GdkDrawable

typedef struct _GdkDrawable GdkDrawable;

An opaque structure representing an object that can be drawn onto. This can be a GdkPixmap, a GdkBitmap, or a GdkWindow.

gdk_drawable_ref ()

GdkDrawable*        gdk_drawable_ref                    (GdkDrawable *drawable);

Deprecated equivalent of calling g_object_ref() on drawable. (Drawables were not objects in previous versions of GDK.)

gdk_drawable_unref ()

void                gdk_drawable_unref                  (GdkDrawable *drawable);

Deprecated equivalent of calling g_object_unref() on drawable.

gdk_drawable_set_data ()

void                gdk_drawable_set_data               (GdkDrawable *drawable,
                                                         const gchar *key,
                                                         gpointer data,
                                                         GDestroyNotify destroy_func);

This function is equivalent to g_object_set_data(), the GObject variant should be used instead.

gdk_drawable_get_data ()

gpointer            gdk_drawable_get_data               (GdkDrawable *drawable,
                                                         const gchar *key);

Equivalent to g_object_get_data(); the GObject variant should be used instead.

gdk_drawable_get_display ()

GdkDisplay*         gdk_drawable_get_display            (GdkDrawable *drawable);

Gets the GdkDisplay associated with a GdkDrawable.

Since 2.2

gdk_drawable_get_screen ()

GdkScreen*          gdk_drawable_get_screen             (GdkDrawable *drawable);

Gets the GdkScreen associated with a GdkDrawable.

Since 2.2

gdk_drawable_get_visual ()

GdkVisual*          gdk_drawable_get_visual             (GdkDrawable *drawable);

Gets the GdkVisual describing the pixel format of drawable.

gdk_drawable_set_colormap ()

void                gdk_drawable_set_colormap           (GdkDrawable *drawable,
                                                         GdkColormap *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 GdkGC to draw to a drawable, or copying one drawable to another, the colormaps should match.

gdk_drawable_get_colormap ()

GdkColormap*        gdk_drawable_get_colormap           (GdkDrawable *drawable);

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

gdk_drawable_get_depth ()

gint                gdk_drawable_get_depth              (GdkDrawable *drawable);

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.

gdk_drawable_get_size ()

void                gdk_drawable_get_size               (GdkDrawable *drawable,
                                                         gint *width,
                                                         gint *height);

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

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.

gdk_drawable_get_clip_region ()

GdkRegion*          gdk_drawable_get_clip_region        (GdkDrawable *drawable);

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.

gdk_drawable_get_visible_region ()

GdkRegion*          gdk_drawable_get_visible_region     (GdkDrawable *drawable);

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.

gdk_draw_point ()

void                gdk_draw_point                      (GdkDrawable *drawable,
                                                         GdkGC *gc,
                                                         gint x,
                                                         gint y);

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

gdk_draw_points ()

void                gdk_draw_points                     (GdkDrawable *drawable,
                                                         GdkGC *gc,
                                                         GdkPoint *points,
                                                         gint npoints);

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

gdk_draw_line ()

void                gdk_draw_line                       (GdkDrawable *drawable,
                                                         GdkGC *gc,
                                                         gint x1_,
                                                         gint y1_,
                                                         gint x2_,
                                                         gint y2_);

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

gdk_draw_lines ()

void                gdk_draw_lines                      (GdkDrawable *drawable,
                                                         GdkGC *gc,
                                                         GdkPoint *points,
                                                         gint npoints);

Draws a series of lines connecting the given points. The way in which joins between lines are draw is determined by the GdkCapStyle value in the GdkGC. This can be set with gdk_gc_set_line_attributes().

gdk_draw_pixbuf ()

void                gdk_draw_pixbuf                     (GdkDrawable *drawable,
                                                         GdkGC *gc,
                                                         GdkPixbuf *pixbuf,
                                                         gint src_x,
                                                         gint src_y,
                                                         gint dest_x,
                                                         gint dest_y,
                                                         gint width,
                                                         gint height,
                                                         GdkRgbDither dither,
                                                         gint x_dither,
                                                         gint 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-NULL 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.

