File saving

## File saving File saving — Saving a pixbuf to a file. |

## Synopsis

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

    gboolean            gdk_pixbuf_savev                    (GdkPixbuf *pixbuf,
                                                             const char *filename,
                                                             const char *type,
                                                             char **option_keys,
                                                             char **option_values,
                                                             GError **error);
    gboolean            gdk_pixbuf_save                     (GdkPixbuf *pixbuf,
                                                             const char *filename,
                                                             const char *type,
                                                             GError **error,
                                                             ...);
    gboolean            (*GdkPixbufSaveFunc)                (const gchar *buf,
                                                             gsize count,
                                                             GError **error,
                                                             gpointer data);
    gboolean            gdk_pixbuf_save_to_callback         (GdkPixbuf *pixbuf,
                                                             GdkPixbufSaveFunc save_func,
                                                             gpointer user_data,
                                                             const char *type,
                                                             GError **error,
                                                             ...);
    gboolean            gdk_pixbuf_save_to_callbackv        (GdkPixbuf *pixbuf,
                                                             GdkPixbufSaveFunc save_func,
                                                             gpointer user_data,
                                                             const char *type,
                                                             char **option_keys,
                                                             char **option_values,
                                                             GError **error);
    gboolean            gdk_pixbuf_save_to_buffer           (GdkPixbuf *pixbuf,
                                                             gchar **buffer,
                                                             gsize *buffer_size,
                                                             const char *type,
                                                             GError **error,
                                                             ...);
    gboolean            gdk_pixbuf_save_to_bufferv          (GdkPixbuf *pixbuf,
                                                             gchar **buffer,
                                                             gsize *buffer_size,
                                                             const char *type,
                                                             char **option_keys,
                                                             char **option_values,
                                                             GError **error);
    gboolean            gdk_pixbuf_save_to_stream           (GdkPixbuf *pixbuf,
                                                             GOutputStream *stream,
                                                             const char *type,
                                                             GCancellable *cancellable,
                                                             GError **error,
                                                             ...);

## Description

These functions allow to save a GdkPixbuf in a number of file formats. The formatted data can be written to a file or to a memory buffer. &gdk-pixbuf; can also call a user-defined callback on the data, which allows to e.g. write the image to a socket or store it in a database.

## Details

### gdk_pixbuf_savev ()

    gboolean            gdk_pixbuf_savev                    (GdkPixbuf *pixbuf,
                                                             const char *filename,
                                                             const char *type,
                                                             char **option_keys,
                                                             char **option_values,
                                                             GError **error);

Saves pixbuf to a file in `type`, which is currently "jpeg", "png", "tiff", "ico" or "bmp". If `error` is set, `FALSE` will be returned. See `gdk_pixbuf_save()` for more details.

`pixbuf` : | a GdkPixbuf.
`filename` : | name of file to save.
`type` : | name of file format.
`option_keys` : | name of options to set, `NULL`-terminated. [array zero-terminated=1]
`option_values` : | values for named options. [array zero-terminated=1]
`error` : | return location for error, or `NULL`. [allow-none]
Returns : | whether an error was set

### gdk_pixbuf_save ()

    gboolean            gdk_pixbuf_save                     (GdkPixbuf *pixbuf,
                                                             const char *filename,
                                                             const char *type,
                                                             GError **error,
                                                             ...);

Saves pixbuf to a file in format `type`. By default, "jpeg", "png", "ico" and "bmp" are possible file formats to save in, but more formats may be installed. The list of all writable formats can be determined in the following way:

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    void add_if_writable (GdkPixbufFormat *data, GSList **list)
    {
      if (gdk_pixbuf_format_is_writable (data))
        *list = g_slist_prepend (*list, data);
    }

    GSList *formats = gdk_pixbuf_get_formats ();
    GSList *writable_formats = NULL;
    g_slist_foreach (formats, add_if_writable, &writable_formats);
    g_slist_free (formats);

If `error` is set, `FALSE` will be returned. Possible errors include those in the GDK_PIXBUF_ERROR domain and those in the G_FILE_ERROR domain.

