class GdkPixbuf::Pixbuf

Overview

A pixel buffer.

Gdk::Pixbuf 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 Gdk::Pixbuf

The most basic way to create a pixbuf is to wrap an existing pixel buffer with a Gdk::Pixbuf::Pixbuf instance. You can use the [ctor@Gdk::Pixbuf.Pixbuf.new_from_data] function to do this.

Every time you create a new Gdk::Pixbuf 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 Gdk::Pixbuf 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@Gdk::Pixbuf.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.

As a special case, you can use the [ctor@Gdk::Pixbuf.Pixbuf.new_from_xpm_data] function to create a pixbuf from inline XPM image data.

You can also copy an existing pixbuf with the 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 #Pixbuf instance for it.

Reference counting

Gdk::Pixbuf 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 Gdk::Pixbuf will be freed when its reference count drops to zero. Newly-created Gdk::Pixbuf 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@Gdk::Pixbuf.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 Gdk::Pixbuf::Pixbuf#copy instead, or compute the width in bytes of the last row as:

WARNING ⚠️ The following code is in c ⚠️

last_row = width * ((n_channels * bits_per_sample + 7) / 8);

The same rule applies when iterating over each row of a Gdk::Pixbuf pixels array.

The following code illustrates a simple put_pixel() function for RGB pixbufs with 8 bits per channel with an alpha channel.

WARNING ⚠️ The following code is in c ⚠️

static void
put_pixel (Gdk::Pixbuf *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 Gdk::Pixbuf 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 Gdk::PixBuf 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, Gdk::Pixbuf provides the [class@Gdk::Pixbuf.PixbufLoader`] API for progressive image loading.

Saving images

The Gdk::Pixbuf class 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. 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.

Included Modules

Defined in:

lib/gi-crystal/src/auto/gdk_pixbuf-2.0/pixbuf.cr

Constructors

Class Method Summary

Instance Method Summary

Instance methods inherited from module Gio::LoadableIcon

load(size : Int32, cancellable : Gio::Cancellable | Nil) : Gio::InputStream load, load_async(size : Int32, cancellable : Gio::Cancellable | Nil, callback : Gio::AsyncReadyCallback | Nil, user_data : Pointer(Void) | Nil) : Nil load_async, load_finish(res : Gio::AsyncResult) : Gio::InputStream load_finish, to_unsafe to_unsafe

Constructor methods inherited from module Gio::LoadableIcon

cast(obj : GObject::Object) : self cast

Class methods inherited from module Gio::LoadableIcon

cast?(obj : GObject::Object) : self | Nil cast?, g_type : UInt64 g_type

Instance methods inherited from module Gio::Icon

equal(icon2 : Gio::Icon | Nil) : Bool equal, new_for_string(str : String) : Gio::Icon new_for_string, serialize : GLib::Variant | Nil serialize, to_string : String | Nil to_string, to_unsafe to_unsafe

Constructor methods inherited from module Gio::Icon

cast(obj : GObject::Object) : self cast

Class methods inherited from module Gio::Icon

cast?(obj : GObject::Object) : self | Nil cast?, deserialize(value : _) : Gio::Icon | Nil deserialize, g_type : UInt64 g_type, hash(icon : Pointer(Void)) : UInt32 hash

Instance methods inherited from class GObject::Object

==(other : self) ==, bind_property(source_property : String, target : GObject::Object, target_property : String, flags : GObject::BindingFlags) : GObject::Binding bind_property, bind_property_full(source_property : String, target : GObject::Object, target_property : String, flags : GObject::BindingFlags, transform_to : GObject::Closure, transform_from : GObject::Closure) : GObject::Binding bind_property_full, data(key : String) : Pointer(Void) | Nil data, finalize finalize, freeze_notify : Nil freeze_notify, getv(names : Enumerable(String), values : Enumerable(_)) : Nil getv, hash(hasher) hash, notify(property_name : String) : Nil notify, notify_by_pspec(pspec : GObject::ParamSpec) : Nil notify_by_pspec, notify_signal notify_signal, property(property_name : String, value : _) : Nil property, qdata(quark : UInt32) : Pointer(Void) | Nil qdata, ref_count : UInt32 ref_count, run_dispose : Nil run_dispose, set_data(key : String, data : Pointer(Void) | Nil) : Nil set_data, set_property(property_name : String, value : _) : Nil set_property, steal_data(key : String) : Pointer(Void) | Nil steal_data, steal_qdata(quark : UInt32) : Pointer(Void) | Nil steal_qdata, thaw_notify : Nil thaw_notify, to_unsafe : Pointer(Void) to_unsafe, watch_closure(closure : GObject::Closure) : Nil watch_closure

