size; int horizontal_buffer_size; int ring_buffer_size; int encode_buffer_size; } stbir__info; static const float stbir__max_uint8_as_float = 255.0f; static const float stbir__max_uint16_as_float = 65535.0f; static const double stbir__max_uint32_as_float = 4294967295.0; forceinline int stbir__min(int a, int b) { return a < b ? a : b; } forceinline float stbir__saturate(float x) { if (x < 0) return 0; if (x > 1) return 1; return x; } #ifdef STBIR_SATURATE_INT forceinline uint8_t stbir__saturate8(int x) { if ((unsigned int)x <= 255) return x; if (x < 0) return 0; return 255; } forceinline uint16_t stbir__saturate16(int x) { if ((unsigned int)x <= 65535) return x; if (x < 0) return 0; return 65535; } #endif static float stbir__srgb_uchar_to_linear_float[256] = { 0.000000f, 0.000304f, 0.000607f, 0.000911f, 0.001214f, 0.001518f, 0.001821f, 0.002125f, 0.002428f, 0.002732f, 0.003035f, 0.003347f, 0.003677f, 0.004025f, 0.004391f, 0.004777f, 0.005182f, 0.005605f, 0.006049f, 0.006512f, 0.006995f, 0.007499f, 0.008023f, 0.008568f, 0.009134f, 0.009721f, 0.010330f, 0.010960f, 0.011612f, 0.012286f, 0.012983f, 0.013702f, 0.014444f, 0.015209f, 0.015996f, 0.016807f, 0.017642f, 0.018500f, 0.019382f, 0.020289f, 0.021219f, 0.022174f, 0.023153f, 0.024158f, 0.025187f, 0.026241f, 0.027321f, 0.028426f, 0.029557f, 0.030713f, 0.031896f, 0.033105f, 0.034340f, 0.035601f, 0.036889f, 0.038204f, 0.039546f, 0.040915f, 0.042311f, 0.043735f, 0.045186f, 0.046665f, 0.048172f, 0.049707f, 0.051269f, 0.052861f, 0.054480f, 0.056128f, 0.057805f, 0.059511f, 0.061246f, 0.063010f, 0.064803f, 0.066626f, 0.068478f, 0.070360f, 0.072272f, 0.074214f, 0.076185f, 0.078187f, 0.080220f, 0.082283f, 0.084376f, 0.086500f, 0.088656f, 0.090842f, 0.093059f, 0.095307f, 0.097587f, 0.099899f, 0.102242f, 0.104616f, 0.107023f, 0.109462f, 0.111932f, 0.114435f, 0.116971f, 0.119538f, 0.122139f, 0.124772f, 0.127438f, 0.130136f, 0.132868f, 0.135633f, 0.138432f, 0.141263f, 0.144128f, 0.147027f, 0.149960f, 0.152926f, 0.155926f, 0.158961f, 0.162029f, 0.165132f, 0.168269f, 0.171441f, 0.174647f, 0.177888f, 0.181164f, 0.184475f, 0.187821f, 0.191202f, 0.194618f, 0.198069f, 0.201556f, 0.205079f, 0.208637f, 0.212231f, 0.215861f, 0.219526f, 0.223228f, 0.226966f, 0.230740f, 0.234551f, 0.238398f, 0.242281f, 0.246201f, 0.250158f, 0.254152f, 0.258183f, 0.262251f, 0.266356f, 0.270498f, 0.274677f, 0.278894f, 0.283149f, 0.287441f, 0.291771f, 0.296138f, 0.300544f, 0.304987f, 0.309469f, 0.313989f, 0.318547f, 0.323143f, 0.327778f, 0.332452f, 0.337164f, 0.341914f, 0.346704f, 0.351533f, 0.356400f, 0.361307f, 0.366253f, 0.371238f, 0.376262f, 0.381326f, 0.386430f, 0.391573f, 0.396755f, 0.401978f, 0.407240f, 0.412543f, 0.417885f, 0.423268f, 0.428691f, 0.434154f, 0.439657f, 0.445201f, 0.450786f, 0.456411f, 0.462077f, 0.467784f, 0.473532f, 0.479320f, 0.485150f, 0.491021f, 0.496933f, 0.502887f, 0.508881f, 0.514918f, 0.520996f, 0.527115f, 0.533276f, 0.539480f, 0.545725f, 0.552011f, 0.558340f, 0.564712f, 0.571125f, 0.577581f, 0.584078f, 0.590619f, 0.597202f, 0.603827f, 0.610496f, 0.617207f, 0.623960f, 0.630757f, 0.637597f, 0.644480f, 0.651406f, 0.658375f, 0.665387f, 0.672443f, 0.679543f, 0.686685f, 0.693872f, 0.701102f, 0.708376f, 0.715694f, 0.723055f, 0.730461f, 0.737911f, 0.745404f, 0.752942f, 0.760525f, 0.768151f, 0.775822f, 0.783538f, 0.791298f, 0.799103f, 0.806952f, 0.814847f, 0.822786f, 0.830770f, 0.838799f, 0.846873f, 0.854993f, 0.863157f, 0.871367f, 0.879622f, 0.887923f, 0.896269f, 0.904661f, 0.913099f, 0.921582f, 0.930111f, 0.938686f, 0.947307f, 0.955974f, 0.964686f, 0.973445f, 0.982251f, 0.991102f, 1.0f}; static float stbir__srgb_to_linear(float f) { if (f <= 0.04045f) return f / 12.92f; else return (float)pow((f + 0.055f) / 1.055f, 2.4f); } static float stbir__linear_to_srgb(float f) { if (f <= 0.0031308f) return f * 12.92f; else return 1.055f * (float)pow(f, 1 / 2.4f) - 0.055f; } #ifndef STBIR_NON_IEEE_FLOAT // From https://gist.github.com/rygorous/2203834 typedef union { uint32_t u; float f; } stbir__FP32; static const uint32_t fp32_to_srgb8_tab4[104] = { 0x0073000d, 0x007a000d, 0x0080000d, 0x0087000d, 0x008d000d, 0x0094000d, 0x009a000d, 0x00a1000d, 0x00a7001a, 0x00b4001a, 0x00c1001a, 0x00ce001a, 0x00da001a, 0x00e7001a, 0x00f4001a, 0x0101001a, 0x010e0033, 0x01280033, 0x01410033, 0x015b0033, 0x01750033, 0x018f0033, 0x01a80033, 0x01c20033, 0x01dc0067, 0x020f0067, 0x02430067, 0x02760067, 0x02aa0067, 0x02dd0067, 0x03110067, 0x03440067, 0x037800ce, 0x03df00ce, 0x044600ce, 0x04ad00ce, 0x051400ce, 0x057b00c5, 0x05dd00bc, 0x063b00b5, 0x06970158, 0x07420142, 0x07e30130, 0x087b0120, 0x090b0112, 0x09940106, 0x0a1700fc, 0x0a9500f2, 0x0b0f01cb, 0x0bf401ae, 0x0ccb0195, 0x0d950180, 0x0e56016e, 0x0f0d015e, 0x0fbc0150, 0x10630143, 0x11070264, 0x1238023e, 0x1357021d, 0x14660201, 0x156601e9, 0x165a01d3, 0x174401c0, 0x182401af, 0x18fe0331, 0x1a9602fe, 0x1c1502d2, 0x1d7e02ad, 0x1ed4028d, 0x201a0270, 0x21520256, 0x227d0240, 0x239f0443, 0x25c003fe, 0x27bf03c4, 0x29a10392, 0x2b6a0367, 0x2d1d0341, 0x2ebe031f, 0x304d0300, 0x31d105b0, 0x34a80555, 0x37520507, 0x39d504c5, 0x3c37048b, 0x3e7c0458, 0x40a8042a, 0x42bd0401, 0x44c20798, 0x488e071e, 0x4c1c06b6, 0x4f76065d, 0x52a50610, 0x55ac05cc, 0x5892058f, 0x5b590559, 0x5e0c0a23, 0x631c0980, 0x67db08f6, 0x6c55087f, 0x70940818, 0x74a007bd, 0x787d076c, 0x7c330723, }; static uint8_t stbir__linear_to_srgb_uchar(float in) { static const stbir__FP32 almostone = {0x3f7fffff}; // 1-eps static const stbir__FP32 minval = {(127 - 13) << 23}; uint32_t tab, bias, scale, t; stbir__FP32 f; // Clamp to [2^(-13), 1-eps]; these two values map to 0 and 1, respectively. // The tests are carefully written so that NaNs map to 0, same as in the // reference implementation. if (!(in > minval.f)) // written this way to catch NaNs in = minval.f; if (in > almostone.f) in = almostone.f; // Do the table lookup and unpack bias, scale f.f = in; tab = fp32_to_srgb8_tab4[(f.u - minval.u) >> 20]; bias = (tab >> 16) << 9; scale = tab & 0xffff; // Grab next-highest mantissa bits and perform linear interpolation t = (f.u >> 12) & 0xff; return (unsigned char)((bias + scale * t) >> 16); } #else // sRGB transition values, scaled by 1<<28 static int stbir__srgb_offset_to_linear_scaled[256] = { 0, 40738, 122216, 203693, 285170, 366648, 448125, 529603, 611080, 692557, 774035, 855852, 942009, 1033024, 1128971, 1229926, 1335959, 1447142, 1563542, 1685229, 1812268, 1944725, 2082664, 2226148, 2375238, 2529996, 2690481, 2856753, 3028870, 3206888, 3390865, 3580856, 3776916, 3979100, 4187460, 4402049, 4622919, 4850123, 5083710, 5323731, 5570236, 5823273, 6082892, 6349140, 6622065, 6901714, 7188133, 7481369, 7781466, 8088471, 8402427, 8723380, 9051372, 9386448, 9728650, 10078021, 10434603, 10798439, 11169569, 11548036, 11933879, 12327139, 12727857, 13136073, 13551826, 13975156, 14406100, 14844697, 15290987, 15745007, 16206795, 16676389, 17153826, 17639142, 18132374, 18633560, 19142734, 19659934, 20185196, 20718552, 21260042, 21809696, 22367554, 22933648, 23508010, 24090680, 24681686, 25281066, 25888850, 26505076, 27129772, 27762974, 28404716, 29055026, 29713942, 30381490, 31057708, 31742624, 32436272, 33138682, 33849884, 34569912, 35298800, 36036568, 36783260, 37538896, 38303512, 39077136, 39859796, 40651528, 41452360, 42262316, 43081432, 43909732, 44747252, 45594016, 46450052, 47315392, 48190064, 49074096, 49967516, 50870356, 51782636, 52704392, 53635648, 54576432, 55526772, 56486700, 57456236, 58435408, 59424248, 60422780, 61431036, 62449032, 63476804, 64514376, 65561776, 66619028, 67686160, 68763192, 69850160, 70947088, 72053992, 73170912, 74297864, 75434880, 76581976, 77739184, 78906536, 80084040, 81271736, 82469648, 83677792, 84896192, 86124888, 87363888, 88613232, 89872928, 91143016, 92423512, 93714432, 95015816, 96327688, 97650056, 98982952, 100326408, 101680440, 103045072, 104420320, 105806224, 107202800, 108610064, 110028048, 111456776, 112896264, 114346544, 115807632, 117279552, 118762328, 120255976, 121760536, 123276016, 124802440, 126339832, 127888216, 129447616, 131018048, 132599544, 134192112, 135795792, 137410592, 139036528, 140673648, 142321952, 143981456, 145652208, 147334208, 149027488, 150732064, 152447968, 154175200, 155913792, 157663776, 159425168, 161197984, 162982240, 164777968, 166585184, 168403904, 170234160, 172075968, 173929344, 175794320, 177670896, 179559120, 181458992, 183370528, 185293776, 187228736, 189175424, 191133888, 193104112, 195086128, 197079968, 199085648, 201103184, 203132592, 205173888, 207227120, 209292272, 211369392, 213458480, 215559568, 217672656, 219797792, 221934976, 224084240, 226245600, 228419056, 230604656, 232802400, 235012320, 237234432, 239468736, 241715280, 243974080, 246245120, 248528464, 250824112, 253132064, 255452368, 257785040, 260130080, 262487520, 264857376, 267239664, }; static uint8_t stbir__linear_to_srgb_uchar(float f) { int x = (int)(f * (1 << 28)); // has headroom so you don't need to clamp int v = 0; int i; // Refine the guess with a short binary search. i = v + 128; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i; i = v + 64; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i; i = v + 32; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i; i = v + 16; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i; i = v + 8; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i; i = v + 4; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i; i = v + 2; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i; i = v + 1; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i; return (uint8_t)v; } #endif static float stbir__filter_trapezoid(float x, float scale) { float halfscale = scale / 2; float t = 0.5f + halfscale; STBIR_ASSERT(scale <= 1); x = (float)fabs(x); if (x >= t) return 0; else { float r = 0.5f - halfscale; if (x <= r) return 1; else return (t - x) / scale; } } static float stbir__support_trapezoid(float scale) { STBIR_ASSERT(scale <= 1); return 0.5f + scale / 2; } static float stbir__filter_triangle(float x, float s) { STBIR__UNUSED_PARAM(s); x = (float)fabs(x); if (x <= 1.0f) return 1 - x; else return 0; } static float stbir__filter_cubic(float x, float s) { STBIR__UNUSED_PARAM(s); x = (float)fabs(x); if (x < 1.0f) return (4 + x * x * (3 * x - 6)) / 6; else if (x < 2.0f) return (8 + x * (-12 + x * (6 - x))) / 6; return (0.0f); } static float stbir__filter_catmullrom(float x, float s) { STBIR__UNUSED_PARAM(s); x = (float)fabs(x); if (x < 1.0f) return 1 - x * x * (2.5f - 1.5f * x); else if (x < 2.0f) return 2 - x * (4 + x * (0.5f * x - 2.5f)); return (0.0f); } static float stbir__filter_mitchell(float x, float s) { STBIR__UNUSED_PARAM(s); x = (float)fabs(x); if (x < 1.0f) return (16 + x * x * (21 * x - 36)) / 18; else if (x < 2.0f) return (32 + x * (-60 + x * (36 - 7 * x))) / 18; return (0.0f); } static float stbir__support_zero(float s) { STBIR__UNUSED_PARAM(s); return 0; } static float stbir__support_one(float s) { STBIR__UNUSED_PARAM(s); return 1; } static float stbir__support_two(float s) { STBIR__UNUSED_PARAM(s); return 2; } static stbir__filter_info stbir__filter_info_table[] = { {NULL, stbir__support_zero}, {stbir__filter_trapezoid, stbir__support_trapezoid}, {stbir__filter_triangle, stbir__support_one}, {stbir__filter_cubic, stbir__support_two}, {stbir__filter_catmullrom, stbir__support_two}, {stbir__filter_mitchell, stbir__support_two}, }; forceinline int stbir__use_upsampling(float ratio) { return ratio > 1; } forceinline int stbir__use_width_upsampling(stbir__info* stbir_info) { return stbir__use_upsampling(stbir_info->horizontal_scale); } forceinline int stbir__use_height_upsampling(stbir__info* stbir_info) { return stbir__use_upsampling(stbir_info->vertical_scale); } // This is the maximum number of input samples that can affect an output sample // with the given filter static int stbir__get_filter_pixel_width(stbir_filter filter, float scale) { STBIR_ASSERT(filter != 0); STBIR_ASSERT(filter < STBIR__ARRAY_SIZE(stbir__filter_info_table)); if (stbir__use_upsampling(scale)) return (int)ceil(stbir__filter_info_table[filter].support(1 / scale) * 2); else return (int)ceil(stbir__filter_info_table[filter].support(scale) * 2 / scale); } // This is how much to expand buffers to account for filters seeking outside // the image boundaries. static int stbir__get_filter_pixel_margin(stbir_filter filter, float scale) { return stbir__get_filter_pixel_width(filter, scale) / 2; } static int stbir__get_coefficient_width(stbir_filter filter, float scale) { if (stbir__use_upsampling(scale)) return (int)ceil(stbir__filter_info_table[filter].support(1 / scale) * 2); else return (int)ceil(stbir__filter_info_table[filter].support(scale) * 2); } static int stbir__get_contributors(float scale, stbir_filter filter, int input_size, int output_size) { if (stbir__use_upsampling(scale)) return output_size; else return (input_size + stbir__get_filter_pixel_margin(filter, scale) * 2); } static int stbir__get_total_horizontal_coefficients(stbir__info* info) { return info->horizontal_num_contributors * stbir__get_coefficient_width(info->horizontal_filter, info->horizontal_scale); } static int stbir__get_total_vertical_coefficients(stbir__info* info) { return info->vertical_num_contributors * stbir__get_coefficient_width(info->vertical_filter, info->vertical_scale); } static stbir__contributors* stbir__get_contributor( stbir__contributors* contributors, int n) { return &contributors[n]; } // For perf reasons this code is duplicated in // stbir__resample_horizontal_upsample/downsample, if you change it here change // it there too. static float* stbir__get_coefficient(float* coefficients, stbir_filter filter, float scale, int n, int c) { int width = stbir__get_coefficient_width(filter, scale); return &coefficients[width * n + c]; } static int stbir__edge_wrap_slow(stbir_edge edge, int n, int max) { switch (edge) { case STBIR_EDGE_ZERO: return 0; // we'll decode the wrong pixel here, and then overwrite with // 0s later case STBIR_EDGE_CLAMP: if (n < 0) return 0; if (n >= max) return max - 1; return n; // NOTREACHED case STBIR_EDGE_REFLECT: { if (n < 0) { if (n < max) return -n; else return max - 1; } if (n >= max) { int max2 = max * 2; if (n >= max2) return 0; else return max2 - n - 1; } return n; // NOTREACHED } case STBIR_EDGE_WRAP: if (n >= 0) return (n % max); else { int m = (-n) % max; if (m != 0) m = max - m; return (m); } // NOTREACHED default: STBIR_ASSERT(!"Unimplemented edge type"); return 0; } } forceinline int stbir__edge_wrap(stbir_edge edge, int n, int max) { // avoid per-pixel switch if (n >= 0 && n < max) return n; return stbir__edge_wrap_slow(edge, n, max); } // What input pixels contribute to this output pixel? static void stbir__calculate_sample_range_upsample( int n, float out_filter_radius, float scale_ratio, float out_shift, int* in_first_pixel, int* in_last_pixel, float* in_center_of_out) { float out_pixel_center = (float)n + 0.5f; float out_pixel_influence_lowerbound = out_pixel_center - out_filter_radius; float out_pixel_influence_upperbound = out_pixel_center + out_filter_radius; float in_pixel_influence_lowerbound = (out_pixel_influence_lowerbound + out_shift) / scale_ratio; float in_pixel_influence_upperbound = (out_pixel_influence_upperbound + out_shift) / scale_ratio; *in_center_of_out = (out_pixel_center + out_shift) / scale_ratio; *in_first_pixel = (int)(floor(in_pixel_influence_lowerbound + 0.5)); *in_last_pixel = (int)(floor(in_pixel_influence_upperbound - 0.5)); } // What output pixels does this input pixel contribute to? static void stbir__calculate_sample_range_downsample( int n, float in_pixels_radius, float scale_ratio, float out_shift, int* out_first_pixel, int* out_last_pixel, float* out_center_of_in) { float in_pixel_center = (float)n + 0.5f; float in_pixel_influence_lowerbound = in_pixel_center - in_pixels_radius; float in_pixel_influence_upperbound = in_pixel_center + in_pixels_radius; float out_pixel_influence_lowerbound = in_pixel_influence_lowerbound * scale_ratio - out_shift; float out_pixel_influence_upperbound = in_pixel_influence_upperbound * scale_ratio - out_shift; *out_center_of_in = in_pixel_center * scale_ratio - out_shift; *out_first_pixel = (int)(floor(out_pixel_influence_lowerbound + 0.5)); *out_last_pixel = (int)(floor(out_pixel_influence_upperbound - 0.5)); } static void stbir__calculate_coefficients_upsample( stbir_filter filter, float scale, int in_first_pixel, int in_last_pixel, float in_center_of_out, stbir__contributors* contributor, float* coefficient_group) { int i; float total_filter = 0; float filter_scale; STBIR_ASSERT( in_last_pixel - in_first_pixel <= (int)ceil(stbir__filter_info_table[filter].support(1 / scale) * 2)); // Taken directly from stbir__get_coefficient_width() // which we can't call because we don't know if we're // horizontal or vertical. contributor->n0 = in_first_pixel; contributor->n1 = in_last_pixel; STBIR_ASSERT(contributor->n1 >= contributor->n0); for (i = 0; i <= in_last_pixel - in_first_pixel; i++) { float in_pixel_center = (float)(i + in_first_pixel) + 0.5f; coefficient_group[i] = stbir__filter_info_table[filter].kernel( in_center_of_out - in_pixel_center, 1 / scale); // If the coefficient is zero, skip it. (Don't do the <0 check here, we want // the influence of those outside pixels.) if (i == 0 && !coefficient_group[i]) { contributor->n0 = ++in_first_pixel; i--; continue; } total_filter += coefficient_group[i]; } STBIR_ASSERT(stbir__filter_info_table[filter].kernel( (float)(in_last_pixel + 1) + 0.5f - in_center_of_out, 1 / scale) == 0); STBIR_ASSERT(total_filter > 0.9); STBIR_ASSERT(total_filter < 1.1f); // Make sure it's not way off. // Make sure the sum of all coefficients is 1. filter_scale = 1 / total_filter; for (i = 0; i <= in_last_pixel - in_first_pixel; i++) coefficient_group[i] *= filter_scale; for (i = in_last_pixel - in_first_pixel; i >= 0; i--) { if (coefficient_group[i]) break; // This line has no weight. We can skip it. contributor->n1 = contributor->n0 + i - 1; } } static void stbir__calculate_coefficients_downsample( stbir_filter filter, float scale_ratio, int out_first_pixel, int out_last_pixel, float out_center_of_in, stbir__contributors* contributor, float* coefficient_group) { int i; STBIR_ASSERT( out_last_pixel - out_first_pixel <= (int)ceil(stbir__filter_info_table[filter].support(scale_ratio) * 2)); // Taken directly from stbir__get_coefficient_width() // which we can't call because we don't know if we're // horizontal or vertical. contributor->n0 = out_first_pixel; contributor->n1 = out_last_pixel; STBIR_ASSERT(contributor->n1 >= contributor->n0); for (i = 0; i <= out_last_pixel - out_first_pixel; i++) { float out_pixel_center = (float)(i + out_first_pixel) + 0.5f; float x = out_pixel_center - out_center_of_in; coefficient_group[i] = stbir__filter_info_table[filter].kernel(x, scale_ratio) * scale_ratio; } STBIR_ASSERT(stbir__filter_info_table[filter].kernel( (float)(out_last_pixel + 1) + 0.5f - out_center_of_in, scale_ratio) == 0); for (i = out_last_pixel - out_first_pixel; i >= 0; i--) { if (coefficient_group[i]) break; // This line has no weight. We can skip it. contributor->n1 = contributor->n0 + i - 1; } } static void stbir__normalize_downsample_coefficients( stbir__contributors* contributors, float* coefficients, stbir_filter filter, float scale_ratio, int input_size, int output_size) { int num_contributors = stbir__get_contributors(scale_ratio, filter, input_size, output_size); int num_coefficients = stbir__get_coefficient_width(filter, scale_ratio); int i, j; int skip; for (i = 0; i < output_size; i++) { float scale; float total = 0; for (j = 0; j < num_contributors; j++) { if (i >= contributors[j].n0 && i <= contributors[j].n1) { float coefficient = *stbir__get_coefficient( coefficients, filter, scale_ratio, j, i - contributors[j].n0); total += coefficient; } else if (i < contributors[j].n0) break; } STBIR_ASSERT(total > 0.9f); STBIR_ASSERT(total < 1.1f); scale = 1 / total; for (j = 0; j < num_contributors; j++) { if (i >= contributors[j].n0 && i <= contributors[j].n1) *stbir__get_coefficient(coefficients, filter, scale_ratio, j, i - contributors[j].n0) *= scale; else if (i < contributors[j].n0) break; } } // Optimize: Skip zero coefficients and contributions outside of image bounds. // Do this after normalizing because normalization depends on the n0/n1 // values. for (j = 0; j < num_contributors; j++) { int range, max, width; skip = 0; while (*stbir__get_coefficient(coefficients, filter, scale_ratio, j, skip) == 0) skip++; contributors[j].n0 += skip; while (contributors[j].n0 < 0) { contributors[j].n0++; skip++; } range = contributors[j].n1 - contributors[j].n0 + 1; max = stbir__min(num_coefficients, range); width = stbir__get_coefficient_width(filter, scale_ratio); for (i = 0; i < max; i++) { if (i + skip >= width) break; *stbir__get_coefficient(coefficients, filter, scale_ratio, j, i) = *stbir__get_coefficient(coefficients, filter, scale_ratio, j, i + skip); } continue; } // Using min to avoid writing into invalid pixels. for (i = 0; i < num_contributors; i++) contributors[i].n1 = stbir__min(contributors[i].n1, output_size - 1); } // Each scan line uses the same kernel values so we should calculate the kernel // values once and then we can use them for every scan line. static void stbir__calculate_filters(stbir__contributors* contributors, float* coefficients, stbir_filter filter, float scale_ratio, float shift, int input_size, int output_size) { int n; int total_contributors = stbir__get_contributors(scale_ratio, filter, input_size, output_size); if (stbir__use_upsampling(scale_ratio)) { float out_pixels_radius = stbir__filter_info_table[filter].support(1 / scale_ratio) * scale_ratio; // Looping through out pixels for (n = 0; n < total_contributors; n++) { float in_center_of_out; // Center of the current out pixel in the in // pixel space int in_first_pixel, in_last_pixel; stbir__calculate_sample_range_upsample(n, out_pixels_radius, scale_ratio, shift, &in_first_pixel, &in_last_pixel, &in_center_of_out); stbir__calculate_coefficients_upsample( filter, scale_ratio, in_first_pixel, in_last_pixel, in_center_of_out, stbir__get_contributor(contributors, n), stbir__get_coefficient(coefficients, filter, scale_ratio, n, 0)); } } else { float in_pixels_radius = stbir__filter_info_table[filter].support(scale_ratio) / scale_ratio; // Looping through in pixels for (n = 0; n < total_contributors; n++) { float out_center_of_in; // Center of the current out pixel in the in // pixel space int out_first_pixel, out_last_pixel; int n_adjusted = n - stbir__get_filter_pixel_margin(filter, scale_ratio); stbir__calculate_sample_range_downsample( n_adjusted, in_pixels_radius, scale_ratio, shift, &out_first_pixel, &out_last_pixel, &out_center_of_in); stbir__calculate_coefficients_downsample( filter, scale_ratio, out_first_pixel, out_last_pixel, out_center_of_in, stbir__get_contributor(contributors, n), stbir__get_coefficient(coefficients, filter, scale_ratio, n, 0)); } stbir__normalize_downsample_coefficients(contributors, coefficients, filter, scale_ratio, input_size, output_size); } } static float* stbir__get_decode_buffer(stbir__info* stbir_info) { // The 0 index of the decode buffer starts after the margin. This makes // it okay to use negative indexes on the decode buffer. return &stbir_info->decode_buffer[stbir_info->horizontal_filter_pixel_margin * stbir_info->channels]; } #define STBIR__DECODE(type, colorspace) \ ((type) * (STBIR_MAX_COLORSPACES) + (colorspace)) static optimizespeed void stbir__decode_scanline(stbir__info* stbir_info, int n) { int c; int channels = stbir_info->channels; int alpha_channel = stbir_info->alpha_channel; int type = stbir_info->type; int colorspace = stbir_info->colorspace; int input_w = stbir_info->input_w; size_t input_stride_bytes = stbir_info->input_stride_bytes; float* decode_buffer = stbir__get_decode_buffer(stbir_info); stbir_edge edge_horizontal = stbir_info->edge_horizontal; stbir_edge edge_vertical = stbir_info->edge_vertical; size_t in_buffer_row_offset = stbir__edge_wrap(edge_vertical, n, stbir_info->input_h) * input_stride_bytes; const void* input_data = (char*)stbir_info->input_data + in_buffer_row_offset; int max_x = input_w + stbir_info->horizontal_filter_pixel_margin; int decode = STBIR__DECODE(type, colorspace); int x = -stbir_info->horizontal_filter_pixel_margin; // special handling for STBIR_EDGE_ZERO because it needs to return an item // that doesn't appear in the input, and we want to avoid paying overhead on // every pixel if not STBIR_EDGE_ZERO if (edge_vertical == STBIR_EDGE_ZERO && (n < 0 || n >= stbir_info->input_h)) { for (; x < max_x; x++) for (c = 0; c < channels; c++) decode_buffer[x * channels + c] = 0; return; } switch (decode) { case STBIR__DECODE(STBIR_TYPE_UINT8, STBIR_COLORSPACE_LINEAR): for (; x < max_x; x++) { int decode_pixel_index = x * channels; int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels; for (c = 0; c < channels; c++) decode_buffer[decode_pixel_index + c] = ((float)(( const unsigned char*)input_data)[input_pixel_index + c]) / stbir__max_uint8_as_float; } break; case STBIR__DECODE(STBIR_TYPE_UINT8, STBIR_COLORSPACE_SRGB): for (; x < max_x; x++) { int decode_pixel_index = x * channels; int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels; for (c = 0; c < channels; c++) decode_buffer[decode_pixel_index + c] = stbir__srgb_uchar_to_linear_float[( (const unsigned char*)input_data)[input_pixel_index + c]]; if (!(stbir_info->flags & STBIR_FLAG_ALPHA_USES_COLORSPACE)) decode_buffer[decode_pixel_index + alpha_channel] = ((float)((const unsigned char*) input_data)[input_pixel_index + alpha_channel]) / stbir__max_uint8_as_float; } break; case STBIR__DECODE(STBIR_TYPE_UINT16, STBIR_COLORSPACE_LINEAR): for (; x < max_x; x++) { int decode_pixel_index = x * channels; int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels; for (c = 0; c < channels; c++) decode_buffer[decode_pixel_index + c] = ((float)(( const unsigned short*)input_data)[input_pixel_index + c]) / stbir__max_uint16_as_float; } break; case STBIR__DECODE(STBIR_TYPE_UINT16, STBIR_COLORSPACE_SRGB): for (; x < max_x; x++) { int decode_pixel_index = x * channels; int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels; for (c = 0; c < channels; c++) decode_buffer[decode_pixel_index + c] = stbir__srgb_to_linear( ((float)(( const unsigned short*)input_data)[input_pixel_index + c]) / stbir__max_uint16_as_float); if (!(stbir_info->flags & STBIR_FLAG_ALPHA_USES_COLORSPACE)) decode_buffer[decode_pixel_index + alpha_channel] = ((float)((const unsigned short*) input_data)[input_pixel_index + alpha_channel]) / stbir__max_uint16_as_float; } break; case STBIR__DECODE(STBIR_TYPE_UINT32, STBIR_COLORSPACE_LINEAR): for (; x < max_x; x++) { int decode_pixel_index = x * channels; int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels; for (c = 0; c < channels; c++) decode_buffer[decode_pixel_index + c] = (float)(((double)((const unsigned int*) input_data)[input_pixel_index + c]) / stbir__max_uint32_as_float); } break; case STBIR__DECODE(STBIR_TYPE_UINT32, STBIR_COLORSPACE_SRGB): for (; x < max_x; x++) { int decode_pixel_index = x * channels; int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels; for (c = 0; c < channels; c++) decode_buffer[decode_pixel_index + c] = stbir__srgb_to_linear( (float)(((double)((const unsigned int*) input_data)[input_pixel_index + c]) / stbir__max_uint32_as_float)); if (!