From 97f6946c8d1603dc6faa8689bd7e63aa2cea4a36 Mon Sep 17 00:00:00 2001
From: Simon Ser <contact@emersion.fr>
Date: Sat, 24 Aug 2024 11:14:54 +0200
Subject: [PATCH] output: add color transform to state

Color transforms are better suited than raw gamma tables, because:

- They don't need to get copied around: they are ref'counted.
- They can represent more color operations (will be useful for the
  upcoming KMS color pipeline API, and for the Wayland color
  management protocol).
---
 include/wlr/types/wlr_output.h | 10 ++++++++++
 types/output/output.c          |  4 ++++
 types/output/state.c           | 20 +++++++++++++++++++-
 3 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/include/wlr/types/wlr_output.h b/include/wlr/types/wlr_output.h
index 31b757062..6473ece4f 100644
--- a/include/wlr/types/wlr_output.h
+++ b/include/wlr/types/wlr_output.h
@@ -74,6 +74,7 @@ enum wlr_output_state_field {
 	WLR_OUTPUT_STATE_LAYERS = 1 << 10,
 	WLR_OUTPUT_STATE_WAIT_TIMELINE = 1 << 11,
 	WLR_OUTPUT_STATE_SIGNAL_TIMELINE = 1 << 12,
+	WLR_OUTPUT_STATE_COLOR_TRANSFORM = 1 << 13,
 };
 
 enum wlr_output_state_mode_type {
@@ -132,6 +133,8 @@ struct wlr_output_state {
 	uint64_t wait_point;
 	struct wlr_drm_syncobj_timeline *signal_timeline;
 	uint64_t signal_point;
+
+	struct wlr_color_transform *color_transform;
 };
 
 struct wlr_output_impl;
@@ -586,6 +589,13 @@ void wlr_output_state_set_wait_timeline(struct wlr_output_state *state,
  */
 void wlr_output_state_set_signal_timeline(struct wlr_output_state *state,
 	struct wlr_drm_syncobj_timeline *timeline, uint64_t dst_point);
+/**
+ * Set the color transform for an output.
+ *
+ * The color transform is applied after blending output layers.
+ */
+void wlr_output_state_set_color_transform(struct wlr_output_state *state,
+	struct wlr_color_transform *tr);
 
 /**
  * Copies the output state from src to dst. It is safe to then
diff --git a/types/output/output.c b/types/output/output.c
index 55f8a7645..9e63ec76e 100644
--- a/types/output/output.c
+++ b/types/output/output.c
@@ -651,6 +651,10 @@ static bool output_basic_test(struct wlr_output *output,
 		wlr_log(WLR_DEBUG, "Tried to set the subpixel layout on a disabled output");
 		return false;
 	}
+	if (!enabled && state->committed & WLR_OUTPUT_STATE_COLOR_TRANSFORM) {
+		wlr_log(WLR_DEBUG, "Tried to set a color transform on a disabled output");
+		return false;
+	}
 
 	if (state->committed & WLR_OUTPUT_STATE_LAYERS) {
 		if (state->layers_len != (size_t)wl_list_length(&output->layers)) {
diff --git a/types/output/state.c b/types/output/state.c
index 72849c027..1a7b00508 100644
--- a/types/output/state.c
+++ b/types/output/state.c
@@ -1,6 +1,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <wlr/render/drm_syncobj.h>
+#include <wlr/render/color.h>
 #include <wlr/util/log.h>
 #include "types/wlr_output.h"
 
@@ -133,6 +134,17 @@ void wlr_output_state_set_signal_timeline(struct wlr_output_state *state,
 	state->signal_point = dst_point;
 }
 
+void wlr_output_state_set_color_transform(struct wlr_output_state *state,
+		struct wlr_color_transform *tr) {
+	state->committed |= WLR_OUTPUT_STATE_COLOR_TRANSFORM;
+	wlr_color_transform_unref(state->color_transform);
+	if (tr) {
+		state->color_transform = wlr_color_transform_ref(tr);
+	} else {
+		state->color_transform = NULL;
+	}
+}
+
 bool wlr_output_state_copy(struct wlr_output_state *dst,
 		const struct wlr_output_state *src) {
 	struct wlr_output_state copy = *src;
@@ -140,7 +152,8 @@ bool wlr_output_state_copy(struct wlr_output_state *dst,
 		WLR_OUTPUT_STATE_DAMAGE |
 		WLR_OUTPUT_STATE_GAMMA_LUT |
 		WLR_OUTPUT_STATE_WAIT_TIMELINE |
-		WLR_OUTPUT_STATE_SIGNAL_TIMELINE);
+		WLR_OUTPUT_STATE_SIGNAL_TIMELINE |
+		WLR_OUTPUT_STATE_COLOR_TRANSFORM);
 	copy.buffer = NULL;
 	copy.buffer_src_box = (struct wlr_fbox){0};
 	copy.buffer_dst_box = (struct wlr_box){0};
@@ -149,6 +162,7 @@ bool wlr_output_state_copy(struct wlr_output_state *dst,
 	copy.gamma_lut_size = 0;
 	copy.wait_timeline = NULL;
 	copy.signal_timeline = NULL;
+	copy.color_transform = NULL;
 
 	if (src->committed & WLR_OUTPUT_STATE_BUFFER) {
 		wlr_output_state_set_buffer(&copy, src->buffer);
@@ -178,6 +192,10 @@ bool wlr_output_state_copy(struct wlr_output_state *dst,
 			src->signal_point);
 	}
 
+	if (src->committed & WLR_OUTPUT_STATE_COLOR_TRANSFORM) {
+		wlr_output_state_set_color_transform(&copy, src->color_transform);
+	}
+
 	wlr_output_state_finish(dst);
 	*dst = copy;
 	return true;