gtk2/docs/reference/gdk/tmpl/drawing.sgml

<!-- ##### SECTION Title ##### -->
Drawing Primitives

<!-- ##### SECTION Short_Description ##### -->
functions for drawing points, lines, arcs, and text.

<!-- ##### SECTION Long_Description ##### -->
<para>
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.
</para>
<para>
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
<link linkend="gdk-Graphics-Contexts">Graphics Contexts</link> section for
more information.
</para>

<!-- ##### SECTION See_Also ##### -->
<para>

</para>

<!-- ##### ENUM GdkFill ##### -->
<para>
Used to specify the way in which drawing operations are performed.
See gdk_gc_set_fill().
</para>

@GDK_SOLID: graphics are drawn in a solid color, usually the foreground color
of the #GdkGC.
@GDK_TILED: graphics are drawn using a tile pixmap. See gdk_gc_set_tile().
@GDK_STIPPLED: graphics are drawn with a stipple (a pixmap with a depth of 1).
Bits set in the stipple are drawn in the foreground color. Bits not set in the
stipple are left as they are. See gdk_gc_set_stipple().
@GDK_OPAQUE_STIPPLED: graphics are drawn with a stipple, as in @GDK_STIPPLED,
except that the bits not set in the stipple are drawn in the background color
instead of being left as they are. See gdk_gc_set_stipple().

<!-- ##### ENUM GdkFillRule ##### -->
<para>
The method for determining which pixels are included in a region, when
creating a #GdkRegion from a polygon.
The fill rule is only relevant for polygons which overlap themselves.
</para>

@GDK_EVEN_ODD_RULE: areas which are overlapped an odd number of times are
included in the region, while areas overlapped an even number of times are not.
@GDK_WINDING_RULE: overlapping areas are always included.


<!-- ##### ENUM GdkLineStyle ##### -->
<para>
Used to specify how lines are drawn. See gdk_gc_set_line_attributes().
</para>

@GDK_LINE_SOLID: lines are drawn in a solid color, the foreground color.
@GDK_LINE_ON_OFF_DASH: dashed lines are drawn, with the pixels between the
dashes left as they are. The #GdkCapStyle is applied to each end of the dashes.
@GDK_LINE_DOUBLE_DASH: dashed lines are drawn, alternating between the
foreground and background colors. The %GDK_CAP_BUTT style is used where
dashes and gaps meet.

<!-- ##### ENUM GdkCapStyle ##### -->
<para>
Used to specify how the ends of lines and dashes are drawn.
See gdk_gc_set_line_attributes().
</para>

@GDK_CAP_NOT_LAST: this is equivalent to %GDK_CAP_BUTT, except that for a line
width of 0 the final endpoint is not drawn.
@GDK_CAP_BUTT: the ends of the line are square with no projection beyond the
endpoint.
@GDK_CAP_ROUND: the ends of the line are rounded using a circular arc centered
on the endpoint. This is equivalent to %GDK_CAP_BUTT when the line width is 0.
@GDK_CAP_PROJECTING: the ends of the line are square, but project beyond the
endpoint to a distance of half the line width.
This is equivalent to %GDK_CAP_BUTT when the line width is 0.

<!-- ##### ENUM GdkJoinStyle ##### -->
<para>
Used to specify how the the joins between lines are drawn.
See gdk_gc_set_line_attributes().
</para>

@GDK_JOIN_MITER: the ends of the lines are extended to meet at a point.
If the angle between the lines is less than 11 degrees, %GDK_JOIN_BEVEL is
used instead.
@GDK_JOIN_ROUND: the ends of the lines are rounded with a circular arc
centered on the joinpoint, with a diameter equal to the line width.
@GDK_JOIN_BEVEL: the lines have %GDK_CAP_BUTT cap styles, with the triangular
notch filled.

<!-- ##### FUNCTION gdk_draw_point ##### -->
<para>
Draws a point, using the foreground color and other attributes of the #GdkGC.
</para>

@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.


