#include <drawable.h>

Inheritance diagram for Gdk::Drawable:

Public Member Functions
virtual	~Drawable ()

GdkDrawable *	gobj ()
	Provides access to the underlying C GObject. More...

const GdkDrawable *	gobj () const
	Provides access to the underlying C GObject. More...

GdkDrawable *	gobj_copy ()
	Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs. More...

void	get_size (int &width, int &height)

void	get_size (int &width, int &height) const

int	get_depth () const

void	set_colormap (const Glib::RefPtr< Colormap > &colormap)

Glib::RefPtr< Colormap >	get_colormap ()

Glib::RefPtr< Visual >	get_visual ()

void	draw_point (const Glib::RefPtr< const GC > &gc, int x, int y)

void	draw_points (const Glib::RefPtr< const GC > &gc, const Glib::ArrayHandle< Point > &points)

void	draw_line (const Glib::RefPtr< const GC > &gc, int x1, int y1, int x2, int y2)

void	draw_lines (const Glib::RefPtr< const GC > &gc, const Glib::ArrayHandle< Point > &points)

void	draw_rectangle (const Glib::RefPtr< const GC > &gc, bool filled, int x, int y, int width, int height)

void	draw_arc (const Glib::RefPtr< const GC > &gc, bool filled, int x, int y, int width, int height, int angle1, int angle2)

void	draw_polygon (const Glib::RefPtr< const GC > &gc, bool filled, const Glib::ArrayHandle< Point > &points)

void	draw_drawable (const Glib::RefPtr< const GC > &gc, const Glib::RefPtr< const Drawable > &src, int xsrc, int ysrc, int xdest, int ydest, int width=-1, int height=-1)

void	draw_image (const Glib::RefPtr< const GC > &gc, const Glib::RefPtr< const Image > &image, int xsrc, int ysrc, int xdest, int ydest, int width=-1, int height=-1)

void	draw_segments (const Glib::RefPtr< const GC > &gc, GdkSegment *segs, int n_segs)

void	draw_glyphs (const Glib::RefPtr< const GC > &gc, const Glib::RefPtr< const Pango::Font > &font, int x, int y, const Pango::GlyphString &glyphs)

void	draw_layout_line (const Glib::RefPtr< const GC > &gc, int x, int y, const Glib::RefPtr< const Pango::LayoutLine > &line)

void	draw_layout_line (const Glib::RefPtr< const GC > &gc, int x, int y, const Glib::RefPtr< const Pango::LayoutLine > &line, const Color &foreground, const Color &background)

void	draw_layout (const Glib::RefPtr< const GC > &gc, int x, int y, const Glib::RefPtr< const Pango::Layout > &layout)

void	draw_layout (const Glib::RefPtr< const GC > &gc, int x, int y, const Glib::RefPtr< const Pango::Layout > &layout, const Color &foreground, const Color &background)

void	draw_pixbuf (const Glib::RefPtr< const GC > &gc, const Glib::RefPtr< Pixbuf > &pixbuf, int src_x, int src_y, int dest_x, int dest_y, int width, int height, RgbDither dither, int x_dither, int y_dither)

void	draw_pixbuf (const Glib::RefPtr< Pixbuf > &pixbuf, int src_x, int src_y, int dest_x, int dest_y, int width, int height, RgbDither dither, int x_dither, int y_dither)

Glib::RefPtr< Image >	get_image (int x, int y, int width, int height) const

void	copy_to_image (const Glib::RefPtr< Image > &image, int src_x, int src_y, int dest_x, int dest_y, int width, int height) const