(stbir_info->flags & STBIR_FLAG_ALPHA_USES_COLORSPACE)) decode_buffer[decode_pixel_index + alpha_channel] = (float)(((double)(( const unsigned int*)input_data)[input_pixel_index + alpha_channel]) / stbir__max_uint32_as_float); } break; case STBIR__DECODE(STBIR_TYPE_FLOAT, STBIR_COLORSPACE_LINEAR): for (; x < max_x; x++) { int decode_pixel_index = x * channels; int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels; for (c = 0; c < channels; c++) decode_buffer[decode_pixel_index + c] = ((const float*)input_data)[input_pixel_index + c]; } break; case STBIR__DECODE(STBIR_TYPE_FLOAT, STBIR_COLORSPACE_SRGB): for (; x < max_x; x++) { int decode_pixel_index = x * channels; int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels; for (c = 0; c < channels; c++) decode_buffer[decode_pixel_index + c] = stbir__srgb_to_linear( ((const float*)input_data)[input_pixel_index + c]); if (!(stbir_info->flags & STBIR_FLAG_ALPHA_USES_COLORSPACE)) decode_buffer[decode_pixel_index + alpha_channel] = ((const float*)input_data)[input_pixel_index + alpha_channel]; } break; default: STBIR_ASSERT(!"Unknown type/colorspace/channels combination."); break; } if (!(stbir_info->flags & STBIR_FLAG_ALPHA_PREMULTIPLIED)) { for (x = -stbir_info->horizontal_filter_pixel_margin; x < max_x; x++) { int decode_pixel_index = x * channels; // If the alpha value is 0 it will clobber the color values. Make sure // it's not. float alpha = decode_buffer[decode_pixel_index + alpha_channel]; #ifndef STBIR_NO_ALPHA_EPSILON if (stbir_info->type != STBIR_TYPE_FLOAT) { alpha += STBIR_ALPHA_EPSILON; decode_buffer[decode_pixel_index + alpha_channel] = alpha; } #endif for (c = 0; c < channels; c++) { if (c == alpha_channel) continue; decode_buffer[decode_pixel_index + c] *= alpha; } } } if (edge_horizontal == STBIR_EDGE_ZERO) { for (x = -stbir_info->horizontal_filter_pixel_margin; x < 0; x++) { for (c = 0; c < channels; c++) decode_buffer[x * channels + c] = 0; } for (x = input_w; x < max_x; x++) { for (c = 0; c < channels; c++) decode_buffer[x * channels + c] = 0; } } } static float* stbir__get_ring_buffer_entry(float* ring_buffer, int index, int ring_buffer_length) { return &ring_buffer[index * ring_buffer_length]; } static float* stbir__add_empty_ring_buffer_entry(stbir__info* stbir_info, int n) { int ring_buffer_index; float* ring_buffer; stbir_info->ring_buffer_last_scanline = n; if (stbir_info->ring_buffer_begin_index < 0) { ring_buffer_index = stbir_info->ring_buffer_begin_index = 0; stbir_info->ring_buffer_first_scanline = n; } else { ring_buffer_index = (stbir_info->ring_buffer_begin_index + (stbir_info->ring_buffer_last_scanline - stbir_info->ring_buffer_first_scanline)) % stbir_info->ring_buffer_num_entries; STBIR_ASSERT(ring_buffer_index != stbir_info->ring_buffer_begin_index); } ring_buffer = stbir__get_ring_buffer_entry( stbir_info->ring_buffer, ring_buffer_index, stbir_info->ring_buffer_length_bytes / sizeof(float)); memset(ring_buffer, 0, stbir_info->ring_buffer_length_bytes); return ring_buffer; } static void stbir__resample_horizontal_upsample(stbir__info* stbir_info, float* output_buffer) { int x, k; int output_w = stbir_info->output_w; int channels = stbir_info->channels; float* decode_buffer = stbir__get_decode_buffer(stbir_info); stbir__contributors* horizontal_contributors = stbir_info->horizontal_contributors; float* horizontal_coefficients = stbir_info->horizontal_coefficients; int coefficient_width = stbir_info->horizontal_coefficient_width; for (x = 0; x < output_w; x++) { int n0 = horizontal_contributors[x].n0; int n1 = horizontal_contributors[x].n1; int out_pixel_index = x * channels; int coefficient_group = coefficient_width * x; int coefficient_counter = 0; STBIR_ASSERT(n1 >= n0); STBIR_ASSERT(n0 >= -stbir_info->horizontal_filter_pixel_margin); STBIR_ASSERT(n1 >= -stbir_info->horizontal_filter_pixel_margin); STBIR_ASSERT(n0 < stbir_info->input_w + stbir_info->horizontal_filter_pixel_margin); STBIR_ASSERT(n1 < stbir_info->input_w + stbir_info->horizontal_filter_pixel_margin); switch (channels) { case 1: for (k = n0; k <= n1; k++) { int in_pixel_index = k * 1; float coefficient = horizontal_coefficients[coefficient_group + coefficient_counter++]; STBIR_ASSERT(coefficient != 0); output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient; } break; case 2: for (k = n0; k <= n1; k++) { int in_pixel_index = k * 2; float coefficient = horizontal_coefficients[coefficient_group + coefficient_counter++]; STBIR_ASSERT(coefficient != 0); output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient; output_buffer[out_pixel_index + 1] += decode_buffer[in_pixel_index + 1] * coefficient; } break; case 3: for (k = n0; k <= n1; k++) { int in_pixel_index = k * 3; float coefficient = horizontal_coefficients[coefficient_group + coefficient_counter++]; STBIR_ASSERT(coefficient != 0); output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient; output_buffer[out_pixel_index + 1] += decode_buffer[in_pixel_index + 1] * coefficient; output_buffer[out_pixel_index + 2] += decode_buffer[in_pixel_index + 2] * coefficient; } break; case 4: for (k = n0; k <= n1; k++) { int in_pixel_index = k * 4; float coefficient = horizontal_coefficients[coefficient_group + coefficient_counter++]; STBIR_ASSERT(coefficient != 0); output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient; output_buffer[out_pixel_index + 1] += decode_buffer[in_pixel_index + 1] * coefficient; output_buffer[out_pixel_index + 2] += decode_buffer[in_pixel_index + 2] * coefficient; output_buffer[out_pixel_index + 3] += decode_buffer[in_pixel_index + 3] * coefficient; } break; default: for (k = n0; k <= n1; k++) { int in_pixel_index = k * channels; float coefficient = horizontal_coefficients[coefficient_group + coefficient_counter++]; int c; STBIR_ASSERT(coefficient != 0); for (c = 0; c < channels; c++) output_buffer[out_pixel_index + c] += decode_buffer[in_pixel_index + c] * coefficient; } break; } } } static void stbir__resample_horizontal_downsample(stbir__info* stbir_info, float* output_buffer) { int x, k; int input_w = stbir_info->input_w; int channels = stbir_info->channels; float* decode_buffer = stbir__get_decode_buffer(stbir_info); stbir__contributors* horizontal_contributors = stbir_info->horizontal_contributors; float* horizontal_coefficients = stbir_info->horizontal_coefficients; int coefficient_width = stbir_info->horizontal_coefficient_width; int filter_pixel_margin = stbir_info->horizontal_filter_pixel_margin; int max_x = input_w + filter_pixel_margin * 2; STBIR_ASSERT(!stbir__use_width_upsampling(stbir_info)); switch (channels) { case 1: for (x = 0; x < max_x; x++) { int n0 = horizontal_contributors[x].n0; int n1 = horizontal_contributors[x].n1; int in_x = x - filter_pixel_margin; int in_pixel_index = in_x * 1; int max_n = n1; int coefficient_group = coefficient_width * x; for (k = n0; k <= max_n; k++) { int out_pixel_index = k * 1; float coefficient = horizontal_coefficients[coefficient_group + k - n0]; STBIR_ASSERT(coefficient != 0); output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient; } } break; case 2: for (x = 0; x < max_x; x++) { int n0 = horizontal_contributors[x].n0; int n1 = horizontal_contributors[x].n1; int in_x = x - filter_pixel_margin; int in_pixel_index = in_x * 2; int max_n = n1; int coefficient_group = coefficient_width * x; for (k = n0; k <= max_n; k++) { int out_pixel_index = k * 2; float coefficient = horizontal_coefficients[coefficient_group + k - n0]; STBIR_ASSERT(coefficient != 0); output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient; output_buffer[out_pixel_index + 1] += decode_buffer[in_pixel_index + 1] * coefficient; } } break; case 3: for (x = 0; x < max_x; x++) { int n0 = horizontal_contributors[x].n0; int n1 = horizontal_contributors[x].n1; int in_x = x - filter_pixel_margin; int in_pixel_index = in_x * 3; int max_n = n1; int coefficient_group = coefficient_width * x; for (k = n0; k <= max_n; k++) { int out_pixel_index = k * 3; float coefficient = horizontal_coefficients[coefficient_group + k - n0]; STBIR_ASSERT(coefficient != 0); output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient; output_buffer[out_pixel_index + 1] += decode_buffer[in_pixel_index + 1] * coefficient; output_buffer[out_pixel_index + 2] += decode_buffer[in_pixel_index + 2] * coefficient; } } break; case 4: for (x = 0; x < max_x; x++) { int n0 = horizontal_contributors[x].n0; int n1 = horizontal_contributors[x].n1; int in_x = x - filter_pixel_margin; int in_pixel_index = in_x * 4; int max_n = n1; int coefficient_group = coefficient_width * x; for (k = n0; k <= max_n; k++) { int out_pixel_index = k * 4; float coefficient = horizontal_coefficients[coefficient_group + k - n0]; STBIR_ASSERT(coefficient != 0); output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient; output_buffer[out_pixel_index + 1] += decode_buffer[in_pixel_index + 1] * coefficient; output_buffer[out_pixel_index + 2] += decode_buffer[in_pixel_index + 2] * coefficient; output_buffer[out_pixel_index + 3] += decode_buffer[in_pixel_index + 3] * coefficient; } } break; default: for (x = 0; x < max_x; x++) { int n0 = horizontal_contributors[x].n0; int n1 = horizontal_contributors[x].n1; int in_x = x - filter_pixel_margin; int in_pixel_index = in_x * channels; int max_n = n1; int coefficient_group = coefficient_width * x; for (k = n0; k <= max_n; k++) { int c; int out_pixel_index = k * channels; float coefficient = horizontal_coefficients[coefficient_group + k - n0]; STBIR_ASSERT(coefficient != 0); for (c = 0; c < channels; c++) output_buffer[out_pixel_index + c] += decode_buffer[in_pixel_index + c] * coefficient; } } break; } } static void