render/color: introduce wlr_color_transform

render/color.c

@@ -0,0 +1,94 @@
+#include <lcms2.h>
+#include <stdlib.h>
+#include <wlr/render/color.h>
+#include <wlr/util/log.h>
+
+static void handle_lcms_error(cmsContext ctx, cmsUInt32Number code, const char *text) {
+	wlr_log(WLR_ERROR, "[lcms] %s", text);
+}
+
+bool wlr_color_transform_init_srgb_to_icc(struct wlr_color_transform *tr,
+		const void *data, size_t size) {
+	bool ok = false;
+
+	cmsContext ctx = cmsCreateContext(NULL, NULL);
+	if (ctx == NULL) {
+		wlr_log(WLR_ERROR, "cmsCreateContext failed");
+		return false;
+	}
+
+	cmsSetLogErrorHandlerTHR(ctx, handle_lcms_error);
+
+	cmsHPROFILE icc_profile = cmsOpenProfileFromMemTHR(ctx, data, size);
+	if (icc_profile == NULL) {
+		wlr_log(WLR_ERROR, "cmsOpenProfileFromMemTHR failed");
+		goto out_ctx;
+	}
+
+	if (cmsGetDeviceClass(icc_profile) != cmsSigDisplayClass) {
+		wlr_log(WLR_ERROR, "ICC profile must have the Display device class");
+		goto out_icc_profile;
+	}
+
+	cmsHPROFILE srgb_profile = cmsCreate_sRGBProfile();
+	if (srgb_profile == NULL) {
+		wlr_log(WLR_ERROR, "cmsCreate_sRGBProfile failed");
+		goto out_icc_profile;
+	}
+
+	cmsHTRANSFORM lcms_tr = cmsCreateTransformTHR(ctx,
+		srgb_profile, TYPE_RGB_FLT, icc_profile, TYPE_RGB_FLT,
+		INTENT_RELATIVE_COLORIMETRIC, 0);
+	if (lcms_tr == NULL) {
+		wlr_log(WLR_ERROR, "cmsCreateTransformTHR failed");
+		goto out_srgb_profile;
+	}
+
+	size_t dim_len = 33;
+	float *lut_3d = calloc(3 * dim_len * dim_len * dim_len, sizeof(float));
+	if (lut_3d == NULL) {
+		wlr_log_errno(WLR_ERROR, "Allocation failed");
+		goto out_lcms_tr;
+	}
+
+	float factor = 1.0f / (dim_len - 1);
+	for (size_t b_index = 0; b_index < dim_len; b_index++) {
+		for (size_t g_index = 0; g_index < dim_len; g_index++) {
+			for (size_t r_index = 0; r_index < dim_len; r_index++) {
+				float rgb_in[3] = {
+					r_index * factor,
+					g_index * factor,
+					b_index * factor,
+				};
+				float rgb_out[3];
+				cmsDoTransform(lcms_tr, rgb_in, rgb_out, 1);
+
+				size_t offset = 3 * (r_index + dim_len * g_index + dim_len * dim_len * b_index);
+				// TODO: maybe clamp values to [0.0, 1.0] here?
+				lut_3d[offset] = rgb_out[0];
+				lut_3d[offset + 1] = rgb_out[1];
+				lut_3d[offset + 2] = rgb_out[2];
+			}
+		}
+	}
+
+	ok = true;
+	*tr = (struct wlr_color_transform){
+		.lut_3d = lut_3d,
+		.dim_len = dim_len,
+	};
+
+out_lcms_tr:
+	cmsDeleteTransform(lcms_tr);
+out_srgb_profile:
+	cmsCloseProfile(srgb_profile);
+out_icc_profile:
+	cmsCloseProfile(icc_profile);
+out_ctx:
+	cmsDeleteContext(ctx);
+	return ok;
+}
+
+void wlr_color_transform_finish(struct wlr_color_transform *tr) {
+	free(tr->lut_3d);
+}

render/meson.build

@@ -38,3 +38,9 @@ endif
 subdir('pixman')
 
 subdir('allocator')
+
+lcms2 = dependency('lcms2', required: get_option('color-management'))
+if lcms2.found()
+	wlr_deps += lcms2
+	wlr_files += files('color.c')
+endif