Region	get_clip_region () const

Region	get_visible_region () const

void	draw_rgb_image (const Glib::RefPtr< const GC > &gc, int x, int y, int width, int height, RgbDither dith, const guchar *rgb_buf, int rowstride)

void	draw_rgb_image_dithalign (const Glib::RefPtr< const GC > &gc, int x, int y, int width, int height, RgbDither dith, const guchar *rgb_buf, int rowstride, int xdith, int ydith)

void	draw_rgb_32_image (const Glib::RefPtr< const GC > &gc, int x, int y, int width, int height, RgbDither dith, const guchar *rgb_buf, int rowstride)

void	draw_rgb_32_image_dithalign (const Glib::RefPtr< const GC > &gc, int x, int y, int width, int height, RgbDither dith, const guchar *buf, int rowstride, int xdith, int ydith)

void	draw_gray_image (const Glib::RefPtr< const GC > &gc, int x, int y, int width, int height, RgbDither dith, const guchar *rgb_buf, int rowstride)

void	draw_indexed_image (const Glib::RefPtr< const GC > &gc, int x, int y, int width, int height, RgbDither dith, const guchar *rgb_buf, int rowstride, const RgbCmap &cmap)

Glib::RefPtr< Screen >	get_screen ()

Glib::RefPtr< const Screen >	get_screen () const

Glib::RefPtr< Display >	get_display ()

Glib::RefPtr< const Display >	get_display () const

Cairo::RefPtr< Cairo::Context >	create_cairo_context ()

Static Public Member Functions
static GType	get_type () G_GNUC_CONST

static Glib::RefPtr< Drawable >	create ()

Protected Member Functions
	Drawable ()

Related Functions
(Note that these are not member functions.)
Glib::RefPtr< Gdk::Drawable >	wrap (GdkDrawable *object, bool take_copy=false)

Detailed Description

Drawing Primitives. Gdk::Drawable is the base class for all of the objects that accept drawing commands. The available drawables include pixmaps, windows, and bitmaps. Drawable is abstract as there is no such type on the server side.

To use a drawable, create a concrete Drawable of the type you wish to use and a Gdk::GC (graphics context) for that Drawable. With the GC you can draw lines, text, arcs and such.

An alternative is to create a Cairo::Context with get_cairo_context() while you handle the 'exposed' event of the drawable. For more about this, please see "Using cairo with GTK+" in the "Common questions" section of the GTK+ Reference Manual.

Definition at line 110 of file drawable.h.

Constructor & Destructor Documentation

◆ ~Drawable()

virtual Gdk::Drawable::~Drawable ( )

virtual

◆ Drawable()

Gdk::Drawable::Drawable ( )

protected

Member Function Documentation

◆ copy_to_image()

void Gdk::Drawable::copy_to_image	(	const Glib::RefPtr< Image > &	image,
		int	src_x,
		int	src_y,
		int	dest_x,
		int	dest_y,
		int	width,
		int	height
	)		const

◆ create()

static Glib::RefPtr<Drawable> Gdk::Drawable::create ( )

static

◆ create_cairo_context()

Cairo::RefPtr<Cairo::Context> Gdk::Drawable::create_cairo_context ( )

Creates a Cairo context for drawing to drawable.

Returns: A newly created Cairo context.

◆ draw_arc()

void Gdk::Drawable::draw_arc	(	const Glib::RefPtr< const GC > &	gc,
		bool	filled,
		int	x,
		int	y,
		int	width,
		int	height,
		int	angle1,
		int	angle2
	)

Draws an arc or a filled 'pie slice'. The arc is defined by the bounding rectangle of the entire ellipse, and the start and end angles of the part of the ellipse to be drawn.

Deprecated: 2.22: Use cairo_arc() and cairo_fill() or cairo_stroke() instead. Note that arcs just like any drawing operation in Cairo are antialiased unless you call cairo_set_antialias().

Parameters

gc	A Gdk::GC.
filled	`true` if the arc should be filled, producing a 'pie slice'.
x	The x coordinate of the left edge of the bounding rectangle.
y	The y coordinate of the top edge of the bounding rectangle.
width	The width of the bounding rectangle.
height	The height of the bounding rectangle.
angle1	The start angle of the arc, relative to the 3 o'clock position, counter-clockwise, in 1/64ths of a degree.
angle2	The end angle of the arc, relative to angle1, in 1/64ths of a degree.

