309 lines
7.6 KiB
C
309 lines
7.6 KiB
C
/* Copyright 1994, 1995 by Abacus Research and
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* Development, Inc. All rights reserved.
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*/
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#if !defined (OMIT_RCSID_STRINGS)
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char ROMlib_rcsid_qCConv[] =
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"$Id: qCConv.c 63 2004-12-24 18:19:43Z ctm $";
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#endif
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#include "rsys/common.h"
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#include "QuickDraw.h"
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/* cmy and rgb color spaces are simply complements */
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P2 (PUBLIC pascal trap, void, CMY2RGB,
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CMYColor *, cmy_color,
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RGBColor *, rgb_color)
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{
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rgb_color->red = ~cmy_color->cyan;
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rgb_color->green = ~cmy_color->magenta;
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rgb_color->blue = ~cmy_color->yellow;
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}
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P2 (PUBLIC pascal trap, void, RGB2CMY,
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RGBColor *, rgb_color,
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CMYColor *, cmy_color)
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{
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/* use `bar = ~foo' instead of `bar = CW (MaxSmallFract - CW (foo))'
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to compute the complement value */
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cmy_color->cyan = ~rgb_color->red;
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cmy_color->magenta = ~rgb_color->green;
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cmy_color->yellow = ~rgb_color->blue;
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}
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#define SF_MULT(x,y) (((x) * (y)) / 65535)
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#define SF_DIV(x,y) (((x) * 65535) / (y))
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#define C_TO_SF(c) ((c) * 65535)
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#define SF_TO_C(sf) ((sf) / 65535)
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#define ANGLE_TO_SF(angle) (C_TO_SF (angle) / 360)
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static inline unsigned short
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value (unsigned long n1, unsigned long n2, unsigned long hue)
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{
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if (hue < ANGLE_TO_SF (60))
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return CW (n1 + SF_MULT (n2 - n1,
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SF_MULT (hue, C_TO_SF (6))));
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else if (hue < ANGLE_TO_SF (180))
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return CW (n2);
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else if (hue < ANGLE_TO_SF (240))
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return CW (n1 + SF_MULT (n2 - n1,
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SF_MULT (ANGLE_TO_SF (240) - hue,
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C_TO_SF (6))));
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else
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return CW (n1);
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}
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P2 (PUBLIC pascal trap, void, HSL2RGB,
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HSLColor *, hsl_color,
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RGBColor *, rgb_color)
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{
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if (hsl_color->saturation == CWC (0))
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{
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rgb_color->red = hsl_color->lightness;
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rgb_color->green = hsl_color->lightness;
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rgb_color->blue = hsl_color->lightness;
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}
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else
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{
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unsigned long m1, m2;
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/* the hue represents a angle in the range [0, 360) */
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unsigned long h = CW (hsl_color->hue);
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unsigned long s = CW (hsl_color->saturation);
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unsigned long l = CW (hsl_color->lightness);
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if (l <= (MaxSmallFract / 2))
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m2 = SF_MULT (l, (C_TO_SF (1) + s));
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else
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m2 = l + s - SF_MULT (l, s);
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m1 = SF_MULT (l, C_TO_SF (2)) - m2;
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rgb_color->red = value (m1, m2,
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(h >= ANGLE_TO_SF (240)) ? (h - ANGLE_TO_SF (240))
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: (h + ANGLE_TO_SF (120)));
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rgb_color->green = value (m1, m2, h);
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rgb_color->blue = value (m1, m2,
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(h < ANGLE_TO_SF (120)) ? (h + ANGLE_TO_SF (240))
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: (h - ANGLE_TO_SF (120)));
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}
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}
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P2 (PUBLIC pascal trap, void, RGB2HSL,
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RGBColor *, rgb_color,
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HSLColor *, hsl_color)
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{
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unsigned long r = CW (rgb_color->red);
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unsigned long g = CW (rgb_color->green);
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unsigned long b = CW (rgb_color->blue);
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unsigned long max = MAX (r, MAX (g, b));
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unsigned long min = MIN (r, MIN (g, b));
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unsigned long h;
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unsigned long s;
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unsigned long l = (min + max) / 2;
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if (min == max)
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{
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/* achromatic case, because all rgb color components
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are equal */
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s = 0;
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/* the value of h in this case is meaningless, should
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investigate what the Mac color conversion routines do */
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h = 0;
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}
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else
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{
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unsigned long delta = max - min;
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if (l <= (MaxSmallFract / 2))
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{
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s = SF_DIV (delta, max + min);
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gui_assert (s <= MaxSmallFract);
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}
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else
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{
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s = SF_DIV (delta, C_TO_SF (2) - max - min);
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gui_assert (s <= MaxSmallFract);
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}
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if (r == max)
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{
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if (g >= b)
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h = SF_MULT (SF_DIV (g - b, delta), ANGLE_TO_SF (60));
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else
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h = ANGLE_TO_SF (360) - SF_MULT (SF_DIV (b - g, delta), ANGLE_TO_SF (60));
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}
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else if (g == max)
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{
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if (b >= r)
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h = ANGLE_TO_SF (120) + SF_MULT (SF_DIV (b - r, delta), ANGLE_TO_SF (60));
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else
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h = ANGLE_TO_SF (120) - SF_MULT (SF_DIV (r - b, delta), ANGLE_TO_SF (60));
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}
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else if (b == max)
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{
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if (r >= g)
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h = ANGLE_TO_SF (240) + SF_MULT (SF_DIV (r - g, delta), ANGLE_TO_SF (60));
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else
