mirrors/wlroots
1
0
Fork 0
mirror of https://gitlab.freedesktop.org/wlroots/wlroots.git synced 2025-10-28 05:40:11 -04:00
Code Issues Projects Releases Packages Wiki Activity Actions

render/color: add wlr_color_primaries_to_xyz()

Browse source
This commit is contained in:
Simon Ser 2025-01-27 18:04:02 +01:00
parent d8ad4809fc
commit 156201fe71
3 changed files with 68 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

5
include/render/color.h
View file

@ -45,4 +45,9 @@ struct wlr_color_transform_lut3d {
struct wlr_color_transform_lut3d *wlr_color_transform_lut3d_from_base(
struct wlr_color_transform *tr);
/**
* Compute the matrix to convert RGB color values to CIE 1931 XYZ.
*/
void wlr_color_primaries_to_xyz(const struct wlr_color_primaries *primaries, float matrix[static 9]);
#endif

14
include/wlr/render/color.h
View file

@ -12,6 +12,20 @@
#include <stdbool.h>
#include <sys/types.h>
/**
* CIE 1931 xy chromaticity coordinates.
*/
struct wlr_color_cie1931_xy {
float x, y;
};
/**
* Color primaries and white point describing a color volume.
*/
struct wlr_color_primaries {
struct wlr_color_cie1931_xy red, green, blue, white;
};
/**
* A color transformation formula, which maps a linear color space with
* sRGB primaries to an output color space.

49
render/color.c
View file

@ -1,7 +1,9 @@
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include <wlr/render/color.h>
#include "render/color.h"
#include "util/matrix.h"
struct wlr_color_transform *wlr_color_transform_init_srgb(void) {
struct wlr_color_transform *tx = calloc(1, sizeof(struct wlr_color_transform));
@ -50,3 +52,50 @@ struct wlr_color_transform_lut3d *wlr_color_transform_lut3d_from_base(
struct wlr_color_transform_lut3d *lut3d = wl_container_of(tr, lut3d, base);
return lut3d;
}
static void multiply_matrix_vector(float out[static 3], float m[static 9], float v[static 3]) {
float result[3] = {
m[0] * v[0] + m[1] * v[1] + m[2] * v[2],
m[3] * v[0] + m[4] * v[1] + m[5] * v[2],
m[6] * v[0] + m[7] * v[1] + m[8] * v[2],
};
memcpy(out, result, sizeof(result));
}
static void xy_to_xyz(float out[static 3], struct wlr_color_cie1931_xy src) {
if (src.y == 0) {
out[0] = out[1] = out[2] = 0;
return;
}
out[0] = src.x / src.y;
out[1] = 1;
out[2] = (1 - src.x - src.y) / src.y;
}
void wlr_color_primaries_to_xyz(const struct wlr_color_primaries *primaries, float matrix[static 9]) {
// See: http://www.brucelindbloom.com/index.html?Eqn_RGB_XYZ_Matrix.html
float r[3], g[3], b[3], w[3];
xy_to_xyz(r, primaries->red);
xy_to_xyz(g, primaries->green);
xy_to_xyz(b, primaries->blue);
xy_to_xyz(w, primaries->white);
float xyz_matrix[9] = {
r[0], g[0], b[0],
r[1], g[1], b[1],
r[2], g[2], b[2],
};
matrix_invert(xyz_matrix, xyz_matrix);
float S[3];
multiply_matrix_vector(S, xyz_matrix, w);
float result[] = {
S[0] * r[0], S[1] * g[0], S[2] * b[0],
S[0] * r[1], S[1] * g[1], S[2] * b[1],
S[0] * r[2], S[1] * g[2], S[2] * b[2],
};
memcpy(matrix, result, sizeof(result));
}