66 lines
3.6 KiB
C
66 lines
3.6 KiB
C
|
/*-*- 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 "dsp/tty/quant.h"
|
||
|
|
#include "libc/testlib/testlib.h"
|
||
|
|
|
||
|
|
struct TtyRgb res;
|
||
|
|
|
||
|
|
TEST(rgb2ansi, testDesaturatedPurple_isQuantizedBetterThanEuclideanDistance) {
|
||
|
|
ttyquantinit(kTtyQuantXterm256, kTtyQuantRgb, kTtyBlocksUnicode);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* the challenge to the xterm256 palette is that it was likely
|
||
|
|
* intended for just syntax highlighting, rather than accurately
|
||
|
|
* modeling the natural phenomenon of illumination.
|
||
|
|
*
|
||
|
|
* as a syntax highlighting palette, it focuses mostly on bright
|
||
|
|
* saturated colors, while also providing a really good greyscale for
|
||
|
|
* everything else.
|
||
|
|
*
|
||
|
|
* as such, if one were to project the colors of this palette into a
|
||
|
|
* three-dimensional space, we might see something like an HSV cone,
|
||
|
|
* where all the color samples are projected mostly around the outside
|
||
|
|
* of the cone, and the greyscale dots tracing through the middle.
|
||
|
|
*
|
||
|
|
* if we want to convert an a real color into an xterm color, we can
|
||
|
|
* use euclidean distance functions to pick the closest color, such as
|
||
|
|
* sum of squared distance. however this will only work well if it's
|
||
|
|
* either a pure grey color, or a bright saturated one.
|
||
|
|
*
|
||
|
|
* but euclidean distance doesnt work well for the sorts of colors
|
||
|
|
* that are generally used for things like film, which conservatively
|
||
|
|
* edits for the colors more towards the middle of the space; and as
|
||
|
|
* such, which basically causes the distance function to pick greys
|
||
|
|
* for almost everything.
|
||
|
|
*/
|
||
|
|
|
||
|
|
res = rgb2tty(0x56, 0x38, 0x66);
|
||
|
|
|
||
|
|
/* EXPECT_NE(0x4e, res.r); */
|
||
|
|
/* EXPECT_NE(0x4e, res.g); */
|
||
|
|
/* EXPECT_NE(0x4e, res.b); */
|
||
|
|
/* EXPECT_NE(239, res.xt); */
|
||
|
|
|
||
|
|
/* EXPECT_EQ(0x5f, res.r); */
|
||
|
|
/* EXPECT_EQ(0x00, res.g); */
|
||
|
|
/* EXPECT_EQ(0x5f, res.b); */
|
||
|
|
/* EXPECT_EQ(53, res.xt); */
|
||
|
|
}
|