◆ draw_drawable()

void Gdk::Drawable::draw_drawable	(	const Glib::RefPtr< const GC > &	gc,
		const Glib::RefPtr< const Drawable > &	src,
		int	xsrc,
		int	ysrc,
		int	xdest,
		int	ydest,
		int	width = `-1`,
		int	height = `-1`
	)

Copies the width x height region of src at coordinates ( xsrc, ysrc) to coordinates ( xdest, ydest) in drawable. width and/or height may be given as -1, in which case the entire src drawable will be copied.

Most fields in gc are not used for this operation, but notably the clip mask or clip region will be honored.

The source and destination drawables must have the same visual and colormap, or errors will result. (On X11, failure to match visual/colormap results in a BadMatch error from the X server.) A common cause of this problem is an attempt to draw a bitmap to a color drawable. The way to draw a bitmap is to set the bitmap as the stipple on the Gdk::GC, set the fill mode to Gdk::STIPPLED, and then draw the rectangle.

Deprecated: 2.22: Use gdk_cairo_set_source_pixmap(), cairo_rectangle() and cairo_fill() to draw pixmap on top of other drawables. Also keep in mind that the limitations on allowed sources do not apply to Cairo.

Parameters

gc	A Gdk::GC sharing the drawable's visual and colormap.
src	The source Gdk::Drawable, which may be the same as drawable.
xsrc	X position in src of rectangle to draw.
ysrc	Y position in src of rectangle to draw.
xdest	X position in drawable where the rectangle should be drawn.
ydest	Y position in drawable where the rectangle should be drawn.
width	Width of rectangle to draw, or -1 for entire src width.
height	Height of rectangle to draw, or -1 for entire src height.

◆ draw_glyphs()

void Gdk::Drawable::draw_glyphs	(	const Glib::RefPtr< const GC > &	gc,
		const Glib::RefPtr< const Pango::Font > &	font,
		int	x,
		int	y,
		const Pango::GlyphString &	glyphs
	)

This is a low-level function; 99% of text rendering should be done using gdk_draw_layout() instead.

A glyph is a single image in a font. This function draws a sequence of glyphs. To obtain a sequence of glyphs you have to understand a lot about internationalized text handling, which you don't want to understand; thus, use gdk_draw_layout() instead of this function, gdk_draw_layout() handles the details.

Deprecated: 2.22: Use pango_cairo_show_glyphs() instead.

Parameters

gc	A Gdk::GC.
font	Font to be used.
x	X coordinate of baseline origin.
y	Y coordinate of baseline origin.
glyphs	The glyph string to draw.

◆ draw_gray_image()

void Gdk::Drawable::draw_gray_image	(	const Glib::RefPtr< const GC > &	gc,
		int	x,
		int	y,
		int	width,
		int	height,
		RgbDither	dith,
		const guchar *	rgb_buf,
		int	rowstride
	)

◆ draw_image()

void Gdk::Drawable::draw_image	(	const Glib::RefPtr< const GC > &	gc,
		const Glib::RefPtr< const Image > &	image,
		int	xsrc,
		int	ysrc,
		int	xdest,
		int	ydest,
		int	width = `-1`,
		int	height = `-1`
	)

Draws a Gdk::Image onto a drawable. The depth of the Gdk::Image must match the depth of the Gdk::Drawable.

Deprecated: 2.22: Do not use Gdk::Image anymore, instead use Cairo image surfaces.

Parameters

gc	A Gdk::GC.
image	The Gdk::Image to draw.
xsrc	The left edge of the source rectangle within image.
ysrc	The top of the source rectangle within image.
xdest	The x coordinate of the destination within drawable.
ydest	The y coordinate of the destination within drawable.
width	The width of the area to be copied, or -1 to make the area extend to the right edge of image.
height	The height of the area to be copied, or -1 to make the area extend to the bottom edge of image.

◆ draw_indexed_image()

void Gdk::Drawable::draw_indexed_image	(	const Glib::RefPtr< const GC > &	gc,
		int	x,
		int	y,
		int	width,
		int	height,
		RgbDither	dith,
		const guchar *	rgb_buf,
		int	rowstride,
		const RgbCmap &	cmap
	)

◆ draw_layout() [1/2]

void Gdk::Drawable::draw_layout	(	const Glib::RefPtr< const GC > &	gc,
		int	x,
		int	y,
		const Glib::RefPtr< const Pango::Layout > &	layout
	)

Render a Pango::Layout onto a GDK drawable

If the layout's Pango::Context has a transformation matrix set, then x and y specify the position of the top left corner of the bounding box (in device space) of the transformed layout.

