class: Pixbuf

[76:7] extends: object

A pixel buffer. GdkPixbuf contains information about an image's pixel data, its color space, bits per sample, width and height, and the rowstride (the number of bytes between the start of one row and the start of the next). ## Creating new GdkPixbuf The most basic way to create a pixbuf is to wrap an existing pixel buffer with a [class@GdkPixbuf.Pixbuf] instance. You can use the [ctor@GdkPixbuf.Pixbuf.new_from_data] function to do this. Every time you create a new GdkPixbuf instance for some data, you will need to specify the destroy notification function that will be called when the data buffer needs to be freed; this will happen when a GdkPixbuf is finalized by the reference counting functions. If you have a chunk of static data compiled into your application, you can pass in NULL as the destroy notification function so that the data will not be freed. The [ctor@GdkPixbuf.Pixbuf.new] constructor function can be used as a convenience to create a pixbuf with an empty buffer; this is equivalent to allocating a data buffer using malloc() and then wrapping it with gdk_pixbuf_new_from_data(). The gdk_pixbuf_new() function will compute an optimal rowstride so that rendering can be performed with an efficient algorithm. You can also copy an existing pixbuf with the [method@Pixbuf.copy] function. This is not the same as just acquiring a reference to the old pixbuf instance: the copy function will actually duplicate the pixel data in memory and create a new [class@Pixbuf] instance for it. ## Reference counting GdkPixbuf structures are reference counted. This means that an application can share a single pixbuf among many parts of the code. When a piece of the program needs to use a pixbuf, it should acquire a reference to it by calling g_object_ref(); when it no longer needs the pixbuf, it should release the reference it acquired by calling g_object_unref(). The resources associated with a GdkPixbuf will be freed when its reference count drops to zero. Newly-created GdkPixbuf instances start with a reference count of one. ## Image Data Image data in a pixbuf is stored in memory in an uncompressed, packed format. Rows in the image are stored top to bottom, and in each row pixels are stored from left to right. There may be padding at the end of a row. The "rowstride" value of a pixbuf, as returned by [method@GdkPixbuf.Pixbuf.get_rowstride], indicates the number of bytes between rows. NOTE: If you are copying raw pixbuf data with memcpy() note that the last row in the pixbuf may not be as wide as the full rowstride, but rather just as wide as the pixel data needs to be; that is: it is unsafe to do memcpy (dest, pixels, rowstride * height) to copy a whole pixbuf. Use [method@GdkPixbuf.Pixbuf.copy] instead, or compute the width in bytes of the last row as: c last_row = width * ((n_channels * bits_per_sample + 7) / 8); The same rule applies when iterating over each row of a GdkPixbuf pixels array. The following code illustrates a simple put_pixel() function for RGB pixbufs with 8 bits per channel with an alpha channel. c static void put_pixel (GdkPixbuf *pixbuf, int x, int y, guchar red, guchar green, guchar blue, guchar alpha) { int n_channels = gdk_pixbuf_get_n_channels (pixbuf); // Ensure that the pixbuf is valid g_assert (gdk_pixbuf_get_colorspace (pixbuf) == GDK_COLORSPACE_RGB); g_assert (gdk_pixbuf_get_bits_per_sample (pixbuf) == 8); g_assert (gdk_pixbuf_get_has_alpha (pixbuf)); g_assert (n_channels == 4); int width = gdk_pixbuf_get_width (pixbuf); int height = gdk_pixbuf_get_height (pixbuf); // Ensure that the coordinates are in a valid range g_assert (x >= 0 && x < width); g_assert (y >= 0 && y < height); int rowstride = gdk_pixbuf_get_rowstride (pixbuf); // The pixel buffer in the GdkPixbuf instance guchar *pixels = gdk_pixbuf_get_pixels (pixbuf); // The pixel we wish to modify guchar *p = pixels + y * rowstride + x * n_channels; p[0] = red; p[1] = green; p[2] = blue; p[3] = alpha; } ## Loading images The GdkPixBuf class provides a simple mechanism for loading an image from a file in synchronous and asynchronous fashion. For GUI applications, it is recommended to use the asynchronous stream API to avoid blocking the control flow of the application. Additionally, GdkPixbuf provides the [class@GdkPixbuf.PixbufLoader] API for progressive image loading. ## Saving images The GdkPixbufclass provides methods for saving image data in a number of file formats. The formatted data can be written to a file or to a memory buffer.GdkPixbuf` 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.