Constructor methods inherited from class GObject::Object

cast(obj : GObject::Object) : self cast, new(pointer : Pointer(Void), transfer : GICrystal::Transfer)
new
new
, newv(object_type : UInt64, parameters : Enumerable(GObject::Parameter)) : self newv

Class methods inherited from class GObject::Object

cast?(obj : GObject::Object) : self | Nil cast?, compat_control(what : UInt64, data : Pointer(Void) | Nil) : UInt64 compat_control, g_type : UInt64 g_type, interface_find_property(g_iface : GObject::TypeInterface, property_name : String) : GObject::ParamSpec interface_find_property, interface_list_properties(g_iface : GObject::TypeInterface) : Enumerable(GObject::ParamSpec) interface_list_properties

Constructor Detail

def self.new(colorspace : GdkPixbuf::Colorspace, has_alpha : Bool, bits_per_sample : Int32, width : Int32, height : Int32) : self | Nil #

Creates a new Gdk::Pixbuf 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.


[View source]
def self.new #

Initialize a new Pixbuf.


[View source]
def self.new(*, bits_per_sample : Int32 | Nil = nil, colorspace : GdkPixbuf::Colorspace | Nil = nil, has_alpha : Bool | Nil = nil, height : Int32 | Nil = nil, n_channels : Int32 | Nil = nil, pixel_bytes : GLib::Bytes | Nil = nil, pixels : Pointer(Void) | Nil = nil, rowstride : Int32 | Nil = nil, width : Int32 | Nil = nil) #

[View source]
def self.new_from_bytes(data : GLib::Bytes, colorspace : GdkPixbuf::Colorspace, has_alpha : Bool, bits_per_sample : Int32, width : Int32, height : Int32, rowstride : Int32) : self #

Creates a new #Gdk::Pixbuf 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.


[View source]
def self.new_from_data(data : Bytes, colorspace : GdkPixbuf::Colorspace, has_alpha : Bool, bits_per_sample : Int32, width : Int32, height : Int32, rowstride : Int32, destroy_fn : GdkPixbuf::PixbufDestroyNotify | Nil, destroy_fn_data : Pointer(Void) | Nil) : self #

Creates a new #Gdk::Pixbuf out of in-memory image data.

Currently only RGB images with 8 bits per sample are supported.

Since you are providing a pre-allocated pixel buffer, you must also specify a way to free that data. This is done with a function of type Gdk::PixbufDestroyNotify. When a pixbuf created with is finalized, your destroy notification function will be called, and it is its responsibility to free the pixel array.

See also: Gdk::Pixbuf::Pixbuf#new_from_bytes


[View source]
def self.new_from_inline(data : Bytes, copy_pixels : Bool) : self #

Creates a Gdk::Pixbuf from a flat representation that is suitable for storing as inline data in a program.

This is useful if you want to ship a program with images, but don't want to depend on any external files.

Gdk::Pixbuf ships with a program called gdk-pixbuf-csource, which allows for conversion of Gdk::Pixbufs into such a inline representation.

In almost all cases, you should pass the --raw option to gdk-pixbuf-csource. A sample invocation would be:

gdk-pixbuf-csource --raw --name=myimage_inline myimage.png

For the typical case where the inline pixbuf is read-only static data, you don't need to copy the pixel data unless you intend to write to it, so you can pass FALSE for copy_pixels. If you pass --rle to gdk-pixbuf-csource, a copy will be made even if copy_pixels is FALSE, so using this option is generally a bad idea.

If you create a pixbuf from const inline data compiled into your program, it's probably safe to ignore errors and disable length checks, since things will always succeed:

WARNING ⚠️ The following code is in c ⚠️

pixbuf = gdk_pixbuf_new_from_inline (-1, myimage_inline, FALSE, NULL);

For non-const inline data, you could get out of memory. For untrusted inline data located at runtime, you could have corrupt inline data in addition.

DEPRECATED


[View source]
def self.new_from_xpm_data(data : Enumerable(String)) : self #

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.