If you're using GTK+, the usual way to obtain a Pango::Layout is gtk_widget_create_pango_layout().

Parameters

gc	Base graphics context to use.
x	The X position of the left of the layout (in pixels).
y	The Y position of the top of the layout (in pixels).
layout	A Pango::Layout.

◆ draw_layout() [2/2]

void Gdk::Drawable::draw_layout	(	const Glib::RefPtr< const GC > &	gc,
		int	x,
		int	y,
		const Glib::RefPtr< const Pango::Layout > &	layout,
		const Color &	foreground,
		const Color &	background
	)

Render a Pango::Layout onto a Gdk::Drawable, overriding the layout's normal colors with foreground and/or background. foreground and background need not be allocated.

If the layout's Pango::Context has a transformation matrix set, then x and y specify the position of the top left corner of the bounding box (in device space) of the transformed layout.

If you're using GTK+, the ususal way to obtain a Pango::Layout is gtk_widget_create_pango_layout().

Parameters

gc	Base graphics context to use.
x	The X position of the left of the layout (in pixels).
y	The Y position of the top of the layout (in pixels).
layout	A Pango::Layout.
foreground	Foreground override color, or `0` for none.
background	Background override color, or `0` for none.

◆ draw_layout_line() [1/2]

void Gdk::Drawable::draw_layout_line	(	const Glib::RefPtr< const GC > &	gc,
		int	x,
		int	y,
		const Glib::RefPtr< const Pango::LayoutLine > &	line
	)

Render a Pango::LayoutLine onto an GDK drawable

If the layout's Pango::Context has a transformation matrix set, then x and y specify the position of the left edge of the baseline (left is in before-tranform user coordinates) in after-transform device coordinates.

Parameters

gc	Base graphics to use.
x	The x position of start of string (in pixels).
y	The y position of baseline (in pixels).
line	A Pango::LayoutLine.

◆ draw_layout_line() [2/2]

void Gdk::Drawable::draw_layout_line	(	const Glib::RefPtr< const GC > &	gc,
		int	x,
		int	y,
		const Glib::RefPtr< const Pango::LayoutLine > &	line,
		const Color &	foreground,
		const Color &	background
	)

Render a Pango::LayoutLine onto a Gdk::Drawable, overriding the layout's normal colors with foreground and/or background. foreground and background need not be allocated.

If the layout's Pango::Context has a transformation matrix set, then x and y specify the position of the left edge of the baseline (left is in before-tranform user coordinates) in after-transform device coordinates.

Parameters

gc	Base graphics to use.
x	The x position of start of string (in pixels).
y	The y position of baseline (in pixels).
line	A Pango::LayoutLine.
foreground	Foreground override color, or `0` for none.
background	Background override color, or `0` for none.

◆ draw_line()

void Gdk::Drawable::draw_line	(	const Glib::RefPtr< const GC > &	gc,
		int	x1,
		int	y1,
		int	x2,
		int	y2
	)

Draws a line, using the foreground color and other attributes of the Gdk::GC.

Deprecated: 2.22: Use cairo_line_to() and cairo_stroke() instead. Be aware that the default line width in Cairo is 2 pixels and that your coordinates need to describe the center of the line. To draw a single pixel wide pixel-aligned line, you would use:

[C example ellipted] See also the Cairo FAQ on this topic.

Parameters

gc	A Gdk::GC.
x1	The x coordinate of the start point.
y1	The y coordinate of the start point.
x2	The x coordinate of the end point.
y2	The y coordinate of the end point.