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h = ANGLE_TO_SF (240) - SF_MULT (SF_DIV (g - r, delta), ANGLE_TO_SF (60));
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}
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else
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gui_fatal("r = 0x%lx, g = 0x%lx, b = 0x%lx", r, g, b);
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}
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hsl_color->hue = CW (h);
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hsl_color->saturation = CW (s);
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hsl_color->lightness = CW (l);
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}
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P2 (PUBLIC pascal trap, void, HSV2RGB,
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HSVColor *, hsv_color,
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RGBColor *, rgb_color)
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{
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if (hsv_color->saturation == CWC (0))
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{
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rgb_color->red = hsv_color->value;
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rgb_color->green = hsv_color->value;
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rgb_color->blue = hsv_color->value;
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}
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else
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{
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/* the hue represents a angle in the range [0, 360) */
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unsigned long h = CW (hsv_color->hue);
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unsigned long s = CW (hsv_color->saturation);
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unsigned long v = CW (hsv_color->value);
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/* one of the six color verticies of the hex cone, [0, 6) */
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unsigned sextant = SF_TO_C (h * 6);
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/* `fractional' portion of h, in the range [0,1] */
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/* unsigned long f = 6 * (h % ANGLE_TO_SF (60)); */
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unsigned long f = 6 * (h - ANGLE_TO_SF (sextant * 60));
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unsigned long p = SF_MULT (v, C_TO_SF (1) - s);
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unsigned long q = SF_MULT (v, C_TO_SF (1) - SF_MULT (s, f));
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unsigned long t = SF_MULT (v, (C_TO_SF (1)
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- SF_MULT (s, C_TO_SF (1) - f)));
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switch (sextant)
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{
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case 0:
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rgb_color->red = CW (v);
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rgb_color->green = CW (t);
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rgb_color->blue = CW (p);
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break;
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case 1:
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rgb_color->red = CW (q);
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rgb_color->green = CW (v);
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rgb_color->blue = CW (p);
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break;
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case 2:
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rgb_color->red = CW (p);
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rgb_color->green = CW (v);
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rgb_color->blue = CW (t);
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break;
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case 3:
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rgb_color->red = CW (p);
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rgb_color->green = CW (q);
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rgb_color->blue = CW (v);
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break;
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case 4:
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rgb_color->red = CW (t);
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rgb_color->green = CW (p);
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rgb_color->blue = CW (v);
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break;
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case 5:
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case 6:
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rgb_color->red = CW (v);
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rgb_color->green = CW (p);
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rgb_color->blue = CW (q);
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break;
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default:
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gui_fatal ("sextant = %d", sextant);
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}
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}
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}
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P2 (PUBLIC pascal trap, void, RGB2HSV,
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RGBColor *, rgb_color,
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HSVColor *, hsv_color)
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{
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unsigned long r = CW (rgb_color->red);
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unsigned long g = CW (rgb_color->green);
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unsigned long b = CW (rgb_color->blue);
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unsigned long max = MAX (r, MAX (g, b));
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unsigned long min = MIN (r, MIN (g, b));
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unsigned long h;
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unsigned long s;
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unsigned long v = max;
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if (max != 0)
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{
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s = SF_DIV (max - min, max);
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gui_assert (s <= MaxSmallFract);
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}
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else
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s = 0;
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if (s == 0)
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{
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/* the value of h in this case is meaningless, should
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investigate what the Mac color conversion routines do */
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h = 0;
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}
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else
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{
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unsigned long delta = max - min;
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if (r == max)
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{
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if (g >= b)
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h = SF_MULT (SF_DIV (g - b, delta), ANGLE_TO_SF (60));
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else
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h = ANGLE_TO_SF (360) - SF_MULT (SF_DIV (b - g, delta), ANGLE_TO_SF (60));
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}
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else if (g == max)
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{
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if (b >= r)
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h = ANGLE_TO_SF (120) + SF_MULT (SF_DIV (b - r, delta), ANGLE_TO_SF (60));
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else
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h = ANGLE_TO_SF (120) - SF_MULT (SF_DIV (r - b, delta), ANGLE_TO_SF (60));
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}
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else if (b == max)
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{
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if (r >= g)
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h = ANGLE_TO_SF (240) + SF_MULT (SF_DIV (r - g, delta), ANGLE_TO_SF (60));
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else
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h = ANGLE_TO_SF (240) - SF_MULT (SF_DIV (g - r, delta), ANGLE_TO_SF (60));
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}
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else
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gui_fatal ("r = 0x%lx, g = 0x%lx, b = 0x%lx", r, g, b);
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}
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hsv_color->hue = CW (h);
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hsv_color->saturation = CW (s);
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hsv_color->value = CW (v);
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}
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P1 (PUBLIC pascal trap, SmallFract, Fix2SmallFract,
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Fixed, f)
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{
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return f & 0xFFFF;
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}
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P1 (PUBLIC pascal trap, Fixed, SmallFract2Fix,
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SmallFract, sf)
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{
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return sf;
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}
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