[cairo] [PATCH 1/3] win32: introduce new flag to mark surfaces supporting solid brush drawing

[Vasily Galkin]

This is beginning of a patch series that speedups the CAIRO_OPERATOR_SOURCE
when used to copy data
to a argb32 cairo	surface corresponding to a win32 dc
from a "backbuffer" - DibSection-based cairo surface
created with cairo_surface_create_similar().

This initial patch presents only private header changes
without changing any implementation logic.

The big problem with argb32 surfaces and gdi is the gdi's inability to
correctly set alpha channel on all operations except BitBlt and AlphaBlend

So CAIRO_WIN32_SURFACE_CAN_RGB_BRUSH flag introduced in this commit
will be used as a mark that surfaces that correctly such handle brushes -
essentially all surface types except argb32.
_cairo_win32_flags_for_dc receives new argument
that would be used in flag calculation.
---
 src/win32/cairo-win32-device.c           | 2 +-
 src/win32/cairo-win32-display-surface.c  | 4 ++--
 src/win32/cairo-win32-printing-surface.c | 2 +-
 src/win32/cairo-win32-private.h          | 5 ++++-
 4 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/src/win32/cairo-win32-device.c b/src/win32/cairo-win32-device.c
index c60c494..309f16c 100644
--- a/src/win32/cairo-win32-device.c
+++ b/src/win32/cairo-win32-device.c
@@ -153,7 +153,7 @@ _cairo_win32_device_get (void)
 }
 
 unsigned
-_cairo_win32_flags_for_dc (HDC dc)
+_cairo_win32_flags_for_dc (HDC dc, cairo_format_t format)
 {
     uint32_t flags = 0;
     int cap;
diff --git a/src/win32/cairo-win32-display-surface.c b/src/win32/cairo-win32-display-surface.c
index 92d1f6c..0d737f5 100644
--- a/src/win32/cairo-win32-display-surface.c
+++ b/src/win32/cairo-win32-display-surface.c
@@ -258,7 +258,7 @@ _create_dc_and_bitmap (cairo_win32_display_surface_t *surface,
 	}
     }
 
-    surface->win32.flags = _cairo_win32_flags_for_dc (surface->win32.dc);
+    surface->win32.flags = _cairo_win32_flags_for_dc (surface->win32.dc, format);
 
     return CAIRO_STATUS_SUCCESS;
 
@@ -973,7 +973,7 @@ cairo_win32_surface_create_with_format (HDC hdc, cairo_format_t format)
     surface->is_dib = FALSE;
     surface->saved_dc_bitmap = NULL;
 
-    surface->win32.flags = _cairo_win32_flags_for_dc (surface->win32.dc);
+    surface->win32.flags = _cairo_win32_flags_for_dc (surface->win32.dc, format);
 
     device = _cairo_win32_device_get ();
 
diff --git a/src/win32/cairo-win32-printing-surface.c b/src/win32/cairo-win32-printing-surface.c
index 7f374a0..8496077 100644
--- a/src/win32/cairo-win32-printing-surface.c
+++ b/src/win32/cairo-win32-printing-surface.c
@@ -2159,7 +2159,7 @@ cairo_win32_printing_surface_create (HDC hdc)
 	return _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_NO_MEMORY));
     }
 
-    surface->win32.flags = _cairo_win32_flags_for_dc (surface->win32.dc);
+    surface->win32.flags = _cairo_win32_flags_for_dc (surface->win32.dc, CAIRO_FORMAT_RGB24);
     surface->win32.flags |= CAIRO_WIN32_SURFACE_FOR_PRINTING;
 
     _cairo_win32_printing_surface_init_ps_mode (surface);
diff --git a/src/win32/cairo-win32-private.h b/src/win32/cairo-win32-private.h
index 6fdf96f..79e1e0f 100644
--- a/src/win32/cairo-win32-private.h
+++ b/src/win32/cairo-win32-private.h
@@ -81,6 +81,9 @@ enum {
 
     /* Whether we can use the CHECKJPEGFORMAT escape function */
     CAIRO_WIN32_SURFACE_CAN_CHECK_PNG = (1<<8),
+
+    /* Whether we can use gdi drawing with solid rgb brush with this surface */
+    CAIRO_WIN32_SURFACE_CAN_RGB_BRUSH = (1<<9),
 };
 
 typedef struct _cairo_win32_surface {
@@ -186,7 +189,7 @@ _cairo_win32_surface_get_extents (void		          *abstract_surface,
 				  cairo_rectangle_int_t   *rectangle);
 
 uint32_t
-_cairo_win32_flags_for_dc (HDC dc);
+_cairo_win32_flags_for_dc (HDC dc, cairo_format_t format);
 
 cairo_int_status_t
 _cairo_win32_surface_emit_glyphs (cairo_win32_surface_t *dst,
-- 
2.9.3