colorstate: Change the rendering color state api

Pass an extra boolean that tells whether the target image is GL_SRGB,
in which case, the rendering color state must be srgb-linear.

Update all callers to pass FALSE, except for the one call in
the node processor, where we want to take GL_LINEAR into account.

Also update the draw context begin_frame implementations to just
return GDK_COLOR_STATE_SRGB now.

gdk/gdkcolorstateprivate.h

@@ -78,8 +78,15 @@ GdkColorState * gdk_color_state_new_for_cicp            (const GdkCicp
                                                          GError                **error);
 
 static inline GdkColorState *
-gdk_color_state_get_rendering_color_state (GdkColorState *self)
+gdk_color_state_get_rendering_color_state (GdkColorState *self,
+                                           gboolean       srgb)
 {
+  if (srgb)
+    {
+      self = gdk_color_state_get_no_srgb_tf (self);
+      g_assert (self);
+    }
+
   if (GDK_DEBUG_CHECK (HDR))
     self = GDK_COLOR_STATE_REC2100_PQ;
 

gdk/gdkglcontext.c

@@ -637,10 +637,7 @@ gdk_gl_context_real_begin_frame (GdkDrawContext  *draw_context,
   else
     *out_depth = GDK_MEMORY_U8;
 
-  if (*out_depth == GDK_MEMORY_U8_SRGB)
-    *out_color_state = gdk_color_state_get_no_srgb_tf (color_state);
-  else
-    *out_color_state = color_state;
+  *out_color_state = color_state;
 #else
   *out_color_state = gdk_color_state_get_srgb ();
   *out_depth = GDK_MEMORY_U8;

gdk/gdkvulkancontext.c

@@ -678,10 +678,7 @@ gdk_vulkan_context_begin_frame (GdkDrawContext  *draw_context,
 
   cairo_region_union (region, priv->regions[priv->draw_index]);
 
-  if (priv->current_depth == GDK_MEMORY_U8_SRGB)
-    *out_color_state = gdk_color_state_get_no_srgb_tf (color_state);
-  else
-    *out_color_state = color_state;
+  *out_color_state = color_state;
   *out_depth = priv->current_depth;
 }
 

gsk/gpu/gskgpunodeprocessor.c

@@ -3905,7 +3905,7 @@ gsk_gpu_node_processor_process (GskGpuFrame                 *frame,
                                clip,
                                viewport);
 
-  ccs = gdk_color_state_get_rendering_color_state (target_color_state);
+  ccs = gdk_color_state_get_rendering_color_state (target_color_state, gsk_gpu_image_get_flags (target) & GSK_GPU_IMAGE_SRGB);
 
   if (gdk_color_state_equal (ccs, target_color_state))
     {

gsk/gskrendernode.c

@@ -380,7 +380,7 @@ gsk_render_node_draw_ccs (GskRenderNode *node,
                           GdkColorState *ccs)
 {
   /* Check that the calling function did pass a correct color state */
-  g_assert (ccs == gdk_color_state_get_rendering_color_state (ccs));
+  g_assert (ccs == gdk_color_state_get_rendering_color_state (ccs, FALSE));
 
   cairo_save (cr);
 
@@ -413,7 +413,7 @@ gsk_render_node_draw_with_color_state (GskRenderNode *node,
 {
   GdkColorState *ccs;
 
-  ccs = gdk_color_state_get_rendering_color_state (color_state);
+  ccs = gdk_color_state_get_rendering_color_state (color_state, FALSE);
 
   if (gdk_color_state_equal (color_state, ccs))
     {

testsuite/gdk/colorstate-internal.c

@@ -1,6 +1,7 @@
-#include <gdk/gdk.h>
+#include <gtk.h>
 #include "gdkcolorstateprivate.h"
 #include "gdkcolorprivate.h"
+#include "gdkdebugprivate.h"
 #include <math.h>
 
 #include "gdkcolordefs.h"
@@ -158,9 +159,42 @@ test_color_mislabel (void)
   g_assert_true (red1 != red2);
 }
 
+static void
+test_rendering_colorstate (void)
+{
+  struct {
+    GdkColorState *surface;
+    gboolean srgb;
+    GdkColorState *rendering;
+  } tests[] = {
+    { GDK_COLOR_STATE_SRGB,           0, GDK_COLOR_STATE_SRGB           },
+    { GDK_COLOR_STATE_SRGB,           1, GDK_COLOR_STATE_SRGB_LINEAR    },
+    { GDK_COLOR_STATE_SRGB_LINEAR,    0, GDK_COLOR_STATE_SRGB_LINEAR    },
+    { GDK_COLOR_STATE_SRGB_LINEAR,    1, GDK_COLOR_STATE_SRGB_LINEAR    },
+    { GDK_COLOR_STATE_REC2100_PQ,     0, GDK_COLOR_STATE_REC2100_PQ     },
+    { GDK_COLOR_STATE_REC2100_PQ,     1, GDK_COLOR_STATE_SRGB_LINEAR    },
+    { GDK_COLOR_STATE_REC2100_LINEAR, 0, GDK_COLOR_STATE_REC2100_LINEAR },
+    { GDK_COLOR_STATE_REC2100_LINEAR, 1, GDK_COLOR_STATE_SRGB_LINEAR    },
+  };
+
+  if (GDK_DEBUG_CHECK (HDR) || GDK_DEBUG_CHECK (LINEAR))
+    {
+      g_test_skip ("Skip because GDK_DEBUG flags hdr or linear are set");
+      return;
+    }
+
+  for (int i = 0; i < G_N_ELEMENTS (tests); i++)
+    {
+      GdkColorState *res = gdk_color_state_get_rendering_color_state (tests[i].surface, tests[i].srgb);
+
+      g_assert_true (gdk_color_state_equal (res, tests[i].rendering));
+    }
+}
+
 int
 main (int argc, char *argv[])
 {
+  gtk_init ();
   (g_test_init) (&argc, &argv, NULL);
 
   for (guint i = 0; i < G_N_ELEMENTS (transfers); i++)
@@ -182,6 +216,7 @@ main (int argc, char *argv[])
   g_test_add_func ("/colorstate/matrix/srgb_to_rec2020", test_srgb_to_rec2020);
   g_test_add_func ("/colorstate/matrix/rec2020_to_srgb", test_rec2020_to_srgb);
   g_test_add_func ("/color/mislabel", test_color_mislabel);
+  g_test_add_func ("/colorstate/rendering", test_rendering_colorstate);
 
   return g_test_run ();
 }