Since 2.2

gdk_draw_segments ()

void                gdk_draw_segments                   (GdkDrawable *drawable,
                                                         GdkGC *gc,
                                                         GdkSegment *segs,
                                                         gint nsegs);

Draws a number of unconnected lines.

GdkSegment

typedef struct {
  gint x1;
  gint y1;
  gint x2;
  gint y2;
} GdkSegment;

Specifies the start and end point of a line for use by the gdk_draw_segments() function.

gdk_draw_rectangle ()

void                gdk_draw_rectangle                  (GdkDrawable *drawable,
                                                         GdkGC *gc,
                                                         gboolean filled,
                                                         gint x,
                                                         gint y,
                                                         gint width,
                                                         gint height);

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

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.

gdk_draw_arc ()

void                gdk_draw_arc                        (GdkDrawable *drawable,
                                                         GdkGC *gc,
                                                         gboolean filled,
                                                         gint x,
                                                         gint y,
                                                         gint width,
                                                         gint height,
                                                         gint angle1,
                                                         gint 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.

gdk_draw_polygon ()

void                gdk_draw_polygon                    (GdkDrawable *drawable,
                                                         GdkGC *gc,
                                                         gboolean filled,
                                                         GdkPoint *points,
                                                         gint npoints);

Draws an outlined or filled polygon.

gdk_draw_trapezoids ()

void                gdk_draw_trapezoids                 (GdkDrawable *drawable,
                                                         GdkGC *gc,
                                                         GdkTrapezoid *trapezoids,
                                                         gint n_trapezoids);

Draws a set of anti-aliased trapezoids. The trapezoids are combined using saturation addition, then drawn over the background as a set. This is low level functionality used internally to implement rotated underlines and backgrouds when rendering a PangoLayout and is likely not useful for applications.

Since 2.6

GdkTrapezoid

typedef struct {
  double y1, x11, x21, y2, x12, x22;
} GdkTrapezoid;

Specifies a trapezpoid for use by the gdk_draw_trapezoids(). The trapezoids used here have parallel, horizontal top and bottom edges.

gdk_draw_glyphs ()

void                gdk_draw_glyphs                     (GdkDrawable *drawable,
                                                         GdkGC *gc,
                                                         PangoFont *font,
                                                         gint x,
                                                         gint y,
                                                         PangoGlyphString *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.

gdk_draw_glyphs_transformed ()

void                gdk_draw_glyphs_transformed         (GdkDrawable *drawable,
                                                         GdkGC *gc,
                                                         PangoMatrix *matrix,
                                                         PangoFont *font,
                                                         gint x,
                                                         gint y,
                                                         PangoGlyphString *glyphs);

Renders a PangoGlyphString onto a drawable, possibly transforming the layed-out coordinates through a transformation matrix. Note that the transformation matrix for font is not changed, so to produce correct rendering results, the font must have been loaded using a PangoContext with an identical transformation matrix to that passed in to this function.

See also gdk_draw_glyphs(), gdk_draw_layout().

Since 2.6

gdk_draw_layout_line ()

void                gdk_draw_layout_line                (GdkDrawable *drawable,
                                                         GdkGC *gc,
                                                         gint x,
                                                         gint y,
                                                         PangoLayoutLine *line);

Render a PangoLayoutLine onto an GDK drawable

If the layout's PangoContext 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.

gdk_draw_layout_line_with_colors ()

void                gdk_draw_layout_line_with_colors    (GdkDrawable *drawable,
                                                         GdkGC *gc,
                                                         gint x,
                                                         gint y,
                                                         PangoLayoutLine *line,
                                                         const GdkColor *foreground,
                                                         const GdkColor *background);

Render a PangoLayoutLine onto a GdkDrawable, overriding the layout's normal colors with foreground and/or background. foreground and background need not be allocated.

