File Loading

File Loading — Loading a pixbuf from a file.

Synopsis

#include <gdk-pixbuf/gdk-pixbuf.h>

#define             gdk_pixbuf_new_from_file
#define             gdk_pixbuf_new_from_file_at_size
#define             gdk_pixbuf_new_from_file_at_scale
GdkPixbufFormat *   gdk_pixbuf_get_file_info            (const gchar *filename,
                                                         gint *width,
                                                         gint *height);
GdkPixbuf *         gdk_pixbuf_new_from_stream          (GInputStream *stream,
                                                         GCancellable *cancellable,
                                                         GError **error);
GdkPixbuf *         gdk_pixbuf_new_from_stream_at_scale (GInputStream *stream,
                                                         gint width,
                                                         gint height,
                                                         gboolean preserve_aspect_ratio,
                                                         GCancellable *cancellable,
                                                         GError **error);

Description

The &gdk-pixbuf; library provides a simple mechanism for loading an image from a file in synchronous fashion. This means that the library takes control of the application while the file is being loaded; from the user's point of view, the application will block until the image is done loading.

This interface can be used by applications in which blocking is acceptable while an image is being loaded. It can also be used to load small images in general. Applications that need progressive loading can use the GdkPixbufLoader functionality instead.

Details

gdk_pixbuf_new_from_file

#define gdk_pixbuf_new_from_file gdk_pixbuf_new_from_file_utf8

Creates a new pixbuf by loading an image from a file. The file format is detected automatically. If NULL is returned, then error will be set. Possible errors are in the GDK_PIXBUF_ERROR and G_FILE_ERROR domains.

filename :

 Name of file to load, in the GLib file name encoding

error :

 Return location for an error

Returns :

 A newly-created pixbuf with a reference count of 1, or NULL if any of several error conditions occurred: the file could not be opened, there was no loader for the file's format, there was not enough memory to allocate the image buffer, or the image file contained invalid data.

gdk_pixbuf_new_from_file_at_size

#define gdk_pixbuf_new_from_file_at_size gdk_pixbuf_new_from_file_at_size_utf8

Creates a new pixbuf by loading an image from a file. The file format is detected automatically. If NULL is returned, then error will be set. Possible errors are in the GDK_PIXBUF_ERROR and G_FILE_ERROR domains.

The image will be scaled to fit in the requested size, preserving the image's aspect ratio. Note that the returned pixbuf may be smaller than width x height, if the aspect ratio requires it. To load and image at the requested size, regardless of aspect ratio, use gdk_pixbuf_new_from_file_at_scale().

filename :

 Name of file to load, in the GLib file name encoding

width :

 The width the image should have or -1 to not constrain the width

height :

 The height the image should have or -1 to not constrain the height

error :

 Return location for an error

Returns :

 A newly-created pixbuf with a reference count of 1, or NULL if any of several error conditions occurred: the file could not be opened, there was no loader for the file's format, there was not enough memory to allocate the image buffer, or the image file contained invalid data.

Since 2.4

gdk_pixbuf_new_from_file_at_scale

#define gdk_pixbuf_new_from_file_at_scale gdk_pixbuf_new_from_file_at_scale_utf8

Creates a new pixbuf by loading an image from a file. The file format is detected automatically. If NULL is returned, then error will be set. Possible errors are in the GDK_PIXBUF_ERROR and G_FILE_ERROR domains. The image will be scaled to fit in the requested size, optionally preserving the image's aspect ratio.

When preserving the aspect ratio, a width of -1 will cause the image to be scaled to the exact given height, and a height of -1 will cause the image to be scaled to the exact given width. When not preserving aspect ratio, a width or height of -1 means to not scale the image at all in that dimension. Negative values for width and height are allowed since 2.8.

filename :

 Name of file to load, in the GLib file name encoding

width :

 The width the image should have or -1 to not constrain the width

height :

 The height the image should have or -1 to not constrain the height

preserve_aspect_ratio :

 TRUE to preserve the image's aspect ratio

error :

 Return location for an error

Returns :

 A newly-created pixbuf with a reference count of 1, or NULL if any of several error conditions occurred: the file could not be opened, there was no loader for the file's format, there was not enough memory to allocate the image buffer, or the image file contained invalid data.

Since 2.6

gdk_pixbuf_get_file_info ()

GdkPixbufFormat *   gdk_pixbuf_get_file_info            (const gchar *filename,
                                                         gint *width,
                                                         gint *height);

Parses an image file far enough to determine its format and size.

filename :

 The name of the file to identify.

width :

 Return location for the width of the image, or NULL

height :

 Return location for the height of the image, or NULL

Returns :

 A GdkPixbufFormat describing the image format of the file or NULL if the image format wasn't recognized. The return value is owned by GdkPixbuf and should not be freed.

Since 2.4

gdk_pixbuf_new_from_stream ()

GdkPixbuf *         gdk_pixbuf_new_from_stream          (GInputStream *stream,
                                                         GCancellable *cancellable,
                                                         GError **error);

Creates a new pixbuf by loading an image from an input stream.

The file format is detected automatically. If NULL is returned, then error will be set. The cancellable can be used to abort the operation from another thread. If the operation was cancelled, the error GIO_ERROR_CANCELLED will be returned. Other possible errors are in the GDK_PIXBUF_ERROR and G_IO_ERROR domains.

The stream is not closed.

stream :

 a GInputStream to load the pixbuf from

cancellable :

 optional GCancellable object, NULL to ignore

error :

 Return location for an error

Returns :

 A newly-created pixbuf, or NULL if any of several error conditions occurred: the file could not be opened, the image format is not supported, there was not enough memory to allocate the image buffer, the stream contained invalid data, or the operation was cancelled.

Since 2.14

gdk_pixbuf_new_from_stream_at_scale ()

GdkPixbuf *         gdk_pixbuf_new_from_stream_at_scale (GInputStream *stream,
                                                         gint width,
                                                         gint height,
                                                         gboolean preserve_aspect_ratio,
                                                         GCancellable *cancellable,
                                                         GError **error);

Creates a new pixbuf by loading an image from an input stream.

The file format is detected automatically. If NULL is returned, then error will be set. The cancellable can be used to abort the operation from another thread. If the operation was cancelled, the error GIO_ERROR_CANCELLED will be returned. Other possible errors are in the GDK_PIXBUF_ERROR and G_IO_ERROR domains.

The image will be scaled to fit in the requested size, optionally preserving the image's aspect ratio. When preserving the aspect ratio, a width of -1 will cause the image to be scaled to the exact given height, and a height of -1 will cause the image to be scaled to the exact given width. When not preserving aspect ratio, a width or height of -1 means to not scale the image at all in that dimension.

The stream is not closed.

stream :

 a GInputStream to load the pixbuf from

width :

 The width the image should have or -1 to not constrain the width

height :

 The height the image should have or -1 to not constrain the height

preserve_aspect_ratio :

 TRUE to preserve the image's aspect ratio

cancellable :

 optional GCancellable object, NULL to ignore

error :

 Return location for an error

Returns :

 A newly-created pixbuf, or NULL if any of several error conditions occurred: the file could not be opened, the image format is not supported, there was not enough memory to allocate the image buffer, the stream contained invalid data, or the operation was cancelled.

Since 2.14

See Also

GdkPixbufLoader.
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