The variable argument list should be `NULL`-terminated; if not empty, it should contain pairs of strings that modify the save parameters. For example:

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    gdk_pixbuf_save (pixbuf, handle, "jpeg", &error,
                     "quality", "100", NULL);

Currently only few parameters exist. JPEG images can be saved with a "quality" parameter; its value should be in the range [0,100].

Text chunks can be attached to PNG images by specifying parameters of the form "tEXt::key", where key is an ASCII string of length 1-79. The values are UTF-8 encoded strings. The PNG compression level can be specified using the "compression" parameter; it's value is in an integer in the range of [0,9].

ICC color profiles can also be embedded into PNG and TIFF images. The "icc-profile" value should be the complete ICC profile encoded into base64.

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    gchar *contents;
    gchar *contents_encode;
    gsize length;
    g_file_get_contents ("/home/hughsie/.color/icc/L225W.icm", &contents, &length, NULL);
    contents_encode = g_base64_encode ((const guchar *) contents, length);
    gdk_pixbuf_save (pixbuf, handle, "png", &error,
                     "icc-profile", contents_encode,
                     NULL);

TIFF images recognize a "compression" option which acceps an integer value. Among the codecs are 1 None, 2 Huffman, 5 LZW, 7 JPEG and 8 Deflate, see the libtiff documentation and tiff.h for all supported codec values.

ICO images can be saved in depth 16, 24, or 32, by using the "depth" parameter. When the ICO saver is given "x_hot" and "y_hot" parameters, it produces a CUR instead of an ICO.

`pixbuf` : | a GdkPixbuf.
`filename` : | name of file to save.
`type` : | name of file format.
`error` : | return location for error, or `NULL`. [allow-none]
`Varargs` : | list of key-value save options
Returns : | whether an error was set

### GdkPixbufSaveFunc ()

    gboolean            (*GdkPixbufSaveFunc)                (const gchar *buf,
                                                             gsize count,
                                                             GError **error,
                                                             gpointer data);

Specifies the type of the function passed to `gdk_pixbuf_save_to_callback()`. It is called once for each block of bytes that is "written" by `gdk_pixbuf_save_to_callback()`. If successful it should return `TRUE`. If an error occurs it should set `error` and return `FALSE`, in which case `gdk_pixbuf_save_to_callback()` will fail with the same error.

`buf` : | bytes to be written. [array length=count][element-type guint8]
`count` : | number of bytes in `buf`.
`error` : | A location to return an error. [out]
`data` : | user data passed to `gdk_pixbuf_save_to_callback()`. [closure]
Returns : | `TRUE` if successful, `FALSE` (with `error` set) if failed.

Since 2.4

### gdk_pixbuf_save_to_callback ()

    gboolean            gdk_pixbuf_save_to_callback         (GdkPixbuf *pixbuf,
                                                             GdkPixbufSaveFunc save_func,
                                                             gpointer user_data,
                                                             const char *type,
                                                             GError **error,
                                                             ...);

Saves pixbuf in format `type` by feeding the produced data to a callback. Can be used when you want to store the image to something other than a file, such as an in-memory buffer or a socket. If `error` is set, `FALSE` will be returned. Possible errors include those in the GDK_PIXBUF_ERROR domain and whatever the save function generates.

See `gdk_pixbuf_save()` for more details.

`pixbuf` : | a GdkPixbuf.
`save_func` : | a function that is called to save each block of data that the save routine generates. [scope call]
`user_data` : | user data to pass to the save function.
`type` : | name of file format.
`error` : | return location for error, or `NULL`. [allow-none]
`Varargs` : | list of key-value save options
Returns : | whether an error was set

Since 2.4

### gdk_pixbuf_save_to_callbackv ()

    gboolean            gdk_pixbuf_save_to_callbackv        (GdkPixbuf *pixbuf,
                                                             GdkPixbufSaveFunc save_func,
                                                             gpointer user_data,
                                                             const char *type,
                                                             char **option_keys,
                                                             char **option_values,
                                                             GError **error);

Saves pixbuf to a callback in format `type`, which is currently "jpeg", "png", "tiff", "ico" or "bmp". If `error` is set, `FALSE` will be returned. See `gdk_pixbuf_save_to_callback()` for more details.

