[gtk/wip/otte/memoryformat: 3/4] memoryformat: Add gdk_memory_format_prefers_high_depth()

[Benjamin Otte <otte src gnome org>]

commit 45274bf0cf3d357c627868f424dae96297ff51f8
Author: Benjamin Otte <otte redhat com>
Date:   Wed Oct 6 17:55:14 2021 +0200

    memoryformat: Add gdk_memory_format_prefers_high_depth()
    
    This is unused so far, but is part of preparations for high depth
    support in renderers.

 gdk/gdkmemoryformat.c        | 36 ++++++++++++++++++++++++++++++++++++
 gdk/gdkmemoryformatprivate.h |  1 +
 2 files changed, 37 insertions(+)
---
diff --git a/gdk/gdkmemoryformat.c b/gdk/gdkmemoryformat.c
index 887466da56..04986b45ee 100644
--- a/gdk/gdkmemoryformat.c
+++ b/gdk/gdkmemoryformat.c
@@ -177,6 +177,7 @@ struct _GdkMemoryFormatDescription
   GdkMemoryAlpha alpha;
   gsize bytes_per_pixel;
   gsize alignment;
+  gboolean prefers_high_depth;
   gboolean supports_gles;
   struct {
     guint internal_format;
@@ -202,6 +203,7 @@ static const GdkMemoryFormatDescription memory_formats[GDK_MEMORY_N_FORMATS] = {
     4,
     G_ALIGNOF (guchar),
     FALSE,
+    FALSE,
     { GL_RGBA8, GL_BGRA, GL_UNSIGNED_BYTE },
     b8g8r8a8_premultiplied_to_float,
     b8g8r8a8_premultiplied_from_float,
@@ -211,6 +213,7 @@ static const GdkMemoryFormatDescription memory_formats[GDK_MEMORY_N_FORMATS] = {
     4,
     G_ALIGNOF (guchar),
     FALSE,
+    FALSE,
     { GL_RGBA8, GL_BGRA, GDK_GL_UNSIGNED_BYTE_FLIPPED },
     a8r8g8b8_premultiplied_to_float,
     a8r8g8b8_premultiplied_from_float,
@@ -219,6 +222,7 @@ static const GdkMemoryFormatDescription memory_formats[GDK_MEMORY_N_FORMATS] = {
     GDK_MEMORY_ALPHA_PREMULTIPLIED,
     4,
     G_ALIGNOF (guchar),
+    FALSE,
     TRUE,
     { GL_RGBA8, GL_RGBA, GL_UNSIGNED_BYTE },
     r8g8b8a8_premultiplied_to_float,
@@ -229,6 +233,7 @@ static const GdkMemoryFormatDescription memory_formats[GDK_MEMORY_N_FORMATS] = {
     4,
     G_ALIGNOF (guchar),
     FALSE,
+    FALSE,
     { GL_RGBA8, GL_BGRA, GL_UNSIGNED_BYTE },
     b8g8r8a8_to_float,
     b8g8r8a8_from_float,
@@ -238,6 +243,7 @@ static const GdkMemoryFormatDescription memory_formats[GDK_MEMORY_N_FORMATS] = {
     4,
     G_ALIGNOF (guchar),
     FALSE,
+    FALSE,
     { GL_RGBA8, GL_RGBA, GDK_GL_UNSIGNED_BYTE_FLIPPED },
     a8r8g8b8_to_float,
     a8r8g8b8_from_float,
@@ -246,6 +252,7 @@ static const GdkMemoryFormatDescription memory_formats[GDK_MEMORY_N_FORMATS] = {
     GDK_MEMORY_ALPHA_STRAIGHT,
     4,
     G_ALIGNOF (guchar),
+    FALSE,
     TRUE,
     { GL_RGBA8, GL_RGBA, GL_UNSIGNED_BYTE },
     r8g8b8a8_to_float,
@@ -256,6 +263,7 @@ static const GdkMemoryFormatDescription memory_formats[GDK_MEMORY_N_FORMATS] = {
     4,
     G_ALIGNOF (guchar),
     FALSE,
+    FALSE,
     { GL_RGBA8, GL_BGRA, GDK_GL_UNSIGNED_BYTE_FLIPPED },
     a8b8g8r8_to_float,
     a8b8g8r8_from_float,
@@ -264,6 +272,7 @@ static const GdkMemoryFormatDescription memory_formats[GDK_MEMORY_N_FORMATS] = {
     GDK_MEMORY_ALPHA_OPAQUE,
     3,
     G_ALIGNOF (guchar),
+    FALSE,
     TRUE,
     { GL_RGBA8, GL_RGB, GL_UNSIGNED_BYTE },
     r8g8b8_to_float,
@@ -274,6 +283,7 @@ static const GdkMemoryFormatDescription memory_formats[GDK_MEMORY_N_FORMATS] = {
     3,
     G_ALIGNOF (guchar),
     FALSE,
+    FALSE,
     { GL_RGB8, GL_BGR, GL_UNSIGNED_BYTE },
     b8g8r8_to_float,
     b8g8r8_from_float,
@@ -283,6 +293,7 @@ static const GdkMemoryFormatDescription memory_formats[GDK_MEMORY_N_FORMATS] = {
     6,
     G_ALIGNOF (guint16),
     TRUE,
+    TRUE,
     { GL_RGB16, GL_RGB, GL_UNSIGNED_SHORT },
     r16g16b16_to_float,
     r16g16b16_from_float,
@@ -292,6 +303,7 @@ static const GdkMemoryFormatDescription memory_formats[GDK_MEMORY_N_FORMATS] = {
     8,
     G_ALIGNOF (guint16),
     TRUE,
+    TRUE,
     { GL_RGBA16, GL_RGBA, GL_UNSIGNED_SHORT },
     r16g16b16a16_to_float,
     r16g16b16a16_from_float,
@@ -301,6 +313,7 @@ static const GdkMemoryFormatDescription memory_formats[GDK_MEMORY_N_FORMATS] = {
     6,
     G_ALIGNOF (guint16),
     TRUE,
+    TRUE,
     { GL_RGB16F, GL_RGB, GL_HALF_FLOAT },
     r16g16b16_float_to_float,
     r16g16b16_float_from_float,
@@ -310,6 +323,7 @@ static const GdkMemoryFormatDescription memory_formats[GDK_MEMORY_N_FORMATS] = {
     8,
     G_ALIGNOF (guint16),
     TRUE,
+    TRUE,
     { GL_RGBA16F, GL_RGBA, GL_HALF_FLOAT },
     r16g16b16a16_float_to_float,
     r16g16b16a16_float_from_float,
@@ -319,6 +333,7 @@ static const GdkMemoryFormatDescription memory_formats[GDK_MEMORY_N_FORMATS] = {
     12,
     G_ALIGNOF (float),
     TRUE,
+    TRUE,
     { GL_RGB32F, GL_RGB, GL_FLOAT },
     r32g32b32_float_to_float,
     r32g32b32_float_from_float,
@@ -328,6 +343,7 @@ static const GdkMemoryFormatDescription memory_formats[GDK_MEMORY_N_FORMATS] = {
     16,
     G_ALIGNOF (float),
     TRUE,
+    TRUE,
     { GL_RGBA32F, GL_RGBA, GL_FLOAT },
     r32g32b32a32_float_to_float,
     r32g32b32a32_float_from_float,
@@ -346,6 +362,26 @@ gdk_memory_format_alignment (GdkMemoryFormat format)
   return memory_formats[format].alignment;
 }
 