stbir__decode_and_resample_upsample(stbir__info* stbir_info, int n) { // Decode the nth scanline from the source image into the decode buffer. stbir__decode_scanline(stbir_info, n); // Now resample it into the ring buffer. if (stbir__use_width_upsampling(stbir_info)) stbir__resample_horizontal_upsample( stbir_info, stbir__add_empty_ring_buffer_entry(stbir_info, n)); else stbir__resample_horizontal_downsample( stbir_info, stbir__add_empty_ring_buffer_entry(stbir_info, n)); // Now it's sitting in the ring buffer ready to be used as source for the // vertical sampling. } static void stbir__decode_and_resample_downsample(stbir__info* stbir_info, int n) { // Decode the nth scanline from the source image into the decode buffer. stbir__decode_scanline(stbir_info, n); memset(stbir_info->horizontal_buffer, 0, stbir_info->output_w * stbir_info->channels * sizeof(float)); // Now resample it into the horizontal buffer. if (stbir__use_width_upsampling(stbir_info)) stbir__resample_horizontal_upsample(stbir_info, stbir_info->horizontal_buffer); else stbir__resample_horizontal_downsample(stbir_info, stbir_info->horizontal_buffer); // Now it's sitting in the horizontal buffer ready to be distributed into the // ring buffers. } // Get the specified scan line from the ring buffer. static float* stbir__get_ring_buffer_scanline( int get_scanline, float* ring_buffer, int begin_index, int first_scanline, int ring_buffer_num_entries, int ring_buffer_length) { int ring_buffer_index = (begin_index + (get_scanline - first_scanline)) % ring_buffer_num_entries; return stbir__get_ring_buffer_entry(ring_buffer, ring_buffer_index, ring_buffer_length); } static void stbir__encode_scanline(stbir__info* stbir_info, int num_pixels, void* output_buffer, float* encode_buffer, int channels, int alpha_channel, int decode) { int x; int n; int num_nonalpha; uint16_t nonalpha[STBIR_MAX_CHANNELS]; if (!(stbir_info->flags & STBIR_FLAG_ALPHA_PREMULTIPLIED)) { for (x = 0; x < num_pixels; ++x) { int pixel_index = x * channels; float alpha = encode_buffer[pixel_index + alpha_channel]; float reciprocal_alpha = alpha ? 1.0f / alpha : 0; // unrolling this produced a 1% slowdown upscaling a large RGBA // linear-space image on my machine - stb for (n = 0; n < channels; n++) if (n != alpha_channel) encode_buffer[pixel_index + n] *= reciprocal_alpha; // We added in a small epsilon to prevent the color channel from being // deleted with zero alpha. Because we only add it for integer types, it // will automatically be discarded on integer conversion, so we don't need // to subtract it back out (which would be problematic for numeric // precision reasons). } } // build a table of all channels that need colorspace correction, so // we don't perform colorspace correction on channels that don't need it. for (x = 0, num_nonalpha = 0; x < channels; ++x) { if (x != alpha_channel || (stbir_info->flags & STBIR_FLAG_ALPHA_USES_COLORSPACE)) { nonalpha[num_nonalpha++] = (uint16_t)x; } } #define STBIR__ROUND_INT(f) ((int)((f) + 0.5)) #define STBIR__ROUND_UINT(f) ((uint32_t)((f) + 0.5)) #ifdef STBIR__SATURATE_INT #define STBIR__ENCODE_LINEAR8(f) \ stbir__saturate8(STBIR__ROUND_INT((f)*stbir__max_uint8_as_float)) #define STBIR__ENCODE_LINEAR16(f) \ stbir__saturate16(STBIR__ROUND_INT((f)*stbir__max_uint16_as_float)) #else #define STBIR__ENCODE_LINEAR8(f) \ (unsigned char)STBIR__ROUND_INT(stbir__saturate(f) * \ stbir__max_uint8_as_float) #define STBIR__ENCODE_LINEAR16(f) \ (unsigned short)STBIR__ROUND_INT(stbir__saturate(f) * \ stbir__max_uint16_as_float) #endif switch (decode) { case STBIR__DECODE(STBIR_TYPE_UINT8, STBIR_COLORSPACE_LINEAR): for (x = 0; x < num_pixels; ++x) { int pixel_index = x * channels; for (n = 0; n < channels; n++) { int index = pixel_index + n; ((unsigned char*)output_buffer)[index] = STBIR__ENCODE_LINEAR8(encode_buffer[index]); } } break; case STBIR__DECODE(STBIR_TYPE_UINT8, STBIR_COLORSPACE_SRGB): for (x = 0; x < num_pixels; ++x) { int pixel_index = x * channels; for (n = 0; n < num_nonalpha; n++) { int index = pixel_index + nonalpha[n]; ((unsigned char*)output_buffer)[index] = stbir__linear_to_srgb_uchar(encode_buffer[index]); } if (!(stbir_info->flags & STBIR_FLAG_ALPHA_USES_COLORSPACE)) ((unsigned char*)output_buffer)[pixel_index + alpha_channel] = STBIR__ENCODE_LINEAR8(encode_buffer[pixel_index + alpha_channel]); } break; case STBIR__DECODE(STBIR_TYPE_UINT16, STBIR_COLORSPACE_LINEAR): for (x = 0; x < num_pixels; ++x) { int pixel_index = x * channels; for (n = 0; n < channels; n++) { int index = pixel_index + n; ((unsigned short*)output_buffer)[index] = STBIR__ENCODE_LINEAR16(encode_buffer[index]); } } break; case STBIR__DECODE(STBIR_TYPE_UINT16, STBIR_COLORSPACE_SRGB): for (x = 0; x < num_pixels; ++x) { int pixel_index = x * channels; for (n = 0; n < num_nonalpha; n++) { int index = pixel_index + nonalpha[n]; ((unsigned short*)output_buffer)[index] = (unsigned short)STBIR__ROUND_INT( stbir__linear_to_srgb(stbir__saturate(encode_buffer[index])) * stbir__max_uint16_as_float); } if (!(stbir_info->flags & STBIR_FLAG_ALPHA_USES_COLORSPACE)) ((unsigned short*)output_buffer)[pixel_index + alpha_channel] = STBIR__ENCODE_LINEAR16( encode_buffer[pixel_index + alpha_channel]); } break; case STBIR__DECODE(STBIR_TYPE_UINT32, STBIR_COLORSPACE_LINEAR): for (x = 0; x < num_pixels; ++x) { int pixel_index = x * channels; for (n = 0; n < channels; n++) { int index = pixel_index + n; ((unsigned int*)output_buffer)[index] = (unsigned int)STBIR__ROUND_UINT( ((double)stbir__saturate(encode_buffer[index])) * stbir__max_uint32_as_float); } } break; case STBIR__DECODE(STBIR_TYPE_UINT32, STBIR_COLORSPACE_SRGB): for (x = 0; x < num_pixels; ++x) { int pixel_index = x * channels; for (n = 0; n < num_nonalpha; n++) { int index = pixel_index + nonalpha[n]; ((unsigned int*)output_buffer)[index] = (unsigned int)STBIR__ROUND_UINT( ((double)stbir__linear_to_srgb( stbir__saturate(encode_buffer[index]))) * stbir__max_uint32_as_float); } if (!(stbir_info->flags & STBIR_FLAG_ALPHA_USES_COLORSPACE)) ((unsigned int*)output_buffer)[pixel_index + alpha_channel] = (unsigned int)STBIR__ROUND_INT( ((double)stbir__saturate( encode_buffer[pixel_index + alpha_channel])) * stbir__max_uint32_as_float); } break; case STBIR__DECODE(STBIR_TYPE_FLOAT, STBIR_COLORSPACE_LINEAR): for (x = 0; x < num_pixels; ++x) { int pixel_index = x * channels; for (n = 0; n < channels; n++) { int index = pixel_index + n; ((float*)output_buffer)[index] = encode_buffer[index]; } } break; case STBIR__DECODE(STBIR_TYPE_FLOAT, STBIR_COLORSPACE_SRGB): for (x = 0; x < num_pixels; ++x) { int pixel_index = x * channels; for (n = 0; n < num_nonalpha; n++) { int index = pixel_index + nonalpha[n]; ((float*)output_buffer)[index] = stbir__linear_to_srgb(encode_buffer[index]); } if (!(stbir_info->flags & STBIR_FLAG_ALPHA_USES_COLORSPACE)) ((float*)output_buffer)[pixel_index + alpha_channel] = encode_buffer[pixel_index + alpha_channel]; } break; default: STBIR_ASSERT(!"Unknown type/colorspace/channels combination."); break; } } static void stbir__resample_vertical_upsample(stbir__info* stbir_info, int n) { int x, k; int output_w = stbir_info->output_w; stbir__contributors* vertical_contributors = stbir_info->vertical_contributors; float* vertical_coefficients = stbir_info->vertical_coefficients; int channels = stbir_info->channels; int alpha_channel = stbir_info->alpha_channel; int type = stbir_info->type; int colorspace = stbir_info->colorspace; int ring_buffer_entries = stbir_info->ring_buffer_num_entries; void* output_data = stbir_info->output_data; float* encode_buffer = stbir_info->encode_buffer; int decode = STBIR__DECODE(type, colorspace); int coefficient_width = stbir_info->vertical_coefficient_width; int coefficient_counter; int contributor = n; float* ring_buffer = stbir_info->ring_buffer; int ring_buffer_begin_index = stbir_info->ring_buffer_begin_index; int ring_buffer_first_scanline = stbir_info->ring_buffer_first_scanline; int ring_buffer_length = stbir_info->ring_buffer_length_bytes / sizeof(float); int n0, n1, output_row_start; int coefficient_group = coefficient_width * contributor; n0 = vertical_contributors[contributor].n0; n1 = vertical_contributors[contributor].n1; output_row_start = n * stbir_info->output_stride_bytes; STBIR_ASSERT(stbir__use_height_upsampling(stbir_info)); memset(encode_buffer, 0, output_w * sizeof(float) * channels); // I tried reblocking this for better cache usage of encode_buffer // (using x_outer, k, x_inner), but it lost speed. -- stb coefficient_counter = 0; switch (channels) { case 1: for (k = n0; k <= n1; k++) { int coefficient_index = coefficient_counter++; float* ring_buffer_entry = stbir__get_ring_buffer_scanline( k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length); float coefficient = vertical_coefficients[coefficient_group + coefficient_index]; for (x = 0; x < output_w; ++x) { int in_pixel_index = x * 1; encode_buffer[in_pixel_index + 0] += ring_buffer_entry[in_pixel_index + 0] * coefficient; } } break; case 2: for (k = n0; k <= n1; k++) { int coefficient_index = coefficient_counter++; float* ring_buffer_entry = stbir__get_ring_buffer_scanline( k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length); float coefficient = vertical_coefficients[coefficient_group + coefficient_index]; for (x = 0; x < output_w; ++x) { int in_pixel_index = x * 2; encode_buffer[in_pixel_index + 0] += ring_buffer_entry[in_pixel_index + 0] * coefficient; encode_buffer[in_pixel_index + 1] += ring_buffer_entry[in_pixel_index + 1] * coefficient; } } break; case 3: for (k = n0; k <= n1; k++) { int coefficient_index = coefficient_counter++; float* ring_buffer_entry = stbir__get_ring_buffer_scanline( k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length); float coefficient = vertical_coefficients[coefficient_group + coefficient_index]; for (x = 0; x < output_w; ++x) { int in_pixel_index = x * 3; encode_buffer[in_pixel_index + 0] += ring_buffer_entry[in_pixel_index + 0] * coefficient; encode_buffer[in_pixel_index + 1] += ring_buffer_entry[in_pixel_index + 1] * coefficient; encode_buffer[in_pixel_index + 2] += ring_buffer_entry[in_pixel_index + 2] * coefficient; } } break; case 4: for (k = n0; k <= n1; k++) { int coefficient_index = coefficient_counter++; float* ring_buffer_entry = stbir__get_ring_buffer_scanline( k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length); float coefficient = vertical_coefficients[coefficient_group + coefficient_index]; for (x = 0; x < output_w; ++x) { int in_pixel_index = x * 4; encode_buffer[in_pixel_index + 0] += ring_buffer_entry[in_pixel_index + 0] * coefficient; encode_buffer[in_pixel_index + 1] += ring_buffer_entry[in_pixel_index + 1] * coefficient; encode_buffer[in_pixel_index + 2] += ring_buffer_entry[in_pixel_index + 2] * coefficient; encode_buffer[in_pixel_index + 3] += ring_buffer_entry[in_pixel_index + 3] * coefficient; } } break; default: for (k = n0; k <= n1; k++) { int coefficient_index = coefficient_counter++; float* ring_buffer_entry = stbir__get_ring_buffer_scanline( k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length); float coefficient = vertical_coefficients[coefficient_group + coefficient_index]; for (x = 0; x < output_w; ++x) { int in_pixel_index = x * channels; int c; for (c = 0; c < channels; c++) encode_buffer[in_pixel_index + c] += ring_buffer_entry[in_pixel_index + c] * coefficient; } } break; } stbir__encode_scanline(stbir_info, output_w, (char*)output_data + output_row_start, encode_buffer, channels, alpha_channel, decode); } static void stbir__resample_vertical_downsample(stbir__info* stbir_info, int n) { int x, k; int output_w = stbir_info->output_w; stbir__contributors* vertical_contributors = stbir_info->vertical_contributors; float* vertical_coefficients = stbir_info->vertical_coefficients; int channels = stbir_info->channels; int ring_buffer_entries = stbir_info->ring_buffer_num_entries; float* horizontal_buffer = stbir_info->horizontal_buffer; int coefficient_width = stbir_info->vertical_coefficient_width; int contributor = n + stbir_info->vertical_filter_pixel_margin; float* ring_buffer = stbir_info->ring_buffer; int ring_buffer_begin_index = stbir_info->ring_buffer_begin_index; int ring_buffer_first_scanline = stbir_info->ring_buffer_first_scanline; int ring_buffer_length = stbir_info->ring_buffer_length_bytes / sizeof(float); int n0, n1; n0 = vertical_contributors[contributor].n0; n1 = vertical_contributors[contributor].n1; STBIR_ASSERT(!stbir__use_height_upsampling(stbir_info)); for (k = n0; k <= n1; k++) { int coefficient_index = k - n0; int coefficient_group = coefficient_width * contributor; float coefficient = vertical_coefficients[coefficient_group + coefficient_index]; float* ring_buffer_entry = stbir__get_ring_buffer_scanline( k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length); switch (channels) { case 1: for (x = 0; x < output_w; x++) { int in_pixel_index = x * 1; ring_buffer_entry[in_pixel_index + 0] += horizontal_buffer[in_pixel_index + 0] * coefficient; } break; case 2: for (x = 0; x < output_w; x++) { int in_pixel_index = x * 2; ring_buffer_entry[in_pixel_index + 0] += horizontal_buffer[in_pixel_index + 0] * coefficient; ring_buffer_entry[in_pixel_index + 1] += horizontal_buffer[in_pixel_index + 1] * coefficient; } break; case 3: for (x = 0; x < output_w; x++) { int in_pixel_index = x * 3; ring_buffer_entry[in_pixel_index + 0] += horizontal_buffer[in_pixel_index + 0] * coefficient; ring_buffer_entry[in_pixel_index + 1] += horizontal_buffer[in_pixel_index + 1] * coefficient; ring_buffer_entry[in_pixel_index + 2] += horizontal_buffer[in_pixel_index + 2] * coefficient; } break; case 4: for (x = 0; x < output_w; x++) { int in_pixel_index = x * 4; ring_buffer_entry[in_pixel_index + 0] += horizontal_buffer[in_pixel_index + 0] * coefficient; ring_buffer_entry[in_pixel_index + 1] += horizontal_buffer[in_pixel_index + 1] * coefficient; ring_buffer_entry[in_pixel_index + 2] += horizontal_buffer[in_pixel_index + 2] * coefficient; ring_buffer_entry[in_pixel_index + 3] += horizontal_buffer[in_pixel_index + 3] * coefficient; } break; default: for (x = 0; x < output_w; x++) { int in_pixel_index = x * channels; int c; for (c = 0; c < channels; c++) ring_buffer_entry[in_pixel_index + c] += horizontal_buffer[in_pixel_index + c] * coefficient; } break; } } } static void stbir__buffer_loop_upsample(stbir__info* stbir_info) { int y; float scale_ratio = stbir_info->vertical_scale; float out_scanlines_radius = stbir__filter_info_table[stbir_info->vertical_filter].support( 1 / scale_ratio) * scale_ratio; STBIR_ASSERT(stbir__use_height_upsampling(stbir_info)); for (y = 0; y < stbir_info->output_h; y++) { float in_center_of_out = 0; // Center of the current out scanline in the in scanline space int in_first_scanline = 0, in_last_scanline = 0; stbir__calculate_sample_range_upsample( y, out_scanlines_radius, scale_ratio, stbir_info->vertical_shift, &in_first_scanline, &in_last_scanline, &in_center_of_out); STBIR_ASSERT(in_last_scanline - in_first_scanline + 1 <= stbir_info->ring_buffer_num_entries); if (stbir_info->ring_buffer_begin_index >= 0) { // Get rid of whatever we don't need anymore. while (in_first_scanline > stbir_info->ring_buffer_first_scanline) { if (stbir_info->ring_buffer_first_scanline == stbir_info->ring_buffer_last_scanline) { // We just popped the last scanline off the ring buffer. // Reset it to the empty state. stbir_info->ring_buffer_begin_index = -1; stbir_info->ring_buffer_first_scanline = 0; stbir_info->ring_buffer_last_scanline = 0; break; } else { stbir_info->ring_buffer_first_scanline++; stbir_info->ring_buffer_begin_index = (stbir_info->ring_buffer_begin_index + 1) % stbir_info->ring_buffer_num_entries; } } } // Load in new ones. if (stbir_info->ring_buffer_begin_index < 0) stbir__decode_and_resample_upsample(stbir_info, in_first_scanline); while (in_last_scanline > stbir_info->ring_buffer_last_scanline) stbir__decode_and_resample_upsample( stbir_info, stbir_info->ring_buffer_last_scanline + 1); // Now all buffers should be ready to write a row of vertical sampling. stbir__resample_vertical_upsample(stbir_info, y); STBIR_PROGRESS_REPORT((float)y / stbir_info->output_h); } } static void stbir__empty_ring_buffer(stbir__info* stbir_info, int first_necessary_scanline) { int output_stride_bytes = stbir_info->output_stride_bytes; int channels = stbir_info->channels; int alpha_channel = stbir_info->alpha_channel; int type = stbir_info->type; int colorspace = stbir_info->colorspace; int output_w = stbir_info->output_w; void* output_data = stbir_info->output_data; int decode = STBIR__DECODE(type, colorspace); float* ring_buffer = stbir_info->ring_buffer; int ring_buffer_length = stbir_info->ring_buffer_length_bytes / sizeof(float); if (stbir_info->ring_buffer_begin_index >= 0) { // Get rid of whatever we don't need anymore. while (first_necessary_scanline > stbir_info->ring_buffer_first_scanline) { if (stbir_info->ring_buffer_first_scanline >= 0 && stbir_info->ring_buffer_first_scanline < stbir_info->output_h) { int output_row_start = stbir_info->ring_buffer_first_scanline * output_stride_bytes; float* ring_buffer_entry = stbir__get_ring_buffer_entry( ring_buffer, stbir_info->ring_buffer_begin_index, ring_buffer_length); stbir__encode_scanline( stbir_info, output_w, (char*)output_data + output_row_start, ring_buffer_entry, channels, alpha_channel, decode); STBIR_PROGRESS_REPORT((float)stbir_info->ring_buffer_first_scanline / stbir_info->output_h); } if (stbir_info->ring_buffer_first_scanline == stbir_info->ring_buffer_last_scanline) { // We just popped the last scanline off the ring buffer. // Reset it to the empty state. stbir_info->ring_buffer_begin_index = -1; stbir_info->ring_buffer_first_scanline = 0; stbir_info->ring_buffer_last_scanline = 0; break; } else { stbir_info->ring_buffer_first_scanline++; stbir_info->ring_buffer_begin_index = (stbir_info->ring_buffer_begin_index + 1) % stbir_info->ring_buffer_num_entries; } } } } static void stbir__buffer_loop_downsample(stbir__info* stbir_info) { int y; float scale_ratio = stbir_info->vertical_scale; int output_h = stbir_info->output_h; float in_pixels_radius = stbir__filter_info_table[stbir_info->vertical_filter].support( scale_ratio) / scale_ratio; int pixel_margin = stbir_info->vertical_filter_pixel_margin; int max_y = stbir_info->input_h + pixel_margin; STBIR_ASSERT(!stbir__use_height_upsampling(stbir_info)); for (y = -pixel_margin; y < max_y; y++) { float out_center_of_in; // Center of the current out scanline in the in // scanline space int out_first_scanline, out_last_scanline; stbir__calculate_sample_range_downsample( y, in_pixels_radius, scale_ratio, stbir_info->vertical_shift, &out_first_scanline, &out_last_scanline, &out_center_of_in); STBIR_ASSERT(out_last_scanline - out_first_scanline + 1 <= stbir_info->ring_buffer_num_entries); if (out_last_scanline < 0 || out_first_scanline >= output_h) continue; stbir__empty_ring_buffer(stbir_info, out_first_scanline); stbir__decode_and_resample_downsample(stbir_info, y); // Load in new ones. if (stbir_info->ring_buffer_begin_index < 0) stbir__add_empty_ring_buffer_entry(stbir_info, out_first_scanline); while (out_last_scanline > stbir_info->ring_buffer_last_scanline) stbir__add_empty_ring_buffer_entry( stbir_info, stbir_info->ring_buffer_last_scanline + 1); // Now the horizontal buffer is ready to write to all ring buffer rows. stbir__resample_vertical_downsample(stbir_info, y); } stbir__empty_ring_buffer(stbir_info, stbir_info->output_h); } static void stbir__setup(stbir__info* info, int input_w, int input_h, int output_w, int output_h, int channels) { info->input_w = input_w; info->input_h = input_h; info->output_w = output_w; info->output_h = output_h; info->channels = channels; } static void stbir__calculate_transform(stbir__info* info, float s0, float t0, float s1, float t1, float* transform) { info->s0 = s0; info->t0 = t0; info->s1 = s1; info->t1 = t1; if (transform) { info->horizontal_scale = transform[0]; info->vertical_scale = transform[1]; info->horizontal_shift = transform[2]; info->vertical_shift = transform[3]; } else { info->horizontal_scale = ((float)info->output_w / info->input_w) / (s1 - s0); info->vertical_scale = ((float)info->output_h / info->input_h) / (t1 - t0); info->horizontal_shift = s0 * info->output_w / (s1 - s0); info->vertical_shift = t0 * info->output_h / (t1 - t0); } } static void stbir__choose_filter(stbir__info* info, stbir_filter h_filter, stbir_filter v_filter) { if (h_filter == 0) h_filter = stbir__use_upsampling(info->horizontal_scale) ? STBIR_DEFAULT_FILTER_UPSAMPLE : STBIR_DEFAULT_FILTER_DOWNSAMPLE; if (v_filter == 0) v_filter = stbir__use_upsampling(info->vertical_scale) ? STBIR_DEFAULT_FILTER_UPSAMPLE : STBIR_DEFAULT_FILTER_DOWNSAMPLE; info->horizontal_filter = h_filter; info->vertical_filter = v_filter; } static uint32_t stbir__calculate_memory(stbir__info* info) { int pixel_margin = stbir__get_filter_pixel_margin(info->horizontal_filter, info->horizontal_scale); int filter_height = stbir__get_filter_pixel_width(info->vertical_filter, info->vertical_scale); info->horizontal_num_contributors = stbir__get_contributors(info->horizontal_scale, info->horizontal_filter, info->input_w, info->output_w); info->vertical_num_contributors = stbir__get_contributors(info->vertical_scale, info->vertical_filter, info->input_h, info->output_h); // One extra entry because floating point precision problems sometimes cause // an extra to be necessary. info->ring_buffer_num_entries = filter_height + 1; info->horizontal_contributors_size = info->horizontal_num_contributors * sizeof(stbir__contributors); info->horizontal_coefficients_size = stbir__get_total_horizontal_coefficients(info) * sizeof(float); info->vertical_contributors_size = info->vertical_num_contributors * sizeof(stbir__contributors); info->vertical_coefficients_size = stbir__get_total_vertical_coefficients(info) * sizeof(float); info->decode_buffer_size = (info->input_w + pixel_margin * 2) * info->channels * sizeof(float); info->horizontal_buffer_size = info->output_w * info->channels * sizeof(float); info->ring_buffer_size = info->output_w * info->channels * info->ring_buffer_num_entries * sizeof(float); info->encode_buffer_size = info->output_w * info->channels * sizeof(float); STBIR_ASSERT(info->horizontal_filter != 0); STBIR_ASSERT(info->horizontal_filter < STBIR__ARRAY_SIZE( stbir__filter_info_table)); // this now happens too late STBIR_ASSERT(info->vertical_filter != 0); STBIR_ASSERT(info->vertical_filter < STBIR__ARRAY_SIZE( stbir__filter_info_table)); // this now happens too late if (stbir__use_height_upsampling(info)) // The horizontal buffer is for when we're downsampling the height and we // can't output the result of sampling the decode buffer directly into the // ring buffers. info->horizontal_buffer_size = 0; else // The encode buffer is to retain precision in the height upsampling method // and isn't used when height downsampling. info->encode_buffer_size = 0; return info->horizontal_contributors_size + info->horizontal_coefficients_size + info->vertical_contributors_size + info->vertical_coefficients_size + info->decode_buffer_size + info->horizontal_buffer_size + info->ring_buffer_size + info->encode_buffer_size; } static int stbir__resize_allocated( stbir__info* info, const void* input_data, int input_stride_in_bytes, void* output_data, int output_stride_in_bytes, int alpha_channel, uint32_t flags, stbir_datatype type, stbir_edge edge_horizontal, stbir_edge edge_vertical, stbir_colorspace colorspace, void* tempmem, size_t tempmem_size_in_bytes) { size_t memory_required = stbir__calculate_memory(info); int width_stride_input = input_stride_in_bytes ? input_stride_in_bytes : info->channels * info->input_w * stbir__type_size[type]; int width_stride_output = output_stride_in_bytes ? output_stride_in_bytes : info->channels * info->output_w * stbir__type_size[type]; #ifdef STBIR_DEBUG_OVERWRITE_TEST #define OVERWRITE_ARRAY_SIZE 8 unsigned char overwrite_output_before_pre[OVERWRITE_ARRAY_SIZE]; unsigned char overwrite_tempmem_before_pre[OVERWRITE_ARRAY_SIZE]; unsigned char overwrite_output_after_pre[OVERWRITE_ARRAY_SIZE]; unsigned char overwrite_tempmem_after_pre[OVERWRITE_ARRAY_SIZE]; size_t begin_forbidden = width_stride_output * (info->output_h - 1) + info->output_w * info->channels * stbir__type_size[type]; memcpy(overwrite_output_before_pre, &((unsigned char*)output_data)[-OVERWRITE_ARRAY_SIZE], OVERWRITE_ARRAY_SIZE); memcpy(overwrite_output_after_pre, &((unsigned char*)output_data)[begin_forbidden], OVERWRITE_ARRAY_SIZE); memcpy(overwrite_tempmem_before_pre, &((unsigned char*)tempmem)[-OVERWRITE_ARRAY_SIZE], OVERWRITE_ARRAY_SIZE); memcpy(overwrite_tempmem_after_pre, &((unsigned char*)tempmem)[tempmem_size_in_bytes], OVERWRITE_ARRAY_SIZE); #endif STBIR_ASSERT(info->channels >= 0); STBIR_ASSERT(info->channels <= STBIR_MAX_CHANNELS); if (info->channels < 0 || info->channels > STBIR_MAX_CHANNELS) return 0; STBIR_ASSERT(info->horizontal_filter < STBIR__ARRAY_SIZE(stbir__filter_info_table)); STBIR_ASSERT(info->vertical_filter < STBIR__ARRAY_SIZE(stbir__filter_info_table)); if (info->horizontal_filter >= STBIR__ARRAY_SIZE(stbir__filter_info_table)) return 0; if (info->vertical_filter >= STBIR__ARRAY_SIZE(stbir__filter_info_table)) return 0; if (alpha_channel < 0) flags |= STBIR_FLAG_ALPHA_USES_COLORSPACE | STBIR_FLAG_ALPHA_PREMULTIPLIED; if (!(flags & STBIR_FLAG_ALPHA_USES_COLORSPACE) || !(flags & STBIR_FLAG_ALPHA_PREMULTIPLIED)) { STBIR_ASSERT(alpha_channel >= 0 && alpha_channel < info->channels); } if (alpha_channel >= info->channels) return 0; STBIR_ASSERT(tempmem); if (!tempmem) return 0; STBIR_ASSERT(tempmem_size_in_bytes >= memory_required); if (tempmem_size_in_bytes < memory_required) return 0; memset(tempmem, 0, tempmem_size_in_bytes); info->input_data = input_data; info->input_stride_bytes = width_stride_input; info->output_data = output_data; info->output_stride_bytes = width_stride_output; info->alpha_channel = alpha_channel; info->flags = flags; info->type = type; info->edge_horizontal = edge_horizontal; info->edge_vertical = edge_vertical; info->colorspace = colorspace; info->horizontal_coefficient_width = stbir__get_coefficient_width( info->horizontal_filter, info->horizontal_scale); info->vertical_coefficient_width = stbir__get_coefficient_width(info->vertical_filter, info->vertical_scale); info->horizontal_filter_pixel_width = stbir__get_filter_pixel_width( info->horizontal_filter, info->horizontal_scale); info->vertical_filter_pixel_width = stbir__get_filter_pixel_width( info->vertical_filter, info->vertical_scale); info->horizontal_filter_pixel_margin = stbir__get_filter_pixel_margin( info->horizontal_filter, info->horizontal_scale); info->vertical_filter_pixel_margin = stbir__get_filter_pixel_margin( info->vertical_filter, info->vertical_scale); info->ring_buffer_length_bytes = info->output_w * info->channels * sizeof(float); info->decode_buffer_pixels = info->input_w + info->horizontal_filter_pixel_margin * 2; #define STBIR__NEXT_MEMPTR(current, newtype) \ (newtype*)(((unsigned char*)current) + current##_size) info->horizontal_contributors = (stbir__contributors*)tempmem; info->horizontal_coefficients = STBIR__NEXT_MEMPTR(info->horizontal_contributors, float); info->vertical_contributors = STBIR__NEXT_MEMPTR(info->horizontal_coefficients, stbir__contributors); info->vertical_coefficients = STBIR__NEXT_MEMPTR(info->vertical_contributors, float); info->decode_buffer = STBIR__NEXT_MEMPTR(info->vertical_coefficients, float); if (stbir__use_height_upsampling(info)) { info->horizontal_buffer = NULL; info->ring_buffer = STBIR__NEXT_MEMPTR(info->decode_buffer, float); info->encode_buffer = STBIR__NEXT_MEMPTR(info->ring_buffer, float); STBIR_ASSERT( (size_t)STBIR__NEXT_MEMPTR(info->encode_buffer, unsigned