Bitmap

## Bitmap Bitmap — Functions for loading images |

## Functions

CoglBool | cogl_is_bitmap ()
CoglBitmap * | cogl_bitmap_new_from_file ()
CoglBitmap * | cogl_bitmap_new_from_buffer ()
CoglBitmap * | cogl_bitmap_new_with_size ()
CoglBitmap * | cogl_bitmap_new_for_data ()
CoglPixelFormat | cogl_bitmap_get_format ()
int | cogl_bitmap_get_width ()
int | cogl_bitmap_get_height ()
int | cogl_bitmap_get_rowstride ()
CoglPixelBuffer * | cogl_bitmap_get_buffer ()
CoglBool | cogl_bitmap_get_size_from_file ()
CoglTexture * | cogl_texture_new_from_bitmap ()
#define | COGL_BITMAP_ERROR

## Types and Values

| CoglBitmap
enum | CoglBitmapError

## Description

Cogl allows loading image data into memory as CoglBitmaps without loading them immediately into GPU textures.

CoglBitmap is available since Cogl 1.0

## Functions

### cogl_is_bitmap ()

    CoglBool
    cogl_is_bitmap (void *object);

Checks whether `object` is a CoglBitmap

#### Parameters

object | a CoglObject pointer |

#### Returns

`TRUE` if the passed `object` represents a bitmap, and `FALSE` otherwise

Since 1.0

### cogl_bitmap_new_from_file ()

    CoglBitmap *
    cogl_bitmap_new_from_file (const char *filename,
                               CoglError **error);

Loads an image file from disk. This function can be safely called from within a thread.

#### Parameters

filename | the file to load. |
error | a CoglError or `NULL`. |

#### Returns

a CoglBitmap to the new loaded image data, or `NULL` if loading the image failed.

[transfer full]

Since 1.0

### cogl_bitmap_new_from_buffer ()

    CoglBitmap *
    cogl_bitmap_new_from_buffer (CoglBuffer *buffer,
                                 CoglPixelFormat format,
                                 int width,
                                 int height,
                                 int rowstride,
                                 int offset);

Wraps some image data that has been uploaded into a CoglBuffer as a CoglBitmap. The data is not copied in this process.

#### Parameters

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. |

#### Returns

a CoglBitmap encapsulating the given `buffer` .

[transfer full]

Since 1.8

Stability Level: Unstable

### cogl_bitmap_new_with_size ()

    CoglBitmap *
    cogl_bitmap_new_with_size (CoglContext *context,
                               unsigned int width,
                               unsigned int height,
                               CoglPixelFormat format);

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_buffer()`. The CoglBuffer API can then be used to fill the bitmap with data.

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()`.

#### Parameters

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 |

#### Returns

a CoglPixelBuffer representing the newly created array or `NULL` on failure.

[transfer full]

Since 1.10

Stability Level: Unstable

### cogl_bitmap_new_for_data ()

    CoglBitmap *
    cogl_bitmap_new_for_data (CoglContext *context,
                              int width,
                              int height,
                              CoglPixelFormat format,
                              int rowstride,
                              uint8_t *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.

#### Parameters

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. |

#### Returns

A new CoglBitmap.

[transfer full]

Since 1.10

Stability Level: Unstable

### cogl_bitmap_get_format ()

    CoglPixelFormat
    cogl_bitmap_get_format (CoglBitmap *bitmap);

#### Parameters

bitmap | A CoglBitmap |

#### Returns

the CoglPixelFormat that the data for the bitmap is in.

Since 1.10

Stability Level: Unstable

### cogl_bitmap_get_width ()

    int
    cogl_bitmap_get_width (CoglBitmap *bitmap);

#### Parameters

bitmap | A CoglBitmap |

#### Returns

the width of the bitmap

Since 1.10

Stability Level: Unstable

### cogl_bitmap_get_height ()

    int
    cogl_bitmap_get_height (CoglBitmap *bitmap);

#### Parameters

bitmap | A CoglBitmap |

#### Returns

the height of the bitmap

Since 1.10

Stability Level: Unstable

### cogl_bitmap_get_rowstride ()

    int
    cogl_bitmap_get_rowstride (CoglBitmap *bitmap);

#### Parameters

bitmap | A CoglBitmap |

#### Returns

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 Level: Unstable

### cogl_bitmap_get_buffer ()

    CoglPixelBuffer *
    cogl_bitmap_get_buffer (CoglBitmap *bitmap);

#### Parameters

bitmap | A CoglBitmap |

#### Returns

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`.

[transfer none]

Since 1.10

Stability Level: Unstable

### cogl_bitmap_get_size_from_file ()

    CoglBool
    cogl_bitmap_get_size_from_file (const char *filename,
                                    int *width,
                                    int *height);

Parses an image file enough to extract the width and height of the bitmap.

#### Parameters

filename | the file to check |
width | return location for the bitmap width, or `NULL`. | [out]
height | return location for the bitmap height, or `NULL`. | [out]

#### Returns

`TRUE` if the image was successfully parsed

Since 1.0

### cogl_texture_new_from_bitmap ()

    CoglTexture *
    cogl_texture_new_from_bitmap (CoglBitmap *bitmap,
                                  CoglTextureFlags flags,
                                  CoglPixelFormat internal_format);

`cogl_texture_new_from_bitmap` has been deprecated since version 1.18 and should not be used in newly-written code.

Use specific constructors such as `cogl_texture_2d_new_from_bitmap()`

Creates a CoglTexture from a CoglBitmap.

#### Parameters

bitmap | A CoglBitmap pointer |
flags | Optional flags for the texture, or `COGL_TEXTURE_NONE` |
internal_format | the CoglPixelFormat to use for the GPU storage of the texture |

#### Returns

A newly created CoglTexture or `NULL` on failure.

[transfer full]

Since 1.0

### COGL_BITMAP_ERROR

    #define COGL_BITMAP_ERROR (cogl_bitmap_error_quark ())

CoglError domain for bitmap errors.

Since 1.4

## Types and Values

### CoglBitmap

    typedef struct _CoglBitmap CoglBitmap;

### enum CoglBitmapError

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 GdkPixbufErrors will be used directly.

#### Members

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. |

Since 1.4