+/*<private>
+ * gdk_memory_format_prefers_high_depth:
+ * @format: a memory format
+ *
+ * Checks if the given format benefits from being rendered
+ * in bit depths higher than 8bits per pixel. See
+ * gsk_render_node_prefers_high_depth() for more information
+ * on this.
+ * Usually this is the case when
+ * gdk_memory_format_bytes_per_pixel() is larger than 4.
+ *
+ * Returns: %TRUE if the format benefits from being
+ *     composited in hgiher bit depths.
+ **/
+gboolean
+gdk_memory_format_prefers_high_depth (GdkMemoryFormat format)
+{
+  return memory_formats[format].prefers_high_depth;
+}
+
 gboolean
 gdk_memory_format_gl_format (GdkMemoryFormat  format,
                              gboolean         gles,
diff --git a/gdk/gdkmemoryformatprivate.h b/gdk/gdkmemoryformatprivate.h
index 8c8e024b23..344e47fade 100644
--- a/gdk/gdkmemoryformatprivate.h
+++ b/gdk/gdkmemoryformatprivate.h
@@ -26,6 +26,7 @@ G_BEGIN_DECLS
 
 gsize                   gdk_memory_format_alignment         (GdkMemoryFormat             format) 
G_GNUC_CONST;
 gsize                   gdk_memory_format_bytes_per_pixel   (GdkMemoryFormat             format) 
G_GNUC_CONST;
+gboolean                gdk_memory_format_prefers_high_depth(GdkMemoryFormat             format) 
G_GNUC_CONST;
 gboolean                gdk_memory_format_gl_format         (GdkMemoryFormat             format,
                                                              gboolean                    gles,
                                                              guint                      *out_internal_format,