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Functions
Description
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()
.
Functions
gdk_drawable_ref ()
GdkDrawable *
gdk_drawable_ref (GdkDrawable *drawable
);
gdk_drawable_ref
has been deprecated since version 2.0 and should not be used in newly-written code.
Use g_object_ref()
instead.
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
);
gdk_drawable_unref
has been deprecated since version 2.0 and should not be used in newly-written code.
Use g_object_unref()
instead.
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
);
gdk_drawable_set_data
is deprecated and should not be used in newly-written code.
This function is equivalent to g_object_set_data()
,
the GObject variant should be used instead.
Parameters
drawable |
||
key |
name to store the data under |
|
data |
arbitrary data |
|
destroy_func |
function to free |
[allow-none] |
gdk_drawable_get_data ()
gpointer gdk_drawable_get_data (GdkDrawable *drawable
,const gchar *key
);
gdk_drawable_get_data
is deprecated and should not be used in newly-written code.
Equivalent to g_object_get_data()
; the GObject variant should be
used instead.
gdk_drawable_get_display ()
GdkDisplay *
gdk_drawable_get_display (GdkDrawable *drawable
);
gdk_drawable_get_display
has been deprecated since version 2.24 and should not be used in newly-written code.
Use gdk_window_get_display()
instead
Gets the GdkDisplay associated with a GdkDrawable.
Since 2.2
gdk_drawable_get_screen ()
GdkScreen *
gdk_drawable_get_screen (GdkDrawable *drawable
);
gdk_drawable_get_screen
has been deprecated since version 2.24 and should not be used in newly-written code.
Use gdk_window_get_screen()
instead
Gets the GdkScreen associated with a GdkDrawable.
Since 2.2
gdk_drawable_get_visual ()
GdkVisual *
gdk_drawable_get_visual (GdkDrawable *drawable
);
gdk_drawable_get_visual
has been deprecated since version 2.24 and should not be used in newly-written code.
Gets the GdkVisual describing the pixel format of drawable
.
gdk_drawable_set_colormap ()
void gdk_drawable_set_colormap (GdkDrawable *drawable
,GdkColormap *colormap
);
gdk_drawable_set_colormap
is deprecated and should not be used in newly-written code.
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
);
gdk_drawable_get_size
has been deprecated since version 2.24 and should not be used in newly-written code.
Use gdk_window_get_width()
and gdk_window_get_height()
for
GdkWindows. Use gdk_pixmap_get_size()
for GdkPixmaps.
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
);
gdk_drawable_get_clip_region
is deprecated and should not be used in newly-written code.
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
);
gdk_draw_point
has been deprecated since version 2.22 and should not be used in newly-written code.
Use cairo_rectangle()
and cairo_fill()
or
cairo_move_to()
and cairo_stroke()
instead.
Draws a point, using the foreground color and other attributes of the GdkGC.
Parameters
drawable |
a GdkDrawable (a GdkWindow or a GdkPixmap). |
|
gc |
a GdkGC. |
|
x |
the x coordinate of the point. |
|
y |
the y coordinate of the point. |
gdk_draw_points ()
void gdk_draw_points (GdkDrawable *drawable
,GdkGC *gc
,const GdkPoint *points
,gint n_points
);
gdk_draw_points
has been deprecated since version 2.22 and should not be used in newly-written code.
Use n_points
calls to cairo_rectangle()
and
cairo_fill()
instead.
Draws a number of points, using the foreground color and other attributes of the GdkGC.
Parameters
drawable |
a GdkDrawable (a GdkWindow or a GdkPixmap). |
|
gc |
a GdkGC. |
|
points |
an array of GdkPoint structures. |
|
n_points |
the number of points to be drawn. |
gdk_draw_line ()
void gdk_draw_line (GdkDrawable *drawable
,GdkGC *gc
,gint x1_
,gint y1_
,gint x2_
,gint y2_
);
gdk_draw_line
has been deprecated since version 2.22 and should not be used in newly-written code.
