libweston: add struct weston_output_color_outcome

This new struct collects all the things that a color manager needs to
set up when any colorimetry aspect of an output changes. The intention
is to make the color manager API less verbose.

In this first step, the new struct is added and replaces the fields in
weston_output.

The intention is for the following color manager API changes to
dynamically allocate this structure. Unfortunately, until that actually
happens, we need a temporary way to allocate it. That is
weston_output::colorout_, which will be removed in the next patch. This
keeps the patches more palatable for review at the cost of some
back-and-forth in code changes.

This is a pure refactoring, no functional changes.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>

include/libweston/libweston.h

@@ -283,6 +283,26 @@ struct weston_head {
 	enum weston_hdcp_protection current_protection;
 };
 
+/** Output properties derived from its color characteristics and profile
+ *
+ * These are constructed by a color manager.
+ *
+ * A weston_output_color_outcome owns (a reference to) everything it contains.
+ *
+ * \ingroup output
+ * \internal
+ */
+struct weston_output_color_outcome {
+	/** sRGB to output color space transformation */
+	struct weston_color_transform *from_sRGB_to_output;
+
+	/** sRGB to blending color space transformation */
+	struct weston_color_transform *from_sRGB_to_blend;
+
+	/** Blending to output color space transformation */
+	struct weston_color_transform *from_blend_to_output;
+};
+
 /** Content producer for heads
  *
  * \rst
@@ -392,12 +412,14 @@ struct weston_output {
 	int scale;
 
 	struct weston_color_profile *color_profile;
-	struct weston_color_transform *from_sRGB_to_output;
-	struct weston_color_transform *from_sRGB_to_blend;
-	struct weston_color_transform *from_blend_to_output;
 	bool from_blend_to_output_by_backend;
 	enum weston_eotf_mode eotf_mode;
 
+	/* XXX: temporary allocation to be removed in the next commit */
+	struct weston_output_color_outcome colorout_;
+
+	struct weston_output_color_outcome *color_outcome;
+
 	int (*enable)(struct weston_output *output);
 	int (*disable)(struct weston_output *output);
 

libweston/color.h

@@ -385,4 +385,7 @@ weston_eotf_mode_to_str(enum weston_eotf_mode e);
 char *
 weston_eotf_mask_to_str(uint32_t eotf_mask);
 
+void
+weston_output_color_outcome_destroy(struct weston_output_color_outcome **pco);
+
 #endif /* WESTON_COLOR_H */

libweston/compositor.c

@@ -6463,15 +6463,24 @@ weston_output_transform_coordinate(struct weston_output *output,
 	*y = p.f[1] / p.f[3];
 }
 
-static void
-weston_output_reset_color_transforms(struct weston_output *output)
+WL_EXPORT void
+weston_output_color_outcome_destroy(struct weston_output_color_outcome **pco)
 {
-	weston_color_transform_unref(output->from_sRGB_to_output);
-	output->from_sRGB_to_output = NULL;
-	weston_color_transform_unref(output->from_sRGB_to_blend);
-	output->from_sRGB_to_blend = NULL;
-	weston_color_transform_unref(output->from_blend_to_output);
-	output->from_blend_to_output = NULL;
+	struct weston_output_color_outcome *co = *pco;
+
+	if (!co)
+		return;
+
+	weston_color_transform_unref(co->from_sRGB_to_output);
+	co->from_sRGB_to_output = NULL;
+	weston_color_transform_unref(co->from_sRGB_to_blend);
+	co->from_sRGB_to_blend = NULL;
+	weston_color_transform_unref(co->from_blend_to_output);
+	co->from_blend_to_output = NULL;
+
+	/* XXX: added in the next commit */
+	/* free(co); */
+	*pco = NULL;
 }
 
 static bool
@@ -6498,11 +6507,15 @@ weston_output_set_color_transforms(struct weston_output *output)
 		return false;
 	}
 
-	weston_output_reset_color_transforms(output);
-	output->from_blend_to_output = blend_to_output;
+	weston_output_color_outcome_destroy(&output->color_outcome);
+
+	/* XXX: temporary allocation to be removed in the next commit */
+	output->color_outcome = &output->colorout_;
+
+	output->color_outcome->from_blend_to_output = blend_to_output;
+	output->color_outcome->from_sRGB_to_output = sRGB_to_output;
+	output->color_outcome->from_sRGB_to_blend = sRGB_to_blend;
 	output->from_blend_to_output_by_backend = false;
-	output->from_sRGB_to_output = sRGB_to_output;
-	output->from_sRGB_to_blend = sRGB_to_blend;
 
 	weston_log("Output '%s' using color profile: %s\n", output->name,
 		   weston_color_profile_get_description(output->color_profile));
@@ -6567,7 +6580,7 @@ weston_compositor_remove_output(struct weston_output *output)
 			weston_view_assign_output(view);
 	}
 
-	weston_output_reset_color_transforms(output);
+	weston_output_color_outcome_destroy(&output->color_outcome);
 
 	weston_presentation_feedback_discard_list(&output->feedback_list);
 
@@ -6986,7 +6999,7 @@ weston_output_enable(struct weston_output *output)
 	 */
 	if (output->enable(output) < 0) {
 		weston_log("Enabling output \"%s\" failed.\n", output->name);
-		weston_output_reset_color_transforms(output);
+		weston_output_color_outcome_destroy(&output->color_outcome);
 		return -1;
 	}
 