<!-- ##### FUNCTION gdk_draw_line ##### -->
<para>
Draws a line, using the foreground color and other attributes of the #GdkGC.
</para>

@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.


<!-- ##### FUNCTION gdk_draw_rectangle ##### -->
<para>
Draws a rectangular outline or filled rectangle, using the foreground color
and other attributes of the #GdkGC.
</para>
<note>
<para>
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.
</para>
</note>

@drawable: a #GdkDrawable (a #GdkWindow or a #GdkPixmap).
@gc: a #GdkGC.
@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.


<!-- ##### FUNCTION gdk_draw_arc ##### -->
<para>
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.
</para>

@drawable: a #GdkDrawable (a #GdkWindow or a #GdkPixmap).
@gc: a #GdkGC.
@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, in the same units as @angle1.


<!-- ##### FUNCTION gdk_draw_polygon ##### -->
<para>
Draws an outlined or filled polygon.
</para>

@drawable: a #GdkDrawable (a #GdkWindow or a #GdkPixmap).
@gc: a #GdkGC.
@filled: TRUE if the polygon should be filled. The polygon is closed
automatically, connecting the last point to the first point if necessary.
@points: an array of #GdkPoint structures specifying the points making up the
polygon.
@npoints: the number of points.


<!-- ##### FUNCTION gdk_draw_string ##### -->
<para>
Draws a string of characters in the given font or fontset.
</para>

@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.


<!-- ##### FUNCTION gdk_draw_text ##### -->
<para>
Draws a number of characters in the given font or fontset.
</para>

@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 @text to draw.


<!-- ##### FUNCTION gdk_draw_text_wc ##### -->
<para>
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.
</para>

@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.


<!-- ##### FUNCTION gdk_draw_pixmap ##### -->
<para>
Draws a pixmap, or a part of a pixmap, onto another drawable.
</para>

@drawable: a #GdkDrawable (a #GdkWindow or a #GdkPixmap).
@gc: a #GdkGC.
@src: the source #GdkPixmap to draw.
@xsrc: the left edge of the source rectangle within @src.
@ysrc: the top of the source rectangle within @src.
@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 the source pixmap.
@height: the height of the area to be copied, or -1 to make the area extend
to the bottom edge of the source pixmap.


<!-- ##### FUNCTION gdk_draw_bitmap ##### -->
<para>

</para>

@drawable: a #GdkDrawable (a #GdkWindow or a #GdkPixmap).
@gc: 
@src: 
@xsrc: 
@ysrc: 
@xdest: 
@ydest: 
@width: 
@height: 


<!-- ##### FUNCTION gdk_draw_image ##### -->
<para>

</para>

@drawable: a #GdkDrawable (a #GdkWindow or a #GdkPixmap).
@gc: 
@image: 
@xsrc: 
@ysrc: 
@xdest: 
@ydest: 
@width: 
@height: 


<!-- ##### FUNCTION gdk_draw_points ##### -->
<para>
Draws a number of points, using the foreground color and other attributes of
the #GdkGC.
</para>

@drawable: a #GdkDrawable (a #GdkWindow or a #GdkPixmap).
@gc: a #GdkGC.
@points: an array of #GdkPoint structures.
@npoints: the number of points to be drawn.


<!-- ##### FUNCTION gdk_draw_segments ##### -->
<para>

</para>

@drawable: a #GdkDrawable (a #GdkWindow or a #GdkPixmap).
@gc: 
@segs: 
@nsegs: 


<!-- ##### STRUCT GdkSegment ##### -->
<para>

</para>

@x1: 
@y1: 
@x2: 
@y2: 

<!-- ##### FUNCTION gdk_draw_lines ##### -->
<para>
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().
</para>

@drawable: a #GdkDrawable (a #GdkWindow or a #GdkPixmap).
@gc: a #GdkGC.
@points: an array of #GdkPoint structures specifying the endpoints of the
lines.
@npoints: the number of endpoints.