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:
1 2 3 4 5 6 |
cairo_set_line_cap (cr, CAIRO_LINE_CAP_SQUARE); cairo_move_to (cr, 0.5, 0.5); cairo_line_to (cr, 9.5, 0.5); cairo_stroke (cr);]| See also <ulink url="http://cairographics.org/FAQ/#sharp_lines">the Cairo FAQ</ulink> on this topic. |
Draws a line, using the foreground color and other attributes of the GdkGC.
Parameters
drawable |
a GdkDrawable (a GdkWindow or a GdkPixmap). |
|
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. |
gdk_draw_lines ()
void gdk_draw_lines (GdkDrawable *drawable
,GdkGC *gc
,const GdkPoint *points
,gint n_points
);
gdk_draw_lines
has been deprecated since version 2.22 and should not be used in newly-written code.
Use cairo_line_to()
and cairo_stroke()
instead. See the
documentation of gdk_draw_line()
for notes on line drawing with Cairo.
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()
.
Parameters
drawable |
a GdkDrawable (a GdkWindow or a GdkPixmap). |
|
gc |
a GdkGC. |
|
points |
an array of GdkPoint structures specifying the endpoints of the |
|
n_points |
the size of the |
gdk_draw_pixbuf ()
void gdk_draw_pixbuf (GdkDrawable *drawable
,GdkGC *gc
,const 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
);
gdk_draw_pixbuf
has been deprecated since version 2.22 and should not be used in newly-written code.
Use gdk_cairo_set_source_pixbuf()
and cairo_paint()
or
cairo_rectangle()
and cairo_fill()
instead.
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.
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
drawable |
Destination drawable. |
|
gc |
[allow-none] | |
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 GdkRGB. |
|
x_dither |
X offset for dither. |
|
y_dither |
Y offset for dither. |
Since 2.2
gdk_draw_segments ()
void gdk_draw_segments (GdkDrawable *drawable
,GdkGC *gc
,const GdkSegment *segs
,gint n_segs
);
gdk_draw_segments
has been deprecated since version 2.22 and should not be used in newly-written code.
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.
Draws a number of unconnected lines.
Parameters
drawable |
a GdkDrawable (a GdkWindow or a GdkPixmap). |
|
gc |
a GdkGC. |
|
segs |
an array of GdkSegment 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
|
gdk_draw_rectangle ()
void gdk_draw_rectangle (GdkDrawable *drawable
,GdkGC *gc
,gboolean filled
,gint x
,gint y
,gint width
,gint height
);
gdk_draw_rectangle
has been deprecated since version 2.22 and should not be used in newly-written code.
Use cairo_rectangle()
and cairo_fill()
or cairo_stroke()
instead. For stroking, the same caveats for converting code apply as for
gdk_draw_line()
.
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.
Parameters
drawable |
a GdkDrawable (a GdkWindow or a GdkPixmap). |
|
gc |
a GdkGC. |
|
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. |
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
);
gdk_draw_arc
has been deprecated since version 2.22 and should not be used in newly-written code.
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()
.
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.
Parameters
drawable |
a GdkDrawable (a GdkWindow or a GdkPixmap). |
|
gc |
a GdkGC. |
|
filled |
|
|
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 |
gdk_draw_polygon ()
void gdk_draw_polygon (GdkDrawable *drawable
,GdkGC *gc
,gboolean filled
,const GdkPoint *points
,gint n_points
);
gdk_draw_polygon
has been deprecated since version 2.22 and should not be used in newly-written code.
Use cairo_line_to()
or cairo_append_path()
and
cairo_fill()
or cairo_stroke()
instead.
Draws an outlined or filled polygon.
Parameters
drawable |
a GdkDrawable (a GdkWindow or a GdkPixmap). |
|
gc |
a GdkGC. |
|
filled |
|
|
points |
an array of GdkPoint structures specifying the points making up the polygon. |
|
n_points |
the number of points. |
gdk_draw_trapezoids ()
void gdk_draw_trapezoids (GdkDrawable *drawable
,GdkGC *gc
,const GdkTrapezoid *trapezoids
,gint n_trapezoids
);
gdk_draw_trapezoids
has been deprecated since version 2.22 and should not be used in newly-written code.