@@ -7146,6 +7159,7 @@ weston_output_release(struct weston_output *output)
 		weston_compositor_remove_output(output);
 
 	weston_color_profile_unref(output->color_profile);
+	assert(output->color_outcome == NULL);
 
 	pixman_region32_fini(&output->region);
 	wl_list_remove(&output->link);

libweston/pixman-renderer.c

@@ -582,7 +582,7 @@ pixman_renderer_repaint_output(struct weston_output *output,
 	pixman_region32_t hw_damage;
 
 	assert(output->from_blend_to_output_by_backend ||
-	       output->from_blend_to_output == NULL);
+	       output->color_outcome->from_blend_to_output == NULL);
 
 	if (!po->hw_buffer) {
 		po->hw_extra_damage = NULL;

libweston/renderer-gl/gl-renderer.c

@@ -740,6 +740,7 @@ triangle_fan_debug(struct gl_renderer *gr,
 	static int color_idx = 0;
 	struct gl_shader_config alt;
 	const GLfloat *col;
+	struct weston_color_transform *ctransf;
 	static const GLfloat color[][4] = {
 			{ 1.0, 0.0, 0.0, 1.0 },
 			{ 0.0, 1.0, 0.0, 1.0 },
@@ -758,8 +759,8 @@ triangle_fan_debug(struct gl_renderer *gr,
 		.unicolor = { col[0], col[1], col[2], col[3] },
 	};
 
-	if (!gl_shader_config_set_color_transform(&alt,
-						  output->from_sRGB_to_blend)) {
+	ctransf = output->color_outcome->from_sRGB_to_blend;
+	if (!gl_shader_config_set_color_transform(&alt, ctransf)) {
 		weston_log("GL-renderer: %s failed to generate a color transformation.\n",
 			   __func__);
 		return;
@@ -932,6 +933,7 @@ static void
 censor_override(struct gl_shader_config *sconf,
 		struct weston_output *output)
 {
+	struct weston_color_transform *ctransf;
 	struct gl_shader_config alt = {
 		.req = {
 			.variant = SHADER_VARIANT_SOLID,
@@ -942,8 +944,8 @@ censor_override(struct gl_shader_config *sconf,
 		.unicolor = { 0.40, 0.0, 0.0, 1.0 },
 	};
 
-	if (!gl_shader_config_set_color_transform(&alt,
-						  output->from_sRGB_to_blend)) {
+	ctransf = output->color_outcome->from_sRGB_to_blend;
+	if (!gl_shader_config_set_color_transform(&alt, ctransf)) {
 		weston_log("GL-renderer: %s failed to generate a color transformation.\n",
 			   __func__);
 	}
@@ -1307,6 +1309,7 @@ draw_output_borders(struct weston_output *output,
 		},
 		.view_alpha = 1.0f,
 	};
+	struct weston_color_transform *ctransf;
 	struct gl_output_state *go = get_output_state(output);
 	struct gl_renderer *gr = get_renderer(output->compositor);
 	struct gl_border_image *top, *bottom, *left, *right;
@@ -1315,7 +1318,8 @@ draw_output_borders(struct weston_output *output,
 	if (border_status == BORDER_STATUS_CLEAN)
 		return; /* Clean. Nothing to do. */
 
-	if (!gl_shader_config_set_color_transform(&sconf, output->from_sRGB_to_output)) {
+	ctransf = output->color_outcome->from_sRGB_to_output;
+	if (!gl_shader_config_set_color_transform(&sconf, ctransf)) {
 		weston_log("GL-renderer: %s failed to generate a color transformation.\n", __func__);
 		return;
 	}
@@ -1550,13 +1554,15 @@ blit_shadow_to_output(struct weston_output *output,
 	struct gl_renderer *gr = get_renderer(output->compositor);
 	double width = output->current_mode->width;
 	double height = output->current_mode->height;
+	struct weston_color_transform *ctransf;
 	pixman_box32_t *rects;
 	int n_rects;
 	int i;
 	pixman_region32_t translated_damage;
 	GLfloat verts[4 * 2];
 
-	if (!gl_shader_config_set_color_transform(&sconf, output->from_blend_to_output)) {
+	ctransf = output->color_outcome->from_blend_to_output;
+	if (!gl_shader_config_set_color_transform(&sconf, ctransf)) {
 		weston_log("GL-renderer: %s failed to generate a color transformation.\n", __func__);
 		return;
 	}
@@ -1624,7 +1630,8 @@ gl_renderer_repaint_output(struct weston_output *output,
 	struct weston_paint_node *pnode;
 
 	assert(output->from_blend_to_output_by_backend ||
-	       output->from_blend_to_output == NULL || shadow_exists(go));
+	       output->color_outcome->from_blend_to_output == NULL ||
+	       shadow_exists(go));
 
 	if (use_output(output) < 0)
 		return;
@@ -3439,7 +3446,7 @@ gl_renderer_output_create(struct weston_output *output,
 	go->begin_render_sync = EGL_NO_SYNC_KHR;
 	go->end_render_sync = EGL_NO_SYNC_KHR;
 
-	if ((output->from_blend_to_output != NULL &&
+	if ((output->color_outcome->from_blend_to_output != NULL &&
 	     output->from_blend_to_output_by_backend == false) ||
 	    quirks->gl_force_full_redraw_of_shadow_fb) {
 		assert(gr->gl_supports_color_transforms);