Re-think colors.

Color is a property of light, and thus doesn't include information
about transparency.  But canvas pixels and object pigments represent
a color and a degree of transparency.  The new type dmnsn_tcolor/
TColor encapsulates that information.

Also, fix the transparent shadow implementation.

1 files changed, 0 insertions, 344 deletions

diff --git a/libdimension/color.c b/libdimension/color.c
deleted file mode 100644
index 862c8ea..0000000
--- a/libdimension/color.c
+++ /dev/null
@@ -1,344 +0,0 @@
-/*************************************************************************
- * Copyright (C) 2009-2011 Tavian Barnes <tavianator@tavianator.com>     *
- *                                                                       *
- * This file is part of The Dimension Library.                           *
- *                                                                       *
- * The Dimension Library is free software; you can redistribute it and/  *
- * or modify it under the terms of the GNU Lesser General Public License *
- * as published by the Free Software Foundation; either version 3 of the *
- * License, or (at your option) any later version.                       *
- *                                                                       *
- * The Dimension Library 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  *
- * Lesser General Public License for more details.                       *
- *                                                                       *
- * You should have received a copy of the GNU Lesser General Public      *
- * License along with this program.  If not, see                         *
- * <http://www.gnu.org/licenses/>.                                       *
- *************************************************************************/
-
-/**
- * @file
- * Color handling.
- */
-
-#include "dimension.h"
-
-/* Standard colors */
-const dmnsn_color dmnsn_black = {
-  .R = 0.0,
-  .G = 0.0,
-  .B = 0.0,
-  .trans  = 0.0,
-  .filter = 0.0,
-};
-const dmnsn_color dmnsn_white = {
-  .R = 1.0,
-  .G = 1.0,
-  .B = 1.0,
-  .trans  = 0.0,
-  .filter = 0.0,
-};
-const dmnsn_color dmnsn_clear = {
-  .R = 0.0,
-  .G = 0.0,
-  .B = 0.0,
-  .trans  = 1.0,
-  .filter = 0.0,
-};
-const dmnsn_color dmnsn_red = {
-  .R = 1.0,
-  .G = 0.0,
-  .B = 0.0,
-  .trans  = 0.0,
-  .filter = 0.0,
-};
-const dmnsn_color dmnsn_green = {
-  .R = 0.0,
-  .G = 1.0,
-  .B = 0.0,
-  .trans  = 0.0,
-  .filter = 0.0,
-};
-const dmnsn_color dmnsn_blue = {
-  .R = 0.0,
-  .G = 0.0,
-  .B = 1.0,
-  .trans  = 0.0,
-  .filter = 0.0,
-};
-const dmnsn_color dmnsn_magenta = {
-  .R = 1.0,
-  .G = 0.0,
-  .B = 1.0,
-  .trans  = 0.0,
-  .filter = 0.0,
-};
-const dmnsn_color dmnsn_orange = {
-  .R = 1.0,
-  .G = 0.21404114048223255,
-  .B = 0.0,
-  .trans  = 0.0,
-  .filter = 0.0,
-};
-const dmnsn_color dmnsn_yellow = {
-  .R = 1.0,
-  .G = 1.0,
-  .B = 0.0,
-  .trans  = 0.0,
-  .filter = 0.0,
-};
-const dmnsn_color dmnsn_cyan = {
-  .R = 0.0,
-  .G = 1.0,
-  .B = 1.0,
-  .filter = 0.0,
-  .trans  = 0.0,
-};
-
-/* sRGB's `C' function. */
-static inline double
-dmnsn_sRGB_C(double Clinear)
-{
-  /*
