cosmopolitan/third_party/stb/stb_image_resize.h

193 lines
8.8 KiB
C

#ifndef COSMOPOLITAN_THIRD_PARTY_STB_STB_IMAGE_RESIZE_H_
#define COSMOPOLITAN_THIRD_PARTY_STB_STB_IMAGE_RESIZE_H_
#if !(__ASSEMBLER__ + __LINKER__ + 0)
COSMOPOLITAN_C_START_
// Easy-to-use API:
//
// * "input pixels" points to an array of image data with 'num_channels'
// channels (e.g. RGB=3, RGBA=4)
// * input_w is input image width (x-axis), input_h is input image height
// (y-axis)
// * stride is the offset between successive rows of image data in memory,
// in bytes. you can
// specify 0 to mean packed continuously in memory
// * alpha channel is treated identically to other channels.
// * colorspace is linear or sRGB as specified by function name
// * returned result is 1 for success or 0 in case of an error.
// #define STBIR_ASSERT() to trigger an assert on parameter validation
// errors.
// * Memory required grows approximately linearly with input and output
// size, but with
// discontinuities at input_w == output_w and input_h == output_h.
// * These functions use a "default" resampling filter defined at compile
// time. To change the filter,
// you can change the compile-time defaults by #defining
// STBIR_DEFAULT_FILTER_UPSAMPLE and STBIR_DEFAULT_FILTER_DOWNSAMPLE, or
// you can use the medium-complexity API.
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);
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);
// The following functions interpret image data as gamma-corrected sRGB.
// Specify STBIR_ALPHA_CHANNEL_NONE if you have no alpha channel,
// or otherwise provide the index of the alpha channel. Flags value
// of 0 will probably do the right thing if you're not sure what
// the flags mean.
#define STBIR_ALPHA_CHANNEL_NONE -1
// Set this flag if your texture has premultiplied alpha. Otherwise, stbir will
// use alpha-weighted resampling (effectively premultiplying, resampling,
// then unpremultiplying).
#define STBIR_FLAG_ALPHA_PREMULTIPLIED (1 << 0)
// The specified alpha channel should be handled as gamma-corrected value even
// when doing sRGB operations.
#define STBIR_FLAG_ALPHA_USES_COLORSPACE (1 << 1)
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);
typedef enum {
STBIR_EDGE_CLAMP = 1,
STBIR_EDGE_REFLECT = 2,
STBIR_EDGE_WRAP = 3,
STBIR_EDGE_ZERO = 4,
} stbir_edge;
// This function adds the ability to specify how requests to sample off the edge
// of the image are handled.
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);
// Medium-complexity API
//
// This extends the easy-to-use API as follows:
//
// * Alpha-channel can be processed separately
// * If alpha_channel is not STBIR_ALPHA_CHANNEL_NONE
// * Alpha channel will not be gamma corrected (unless
// flags&STBIR_FLAG_GAMMA_CORRECT)
// * Filters will be weighted by alpha channel (unless
// flags&STBIR_FLAG_ALPHA_PREMULTIPLIED)
// * Filter can be selected explicitly
// * uint16 image type
// * sRGB colorspace available for all types
// * context parameter for passing to STBIR_MALLOC
typedef enum {
// use same filter type that easy-to-use API chooses
STBIR_FILTER_DEFAULT = 0,
// a trapezoid w/1-pixel wide ramps, same result as box for integer
// scale ratios
STBIR_FILTER_BOX = 1,
// On upsampling, produces same results as bilinear texture filtering
STBIR_FILTER_TRIANGLE = 2,
// The cubic b-spline (aka Mitchell-Netrevalli with B=1,C=0), gaussian-esque
STBIR_FILTER_CUBICBSPLINE = 3,
// An interpolating cubic spline
STBIR_FILTER_CATMULLROM = 4,
// Mitchell-Netrevalli filter with B=1/3, C=1/3
STBIR_FILTER_MITCHELL = 5,
} stbir_filter;
typedef enum {
STBIR_COLORSPACE_LINEAR,
STBIR_COLORSPACE_SRGB,
STBIR_MAX_COLORSPACES,
} stbir_colorspace;
// The following functions are all identical except for the type of the image
// data
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);
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);
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);
// Full-complexity API
//
// This extends the medium API as follows:
//
// * uint32 image type
// * not typesafe
// * separate filter types for each axis
// * separate edge modes for each axis
// * can specify scale explicitly for subpixel correctness
// * can specify image source tile using texture coordinates
typedef enum {
STBIR_TYPE_UINT8,
STBIR_TYPE_UINT16,
STBIR_TYPE_UINT32,
STBIR_TYPE_FLOAT,
STBIR_MAX_TYPES
} stbir_datatype;
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);
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);
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);
// (s0, t0) & (s1, t1) are the top-left and bottom right corner (uv addressing
// style: [0, 1]x[0, 1]) of a region of the input image to use.
COSMOPOLITAN_C_END_
#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
#endif /* COSMOPOLITAN_THIRD_PARTY_STB_STB_IMAGE_RESIZE_H_ */