From 16898ba11b4d6e9e2e64bb2d02d0fb5adbe266e2 Mon Sep 17 00:00:00 2001

From: =?UTF-8?q?=D0=A0=D1=83=D1=81=D0=BB=D0=B0=D0=BD=20=D0=98=D0=B6=D0=B1?=

 =?UTF-8?q?=D1=83=D0=BB=D0=B0=D1=82=D0=BE=D0=B2?= <lrn1986@gmail.com>

Date: Thu, 26 Mar 2015 19:33:43 +0000

Subject: [PATCH 1/2] win32: Add cairo API to set up a Win32 surface for an HDC

 with an alpha channel.

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Signed-off-by: Руслан Ижбулатов <lrn1986@gmail.com>

Reviewed-by: Bryce Harrington <bryce@osg.samsung.com>

---

 src/cairo-win32.h                       |  4 ++

 src/win32/cairo-win32-display-surface.c | 68 +++++++++++++++++++++++++--------

 2 files changed, 56 insertions(+), 16 deletions(-)

diff --git a/src/cairo-win32.h b/src/cairo-win32.h

index 3d2e1c6..db4cac6 100644

--- a/src/cairo-win32.h

+++ b/src/cairo-win32.h

@@ -49,6 +49,10 @@ cairo_public cairo_surface_t *

 cairo_win32_surface_create (HDC hdc);

 cairo_public cairo_surface_t *

+cairo_win32_surface_create_with_format (HDC hdc,

+                                        cairo_format_t format);

+

+cairo_public cairo_surface_t *

 cairo_win32_printing_surface_create (HDC hdc);

 cairo_public cairo_surface_t *

diff --git a/src/win32/cairo-win32-display-surface.c b/src/win32/cairo-win32-display-surface.c

index 965f2c4..1571480 100644

--- a/src/win32/cairo-win32-display-surface.c

+++ b/src/win32/cairo-win32-display-surface.c

@@ -917,31 +917,41 @@ static const cairo_surface_backend_t cairo_win32_display_surface_backend = {

  */

 /**

- * cairo_win32_surface_create:

+ * cairo_win32_surface_create_with_format:

  * @hdc: the DC to create a surface for

+ * @format: format of pixels in the surface to create

  *

  * Creates a cairo surface that targets the given DC.  The DC will be

  * queried for its initial clip extents, and this will be used as the

- * size of the cairo surface.  The resulting surface will always be of

- * format %CAIRO_FORMAT_RGB24; should you need another surface format,

- * you will need to create one through

- * cairo_win32_surface_create_with_dib().

+ * size of the cairo surface.

  *

- * Return value: the newly created surface

+ * Supported formats are:

+ * %CAIRO_FORMAT_ARGB32

+ * %CAIRO_FORMAT_RGB24

  *

- * Since: 1.0

+ * Note: @format only tells cairo how to draw on the surface, not what

+ * the format of the surface is. Namely, cairo does not (and cannot)

+ * check that @hdc actually supports alpha-transparency.

+ *

+ * Return value: the newly created surface, NULL on failure

+ *

+ * Since: 1.14.3

  **/

 cairo_surface_t *

-cairo_win32_surface_create (HDC hdc)

+cairo_win32_surface_create_with_format (HDC hdc, cairo_format_t format)

 {

     cairo_win32_display_surface_t *surface;

-    cairo_format_t format;

     cairo_status_t status;

     cairo_device_t *device;

-    /* Assume that everything coming in as a HDC is RGB24 */

-    format = CAIRO_FORMAT_RGB24;

+    switch (format) {

+    default:

+	return _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_INVALID_FORMAT));

+    case CAIRO_FORMAT_ARGB32:

+    case CAIRO_FORMAT_RGB24:

+	break;

+    }

     surface = malloc (sizeof (*surface));

     if (surface == NULL)

@@ -977,6 +987,28 @@ cairo_win32_surface_create (HDC hdc)

 }

 /**

+ * cairo_win32_surface_create:

+ * @hdc: the DC to create a surface for

+ *

+ * Creates a cairo surface that targets the given DC.  The DC will be

+ * queried for its initial clip extents, and this will be used as the

+ * size of the cairo surface.  The resulting surface will always be of

+ * format %CAIRO_FORMAT_RGB24; should you need another surface format,

+ * you will need to create one through

+ * cairo_win32_surface_create_with_format() or

+ * cairo_win32_surface_create_with_dib().

+ *

+ * Return value: the newly created surface, NULL on failure

+ *

+ * Since: 1.0

+ **/

+cairo_surface_t *

+cairo_win32_surface_create (HDC hdc)

+{

+    return cairo_win32_surface_create_with_format (hdc, CAIRO_FORMAT_RGB24);

+}

+

+/**

  * cairo_win32_surface_create_with_dib:

  * @format: format of pixels in the surface to create

  * @width: width of the surface, in pixels

@@ -1027,12 +1059,16 @@ cairo_win32_surface_create_with_ddb (HDC hdc,

     HDC screen_dc, ddb_dc;

     HBITMAP saved_dc_bitmap;

-    if (format != CAIRO_FORMAT_RGB24)

+    switch (format) {

+    default:

+/* XXX handle these eventually */

+    case CAIRO_FORMAT_A8:

+    case CAIRO_FORMAT_A1:

 	return _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_INVALID_FORMAT));

-/* XXX handle these eventually

-	format != CAIRO_FORMAT_A8 ||

-	format != CAIRO_FORMAT_A1)

-*/

+    case CAIRO_FORMAT_ARGB32:

+    case CAIRO_FORMAT_RGB24:

+	break;

+    }

     if (!hdc) {

 	screen_dc = GetDC (NULL);

-- 

2.4.3