Members

• handleObj
• lib
• retainedCallbacks
• signalHandlerNames
• signalSetterHandlers

Methods

• Pixbuf (colorspace = null, has_alpha = null, bits_per_sample = null, width = null, height = null)

  Creates a new GdkPixbuf structure and allocates a buffer for it. If the allocation of the buffer failed, this function will return NULL. The buffer has an optimal rowstride. Note that the buffer is not cleared; you will have to fill it completely yourself.

  • @p colorspace is Color space for image.
  • @p has_alpha is Whether the image should have transparency information.
  • @p bits_per_sample is Number of bits per color sample.
  • @p width is Width of image in pixels, must be > 0.
  • @p height is Height of image in pixels, must be > 0.

• toNativeHandle (Source)

  Normalizes a constructor argument into a raw pointer carrier. Accepts a raw NativeHandle, a raw NativeBuffer returned from fn.call(...), another generated wrapper exposing handle(), or null. Returns null when the argument carries no pointer.

  • @p Source is the raw handle, raw buffer, wrapper, or null.
  • @r A raw pointer carrier or null when no pointer is present.

• getLib ()

  Returns the opened native library for this generated wrapper.

  • @r The opened native library.

• handle ()

  Returns the wrapped NativeHandle.

  • @r The wrapped NativeHandle.

• isNull ()

  Returns true when the wrapped handle is null.

  • @r A bool.

• describe ()

  Returns a small string for debugging generated wrappers.

  • @r A string.

• asObject ()

  Wraps this handle as Object.

  • @r A Object object.

• asIcon ()

  Wraps this handle as Icon.

  • @r A Icon object.

• asLoadableIcon ()

  Wraps this handle as LoadableIcon.

  • @r A LoadableIcon object.

• apply_embedded_orientation ()

  Takes an existing pixbuf and checks for the presence of an associated "orientation" option. The orientation option may be provided by the JPEG loader (which reads the exif orientation tag) or the TIFF loader (which reads the TIFF orientation tag, and compensates it for the partial transforms performed by libtiff). If an orientation option/tag is present, the appropriate transform will be performed so that the pixbuf is oriented correctly.

• composite (object dest, int dest_x, int dest_y, int dest_width, int dest_height, double offset_x, double offset_y, double scale_x, double scale_y, string interp_type, int overall_alpha)

  Creates a transformation of the source image @src by scaling by @scale_x and @scale_y then translating by @offset_x and @offset_y. This gives an image in the coordinates of the destination pixbuf. The rectangle (@dest_x, @dest_y, @dest_width, @dest_height) is then alpha blended onto the corresponding rectangle of the original destination image. When the destination rectangle contains parts not in the source image, the data at the edges of the source image is replicated to infinity.

  • @p dest is the #GdkPixbuf into which to render the results.
  • @p dest_x is the left coordinate for region to render.
  • @p dest_y is the top coordinate for region to render.
  • @p dest_width is the width of the region to render.
  • @p dest_height is the height of the region to render.
  • @p offset_x is the offset in the X direction (currently rounded to an integer).
  • @p offset_y is the offset in the Y direction (currently rounded to an integer).
  • @p scale_x is the scale factor in the X direction.
  • @p scale_y is the scale factor in the Y direction.
  • @p interp_type is the interpolation type for the transformation..
  • @p overall_alpha is overall alpha for source image (0..255).
  • @r None.

• copy ()

  Creates a new GdkPixbuf with a copy of the information in the specified pixbuf. Note that this does not copy the options set on the original GdkPixbuf, use gdk_pixbuf_copy_options() for this.

• copy_area (int src_x, int src_y, int width, int height, object dest_pixbuf, int dest_x, int dest_y)

  Copies a rectangular area from src_pixbuf to dest_pixbuf. Conversion of pixbuf formats is done automatically. If the source rectangle overlaps the destination rectangle on the same pixbuf, it will be overwritten during the copy operation. Therefore, you can not use this function to scroll a pixbuf.