`pixbuf` : | a GdkPixbuf.
`save_func` : | a function that is called to save each block of data that the save routine generates. [scope call]
`user_data` : | user data to pass to the save function. [closure]
`type` : | name of file format.
`option_keys` : | name of options to set, `NULL`-terminated. [array zero-terminated=1][element-type utf8]
`option_values` : | values for named options. [array zero-terminated=1][element-type utf8]
`error` : | return location for error, or `NULL`. [allow-none]
Returns : | whether an error was set

Since 2.4

### gdk_pixbuf_save_to_buffer ()

    gboolean            gdk_pixbuf_save_to_buffer           (GdkPixbuf *pixbuf,
                                                             gchar **buffer,
                                                             gsize *buffer_size,
                                                             const char *type,
                                                             GError **error,
                                                             ...);

Saves pixbuf to a new buffer in format `type`, which is currently "jpeg", "png", "tiff", "ico" or "bmp". This is a convenience function that uses `gdk_pixbuf_save_to_callback()` to do the real work. Note that the buffer is not nul-terminated and may contain embedded nuls. If `error` is set, `FALSE` will be returned and `buffer` will be set to `NULL`. Possible errors include those in the GDK_PIXBUF_ERROR domain.

See `gdk_pixbuf_save()` for more details.

`pixbuf` : | a GdkPixbuf.
`buffer` : | location to receive a pointer to the new buffer. [array length=buffer_size]
`buffer_size` : | location to receive the size of the new buffer.
`type` : | name of file format.
`error` : | return location for error, or `NULL`. [allow-none]
`Varargs` : | list of key-value save options
Returns : | whether an error was set

Since 2.4

### gdk_pixbuf_save_to_bufferv ()

    gboolean            gdk_pixbuf_save_to_bufferv          (GdkPixbuf *pixbuf,
                                                             gchar **buffer,
                                                             gsize *buffer_size,
                                                             const char *type,
                                                             char **option_keys,
                                                             char **option_values,
                                                             GError **error);

Saves pixbuf to a new buffer in format `type`, which is currently "jpeg", "tiff", "png", "ico" or "bmp". See `gdk_pixbuf_save_to_buffer()` for more details.

`pixbuf` : | a GdkPixbuf.
`buffer` : | location to receive a pointer to the new buffer. [array length=buffer_size][out][element-type guint8]
`buffer_size` : | location to receive the size of the new buffer.
`type` : | name of file format.
`option_keys` : | name of options to set, `NULL`-terminated. [array zero-terminated=1]
`option_values` : | values for named options. [array zero-terminated=1]
`error` : | return location for error, or `NULL`. [allow-none]
Returns : | whether an error was set

Since 2.4

### gdk_pixbuf_save_to_stream ()

    gboolean            gdk_pixbuf_save_to_stream           (GdkPixbuf *pixbuf,
                                                             GOutputStream *stream,
                                                             const char *type,
                                                             GCancellable *cancellable,
                                                             GError **error,
                                                             ...);

Saves `pixbuf` to an output stream.

Supported file formats are currently "jpeg", "tiff", "png", "ico" or "bmp". See `gdk_pixbuf_save_to_buffer()` for more details.

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.

`pixbuf` : | a GdkPixbuf
`stream` : | a GOutputStream to save the pixbuf to
`type` : | name of file format
`cancellable` : | optional GCancellable object, `NULL` to ignore
`error` : | return location for error, or `NULL`. [allow-none]
`Varargs` : | list of key-value save options
Returns : | `TRUE` if the pixbuf was saved successfully, `FALSE` if an error was set.

Since 2.14