◆ draw_lines()

void Gdk::Drawable::draw_lines	(	const Glib::RefPtr< const GC > &	gc,
		const Glib::ArrayHandle< Point > &	points
	)

◆ draw_pixbuf() [1/2]

void Gdk::Drawable::draw_pixbuf	(	const Glib::RefPtr< const GC > &	gc,
		const Glib::RefPtr< Pixbuf > &	pixbuf,
		int	src_x,
		int	src_y,
		int	dest_x,
		int	dest_y,
		int	width,
		int	height,
		RgbDither	dither,
		int	x_dither,
		int	y_dither
	)

Renders a rectangular portion of a pixbuf to a drawable. The destination drawable must have a colormap. All windows have a colormap, however, pixmaps only have colormap by default if they were created with a non-0 window argument. Otherwise a colormap must be set on them with Gdk::Drawable::set_colormap().

On older X servers, rendering pixbufs with an alpha channel involves round trips to the X server, and may be somewhat slow.

The clip mask of gc is ignored, but clip rectangles and clip regions work fine.

If GDK is built with the Sun mediaLib library, the gdk_draw_pixbuf function is accelerated using mediaLib, which provides hardware acceleration on Intel, AMD, and Sparc chipsets. If desired, mediaLib support can be turned off by setting the GDK_DISABLE_MEDIALIB environment variable.

Parameters

gc	A Gdk::GC, used for clipping.
pixbuf	A Gdk::Pixbuf.
src_x	Source X coordinate within pixbuf.
src_y	Source Y coordinates within pixbuf.
dest_x	Destination X coordinate within drawable.
dest_y	Destination Y coordinate within drawable.
width	Width of region to render, in pixels, or -1 to use pixbuf width.
height	Height of region to render, in pixels, or -1 to use pixbuf height.
dither	Dithering mode for Gdk::RGB.
x_dither	X offset for dither.
y_dither	Y offset for dither.

◆ draw_pixbuf() [2/2]

void Gdk::Drawable::draw_pixbuf	(	const Glib::RefPtr< Pixbuf > &	pixbuf,
		int	src_x,
		int	src_y,
		int	dest_x,
		int	dest_y,
		int	width,
		int	height,
		RgbDither	dither,
		int	x_dither,
		int	y_dither
	)

Renders a rectangular portion of a pixbuf to a drawable. The destination drawable must have a colormap. All windows have a colormap, however, pixmaps only have colormap by default if they were created with a non-0 window argument. Otherwise a colormap must be set on them with Gdk::Drawable::set_colormap().

On older X servers, rendering pixbufs with an alpha channel involves round trips to the X server, and may be somewhat slow.

If GDK is built with the Sun mediaLib library, the gdk_draw_pixbuf function is accelerated using mediaLib, which provides hardware acceleration on Intel, AMD, and Sparc chipsets. If desired, mediaLib support can be turned off by setting the GDK_DISABLE_MEDIALIB environment variable.

Parameters

pixbuf	A Gdk::Pixbuf.
src_x	Source X coordinate within pixbuf.
src_y	Source Y coordinates within pixbuf.
dest_x	Destination X coordinate within drawable.
dest_y	Destination Y coordinate within drawable.
width	Width of region to render, in pixels, or -1 to use pixbuf width.
height	Height of region to render, in pixels, or -1 to use pixbuf height.
dither	Dithering mode for Gdk::RGB.
x_dither	X offset for dither.
y_dither	Y offset for dither.

◆ draw_point()

void Gdk::Drawable::draw_point	(	const Glib::RefPtr< const GC > &	gc,
		int	x,
		int	y
	)

Draws a point, using the foreground color and other attributes of the Gdk::GC.

Deprecated: 2.22: Use cairo_rectangle() and cairo_fill() or cairo_move_to() and cairo_stroke() instead.

Parameters

gc	A Gdk::GC.
x	The x coordinate of the point.
y	The y coordinate of the point.

◆ draw_points()

void Gdk::Drawable::draw_points	(	const Glib::RefPtr< const GC > &	gc,
		const Glib::ArrayHandle< Point > &	points
	)

◆ draw_polygon()

void Gdk::Drawable::draw_polygon	(	const Glib::RefPtr< const GC > &	gc,
		bool	filled,
		const Glib::ArrayHandle< Point > &	points
	)

◆ draw_rectangle()

void Gdk::Drawable::draw_rectangle	(	const Glib::RefPtr< const GC > &	gc,
		bool	filled,
		int	x,
		int	y,
		int	width,
		int	height
	)

Draws a rectangular outline or filled rectangle, using the foreground color and other attributes of the Gdk::GC.