Use Cairo path contruction functions and cairo_fill()
instead.
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.
Parameters
drawable |
||
gc |
a GdkGC |
|
trapezoids |
an array of GdkTrapezoid structures |
|
n_trapezoids |
the number of trapezoids to draw |
Since 2.6
gdk_draw_glyphs ()
void gdk_draw_glyphs (GdkDrawable *drawable
,GdkGC *gc
,PangoFont *font
,gint x
,gint y
,PangoGlyphString *glyphs
);
gdk_draw_glyphs
has been deprecated since version 2.22 and should not be used in newly-written code.
Use pango_cairo_show_glyphs()
instead.
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.
Parameters
drawable |
||
gc |
a GdkGC |
|
font |
font to be used |
|
x |
X coordinate of baseline origin |
|
y |
Y coordinate of baseline origin |
|
glyphs |
the glyph string to draw |
gdk_draw_glyphs_transformed ()
void gdk_draw_glyphs_transformed (GdkDrawable *drawable
,GdkGC *gc
,const PangoMatrix *matrix
,PangoFont *font
,gint x
,gint y
,PangoGlyphString *glyphs
);
gdk_draw_glyphs_transformed
has been deprecated since version 2.22 and should not be used in newly-written code.
Use pango_cairo_show_glyphs()
instead.
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()
.
Parameters
drawable |
||
gc |
a GdkGC |
|
matrix |
a PangoMatrix, or |
[allow-none] |
font |
the font in which to draw the string |
|
x |
the x position of the start of the string (in Pango units in user space coordinates) |
|
y |
the y position of the baseline (in Pango units in user space coordinates) |
|
glyphs |
the glyph string to draw |
Since 2.6
gdk_draw_layout_line ()
void gdk_draw_layout_line (GdkDrawable *drawable
,GdkGC *gc
,gint x
,gint y
,PangoLayoutLine *line
);
gdk_draw_layout_line
is deprecated and should not be used in newly-written code.
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
);
gdk_draw_layout_line_with_colors
is deprecated and should not be used in newly-written code.
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.
Parameters
drawable |
the drawable on which to draw the line |
|
gc |
base graphics to use |
|
x |
the x position of start of string (in pixels) |
|
y |
the y position of baseline (in pixels) |
|
line |
||
foreground |
foreground override color, or |
[allow-none] |
background |
background override color, or |
[allow-none] |
gdk_draw_layout ()
void gdk_draw_layout (GdkDrawable *drawable
,GdkGC *gc
,gint x
,gint y
,PangoLayout *layout
);
gdk_draw_layout
is deprecated and should not be used in newly-written code.
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
);
gdk_draw_layout_with_colors
is deprecated and should not be used in newly-written code.
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()
.
Parameters
drawable |
the drawable on which to draw string |
|
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 |
||
foreground |
foreground override color, or |
[allow-none] |
background |
background override color, or |
[allow-none] |
gdk_draw_string ()
void gdk_draw_string (GdkDrawable *drawable
,GdkFont *font
,GdkGC *gc
,gint x
,gint y
,const gchar *string
);
gdk_draw_string
has been deprecated since version 2.4 and should not be used in newly-written code.
Use gdk_draw_layout()
instead.
Draws a string of characters in the given font or fontset.
Parameters
drawable |
a GdkDrawable (a GdkWindow or a GdkPixmap). |
|
font |
a GdkFont. |
|
gc |
a GdkGC. |
|
x |
the x coordinate of the left edge of the text. |
|
y |
the y coordinate of the baseline of the text. |
|
string |
the string of characters to draw. |
gdk_draw_text ()
void gdk_draw_text (GdkDrawable *drawable
,GdkFont *font
,GdkGC *gc
,gint x
,gint y
,const gchar *text
,gint text_length
);
gdk_draw_text
has been deprecated since version 2.4 and should not be used in newly-written code.
