mutter/cogl/cogl-bitmap.h
Robert Bragg df21e20f65 Adds CoglError api
Although we use GLib internally in Cogl we would rather not leak GLib
api through Cogl's own api, except through explicitly namespaced
cogl_glib_ / cogl_gtype_ feature apis.

One of the benefits we see to not leaking GLib through Cogl's public API
is that documentation for Cogl won't need to first introduce the Glib
API to newcomers, thus hopefully lowering the barrier to learning Cogl.

This patch provides a Cogl specific typedef for reporting runtime errors
which by no coincidence matches the typedef for GError exactly.  If Cogl
is built with --enable-glib (default) then developers can even safely
assume that a CoglError is a GError under the hood.

This patch also enforces a consistent policy for when NULL is passed as
an error argument and an error is thrown. In this case we log the error
and abort the application, instead of silently ignoring it. In common
cases where nothing has been implemented to handle a particular error
and/or where applications are just printing the error and aborting
themselves then this saves some typing. This also seems more consistent
with language based exceptions which usually cause a program to abort if
they are not explicitly caught (which passing a non-NULL error signifies
in this case)

Since this policy for NULL error pointers is stricter than the standard
GError convention, there is a clear note in the documentation to warn
developers that are used to using the GError api.

Reviewed-by: Neil Roberts <neil@linux.intel.com>

(cherry picked from commit b068d5ea09ab32c37e8c965fc8582c85d1b2db46)

Note: Since we can't change the Cogl 1.x api the patch was changed to
not rename _error_quark() functions to be _error_domain() functions and
although it's a bit ugly, instead of providing our own CoglError type
that's compatible with GError we simply #define CoglError to GError
unless Cogl is built with glib disabled.

Note: this patch does technically introduce an API break since it drops
the cogl_error_get_type() symbol generated by glib-mkenum (Since the
CoglError enum was replaced by a CoglSystemError enum) but for now we
are assuming that this will not affect anyone currently using the Cogl
API. If this does turn out to be a problem in practice then we would be
able to fix this my manually copying an implementation of
cogl_error_get_type() generated by glib-mkenum into a compatibility
source file and we could also define the original COGL_ERROR_ enums for
compatibility too.

Note: another minor concern with cherry-picking this patch to the 1.14
branch is that an api scanner would be lead to believe that some APIs
have changed, and for example the gobject-introspection parser which
understands the semantics of GError will not understand the semantics of
CoglError. We expect most people that have tried to use
gobject-introspection with Cogl already understand though that it is not
well suited to generating bindings of the Cogl api anyway and we aren't
aware or anyone depending on such bindings for apis involving GErrors.
(GnomeShell only makes very-very minimal use of Cogl via the gjs
bindings for the cogl_rectangle and cogl_color apis.)

The main reason we have cherry-picked this patch to the 1.14 branch
even given the above concerns is that without it it would become very
awkward for us to cherry-pick other beneficial patches from master.
2013-01-22 17:47:39 +00:00