-   * If C represents R, G, and B, then the sRGB values are now found as follows:
-   *
-   *         { 12.92*Clinear,                Clinear <= 0.0031308
-   * Csrgb = {                1/2.4
-   *         { (1.055)*Clinear      - 0.055, Clinear >  0.0031308
-   */
-  if (Clinear == 1.0) {
-    return 1.0; /* Map 1.0 to 1.0 instead of 0.9999999999999999 */
-  } else if (Clinear > 0.0031308) {
-    return 1.055*pow(Clinear, 1.0/2.4) - 0.055;
-  } else {
-    return 12.92*Clinear;
-  }
-}
-
-/* Export dmnsn_sRGB_C */
-double
-dmnsn_sRGB_gamma(double Clinear)
-{
-  return dmnsn_sRGB_C(Clinear);
-}
-
-/* Convert to sRGB space */
-dmnsn_color
-dmnsn_color_to_sRGB(dmnsn_color color)
-{
-  dmnsn_color ret = {
-    .R = dmnsn_sRGB_C(color.R),
-    .G = dmnsn_sRGB_C(color.G),
-    .B = dmnsn_sRGB_C(color.B),
-    .trans  = color.trans,
-    .filter = color.filter,
-  };
-  return ret;
-}
-
-/* Inverse function of sRGB's `C' function, for the reverse conversion. */
-double
-dmnsn_sRGB_C_inv(double CsRGB)
-{
-  /*
-   * If C represents R, G, and B, then the Clinear values are now found as
-   * follows:
-   *
-   *           { Csrgb/12.92,                  Csrgb <= 0.04045
-   * Clinear = {                        1/2.4
-   *           { ((Csrgb + 0.055)/1.055)     , Csrgb >  0.04045
-   */
-  if (CsRGB == 1.0) {
-    return 1.0; /* Map 1.0 to 1.0 instead of 0.9999999999999999 */
-  } else if (CsRGB <= 0.040449936) {
-    return CsRGB/12.92;
-  } else {
-    return pow((CsRGB + 0.055)/1.055, 2.4);
-  }
-}
-
-/* Export dmnsn_sRGB_C_inv */
-double
-dmnsn_sRGB_inverse_gamma(double CsRGB)
-{
-  return dmnsn_sRGB_C_inv(CsRGB);
-}
-
-/* Convert from sRGB space */
-dmnsn_color
-dmnsn_color_from_sRGB(dmnsn_color color)
-{
-  dmnsn_color ret = {
-    .R = dmnsn_sRGB_C_inv(color.R),
-    .G = dmnsn_sRGB_C_inv(color.G),
-    .B = dmnsn_sRGB_C_inv(color.B),
-    .trans  = color.trans,
-    .filter = color.filter,
-  };
-  return ret;
-}
-
-/* Greyscale color intensity */
-double
-dmnsn_color_intensity(dmnsn_color color)
-{
-  return 0.2126*color.R + 0.7152*color.G + 0.0722*color.B;
-}
-
-/* Add two colors */
-dmnsn_color
-dmnsn_color_add(dmnsn_color c1, dmnsn_color c2)
-{
-  dmnsn_color ret = dmnsn_new_color(c1.R + c2.R, c1.G + c2.G, c1.B + c2.B);
-
-  /* Switch into absolute filter and transmittance space */
-  double n1 = dmnsn_color_intensity(c1), n2 = dmnsn_color_intensity(c2);
-  double f1 = c1.filter*c1.trans, f2 = c2.filter*c2.trans;
-  double t1 = c1.trans - f1, t2 = c2.trans - f2;
-  double f = 0.0;
-  if (n1 + n2 >= dmnsn_epsilon)
-    f = (n1*f1 + n2*f2)/(n1 + n2);
-  double t = t1 + t2;
-
-  /* Switch back */
-  ret.trans = f + t;
-  if (ret.trans >= dmnsn_epsilon)
-    ret.filter = f/ret.trans;
-
-  return ret;
-}
-
-/* Subtract two colors */
-dmnsn_color
-dmnsn_color_sub(dmnsn_color c1, dmnsn_color c2)
-{
-  dmnsn_color ret = dmnsn_new_color(c1.R - c2.R, c1.G - c2.G, c1.B - c2.B);
-
-  /* Switch into absolute filter and transmittance space */
-  double n1 = dmnsn_color_intensity(c1), n2 = dmnsn_color_intensity(c2);
-  double f1 = c1.filter*c1.trans, f2 = c2.filter*c2.trans;
-  double t1 = c1.trans - f1, t2 = c2.trans - f2;
-  double f = 0.0;
-  if (n1 - n2 >= dmnsn_epsilon)