[View source]

Class Method Detail

def self.calculate_rowstride(colorspace : GdkPixbuf::Colorspace, has_alpha : Bool, bits_per_sample : Int32, width : Int32, height : Int32) : Int32 #

Calculates the rowstride that an image created with those values would have.

This function is useful for front-ends and backends that want to check image values without needing to create a Gdk::Pixbuf.


[View source]
def self.file_info(filename : String) : GdkPixbuf::PixbufFormat | Nil #

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


[View source]
def self.file_info_async(filename : String, cancellable : Gio::Cancellable | Nil, callback : Gio::AsyncReadyCallback | Nil, user_data : Pointer(Void) | Nil) : Nil #

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

For more details see gdk_pixbuf_get_file_info(), which is the synchronous version of this function.

When the operation is finished, callback will be called in the main thread. You can then call gdk_pixbuf_get_file_info_finish() to get the result of the operation.


[View source]
def self.formats : GLib::SList #

Obtains the available information about the image formats supported by Gdk::Pixbuf.


[View source]
def self.g_type : UInt64 #

Returns the type id (GType) registered in GLib type system.


[View source]
def self.new_from_file(filename : String) : self | Nil #

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.


[View source]
def self.new_from_file_at_scale(filename : String, width : Int32, height : Int32, preserve_aspect_ratio : Bool) : self | Nil #

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.


[View source]
def self.new_from_file_at_size(filename : String, width : Int32, height : Int32) : self | Nil #

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 Gdk::Pixbuf::Pixbuf#new_from_file_at_scale.


[View source]
def self.new_from_resource(resource_path : String) : self | Nil #

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.


[View source]
def self.new_from_resource_at_scale(resource_path : String, width : Int32, height : Int32, preserve_aspect_ratio : Bool) : self | Nil #

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.


[View source]
def self.new_from_stream(stream : Gio::InputStream, cancellable : Gio::Cancellable | Nil) : self | Nil #

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.


[View source]
def self.new_from_stream_async(stream : Gio::InputStream, cancellable : Gio::Cancellable | Nil, callback : Gio::AsyncReadyCallback | Nil, user_data : Pointer(Void) | Nil) : Nil #

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

For more details see gdk_pixbuf_new_from_stream(), which is the synchronous version of this function.

When the operation is finished, callback will be called in the main thread. You can then call gdk_pixbuf_new_from_stream_finish() to get the result of the operation.


[View source]
def self.new_from_stream_at_scale(stream : Gio::InputStream, width : Int32, height : Int32, preserve_aspect_ratio : Bool, cancellable : Gio::Cancellable | Nil) : self | Nil #

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.


[View source]
def self.new_from_stream_at_scale_async(stream : Gio::InputStream, width : Int32, height : Int32, preserve_aspect_ratio : Bool, cancellable : Gio::Cancellable | Nil, callback : Gio::AsyncReadyCallback | Nil, user_data : Pointer(Void) | Nil) : Nil #

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

For more details see gdk_pixbuf_new_from_stream_at_scale(), which is the synchronous version of this function.

When the operation is finished, callback will be called in the main thread. You can then call gdk_pixbuf_new_from_stream_finish() to get the result of the operation.


[View source]
def self.new_from_stream_finish(async_result : Gio::AsyncResult) : self | Nil #

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


[View source]
def self.new_from_xpm_data(*data : String) #

[View source]

Instance Method Detail

def ==(other : self) #
Description copied from class Reference

Returns true if this reference is the same as other. Invokes same?.


def add_alpha(substitute_color : Bool, r : UInt8, g : UInt8, b : UInt8) : GdkPixbuf::Pixbuf #

Takes an existing pixbuf and adds an alpha channel to it.

If the existing pixbuf already had an alpha channel, the channel values are copied from the original; otherwise, the alpha channel is initialized to 255 (full opacity).

If substitute_color is TRUE, then the color specified by the (r, g, b) arguments will be assigned zero opacity. That is, if you pass (255, 255, 255) for the substitute color, all white pixels will become fully transparent.

If substitute_color is FALSE, then the (r, g, b) arguments will be ignored.


[View source]
def apply_embedded_orientation : GdkPixbuf::Pixbuf | Nil #

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.