If the layout's PangoContext 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.

gdk_draw_layout ()

void                gdk_draw_layout                     (GdkDrawable *drawable,
                                                         GdkGC *gc,
                                                         gint x,
                                                         gint y,
                                                         PangoLayout *layout);

Render a PangoLayout onto a GDK drawable

If the layout's PangoContext 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 PangoLayout is gtk_widget_create_pango_layout().

gdk_draw_layout_with_colors ()

void                gdk_draw_layout_with_colors         (GdkDrawable *drawable,
                                                         GdkGC *gc,
                                                         gint x,
                                                         gint y,
                                                         PangoLayout *layout,
                                                         const GdkColor *foreground,
                                                         const GdkColor *background);

Render a PangoLayout onto a GdkDrawable, overriding the layout's normal colors with foreground and/or background. foreground and background need not be allocated.

If the layout's PangoContext 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 PangoLayout is gtk_widget_create_pango_layout().

gdk_draw_string ()

void                gdk_draw_string                     (GdkDrawable *drawable,
                                                         GdkFont *font,
                                                         GdkGC *gc,
                                                         gint x,
                                                         gint y,
                                                         const gchar *string);

Draws a string of characters in the given font or fontset.

gdk_draw_text ()

void                gdk_draw_text                       (GdkDrawable *drawable,
                                                         GdkFont *font,
                                                         GdkGC *gc,
                                                         gint x,
                                                         gint y,
                                                         const gchar *text,
                                                         gint text_length);

Draws a number of characters in the given font or fontset.

gdk_draw_text_wc ()

void                gdk_draw_text_wc                    (GdkDrawable *drawable,
                                                         GdkFont *font,
                                                         GdkGC *gc,
                                                         gint x,
                                                         gint y,
                                                         const GdkWChar *text,
                                                         gint text_length);

Draws a number of wide characters using the given font of fontset. If the font is a 1-byte font, the string is converted into 1-byte characters (discarding the high bytes) before output.

gdk_draw_pixmap

#define gdk_draw_pixmap                gdk_draw_drawable

Draws a pixmap, or a part of a pixmap, onto another drawable.

gdk_draw_drawable ()

void                gdk_draw_drawable                   (GdkDrawable *drawable,
                                                         GdkGC *gc,
                                                         GdkDrawable *src,
                                                         gint xsrc,
                                                         gint ysrc,
                                                         gint xdest,
                                                         gint ydest,
                                                         gint width,
                                                         gint height);

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 GdkGC, set the fill mode to GDK_STIPPLED, and then draw the rectangle.

gdk_draw_image ()

void                gdk_draw_image                      (GdkDrawable *drawable,
                                                         GdkGC *gc,
                                                         GdkImage *image,
                                                         gint xsrc,
                                                         gint ysrc,
                                                         gint xdest,
                                                         gint ydest,
                                                         gint width,
                                                         gint height);

Draws a GdkImage onto a drawable. The depth of the GdkImage must match the depth of the GdkDrawable.

gdk_drawable_get_image ()

GdkImage*           gdk_drawable_get_image              (GdkDrawable *drawable,
                                                         gint x,
                                                         gint y,
                                                         gint width,
                                                         gint height);

A GdkImage stores client-side image data (pixels). In contrast, GdkPixmap and GdkWindow are server-side objects. gdk_drawable_get_image() obtains the pixels from a server-side drawable as a client-side GdkImage. The format of a GdkImage depends on the GdkVisual of the current display, which makes manipulating GdkImage extremely difficult; therefore, in most cases you should use gdk_pixbuf_get_from_drawable() instead of this lower-level function. A GdkPixbuf 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 GdkWindow and partially offscreen or obscured, then the obscured portions of the returned image will contain undefined data.

gdk_drawable_copy_to_image ()

GdkImage*           gdk_drawable_copy_to_image          (GdkDrawable *drawable,
                                                         GdkImage *image,
                                                         gint src_x,
                                                         gint src_y,
                                                         gint dest_x,
                                                         gint dest_y,
                                                         gint width,
                                                         gint height);

Copies a portion of drawable into the client side image structure image. If image is NULL, creates a new image of size width x height and copies into that. See gdk_drawable_get_image() for further details.

Since 2.4