-    f = (n1*f1 - n2*f2)/(n1 - n2);
-  double t = t1 - t2;
-
-  /* Switch back */
-  ret.trans = f + t;
-  if (ret.trans >= dmnsn_epsilon)
-    ret.filter = f/ret.trans;
-
-  return ret;
-}
-
-/* Multiply a color by a scalar */
-dmnsn_color
-dmnsn_color_mul(double n, dmnsn_color color)
-{
-  color.R *= n;
-  color.G *= n;
-  color.B *= n;
-  color.trans *= n;
-  return color;
-}
-
-/* For n in [0, 1] get the color in a gradient between c1 and c2 */
-dmnsn_color
-dmnsn_color_gradient(dmnsn_color c1, dmnsn_color c2, double n)
-{
-  dmnsn_color ret = dmnsn_new_color(
-    n*(c2.R - c1.R) + c1.R,
-    n*(c2.G - c1.G) + c1.G,
-    n*(c2.B - c1.B) + c1.B
-  );
-
-  /* Switch into absolute filter and transmittance space */
-  double f1 = c1.filter*c1.trans, f2 = c2.filter*c2.trans;
-  double t1 = c1.trans - f1, t2 = c2.trans - f2;
-  double f = n*(f2 - f1) + f1;
-  double t = n*(t2 - t1) + t1;
-
-  /* Switch back */
-  ret.trans = f + t;
-  ret.filter = 0.0;
-  if (ret.trans >= dmnsn_epsilon)
-    ret.filter = f/ret.trans;
-
-  return ret;
-}
-
-/* Filters `light' through `filter' */
-dmnsn_color
-dmnsn_filter_light(dmnsn_color light, dmnsn_color filter)
-{
-  dmnsn_color transmitted = dmnsn_color_mul(
-    (1.0 - filter.filter)*filter.trans,
-    light
-  );
-  dmnsn_color filtered = dmnsn_color_mul(
-    filter.filter*filter.trans,
-    dmnsn_color_illuminate(filter, light)
-  );
-
-  dmnsn_color ret = dmnsn_new_color(
-    transmitted.R + filtered.R,
-    transmitted.G + filtered.G,
-    transmitted.B + filtered.B
-  );
-
-  /* Switch into absolute filter and transmittance space */
-  double lf = light.filter*light.trans, ff = filter.filter*filter.trans;
-  double lt = light.trans - lf, ft = filter.trans - ff;
-  double f = lf*(dmnsn_color_intensity(filtered) + ft) + lt*ff;
-  double t = ft*lt;
-
-  /* Switch back */
-  ret.trans = f + t;
-  if (ret.trans >= dmnsn_epsilon)
-    ret.filter = f/ret.trans;
-
-  return ret;
-}
-
-/* Adds the background contribution, `filtered', to `filter' */
-dmnsn_color
-dmnsn_apply_transparency(dmnsn_color filtered, dmnsn_color filter)
-{
-  dmnsn_color ret = dmnsn_color_add(
-    dmnsn_color_mul(1.0 - filter.trans, filter),
-    filtered
-  );
-  ret.trans  = filtered.trans;
-  ret.filter = filtered.filter;
-  return ret;
-}
-
-/* Adds the background contribution of `color' to `filter' */
-dmnsn_color
-dmnsn_apply_filter(dmnsn_color color, dmnsn_color filter)
-{
-  return dmnsn_apply_transparency(dmnsn_filter_light(color, filter), filter);
-}
-
-/* Remove the filter channel */
-dmnsn_color
-dmnsn_remove_filter(dmnsn_color color)
-{
-  double intensity = dmnsn_color_intensity(color);
-  double newtrans = (1.0 - (1.0 - intensity)*color.filter)*color.trans;
-  if (1.0 - newtrans >= dmnsn_epsilon)
-    color = dmnsn_color_mul((1.0 - color.trans)/(1.0 - newtrans), color);
-  color.trans  = newtrans;
-  color.filter = 0.0;
-  return color;
-}
-
-/* Illuminates `color' with `light' */
-dmnsn_color
-dmnsn_color_illuminate(dmnsn_color light, dmnsn_color color)
-{
-  return dmnsn_new_color5(light.R*color.R, light.G*color.G, light.B*color.B,
-                          color.filter, color.trans);
-}