A rectangle drawn filled is 1 pixel smaller in both dimensions than a rectangle outlined. Calling gdk_draw_rectangle (window, gc, true, 0, 0, 20, 20) results in a filled rectangle 20 pixels wide and 20 pixels high. Calling gdk_draw_rectangle (window, gc, false, 0, 0, 20, 20) results in an outlined rectangle with corners at (0, 0), (0, 20), (20, 20), and (20, 0), which makes it 21 pixels wide and 21 pixels high.

Deprecated: 2.22: Use cairo_rectangle() and cairo_fill() or cairo_stroke() instead. For stroking, the same caveats for converting code apply as for gdk_draw_line().

Parameters

gc	A Gdk::GC.
filled	`true` if the rectangle should be filled.
x	The x coordinate of the left edge of the rectangle.
y	The y coordinate of the top edge of the rectangle.
width	The width of the rectangle.
height	The height of the rectangle.

◆ draw_rgb_32_image()

void Gdk::Drawable::draw_rgb_32_image	(	const Glib::RefPtr< const GC > &	gc,
		int	x,
		int	y,
		int	width,
		int	height,
		RgbDither	dith,
		const guchar *	rgb_buf,
		int	rowstride
	)

◆ draw_rgb_32_image_dithalign()

void Gdk::Drawable::draw_rgb_32_image_dithalign	(	const Glib::RefPtr< const GC > &	gc,
		int	x,
		int	y,
		int	width,
		int	height,
		RgbDither	dith,
		const guchar *	buf,
		int	rowstride,
		int	xdith,
		int	ydith
	)

Like gdk_draw_rgb_32_image(), but allows you to specify the dither offsets. See gdk_draw_rgb_image_dithalign() for more details.

Deprecated: 2.22: Cairo handles colors automatically.

Parameters

gc	A Gdk::GC.
x	X coordinate on drawable where image should go.
y	Y coordinate on drawable where image should go.
width	Width of area of image to draw.
height	Height of area of image to draw.
dith	Dithering mode.
buf	RGB image data.
rowstride	Rowstride of RGB image data.
xdith	X dither offset.
ydith	Y dither offset.

◆ draw_rgb_image()

void Gdk::Drawable::draw_rgb_image	(	const Glib::RefPtr< const GC > &	gc,
		int	x,
		int	y,
		int	width,
		int	height,
		RgbDither	dith,
		const guchar *	rgb_buf,
		int	rowstride
	)

◆ draw_rgb_image_dithalign()

void Gdk::Drawable::draw_rgb_image_dithalign	(	const Glib::RefPtr< const GC > &	gc,
		int	x,
		int	y,
		int	width,
		int	height,
		RgbDither	dith,
		const guchar *	rgb_buf,
		int	rowstride,
		int	xdith,
		int	ydith
	)

◆ draw_segments()

void Gdk::Drawable::draw_segments	(	const Glib::RefPtr< const GC > &	gc,
		GdkSegment *	segs,
		int	n_segs
	)

Draws a number of unconnected lines.

Deprecated: 2.22: Use cairo_move_to(), cairo_line_to() and cairo_stroke() instead. See the documentation of gdk_draw_line() for notes on line drawing with Cairo.

Parameters

gc	A Gdk::GC.
segs	An array of Gdk::Segment structures specifying the start and end points of the lines to be drawn.
n_segs	The number of line segments to draw, i.e. the size of the segs array.

◆ get_clip_region()

Region Gdk::Drawable::get_clip_region ( ) const

Computes the region of a drawable that potentially can be written to by drawing primitives. This region will not take into account the clip region for the GC, and may also not take into account other factors such as if the window is obscured by other windows, but no area outside of this region will be affected by drawing primitives.

Returns: A Gdk::Region. This must be freed with Gdk::Region::destroy() when you are done.