[View source]
def bits_per_sample : Int32 #

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


[View source]
def bits_per_sample=(value : Int32) : Int32 #

[View source]
def byte_length : UInt64 #

Returns the length of the pixel data, in bytes.


[View source]
def colorspace : GdkPixbuf::Colorspace #

Queries the color space of a pixbuf.


[View source]
def colorspace=(value : GdkPixbuf::Colorspace) : GdkPixbuf::Colorspace #

[View source]
def composite(dest : GdkPixbuf::Pixbuf, dest_x : Int32, dest_y : Int32, dest_width : Int32, dest_height : Int32, offset_x : Float64, offset_y : Float64, scale_x : Float64, scale_y : Float64, interp_type : GdkPixbuf::InterpType, overall_alpha : Int32) : Nil #

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.


[View source]
def composite_color(dest : GdkPixbuf::Pixbuf, dest_x : Int32, dest_y : Int32, dest_width : Int32, dest_height : Int32, offset_x : Float64, offset_y : Float64, scale_x : Float64, scale_y : Float64, interp_type : GdkPixbuf::InterpType, overall_alpha : Int32, check_x : Int32, check_y : Int32, check_size : Int32, color1 : UInt32, color2 : UInt32) : Nil #

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 alpha blends the rectangle (@dest_x ,@dest_y, dest_width, dest_height) of the resulting image with a checkboard of the colors color1 and color2 and renders it onto the destination image.

If the source image has no alpha channel, and overall_alpha is 255, a fast path is used which omits the alpha blending and just performs the scaling.

See gdk_pixbuf_composite_color_simple() for a simpler variant of this function suitable for many tasks.


[View source]
def composite_color_simple(dest_width : Int32, dest_height : Int32, interp_type : GdkPixbuf::InterpType, overall_alpha : Int32, check_size : Int32, color1 : UInt32, color2 : UInt32) : GdkPixbuf::Pixbuf | Nil #

Creates a new pixbuf by scaling src to dest_width x dest_height and alpha blending the result with a checkboard of colors color1 and color2.


[View source]
def copy : GdkPixbuf::Pixbuf | Nil #

Creates a new Gdk::Pixbuf with a copy of the information in the specified pixbuf.

Note that this does not copy the options set on the original Gdk::Pixbuf, use gdk_pixbuf_copy_options() for this.


[View source]
def copy_area(src_x : Int32, src_y : Int32, width : Int32, height : Int32, dest_pixbuf : GdkPixbuf::Pixbuf, dest_x : Int32, dest_y : Int32) : Nil #

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.


[View source]
def copy_options(dest_pixbuf : GdkPixbuf::Pixbuf) : Bool #

Copies the key/value pair options attached to a Gdk::Pixbuf to another Gdk::Pixbuf.

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.


[View source]
def file_info_finish(async_result : Gio::AsyncResult, width : Int32, height : Int32) : GdkPixbuf::PixbufFormat | Nil #

[View source]
def fill(pixel : UInt32) : Nil #

Clears a pixbuf to the given RGBA value, converting the RGBA value into the pixbuf's pixel format.

The alpha component will be ignored if the pixbuf doesn't have an alpha channel.


[View source]
def flip(horizontal : Bool) : GdkPixbuf::Pixbuf | Nil #

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


[View source]
def has_alpha : Bool #

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


[View source]
def has_alpha=(value : Bool) : Bool #

[View source]
def has_alpha? : Bool #

[View source]
def hash(hasher) #
Description copied from class Reference

See Object#hash(hasher)


def height : Int32 #

Queries the height of a pixbuf.


[View source]
def height=(value : Int32) : Int32 #

[View source]
def init_modules(path : String) : Bool #

[View source]
def n_channels : Int32 #

Queries the number of channels of a pixbuf.


[View source]
def n_channels=(value : Int32) : Int32 #

[View source]
def new_subpixbuf(src_x : Int32, src_y : Int32, width : Int32, height : Int32) : GdkPixbuf::Pixbuf #

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.


[View source]
def option(key : String) : String | Nil #

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.


[View source]
def options : Pointer(Void) #

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 Gdk::Pixbuf::Pixbuf#option=.


[View source]
def pixel_bytes : GLib::Bytes | Nil #

[View source]
def pixel_bytes=(value : GLib::Bytes | Nil) : GLib::Bytes | Nil #

[View source]
def pixels : Bytes #

Queries a pointer to the pixel data of a pixbuf.

