11.9Class GdkDrawable

Functions for drawing points, lines, arcs, and text

Class GdkDrawable

These functions provide support for drawing points, lines, arcs and text onto what are called 'drawables'. Drawables, as the name suggests, are things which support drawing onto them, and are either GdkWindow or GdkPixmap objects.

Many of the drawing operations take a GdkGC argument, which represents a graphics context. This GdkGC contains a number of drawing attributes such as foreground color, background color and line width, and is used to reduce the number of arguments needed for each drawing operation. See the Graphics Contexts section for more information.

Some of the drawing operations take Pango data structures like PangoContext, PangoLayout or PangoLayoutLine as arguments. If you're using GTK+, the ususal way to obtain these structures is via gtk_widget_create_pango_context() or gtk_widget_create_pango_layout().

Methods
draw_lineDraws a line, using the foreground color and other attributes of the GdkGC.
draw_pointDraws a point, using the foreground color and other attributes of the GdkGC.
draw_pointsDraws a number of points, using the foreground color and other attributes of the GdkGC.
get_clip_regionComputes the region of a drawable that potentially can be written to by drawing primitives.
get_colormapGets the colormap for drawable, if one is set; returns NULL otherwise.
get_depthObtains the bit depth of the drawable, that is, the number of bits that make up a pixel in the drawable's visual.
get_screenGets the GdkScreen associated with a GdkDrawable.
get_sizeReturns the size of drawable.
get_visible_regionComputes the region of a drawable that is potentially visible.
get_visualGets the GdkVisual describing the pixel format of drawable.
set_colormapSets the colormap associated with drawable.

Methods

draw_line

Draws a line, using the foreground color and other attributes of the GdkGC.

GdkDrawable.draw_line( gc, x1, y1, x2, y2 )
gc a GdkGC.
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_point

Draws a point, using the foreground color and other attributes of the GdkGC.

GdkDrawable.draw_point( gc, x, y )
gc a GdkGC.
x the x coordinate of the point.
y the y coordinate of the point.

draw_points

Draws a number of points, using the foreground color and other attributes of the GdkGC.

GdkDrawable.draw_points( gc, points )
gc a GdkGC.
points an array of GdkPoint structures.

get_clip_region

Computes the region of a drawable that potentially can be written to by drawing primitives.

GdkDrawable.get_clip_region()
Returna GdkRegion.

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.

get_colormap

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

GdkDrawable.get_colormap()
Returnthe colormap, or NULL

get_depth

Obtains the bit depth of the drawable, that is, the number of bits that make up a pixel in the drawable's visual.

GdkDrawable.get_depth()
Returnnumber of bits per pixel

Examples are 8 bits per pixel, 24 bits per pixel, etc.

get_screen

Gets the GdkScreen associated with a GdkDrawable.

GdkDrawable.get_screen()
Returnthe GdkScreen associated with drawable

get_size

Returns the size of drawable.

GdkDrawable.get_size()
Returnan array [ drawable's width, drawable's height ]

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

get_visible_region

Computes the region of a drawable that is potentially visible.

GdkDrawable.get_visible_region()
Returna GdkRegion.

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

get_visual

Gets the GdkVisual describing the pixel format of drawable.

GdkDrawable.get_visual()
Returna GdkVisual

set_colormap

Sets the colormap associated with drawable.

GdkDrawable.set_colormap( colormap )
colormap a GdkColormap

Normally this will happen automatically when the drawable is created; you on ly 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 GdkGC to draw to a drawable, or copying one drawable to another, the colormaps should match.

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