315 lines
9.0 KiB
C

/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 2007,2008,2009 Intel Corporation.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*
*
*/
#if !defined(__COGL_H_INSIDE__) && !defined(COGL_COMPILATION)
#error "Only <cogl/cogl.h> can be included directly."
#endif
#ifndef __COGL_BITMAP_H__
#define __COGL_BITMAP_H__
#include <cogl/cogl-types.h>
#include <cogl/cogl-buffer.h>
#include <cogl/cogl-context.h>
#include <cogl/cogl-pixel-buffer.h>
#ifdef COGL_HAS_ANDROID_SUPPORT
#include <android/asset_manager.h>
#endif
G_BEGIN_DECLS
typedef struct _CoglBitmap CoglBitmap;
/**
* SECTION:cogl-bitmap
* @short_description: Fuctions for loading images
*
* Cogl allows loading image data into memory as CoglBitmaps without
* loading them immediately into GPU textures.
*
* #CoglBitmap is available since Cogl 1.0
*/
/**
* cogl_bitmap_new_from_file:
* @filename: the file to load.
* @error: a #CoglError or %NULL.
*
* Loads an image file from disk. This function can be safely called from
* within a thread.
*
* Return value: a #CoglBitmap to the new loaded image data, or
* %NULL if loading the image failed.
*
* Since: 1.0
*/
CoglBitmap *
cogl_bitmap_new_from_file (const char *filename,
CoglError **error);
#ifdef COGL_HAS_ANDROID_SUPPORT
/**
* cogl_android_bitmap_new_from_asset:
* @context: A #CoglContext
* @manager: An Android Asset Manager.
* @filename: The file name for the asset
* @error: A return location for a CoglError exception.
*
* Loads an Android asset into a newly allocated #CoglBitmap.
*
* Return value: A newly allocated #CoglBitmap holding the image data of the
* specified asset.
*
* Since: 2.0
*/
CoglBitmap *
cogl_android_bitmap_new_from_asset (CoglContext *context,
AAssetManager *manager,
const char *filename,
CoglError **error);
#endif
#if defined (COGL_ENABLE_EXPERIMENTAL_API)
/**
* cogl_bitmap_new_from_buffer:
* @buffer: A #CoglBuffer containing image data
* @format: The #CoglPixelFormat defining the format of the image data
* in the given @buffer.
* @width: The width of the image data in the given @buffer.
* @height: The height of the image data in the given @buffer.
* @rowstride: The rowstride in bytes of the image data in the given @buffer.
* @offset: The offset into the given @buffer to the first pixel that
* should be considered part of the #CoglBitmap.
*
* Wraps some image data that has been uploaded into a #CoglBuffer as
* a #CoglBitmap. The data is not copied in this process.
*
* Return value: a #CoglBitmap encapsulating the given @buffer.
*
* Since: 1.8
* Stability: unstable
*/
CoglBitmap *
cogl_bitmap_new_from_buffer (CoglBuffer *buffer,
CoglPixelFormat format,
int width,
int height,
int rowstride,
int offset);
/**
* cogl_bitmap_new_with_size:
* @context: A #CoglContext
* @width: width of the bitmap in pixels
* @height: height of the bitmap in pixels
* @format: the format of the pixels the array will store
*
* Creates a new #CoglBitmap with the given width, height and format.
* The initial contents of the bitmap are undefined.
*
* The data for the bitmap will be stored in a newly created
* #CoglPixelBuffer. You can get a pointer to the pixel buffer using
* cogl_bitmap_get_pixel_buffer(). The #CoglBuffer API can then be
* used to fill the bitmap with data.
*
* <note>Cogl will try its best to provide a hardware array you can
* map, write into and effectively do a zero copy upload when creating
* a texture from it with cogl_texture_new_from_bitmap(). For various
* reasons, such arrays are likely to have a stride larger than width
* * bytes_per_pixel. The user must take the stride into account when
* writing into it. The stride can be retrieved with
* cogl_bitmap_get_rowstride().</note>
*
* Return value: a #CoglPixelBuffer representing the newly created array or
* %NULL on failure
*
* Since: 1.10
* Stability: Unstable
*/
CoglBitmap *
cogl_bitmap_new_with_size (CoglContext *context,