  • @p src_x is Source X coordinate within @src_pixbuf..
  • @p src_y is Source Y coordinate within @src_pixbuf..
  • @p width is Width of the area to copy..
  • @p height is Height of the area to copy..
  • @p dest_pixbuf is Destination pixbuf..
  • @p dest_x is X coordinate within @dest_pixbuf..
  • @p dest_y is Y coordinate within @dest_pixbuf..
  • @r None.

• copy_options (object dest_pixbuf)

  Copies the key/value pair options attached to a GdkPixbuf to another GdkPixbuf. This is useful to keep original metadata after having manipulated a file. However be careful to remove metadata which you've already applied, such as the "orientation" option after rotating the image.

  • @p dest_pixbuf is the destination pixbuf.

• flip (bool horizontal)

  Flips a pixbuf horizontally or vertically and returns the result in a new pixbuf.

  • @p horizontal is TRUE to flip horizontally, FALSE to flip vertically.

• get_bits_per_sample ()

  Queries the number of bits per color sample in a pixbuf.

• get_byte_length ()

  Returns the length of the pixel data, in bytes.

• get_colorspace ()

  Queries the color space of a pixbuf.

• get_has_alpha ()

  Queries whether a pixbuf has an alpha channel (opacity information).

• get_height ()

  Queries the height of a pixbuf.

• get_n_channels ()

  Queries the number of channels of a pixbuf.

• get_option (string key)

  Looks up @key in the list of options that may have been attached to the

  • @pixbuf when it was loaded, or that may have been attached by another function using gdk_pixbuf_set_option(). For instance, the ANI loader provides "Title" and "Artist" options. The ICO, XBM, and XPM loaders provide "x_hot" and "y_hot" hot-spot options for cursor definitions. The PNG loader provides the tEXt ancillary chunk key/value pairs as options. Since 2.12, the TIFF and JPEG loaders return an "orientation" option string that corresponds to the embedded TIFF/Exif orientation tag (if present). Since 2.32, the TIFF loader sets the "multipage" option string to "yes" when a multi-page TIFF is loaded. Since 2.32 the JPEG and PNG loaders set "x-dpi" and "y-dpi" if the file contains image density information in dots per inch. Since 2.36.6, the JPEG loader sets the "comment" option with the comment EXIF tag.
  • @p key is a nul-terminated string..

• get_options ()

  Returns a GHashTable with a list of all the options that may have been attached to the pixbuf when it was loaded, or that may have been attached by another function using [method@GdkPixbuf.Pixbuf.set_option].

• get_rowstride ()

  Queries the rowstride of a pixbuf, which is the number of bytes between the start of a row and the start of the next row.

• get_width ()

  Queries the width of a pixbuf.

• new_subpixbuf (int src_x, int src_y, int width, int height)

  Creates a new pixbuf which represents a sub-region of src_pixbuf. The new pixbuf shares its pixels with the original pixbuf, so writing to one affects both. The new pixbuf holds a reference to src_pixbuf, so src_pixbuf will not be finalized until the new pixbuf is finalized. Note that if src_pixbuf is read-only, this function will force it to be mutable.

  • @p src_x is X coord in @src_pixbuf.
  • @p src_y is Y coord in @src_pixbuf.
  • @p width is width of region in @src_pixbuf.
  • @p height is height of region in @src_pixbuf.

• read_pixel_bytes ()

  Provides a #GBytes buffer containing the raw pixel data; the data must not be modified. This function allows skipping the implicit copy that must be made if gdk_pixbuf_get_pixels() is called on a read-only pixbuf.

• ref ()

  Adds a reference to a pixbuf.

• remove_option (string key)

  Removes the key/value pair option attached to a GdkPixbuf.

  • @p key is a nul-terminated string representing the key to remove..

• rotate_simple (string angle)

  Rotates a pixbuf by a multiple of 90 degrees, and returns the result in a new pixbuf. If angle is 0, this function will return a copy of src.

  • @p angle is the angle to rotate by.

• saturate_and_pixelate (object dest, double saturation, bool pixelate)

  Modifies saturation and optionally pixelates src, placing the result in dest. The src and dest pixbufs must have the same image format, size, and rowstride. The src and dest arguments may be the same pixbuf with no ill effects. If saturation is 1.0 then saturation is not changed. If it's less than 1.0, saturation is reduced (the image turns toward grayscale); if greater than 1.0, saturation is increased (the image gets more vivid colors). If pixelate is TRUE, then pixels are faded in a checkerboard pattern to create a pixelated image.

