cogl-bitmap: Encapsulate the CoglBitmap even internally

The CoglBitmap struct is now only defined within cogl-bitmap.c so that
all of its members can now only be accessed with accessor
functions. To get to the data pointer for the bitmap image you must
first call _cogl_bitmap_map and later call _cogl_bitmap_unmap. The map
function takes the same arguments as cogl_pixel_array_map so that
eventually we can make a bitmap optionally internally divert to a
pixel array.

There is a _cogl_bitmap_new_from_data function which constructs a new
bitmap object and takes ownership of the data pointer. The function
gets passed a destroy callback which gets called when the bitmap is
freed. This is similar to how gdk_pixbuf_new_from_data
works. Alternatively NULL can be passed for the destroy function which
means that the caller will manage the life of the pointer (but must
guarantee that it stays alive at least until the bitmap is
freed). This mechanism is used instead of the old approach of creating
a CoglBitmap struct on the stack and manually filling in the
members. It could also later be used to create a CoglBitmap that owns
a GdkPixbuf ref so that we don't necessarily have to copy the
GdkPixbuf data when converting to a bitmap.

There is also _cogl_bitmap_new_shared. This creates a bitmap using a
reference to another CoglBitmap for the data. This is a bit of a hack
but it is needed by the atlas texture backend which wants to divert
the set_region virtual to another texture but it needs to override the
format of the bitmap to ignore the premult flag.

1 files changed, 85 insertions, 24 deletions

diff --git a/cogl/cogl-bitmap-private.h b/cogl/cogl-bitmap-private.h
index cc7cc83d..7aefee63 100644
--- a/cogl/cogl-bitmap-private.h
+++ b/cogl/cogl-bitmap-private.h
@@ -29,16 +29,58 @@
 #include <glib.h>
 
 #include "cogl-handle.h"
+#include "cogl-buffer.h"
 
-struct _CoglBitmap
-{
-  CoglHandleObject _parent;
-  guint8          *data;
-  CoglPixelFormat  format;
-  int              width;
-  int              height;
-  int              rowstride;
-};
+/*
+ * CoglBitmapDestroyNotify:
+ * @data: The image data
+ * @destroy_data: The callback closure data that was given to
+ *   _cogl_bitmap_new_from_data().
+ *
+ * Function prototype that is used to destroy the bitmap data when
+ * _cogl_bitmap_new_from_data() is called.
+ */
+typedef void (* CoglBitmapDestroyNotify) (guint8 *data, void *destroy_data);
+
+/*
+ * _cogl_bitmap_new_from_data:
+ * @data: A pointer to the data. The bitmap will take ownership of this data.
+ * @format: The format of the pixel data.
+ * @width: The width of the bitmap.
+ * @height: The height of the bitmap.
+ * @rowstride: The rowstride of the bitmap (the number of bytes from
+ *   the start of one row of the bitmap to the next).
+ * @destroy_fn: A function to be called when the bitmap is
+ *   destroyed. This should free @data. %NULL can be used instead if
+ *   no free is needed.
+ * @destroy_fn_data: This pointer will get passed to @destroy_fn.
+ *
+ * Creates a bitmap using some existing data. The data is not copied
+ * so the bitmap will take ownership of the data pointer. When the
+ * bitmap is freed @destroy_fn will be called to free the data.
+ *
+ * Return value: A new %CoglBitmap.
+ */
+CoglBitmap *
+_cogl_bitmap_new_from_data (guint8                  *data,
+                            CoglPixelFormat          format,
+                            int                      width,
+                            int                      height,
+                            int                      rowstride,
+                            CoglBitmapDestroyNotify  destroy_fn,
+                            gpointer                 destroy_fn_data);
+
+/* The idea of this function is that it will create a bitmap that
+   shares the actual data with another bitmap. This is needed for the
+   atlas texture backend because it needs upload a bitmap to a sub
+   texture but override the format so that it ignores the premult
+   flag. */
+CoglBitmap *
+_cogl_bitmap_new_shared (CoglBitmap      *shared_bmp,
+                         CoglPixelFormat  format,
+                         int              width,
+                         int              height,
+                         int              rowstride);
 
 gboolean
 _cogl_bitmap_can_convert (CoglPixelFormat src, CoglPixelFormat dst);
@@ -58,13 +100,11 @@ _cogl_bitmap_can_premult (CoglPixelFormat format);
 gboolean
 _cogl_bitmap_fallback_can_premult (CoglPixelFormat format);
 
-gboolean
-_cogl_bitmap_convert (const CoglBitmap *bmp,
-		      CoglBitmap       *dst_bmp,
+CoglBitmap *
+_cogl_bitmap_convert (CoglBitmap *bmp,
 		      CoglPixelFormat   dst_format);
-gboolean
-_cogl_bitmap_fallback_convert (const CoglBitmap *bmp,
-			       CoglBitmap       *dst_bmp,
+CoglBitmap *
+_cogl_bitmap_fallback_convert (CoglBitmap *bmp,
 			       CoglPixelFormat   dst_format);
 
 gboolean
@@ -79,22 +119,19 @@ _cogl_bitmap_premult (CoglBitmap *dst_bmp);
 gboolean
 _cogl_bitmap_fallback_premult (CoglBitmap *dst_bmp);
 
-gboolean
-_cogl_bitmap_from_file (CoglBitmap  *bmp,
-			const char *filename,
+CoglBitmap *
+_cogl_bitmap_from_file (const char *filename,
 			GError     **error);
 
-gboolean
-_cogl_bitmap_fallback_from_file (CoglBitmap  *bmp,
-				 const char *filename);
+CoglBitmap *
+_cogl_bitmap_fallback_from_file (const char *filename);
 
 gboolean
 _cogl_bitmap_convert_premult_status (CoglBitmap      *bmp,
                                      CoglPixelFormat  dst_format);
 
-gboolean
-_cogl_bitmap_convert_format_and_premult (const CoglBitmap *bmp,
-                                         CoglBitmap       *dst_bmp,
+CoglBitmap *
+_cogl_bitmap_convert_format_and_premult (CoglBitmap *bmp,
                                          CoglPixelFormat   dst_format);
 
 void
@@ -112,4 +149,28 @@ _cogl_bitmap_get_size_from_file (const char *filename,
                                  int        *width,
                                  int        *height);
 
+CoglPixelFormat
+_cogl_bitmap_get_format (CoglBitmap *bitmap);
+
+void
+_cogl_bitmap_set_format (CoglBitmap *bitmap,
+                         CoglPixelFormat format);
+
+int
+_cogl_bitmap_get_width (CoglBitmap *bitmap);
+
+int
+_cogl_bitmap_get_height (CoglBitmap *bitmap);
+
+int
+_cogl_bitmap_get_rowstride (CoglBitmap *bitmap);
+
+guint8 *
+_cogl_bitmap_map (CoglBitmap *bitmap,
+                  CoglBufferAccess access,
+                  CoglBufferMapHint hints);
+
+void
+_cogl_bitmap_unmap (CoglBitmap *bitmap);
+
 #endif /* __COGL_BITMAP_H */