GDK Reference Manual
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# Drawing Primitives

## Name

Drawing Primitives -- functions for drawing points, lines, arcs, and text.

## Synopsis

    #include <gdk/gdk.h>

    void        gdk_draw_point                  (GdkDrawable *drawable,
                                                 GdkGC *gc,
                                                 gint x,
                                                 gint y);
    void        gdk_draw_points                 (GdkDrawable *drawable,
                                                 GdkGC *gc,
                                                 GdkPoint *points,
                                                 gint npoints);
    void        gdk_draw_line                   (GdkDrawable *drawable,
                                                 GdkGC *gc,
                                                 gint x1,
                                                 gint y1,
                                                 gint x2,
                                                 gint y2);
    void        gdk_draw_lines                  (GdkDrawable *drawable,
                                                 GdkGC *gc,
                                                 GdkPoint *points,
                                                 gint npoints);
    void        gdk_draw_segments               (GdkDrawable *drawable,
                                                 GdkGC *gc,
                                                 GdkSegment *segs,
                                                 gint nsegs);
    struct      GdkSegment;
    void        gdk_draw_rectangle              (GdkDrawable *drawable,
                                                 GdkGC *gc,
                                                 gint filled,
                                                 gint x,
                                                 gint y,
                                                 gint width,
                                                 gint height);
    void        gdk_draw_arc                    (GdkDrawable *drawable,
                                                 GdkGC *gc,
                                                 gint filled,
                                                 gint x,
                                                 gint y,
                                                 gint width,
                                                 gint height,
                                                 gint angle1,
                                                 gint angle2);
    void        gdk_draw_polygon                (GdkDrawable *drawable,
                                                 GdkGC *gc,
                                                 gint filled,
                                                 GdkPoint *points,
                                                 gint npoints);

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

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

## 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.

## Details

### 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.

`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,
                                                 GdkPoint *points,
                                                 gint npoints);

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

`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.

### 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.

`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,
                                                 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().

`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 size of the `points` array.

### gdk_draw_segments ()

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

Draws a number of unconnected lines.

`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,
`nsegs` : | the number of line segments to draw, i.e. the size of the `segs` array.

### struct GdkSegment

    struct GdkSegment
    {
      gint16 x1;
      gint16 y1;
      gint16 x2;
      gint16 y2;
    };

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

gint16 `x1` | the x coordinate of the start point.
gint16 `y1` | the y coordinate of the start point.
gint16 `x2` | the x coordinate of the end point.
gint16 `y2` | the y coordinate of the end point.

### gdk_draw_rectangle ()

    void        gdk_draw_rectangle              (GdkDrawable *drawable,
                                                 GdkGC *gc,
                                                 gint 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.

> Note: 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.

`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.

### gdk_draw_arc ()

    void        gdk_draw_arc                    (GdkDrawable *drawable,
                                                 GdkGC *gc,
                                                 gint 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.

`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, relative to `angle1`, in 1/64ths of a degree.

### gdk_draw_polygon ()

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

Draws an outlined or filled polygon.

`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.

### 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.

`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);

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

`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.

### 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.

`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_pixmap ()

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

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

`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.

### 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.

`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 `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`.

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