unsigned int width,
unsigned int height,
CoglPixelFormat format);
/**
* cogl_bitmap_new_for_data:
* @context: A #CoglContext
* @width: The width of the bitmap.
* @height: The height of the bitmap.
* @format: The format of the pixel data.
* @rowstride: The rowstride of the bitmap (the number of bytes from
* the start of one row of the bitmap to the next).
* @data: A pointer to the data. The bitmap will take ownership of this data.
*
* Creates a bitmap using some existing data. The data is not copied
* so the application must keep the buffer alive for the lifetime of
* the #CoglBitmap. This can be used for example with
* cogl_framebuffer_read_pixels_into_bitmap() to read data directly
* into an application buffer with the specified rowstride.
*
* Return value: A new #CoglBitmap.
* Since: 1.10
* Stability: unstable
*/
CoglBitmap *
cogl_bitmap_new_for_data (CoglContext *context,
int width,
int height,
CoglPixelFormat format,
int rowstride,
uint8_t *data);
/**
* cogl_bitmap_get_format:
* @bitmap: A #CoglBitmap
*
* Return value: the #CoglPixelFormat that the data for the bitmap is in.
* Since: 1.10
* Stability: unstable
*/
CoglPixelFormat
cogl_bitmap_get_format (CoglBitmap *bitmap);
/**
* cogl_bitmap_get_width:
* @bitmap: A #CoglBitmap
*
* Return value: the width of the bitmap
* Since: 1.10
* Stability: unstable
*/
int
cogl_bitmap_get_width (CoglBitmap *bitmap);
/**
* cogl_bitmap_get_height:
* @bitmap: A #CoglBitmap
*
* Return value: the height of the bitmap
* Since: 1.10
* Stability: unstable
*/
int
cogl_bitmap_get_height (CoglBitmap *bitmap);
/**
* cogl_bitmap_get_rowstride:
* @bitmap: A #CoglBitmap
*
* Return value: the rowstride of the bitmap. This is the number of
* bytes between the address of start of one row to the address of the
* next row in the image.
* Since: 1.10
* Stability: unstable
*/
int
cogl_bitmap_get_rowstride (CoglBitmap *bitmap);
/**
* cogl_bitmap_get_buffer:
* @bitmap: A #CoglBitmap
*
* Return value: the #CoglPixelBuffer that this buffer uses for
* storage. Note that if the bitmap was created with
* cogl_bitmap_new_from_file() then it will not actually be using a
* pixel buffer and this function will return %NULL.
* Stability: unstable
* Since: 1.10
*/
CoglPixelBuffer *
cogl_bitmap_get_buffer (CoglBitmap *bitmap);
#endif /* COGL_ENABLE_EXPERIMENTAL_API */
/**
* cogl_bitmap_get_size_from_file:
* @filename: the file to check
* @width: (out): return location for the bitmap width, or %NULL
* @height: (out): return location for the bitmap height, or %NULL
*
* Parses an image file enough to extract the width and height
* of the bitmap.
*
* Return value: %TRUE if the image was successfully parsed
*
* Since: 1.0
*/
CoglBool
cogl_bitmap_get_size_from_file (const char *filename,
int *width,
int *height);
/**
* cogl_is_bitmap:
* @object: a #CoglObject pointer
*
* Checks whether @object is a #CoglBitmap
*
* Return value: %TRUE if the passed @object represents a bitmap,
* and %FALSE otherwise
*
* Since: 1.0
*/
CoglBool
cogl_is_bitmap (void *object);
/**
* COGL_BITMAP_ERROR:
*
* #CoglError domain for bitmap errors.
*
* Since: 1.4
*/
#define COGL_BITMAP_ERROR (cogl_bitmap_error_quark ())
/**
* CoglBitmapError:
* @COGL_BITMAP_ERROR_FAILED: Generic failure code, something went
* wrong.
* @COGL_BITMAP_ERROR_UNKNOWN_TYPE: Unknown image type.
* @COGL_BITMAP_ERROR_CORRUPT_IMAGE: An image file was broken somehow.
*
* Error codes that can be thrown when performing bitmap
* operations. Note that gdk_pixbuf_new_from_file() can also throw
* errors directly from the underlying image loading library. For
* example, if GdkPixbuf is used then errors #GdkPixbufError<!-- -->s
* will be used directly.
*
* Since: 1.4
*/
typedef enum {
COGL_BITMAP_ERROR_FAILED,
COGL_BITMAP_ERROR_UNKNOWN_TYPE,
COGL_BITMAP_ERROR_CORRUPT_IMAGE
} CoglBitmapError;
uint32_t cogl_bitmap_error_quark (void);
G_END_DECLS
#endif /* __COGL_BITMAP_H__ */