◆ get_colormap()

Glib::RefPtr<Colormap> Gdk::Drawable::get_colormap ( )

Gets the colormap for drawable, if one is set; returns 0 otherwise.

Returns: The colormap, or 0.

◆ get_depth()

int Gdk::Drawable::get_depth ( ) const

Obtains the bit depth of the drawable, that is, the number of bits that make up a pixel in the drawable's visual. Examples are 8 bits per pixel, 24 bits per pixel, etc.

Returns: Number of bits per pixel.

◆ get_display() [1/2]

Glib::RefPtr<Display> Gdk::Drawable::get_display ( )

Gets the Gdk::Display associated with a Gdk::Drawable.

Deprecated: 2.24: Use Gdk::Window::get_display() instead

Returns: The Gdk::Display associated with drawable.

◆ get_display() [2/2]

Glib::RefPtr<const Display> Gdk::Drawable::get_display ( ) const

Gets the Gdk::Display associated with a Gdk::Drawable.

Deprecated: 2.24: Use Gdk::Window::get_display() instead

Returns: The Gdk::Display associated with drawable.

◆ get_image()

Glib::RefPtr<Image> Gdk::Drawable::get_image	(	int	x,
		int	y,
		int	width,
		int	height
	)		const

A Gdk::Image stores client-side image data (pixels). In contrast, Gdk::Pixmap and Gdk::Window are server-side objects. get_image() obtains the pixels from a server-side drawable as a client-side Gdk::Image. The format of a Gdk::Image depends on the Gdk::Visual of the current display, which makes manipulating Gdk::Image extremely difficult; therefore, in most cases you should use the Gdk::Pixbuf::create() method that takes a Gdk::Drawable, instead of this lower-level function. A Gdk::Pixbuf contains image data in a canonicalized RGB format, rather than a display-dependent format. Of course, there's a convenience vs. speed tradeoff here, so you'll want to think about what makes sense for your application.

x, y, width, and height define the region of drawable to obtain as an image.

You would usually copy image data to the client side if you intend to examine the values of individual pixels, for example to darken an image or add a red tint. It would be prohibitively slow to make a round-trip request to the windowing system for each pixel, so instead you get all of them at once, modify them, then copy them all back at once.

If the X server or other windowing system backend is on the local machine, this function may use shared memory to avoid copying the image data.

If the source drawable is a Gdk::Window and partially offscreen or obscured, then the obscured portions of the returned image will contain undefined data.

Parameters

x	X coordinate on drawable.
y	Y coordinate on drawable.
width	Width of region to get.
height	Height or region to get.

Returns: A Gdk::Image containing the contents of drawable.

◆ get_screen() [1/2]

Glib::RefPtr<Screen> Gdk::Drawable::get_screen ( )

Gets the Gdk::Screen associated with a Gdk::Drawable.

Deprecated: 2.24: Use Gdk::Window::get_screen() instead

Returns: The Gdk::Screen associated with drawable.

◆ get_screen() [2/2]

Glib::RefPtr<const Screen> Gdk::Drawable::get_screen ( ) const

Gets the Gdk::Screen associated with a Gdk::Drawable.

Deprecated: 2.24: Use Gdk::Window::get_screen() instead

Returns: The Gdk::Screen associated with drawable.

◆ get_size() [1/2]

void Gdk::Drawable::get_size	(	int &	width,
		int &	height
	)

Fills * width and * height with the size of drawable. width or height can be 0 if you only want the other one.

On the X11 platform, if drawable is a Gdk::Window, the returned size is the size reported in the most-recently-processed configure event, rather than the current size on the X server.

Deprecated: 2.24: Use Gdk::Window::get_width() and Gdk::Window::get_height() for Gdk::Windows. Use gdk_pixmap_get_size() for Gdk::Pixmaps.

Parameters

width	Location to store drawable's width, or `0`.
height	Location to store drawable's height, or `0`.

◆ get_size() [2/2]

void Gdk::Drawable::get_size	(	int &	width,
		int &	height
	)		const

Fills * width and * height with the size of drawable. width or height can be 0 if you only want the other one.

On the X11 platform, if drawable is a Gdk::Window, the returned size is the size reported in the most-recently-processed configure event, rather than the current size on the X server.