This function will cause an implicit copy of the pixbuf data if the pixbuf was created from read-only data.

Please see the section on image data for information about how the pixel data is stored in memory.


[View source]
def pixels=(value : Pointer(Void)) : Pointer(Void) #

[View source]
def read_pixel_bytes : GLib::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.


[View source]
def read_pixels : Pointer(UInt8) #

Provides a read-only pointer to the raw pixel data.

This function allows skipping the implicit copy that must be made if gdk_pixbuf_get_pixels() is called on a read-only pixbuf.


[View source]
def remove_option(key : String) : Bool #

Removes the key/value pair option attached to a Gdk::Pixbuf.


[View source]
def rotate_simple(angle : GdkPixbuf::PixbufRotation) : GdkPixbuf::Pixbuf | Nil #

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.


[View source]
def rowstride : Int32 #

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.


[View source]
def rowstride=(value : Int32) : Int32 #

[View source]
def saturate_and_pixelate(dest : GdkPixbuf::Pixbuf, saturation : Float32, pixelate : Bool) : Nil #

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.


[View source]
def save_to_bufferv(buffer : Bytes, type : String, option_keys : Enumerable(String) | Nil, option_values : Enumerable(String) | Nil) : Bool #

Vector version of gdk_pixbuf_save_to_buffer().

Saves pixbuf to a new buffer in format type, which is currently "jpeg", "tiff", "png", "ico" or "bmp".

See Gdk::Pixbuf::Pixbuf#save_to_buffer for more details.


[View source]
def save_to_callbackv(save_func : GdkPixbuf::PixbufSaveFunc, user_data : Pointer(Void) | Nil, type : String, option_keys : Enumerable(String) | Nil, option_values : Enumerable(String) | Nil) : Bool #

Vector version of gdk_pixbuf_save_to_callback().

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::Pixbuf#save_to_callback for more details.


[View source]
def save_to_stream_finish(async_result : Gio::AsyncResult) : Bool #

[View source]
def save_to_streamv(stream : Gio::OutputStream, type : String, option_keys : Enumerable(String) | Nil, option_values : Enumerable(String) | Nil, cancellable : Gio::Cancellable | Nil) : Bool #

Saves pixbuf to an output stream.

Supported file formats are currently "jpeg", "tiff", "png", "ico" or "bmp".

See Gdk::Pixbuf::Pixbuf#save_to_stream for more details.


[View source]
def save_to_streamv_async(stream : Gio::OutputStream, type : String, option_keys : Enumerable(String) | Nil, option_values : Enumerable(String) | Nil, cancellable : Gio::Cancellable | Nil, callback : Gio::AsyncReadyCallback | Nil, user_data : Pointer(Void) | Nil) : Nil #

Saves pixbuf to an output stream asynchronously.

For more details see gdk_pixbuf_save_to_streamv(), which is the synchronous version of this function.

When the operation is finished, callback will be called in the main thread.

You can then call gdk_pixbuf_save_to_stream_finish() to get the result of the operation.


[View source]
def savev(filename : String, type : String, option_keys : Enumerable(String) | Nil, option_values : Enumerable(String) | Nil) : Bool #

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 Gdk::Pixbuf::Pixbuf#save for more details.


[View source]
def scale(dest : GdkPixbuf::Pixbuf, dest_x : Int32, dest_y : Int32, dest_width : Int32, dest_height : Int32, offset_x : Float64, offset_y : Float64, scale_x : Float64, scale_y : Float64, interp_type : GdkPixbuf::InterpType) : Nil #

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.


[View source]
def scale_simple(dest_width : Int32, dest_height : Int32, interp_type : GdkPixbuf::InterpType) : GdkPixbuf::Pixbuf | Nil #

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 Gdk::Pixbuf::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 Gdk::Pixbuf::Pixbuf#scale and Gdk::Pixbuf::Pixbuf#composite.


[View source]
def set_option(key : String, value : String) : Bool #

Attaches a key/value pair as an option to a Gdk::Pixbuf.

If key already exists in the list of options attached to the pixbuf, the new value is ignored and FALSE is returned.


[View source]
def width : Int32 #

Queries the width of a pixbuf.


[View source]
def width=(value : Int32) : Int32 #

[View source]