  • @p dest is place to write modified version of @src.
  • @p saturation is saturation factor.
  • @p pixelate is whether to pixelate.
  • @r None.

• save_to_streamv (object stream, string type, list option_keys, list option_values, object cancellable)

  Saves pixbuf to an output stream. Supported file formats are currently "jpeg", "tiff", "png", "ico" or "bmp". See [method@GdkPixbuf.Pixbuf.save_to_stream] for more details.

  • @p stream is a GOutputStream to save the pixbuf to.
  • @p type is name of file format.
  • @p option_keys is name of options to set.
  • @p option_values is values for named options.
  • @p cancellable is optional GCancellable object, NULL to ignore.

• savev (string filename, string type, list option_keys, list option_values)

  Vector version of gdk_pixbuf_save(). 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 [method@GdkPixbuf.Pixbuf.save] for more details.

  • @p filename is name of file to save..
  • @p type is name of file format..
  • @p option_keys is name of options to set.
  • @p option_values is values for named options.

• scale (object dest, int dest_x, int dest_y, int dest_width, int dest_height, double offset_x, double offset_y, double scale_x, double scale_y, string interp_type)

  Creates a transformation of the source image @src by scaling by @scale_x and @scale_y then translating by @offset_x and @offset_y, then renders the rectangle (@dest_x, @dest_y, @dest_width, @dest_height) of the resulting image onto the destination image replacing the previous contents. Try to use gdk_pixbuf_scale_simple() first; this function is the industrial-strength power tool you can fall back to, if gdk_pixbuf_scale_simple() isn't powerful enough. If the source rectangle overlaps the destination rectangle on the same pixbuf, it will be overwritten during the scaling which results in rendering artifacts.

  • @p dest is the #GdkPixbuf into which to render the results.
  • @p dest_x is the left coordinate for region to render.
  • @p dest_y is the top coordinate for region to render.
  • @p dest_width is the width of the region to render.
  • @p dest_height is the height of the region to render.
  • @p offset_x is the offset in the X direction (currently rounded to an integer).
  • @p offset_y is the offset in the Y direction (currently rounded to an integer).
  • @p scale_x is the scale factor in the X direction.
  • @p scale_y is the scale factor in the Y direction.
  • @p interp_type is the interpolation type for the transformation..
  • @r None.

• scale_simple (int dest_width, int dest_height, string interp_type)

  Create a new pixbuf containing a copy of src scaled to dest_width x dest_height. This function leaves src unaffected. The interp_type should be GDK_INTERP_NEAREST if you want maximum speed (but when scaling down GDK_INTERP_NEAREST is usually unusably ugly). The default interp_type should be GDK_INTERP_BILINEAR which offers reasonable quality and speed. You can scale a sub-portion of src by creating a sub-pixbuf pointing into src; see [method@GdkPixbuf.Pixbuf.new_subpixbuf]. If dest_width and dest_height are equal to the width and height of src, this function will return an unscaled copy of src. For more complicated scaling/alpha blending see [method@GdkPixbuf.Pixbuf.scale] and [method@GdkPixbuf.Pixbuf.composite].

  • @p dest_width is the width of destination image.
  • @p dest_height is the height of destination image.
  • @p interp_type is the interpolation type for the transformation..

• set_option (string key, string value)

  Attaches a key/value pair as an option to a GdkPixbuf. If key already exists in the list of options attached to the pixbuf, the new value is ignored and FALSE is returned.

  • @p key is a nul-terminated string..
  • @p value is a nul-terminated string..

• unref ()

  Removes a reference from a pixbuf.

  • @r None.

class: PixbufMeta

[834:14] static extends: object

Generated metadata helpers for Pixbuf class surfaces.

Methods

• properties ()

  Returns property metadata for Pixbuf.

  • @r A list.

class: PixbufCtors

[611:14] static extends: object

Alternate constructors for Pixbuf. Usage: PixbufCtors.<name>(...). The primary constructor lives directly on Pixbuf.

Methods

• newFromBytes (object data, string colorspace, bool has_alpha, int bits_per_sample, int width, int height, int rowstride)

  Creates a new #GdkPixbuf out of in-memory readonly image data. Currently only RGB images with 8 bits per sample are supported. This is the GBytes variant of gdk_pixbuf_new_from_data(), useful for language bindings.