Deprecated: 2.24: Use Gdk::Window::get_width() and Gdk::Window::get_height() for Gdk::Windows. Use gdk_pixmap_get_size() for Gdk::Pixmaps.

Parameters

width	Location to store drawable's width, or `0`.
height	Location to store drawable's height, or `0`.

◆ get_type()

static GType Gdk::Drawable::get_type ( )

static

Get the GType for this class, for use with the underlying GObject type system.

◆ get_visible_region()

Region Gdk::Drawable::get_visible_region ( ) const

Computes the region of a drawable that is potentially visible. This does not necessarily take into account if the window is obscured by other windows, but no area outside of this region is visible.

Returns: A Gdk::Region. This must be freed with Gdk::Region::destroy() when you are done.

◆ get_visual()

Glib::RefPtr<Visual> Gdk::Drawable::get_visual ( )

Gets the Gdk::Visual describing the pixel format of drawable.

Deprecated: 2.24: Use Gdk::Window::get_visual()

Returns: A Gdk::Visual.

◆ gobj() [1/2]

GdkDrawable* Gdk::Drawable::gobj ( )

inline

Provides access to the underlying C GObject.

Definition at line 149 of file drawable.h.

◆ gobj() [2/2]

const GdkDrawable* Gdk::Drawable::gobj ( ) const

inline

Provides access to the underlying C GObject.

Definition at line 152 of file drawable.h.

◆ gobj_copy()

GdkDrawable* Gdk::Drawable::gobj_copy ( )

Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs.

◆ set_colormap()

void Gdk::Drawable::set_colormap ( const Glib::RefPtr< Colormap > & colormap )

Sets the colormap associated with drawable. Normally this will happen automatically when the drawable is created; you only need to use this function if the drawable-creating function did not have a way to determine the colormap, and you then use drawable operations that require a colormap. The colormap for all drawables and graphics contexts you intend to use together should match. i.e. when using a Gdk::GC to draw to a drawable, or copying one drawable to another, the colormaps should match.

Parameters

colormap A Gdk::Colormap.

Friends And Related Function Documentation

◆ wrap()

Glib::RefPtr< Gdk::Drawable > wrap	(	GdkDrawable *	object,
		bool	take_copy = `false`
	)

Parameters

object	The C instance.
take_copy	False if the result should take ownership of the C instance. True if it should take a new copy or ref.

Returns: A C++ instance that wraps this C instance.

The documentation for this class was generated from the following file:

drawable.h

Public Member Functions

Static Public Member Functions

Protected Member Functions

Related Functions

Detailed Description

Constructor & Destructor Documentation

◆ ~Drawable()

◆ Drawable()

Member Function Documentation

◆ copy_to_image()

◆ create()

◆ create_cairo_context()

◆ draw_arc()

◆ draw_drawable()

◆ draw_glyphs()

◆ draw_gray_image()

◆ draw_image()

◆ draw_indexed_image()

◆ draw_layout() [1/2]

◆ draw_layout() [2/2]

◆ draw_layout_line() [1/2]

◆ draw_layout_line() [2/2]

◆ draw_line()

◆ draw_lines()

◆ draw_pixbuf() [1/2]

◆ draw_pixbuf() [2/2]

◆ draw_point()

◆ draw_points()

◆ draw_polygon()

◆ draw_rectangle()

◆ draw_rgb_32_image()

◆ draw_rgb_32_image_dithalign()

◆ draw_rgb_image()

◆ draw_rgb_image_dithalign()

◆ draw_segments()

◆ get_clip_region()

◆ get_colormap()

◆ get_depth()

◆ get_display() [1/2]

◆ get_display() [2/2]

◆ get_image()

◆ get_screen() [1/2]

◆ get_screen() [2/2]

◆ get_size() [1/2]

◆ get_size() [2/2]

◆ get_type()

◆ get_visible_region()

◆ get_visual()

◆ gobj() [1/2]

◆ gobj() [2/2]

◆ gobj_copy()

◆ set_colormap()

Friends And Related Function Documentation

◆ wrap()