Use gdk_draw_layout()
instead.
Draws a number of characters in the given font or fontset.
Parameters
drawable |
a GdkDrawable (a GdkWindow or a GdkPixmap). |
|
font |
a GdkFont. |
|
gc |
a GdkGC. |
|
x |
the x coordinate of the left edge of the text. |
|
y |
the y coordinate of the baseline of the text. |
|
text |
the characters to draw. |
|
text_length |
the number of characters of |
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
);
gdk_draw_text_wc
has been deprecated since version 2.4 and should not be used in newly-written code.
Use gdk_draw_layout()
instead.
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.
Parameters
drawable |
a GdkDrawable (a GdkWindow or a GdkPixmap). |
|
font |
a GdkFont. |
|
gc |
a GdkGC. |
|
x |
the x coordinate of the left edge of the text. |
|
y |
the y coordinate of the baseline of the text. |
|
text |
the wide characters to draw. |
|
text_length |
the number of characters to draw. |
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
);
gdk_draw_drawable
has been deprecated since version 2.22 and should not be used in newly-written code.
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.
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.
Parameters
drawable |
||
gc |
a GdkGC sharing the drawable's visual and colormap |
|
src |
the source GdkDrawable, which may be the same as |
|
xsrc |
X position in |
|
ysrc |
Y position in |
|
xdest |
X position in |
|
ydest |
Y position in |
|
width |
width of rectangle to draw, or -1 for entire |
|
height |
height of rectangle to draw, or -1 for entire |
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
);
gdk_draw_image
has been deprecated since version 2.22 and should not be used in newly-written code.
Do not use GdkImage anymore, instead use Cairo image surfaces.
Draws a GdkImage onto a drawable. The depth of the GdkImage must match the depth of the GdkDrawable.
Parameters
drawable |
a GdkDrawable (a GdkWindow or a GdkPixmap). |
|
gc |
a GdkGC. |
|
image |
the GdkImage to draw. |
|
xsrc |
the left edge of the source rectangle within |
|
ysrc |
the top of the source rectangle within |
|
xdest |
the x coordinate of the destination within |
|
ydest |
the y coordinate of the destination within |
|
width |
the width of the area to be copied, or -1 to make the area
extend to the right edge of |
|
height |
the height of the area to be copied, or -1 to make the area
extend to the bottom edge of |
gdk_drawable_get_image ()
GdkImage * gdk_drawable_get_image (GdkDrawable *drawable
,gint x
,gint y
,gint width
,gint height
);
gdk_drawable_get_image
has been deprecated since version 2.22 and should not be used in newly-written code.
Use drawable
as the source and draw to a Cairo image
surface if you want to download contents to the client.
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
);
gdk_drawable_copy_to_image
has been deprecated since version 2.22 and should not be used in newly-written code.
Use drawable
as the source and draw to a Cairo image
surface if you want to download contents to the client.
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.
Parameters
drawable |
||
image |
a GdkDrawable, or |
[allow-none] |
src_x |
x coordinate on |
|
src_y |
y coordinate on |
|
dest_x |
x coordinate within |
|
dest_y |
y coordinate within |
|
width |
width of region to get |
|
height |
height or region to get |
Since 2.4
Types and Values
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.
struct GdkSegment
struct GdkSegment { gint x1; gint y1; gint x2; gint y2; };
Specifies the start and end point of a line for use by the gdk_draw_segments()
function.
struct GdkTrapezoid
struct GdkTrapezoid { double y1, x11, x21, y2, x12, x22; };
Specifies a trapezpoid for use by the gdk_draw_trapezoids()
.
The trapezoids used here have parallel, horizontal top and
bottom edges.
gdk_draw_pixmap
#define gdk_draw_pixmap gdk_draw_drawable
gdk_draw_pixmap
is deprecated and should not be used in newly-written code.
Use gdk_draw_drawable()
instead.
Draws a pixmap, or a part of a pixmap, onto another drawable.