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64 lines
3.5 KiB
C
64 lines
3.5 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "dsp/tty/quant.h"
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#include "libc/testlib/testlib.h"
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struct TtyRgb res;
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TEST(rgb2ansi, testDesaturatedPurple_isQuantizedBetterThanEuclideanDistance) {
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ttyquantsetup(kTtyQuantXterm256, kTtyQuantRgb, kTtyBlocksUnicode);
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/*
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* the challenge to the xterm256 palette is that it was likely
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* intended for just syntax highlighting, rather than accurately
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* modeling the natural phenomenon of illumination.
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*
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* as a syntax highlighting palette, it focuses mostly on bright
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* saturated colors, while also providing a really good greyscale for
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* everything else.
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*
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* as such, if one were to project the colors of this palette into a
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* three-dimensional space, we might see something like an HSV cone,
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* where all the color samples are projected mostly around the outside
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* of the cone, and the greyscale dots tracing through the middle.
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*
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* if we want to convert an a real color into an xterm color, we can
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* use euclidean distance functions to pick the closest color, such as
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* sum of squared distance. however this will only work well if it's
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* either a pure grey color, or a bright saturated one.
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*
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* but euclidean distance doesnt work well for the sorts of colors
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* that are generally used for things like film, which conservatively
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* edits for the colors more towards the middle of the space; and as
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* such, which basically causes the distance function to pick greys
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* for almost everything.
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*/
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res = rgb2tty(0x56, 0x38, 0x66);
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/* EXPECT_NE(0x4e, res.r); */
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/* EXPECT_NE(0x4e, res.g); */
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/* EXPECT_NE(0x4e, res.b); */
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/* EXPECT_NE(239, res.xt); */
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/* EXPECT_EQ(0x5f, res.r); */
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/* EXPECT_EQ(0x00, res.g); */
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/* EXPECT_EQ(0x5f, res.b); */
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/* EXPECT_EQ(53, res.xt); */
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}
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