char) == (size_t)tempmem + tempmem_size_in_bytes); } else { info->horizontal_buffer = STBIR__NEXT_MEMPTR(info->decode_buffer, float); info->ring_buffer = STBIR__NEXT_MEMPTR(info->horizontal_buffer, float); info->encode_buffer = NULL; STBIR_ASSERT((size_t)STBIR__NEXT_MEMPTR(info->ring_buffer, unsigned char) == (size_t)tempmem + tempmem_size_in_bytes); } #undef STBIR__NEXT_MEMPTR // This signals that the ring buffer is empty info->ring_buffer_begin_index = -1; stbir__calculate_filters( info->horizontal_contributors, info->horizontal_coefficients, info->horizontal_filter, info->horizontal_scale, info->horizontal_shift, info->input_w, info->output_w); stbir__calculate_filters(info->vertical_contributors, info->vertical_coefficients, info->vertical_filter, info->vertical_scale, info->vertical_shift, info->input_h, info->output_h); STBIR_PROGRESS_REPORT(0); if (stbir__use_height_upsampling(info)) stbir__buffer_loop_upsample(info); else stbir__buffer_loop_downsample(info); STBIR_PROGRESS_REPORT(1); #ifdef STBIR_DEBUG_OVERWRITE_TEST STBIR_ASSERT(memcmp(overwrite_output_before_pre, &((unsigned char*)output_data)[-OVERWRITE_ARRAY_SIZE], OVERWRITE_ARRAY_SIZE) == 0); STBIR_ASSERT(memcmp(overwrite_output_after_pre, &((unsigned char*)output_data)[begin_forbidden], OVERWRITE_ARRAY_SIZE) == 0); STBIR_ASSERT(memcmp(overwrite_tempmem_before_pre, &((unsigned char*)tempmem)[-OVERWRITE_ARRAY_SIZE], OVERWRITE_ARRAY_SIZE) == 0); STBIR_ASSERT(memcmp(overwrite_tempmem_after_pre, &((unsigned char*)tempmem)[tempmem_size_in_bytes], OVERWRITE_ARRAY_SIZE) == 0); #endif return 1; } static int stbir__resize_arbitrary( void* alloc_context, const void* input_data, int input_w, int input_h, int input_stride_in_bytes, void* output_data, int output_w, int output_h, int output_stride_in_bytes, float s0, float t0, float s1, float t1, float* transform, int channels, int alpha_channel, uint32_t flags, stbir_datatype type, stbir_filter h_filter, stbir_filter v_filter, stbir_edge edge_horizontal, stbir_edge edge_vertical, stbir_colorspace colorspace) { stbir__info info; int result; size_t memory_required; void* extra_memory; stbir__setup(&info, input_w, input_h, output_w, output_h, channels); stbir__calculate_transform(&info, s0, t0, s1, t1, transform); stbir__choose_filter(&info, h_filter, v_filter); memory_required = stbir__calculate_memory(&info); extra_memory = STBIR_MALLOC(memory_required, alloc_context); if (!extra_memory) return 0; result = stbir__resize_allocated( &info, input_data, input_stride_in_bytes, output_data, output_stride_in_bytes, alpha_channel, flags, type, edge_horizontal, edge_vertical, colorspace, extra_memory, memory_required); STBIR_FREE(extra_memory, alloc_context); return result; } int stbir_resize_uint8(const unsigned char* input_pixels, int input_w, int input_h, int input_stride_in_bytes, unsigned char* output_pixels, int output_w, int output_h, int output_stride_in_bytes, int num_channels) { return stbir__resize_arbitrary( NULL, input_pixels, input_w, input_h, input_stride_in_bytes, output_pixels, output_w, output_h, output_stride_in_bytes, 0, 0, 1, 1, NULL, num_channels, -1, 0, STBIR_TYPE_UINT8, STBIR_FILTER_DEFAULT, STBIR_FILTER_DEFAULT, STBIR_EDGE_CLAMP, STBIR_EDGE_CLAMP, STBIR_COLORSPACE_LINEAR); } int stbir_resize_float(const float* input_pixels, int input_w, int input_h, int input_stride_in_bytes, float* output_pixels, int output_w, int output_h, int output_stride_in_bytes, int num_channels) { return stbir__resize_arbitrary( NULL, input_pixels, input_w, input_h, input_stride_in_bytes, output_pixels, output_w, output_h, output_stride_in_bytes, 0, 0, 1, 1, NULL, num_channels, -1, 0, STBIR_TYPE_FLOAT, STBIR_FILTER_DEFAULT, STBIR_FILTER_DEFAULT, STBIR_EDGE_CLAMP, STBIR_EDGE_CLAMP, STBIR_COLORSPACE_LINEAR); } int stbir_resize_uint8_srgb(const unsigned char* input_pixels, int input_w, int input_h, int input_stride_in_bytes, unsigned char* output_pixels, int output_w, int output_h, int output_stride_in_bytes, int num_channels, int alpha_channel, int flags) { return stbir__resize_arbitrary( NULL, input_pixels, input_w, input_h, input_stride_in_bytes, output_pixels, output_w, output_h, output_stride_in_bytes, 0, 0, 1, 1, NULL, num_channels, alpha_channel, flags, STBIR_TYPE_UINT8, STBIR_FILTER_DEFAULT, STBIR_FILTER_DEFAULT, STBIR_EDGE_CLAMP, STBIR_EDGE_CLAMP, STBIR_COLORSPACE_SRGB); } int stbir_resize_uint8_srgb_edgemode(const unsigned char* input_pixels, int input_w, int input_h, int input_stride_in_bytes, unsigned char* output_pixels, int output_w, int output_h, int output_stride_in_bytes, int num_channels, int alpha_channel, int flags, stbir_edge edge_wrap_mode) { return stbir__resize_arbitrary( NULL, input_pixels, input_w, input_h, input_stride_in_bytes, output_pixels, output_w, output_h, output_stride_in_bytes, 0, 0, 1, 1, NULL, num_channels, alpha_channel, flags, STBIR_TYPE_UINT8, STBIR_FILTER_DEFAULT, STBIR_FILTER_DEFAULT, edge_wrap_mode, edge_wrap_mode, STBIR_COLORSPACE_SRGB); } int stbir_resize_uint8_generic(const unsigned char* input_pixels, int input_w, int input_h, int input_stride_in_bytes, unsigned char* output_pixels, int output_w, int output_h, int output_stride_in_bytes, int num_channels, int alpha_channel, int flags, stbir_edge edge_wrap_mode, stbir_filter filter, stbir_colorspace space, void* alloc_context) { return stbir__resize_arbitrary( alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes, output_pixels, output_w, output_h, output_stride_in_bytes, 0, 0, 1, 1, NULL, num_channels, alpha_channel, flags, STBIR_TYPE_UINT8, filter, filter, edge_wrap_mode, edge_wrap_mode, space); } int stbir_resize_uint16_generic(const uint16_t* input_pixels, int input_w, int input_h, int input_stride_in_bytes, uint16_t* output_pixels, int output_w, int output_h, int output_stride_in_bytes, int num_channels, int alpha_channel, int flags, stbir_edge edge_wrap_mode, stbir_filter filter, stbir_colorspace space, void* alloc_context) { return stbir__resize_arbitrary( alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes, output_pixels, output_w, output_h, output_stride_in_bytes, 0, 0, 1, 1, NULL, num_channels, alpha_channel, flags, STBIR_TYPE_UINT16, filter, filter, edge_wrap_mode, edge_wrap_mode, space); } int stbir_resize_float_generic(const float* input_pixels, int input_w, int input_h, int input_stride_in_bytes, float* output_pixels, int output_w, int output_h, int output_stride_in_bytes, int num_channels, int alpha_channel, int flags, stbir_edge edge_wrap_mode, stbir_filter filter, stbir_colorspace space, void* alloc_context) { return stbir__resize_arbitrary( alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes, output_pixels, output_w, output_h, output_stride_in_bytes, 0, 0, 1, 1, NULL, num_channels, alpha_channel, flags, STBIR_TYPE_FLOAT, filter, filter, edge_wrap_mode, edge_wrap_mode, space); } int stbir_resize(const void* input_pixels, int input_w, int input_h, int input_stride_in_bytes, void* output_pixels, int output_w, int output_h, int output_stride_in_bytes, stbir_datatype datatype, int num_channels, int alpha_channel, int flags, stbir_edge edge_mode_horizontal, stbir_edge edge_mode_vertical, stbir_filter filter_horizontal, stbir_filter filter_vertical, stbir_colorspace space, void* alloc_context) { return stbir__resize_arbitrary( alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes, output_pixels, output_w, output_h, output_stride_in_bytes, 0, 0, 1, 1, NULL, num_channels, alpha_channel, flags, datatype, filter_horizontal, filter_vertical, edge_mode_horizontal, edge_mode_vertical, space); } int stbir_resize_subpixel( const void* input_pixels, int input_w, int input_h, int input_stride_in_bytes, void* output_pixels, int output_w, int output_h, int output_stride_in_bytes, stbir_datatype datatype, int num_channels, int alpha_channel, int flags, stbir_edge edge_mode_horizontal, stbir_edge edge_mode_vertical, stbir_filter filter_horizontal, stbir_filter filter_vertical, stbir_colorspace space, void* alloc_context, float x_scale, float y_scale, float x_offset, float y_offset) { float transform[4]; transform[0] = x_scale; transform[1] = y_scale; transform[2] = x_offset; transform[3] = y_offset; return stbir__resize_arbitrary( alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes, output_pixels, output_w, output_h, output_stride_in_bytes, 0, 0, 1, 1, transform, num_channels, alpha_channel, flags, datatype, filter_horizontal, filter_vertical, edge_mode_horizontal, edge_mode_vertical, space); } int stbir_resize_region( const void* input_pixels, int input_w, int input_h, int input_stride_in_bytes, void* output_pixels, int output_w, int output_h, int output_stride_in_bytes, stbir_datatype datatype, int num_channels, int alpha_channel, int flags, stbir_edge edge_mode_horizontal, stbir_edge edge_mode_vertical, stbir_filter filter_horizontal, stbir_filter filter_vertical, stbir_colorspace space, void* alloc_context, float s0, float t0, float s1, float t1) { return stbir__resize_arbitrary( alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes, output_pixels, output_w, output_h, output_stride_in_bytes, s0, t0, s1, t1, NULL, num_channels, alpha_channel, flags, datatype, filter_horizontal, filter_vertical, edge_mode_horizontal, edge_mode_vertical, space); }