115 lines
2.8 KiB
C
115 lines
2.8 KiB
C
// sixel.c (part of mintty)
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// this function is derived from a part of graphics.c
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// in Xterm pl#310 originally written by Ross Combs.
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//
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// Copyright 2013,2014 by Ross Combs
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//
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// All Rights Reserved
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//
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// Permission is hereby granted, free of charge, to any person obtaining a
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// copy of this software and associated documentation files (the
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// "Software"), to deal in the Software without restriction, including
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// without limitation the rights to use, copy, modify, merge, publish,
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// distribute, sublicense, and/or sell copies of the Software, and to
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// permit persons to whom the Software is furnished to do so, subject to
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// the following conditions:
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//
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// The above copyright notice and this permission notice shall be included
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// in all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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// IN NO EVENT SHALL THE ABOVE LISTED COPYRIGHT HOLDER(S) BE LIABLE FOR ANY
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// CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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// TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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// SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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//
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// Except as contained in this notice, the name(s) of the above copyright
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// holders shall not be used in advertising or otherwise to promote the
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// sale, use or other dealings in this Software without prior written
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// authorization.
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#define SIXEL_RGB(r, g, b) (((r) << 16) + ((g) << 8) + (b))
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int
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hls_to_rgb(int hue, int lum, int sat)
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{
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double hs = (hue + 240) % 360;
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double hv = hs / 360.0;
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double lv = lum / 100.0;
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double sv = sat / 100.0;
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double c, x, m, c2;
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double r1, g1, b1;
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int r, g, b;
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int hpi;
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if (sat == 0) {
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r = g = b = lum * 255 / 100;
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return SIXEL_RGB(r, g, b);
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}
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if ((c2 = ((2.0 * lv) - 1.0)) < 0.0) {
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c2 = -c2;
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}
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c = (1.0 - c2) * sv;
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hpi = (int) (hv * 6.0);
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x = (hpi & 1) ? c : 0.0;
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m = lv - 0.5 * c;
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switch (hpi) {
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case 0:
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r1 = c;
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g1 = x;
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b1 = 0.0;
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break;
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case 1:
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r1 = x;
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g1 = c;
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b1 = 0.0;
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break;
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case 2:
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r1 = 0.0;
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g1 = c;
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b1 = x;
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break;
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case 3:
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r1 = 0.0;
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g1 = x;
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b1 = c;
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break;
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case 4:
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r1 = x;
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g1 = 0.0;
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b1 = c;
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break;
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case 5:
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r1 = c;
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g1 = 0.0;
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b1 = x;
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break;
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default:
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return SIXEL_RGB(255, 255, 255);
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}
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r = (int) ((r1 + m) * 100.0 + 0.5);
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g = (int) ((g1 + m) * 100.0 + 0.5);
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b = (int) ((b1 + m) * 100.0 + 0.5);
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if (r < 0) {
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r = 0;
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} else if (r > 100) {
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r = 100;
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}
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if (g < 0) {
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g = 0;
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} else if (g > 100) {
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g = 100;
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}
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if (b < 0) {
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b = 0;
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} else if (b > 100) {
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b = 100;
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}
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return SIXEL_RGB(r * 255 / 100, g * 255 / 100, b * 255 / 100);
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}
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