  • @p data is Image data in 8-bit/sample packed format inside a #GBytes.
  • @p colorspace is Colorspace for the image data.
  • @p has_alpha is Whether the data has an opacity channel.
  • @p bits_per_sample is Number of bits per sample.
  • @p width is Width of the image in pixels, must be > 0.
  • @p height is Height of the image in pixels, must be > 0.
  • @p rowstride is Distance in bytes between row starts.
  • @r A new Pixbuf.

• newFromFile (string filename)

  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: - the file could not be opened - there is no loader for the file's format - there is not enough memory to allocate the image buffer - the image buffer contains invalid data The error domains are GDK_PIXBUF_ERROR and G_FILE_ERROR.

  • @p filename is Name of file to load, in the GLib file name encoding.
  • @r A new Pixbuf.

• newFromFileAtScale (string filename, int width, int height, bool preserve_aspect_ratio)

  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: - the file could not be opened - there is no loader for the file's format - there is not enough memory to allocate the image buffer - the image buffer contains invalid data The error domains are GDK_PIXBUF_ERROR and G_FILE_ERROR. 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.

  • @p filename is Name of file to load, in the GLib file name encoding.
  • @p width is The width the image should have or -1 to not constrain the width.
  • @p height is The height the image should have or -1 to not constrain the height.
  • @p preserve_aspect_ratio is TRUE to preserve the image's aspect ratio.
  • @r A new Pixbuf.

• newFromFileAtSize (string filename, int width, int height)

  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: - the file could not be opened - there is no loader for the file's format - there is not enough memory to allocate the image buffer - the image buffer contains invalid data The error domains are GDK_PIXBUF_ERROR and G_FILE_ERROR. 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 [ctor@GdkPixbuf.Pixbuf.new_from_file_at_scale].

  • @p filename is Name of file to load, in the GLib file name encoding.
  • @p width is The width the image should have or -1 to not constrain the width.
  • @p height is The height the image should have or -1 to not constrain the height.
  • @r A new Pixbuf.

• newFromResource (string resource_path)

  Creates a new pixbuf by loading an image from an resource. The file format is detected automatically. If NULL is returned, then @error will be set.

  • @p resource_path is the path of the resource file.
  • @r A new Pixbuf.

• newFromResourceAtScale (string resource_path, int width, int height, bool preserve_aspect_ratio)

  Creates a new pixbuf by loading an image from an resource. The file format is detected automatically. If NULL is returned, then @error will be set. 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.
  • @p resource_path is the path of the resource file.
  • @p width is The width the image should have or -1 to not constrain the width.
  • @p height is The height the image should have or -1 to not constrain the height.
  • @p preserve_aspect_ratio is TRUE to preserve the image's aspect ratio.
  • @r A new Pixbuf.

• newFromStream (object stream, object cancellable)

  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 G_IO_ERROR_CANCELLED will be returned. Other possible errors are in the GDK_PIXBUF_ERROR and G_IO_ERROR domains. The stream is not closed.

  • @p stream is a GInputStream to load the pixbuf from.
  • @p cancellable is optional GCancellable object, NULL to ignore.
  • @r A new Pixbuf.

• newFromStreamAtScale (object stream, int width, int height, bool preserve_aspect_ratio, object cancellable)

  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 G_IO_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. If both width and height are given, this function will behave as if the smaller of the two values is passed as -1. 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.

  • @p stream is a GInputStream to load the pixbuf from.
  • @p width is The width the image should have or -1 to not constrain the width.
  • @p height is The height the image should have or -1 to not constrain the height.
  • @p preserve_aspect_ratio is TRUE to preserve the image's aspect ratio.
  • @p cancellable is optional GCancellable object, NULL to ignore.
  • @r A new Pixbuf.

• newFromStreamFinish (object async_result)

  Finishes an asynchronous pixbuf creation operation started with gdk_pixbuf_new_from_stream_async().

  • @p async_result is a GAsyncResult.
  • @r A new Pixbuf.

• newFromXpmData (list data)

  Creates a new pixbuf by parsing XPM data in memory. This data is commonly the result of including an XPM file into a program's C source.

  • @p data is Pointer to inline XPM data..
  • @r A new Pixbuf.