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| -rw-r--r-- | README | 3 | ||||
| -rw-r--r-- | src/libclut.h | 159 |
2 files changed, 160 insertions, 2 deletions
@@ -2,8 +2,7 @@ NAME libclut - A C colour lookup table library DESCRIPTION - libclut is header-only C library for manipulating - colour lookup tables. + libclut is C library for manipulating colour lookup tables. SEE ALSO libred(7), redshift(1), blueshift(1), libgamma(7) diff --git a/src/libclut.h b/src/libclut.h new file mode 100644 index 0000000..6ef81eb --- /dev/null +++ b/src/libclut.h @@ -0,0 +1,159 @@ +/** + * Copyright © 2016 Mattias Andrée <maandree@member.fsf.org> + * + * 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, either version 3 of the License, or + * (at your option) any later version. + * + * 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, see <http://www.gnu.org/licenses/>. + */ +#ifndef LIBCLUT_H +#define LIBCLUT_H + +#include <stddef.h> + + + +/** + * Modify a ramp. + * + * None of the parameter may have side-effects. + * + * This is intended for internal use. + * + * @param ramp Pointer to the gamma ramps, must have and array + * named `channel` and a scalar named `channel` followed + * by "_size". + * @param channel The channel, must be either "red", "green", or "blue". + * @param type The data type used for each stop in the ramps. + * @param expr Expression that evalutes the value a stop should have. + * It can use the variable `LIBCLUT_VALUE` to get the + * current value of the stop. + */ +#define libclut__(ramp, channel, type, expr) \ + do \ + { \ + size_t i__, n__ = (ramp)->channel##_size; \ + type LIBCLUT_VALUE; \ + for (i__ = 0; i__ < n__; i__++) \ + { \ + LIBCLUT_VALUE = (ramp)->channel[i__]; \ + (ramp)->channel[i__] = (type)(expr); \ + } \ + } \ + while (0) + + + +/** + * Apply contrast correction on the colour curves using sRGB. + * + * In this context, contrast is a measure of difference between + * the whitepoint and blackpoint, if the difference is 0 than + * they are both grey. + * + * None of the parameter may have side-effects. + * + * @param ramp Pointer to the gamma ramps, must have the arrays + * `red`, `green`, and `blue`, and the scalars + * `red_size`, `green_size`, and `blue_size`. Ramp + * structures from libgamma can be used. + * @param max The maximum value on each stop in the ramps. + * @param type The data type used for each stop in the ramps. + * @param r The contrast parameter for the red curve. + * @param g The contrast parameter for the green curve. + * @param b The contrast parameter for the blue curve. + */ +#define libclut_rgb_contrast(ramp, max, type, r, g, b) \ + do \ + { \ + if (r != 1.0) libclut__(ramp, red, type, LIBCLUT_VALUE - (max) / 2.0 * r + (max) / 2.0); \ + if (g != 1.0) libclut__(ramp, green, type, LIBCLUT_VALUE - (max) / 2.0 * g + (max) / 2.0); \ + if (b != 1.0) libclut__(ramp, blue, type, LIBCLUT_VALUE - (max) / 2.0 * b + (max) / 2.0); \ + } \ + while (0) + + +/** + * Apply contrast correction on the colour curves using CIE xyY. + * + * In this context, contrast is a measure of difference between + * the whitepoint and blackpoint, if the difference is 0 than + * they are both grey. + * + * None of the parameter may have side-effects. + * + * @param ramp Pointer to the gamma ramps, must have the arrays + * `red`, `green`, and `blue`, and the scalars + * `red_size`, `green_size`, and `blue_size`. Ramp + * structures from libgamma can be used. + * @param max The maximum value on each stop in the ramps. + * @param type The data type used for each stop in the ramps. + * @param r The contrast parameter for the red curve. + * @param g The contrast parameter for the green curve. + * @param b The contrast parameter for the blue curve. + */ +#define libclut_cie_contrast(ramp, max, type, r, g, b) \ + do \ + { \ + size_t rn__ = (ramp)->red_size; \ + size_t gn__ = (ramp)->green_size; \ + size_t bn__ = (ramp)->blue_size; \ + size_t i__; \ + double x__, y__, Y__, r__, g__, b__; \ + type* rs__ = (ramp)->red; \ + type* gs__ = (ramp)->green; \ + type* bs__ = (ramp)->blue; \ + if ((r == g) && (g == b) && (rn__ == gn__) && (gn__ == bn__)) \ + { \ + if (r == 1.0) \ + break; \ + for (i__ = 0; i__ < rn__; i__) \ + { \ + libclut_model_srgb_to_ciexyy(rs__[i__] / ((double)(max)), gs__[i__] / ((double)(max)), \ + bs__[i__] / ((double)(max)), &x__, &y__, &Y__); \ + libclut_model_ciexyy_to_srgb(x__, y__, (Y__ - 0.5) * r * 0.5, &r__, &g__, &b__); \ + rs__[i__] = (type)(r__ * (double)(max)); \ + gs__[i__] = (type)(g__ * (double)(max)); \ + bs__[i__] = (type)(b__ * (double)(max)); \ + } \ + } \ + else \ + { \ + if ((r == 1.0) && (g == 1.0) && (b == 1.0)) \ + break; \ + libclut_model_srgb_to_ciexyy(rs__[i__] / ((double)(max)), gs__[i__] / ((double)(max)), \ + bs__[i__] / ((double)(max)), &x__, &y__, &Y__); \ + for (i__ = 0; i__ < rn__; i__) \ + { \ + if (r != 1.0) \ + { \ + libclut_model_ciexyy_to_srgb(x__, y__, (Y__ - 0.5) * r * 0.5, &r__, &g__, &b__); \ + rs__[i__] = (type)(r__ * (double)(max)); \ + } \ + if (g != 1.0) \ + { \ + libclut_model_ciexyy_to_srgb(x__, y__, (Y__ - 0.5) * g * 0.5, &r__, &g__, &b__); \ + gs__[i__] = (type)(g__ * (double)(max)); \ + } \ + if (b != 1.0) \ + { \ + libclut_model_ciexyy_to_srgb(x__, y__, (Y__ - 0.5) * b * 0.5, &r__, &g__, &b__); \ + bs__[i__] = (type)(b__ * (double)(max)); \ + } \ + } \ + } \ + } \ + while (0) + + + +#endif + |