NAME
XDrawLine, XDrawLines, XDrawSegments, XSegment - draw lines, polygons, and line
structure
SYNTAX
int
XDrawLine(Display * display, Drawable d, GC gc, int
x1, int y1, int x2, int y2);
int
XDrawLines(Display * display, Drawable d, GC gc, XPoint
*points, int npoints, int mode);
int
XDrawSegments(Display * display, Drawable d, GC gc,
XSegment * segments, int nsegments);
ARGUMENTS
- d
- Specifies the drawable.
- display
- Specifies the connection to the X server.
- gc
- Specifies the GC.
- mode
- Specifies the coordinate mode. You can pass
CoordModeOrigin or CoordModePrevious.
- npoints
- Specifies the number of points in the array.
- nsegments
- Specifies the number of segments in the array.
- points
- Specifies an array of points.
- segments
- Specifies an array of segments.
- x1
-
- y1
-
- x2
-
- y2
- Specify the points (x1, y1) and (x2, y2) to be
connected.
DESCRIPTION
The
XDrawLine function uses the components of the specified GC to draw a
line between the specified set of points (x1, y1) and (x2, y2). It does not
perform joining at coincident endpoints. For any given line,
XDrawLine
does not draw a pixel more than once. If lines intersect, the intersecting
pixels are drawn multiple times.
The
XDrawLines function uses the components of the specified GC to draw
npoints-1 lines between each pair of points (point[i], point[i+1]) in the
array of
XPoint structures. It draws the lines in the order listed in
the array. The lines join correctly at all intermediate points, and if the
first and last points coincide, the first and last lines also join correctly.
For any given line,
XDrawLines does not draw a pixel more than once. If
thin (zero line-width) lines intersect, the intersecting pixels are drawn
multiple times. If wide lines intersect, the intersecting pixels are drawn
only once, as though the entire
PolyLine protocol request were a
single, filled shape.
CoordModeOrigin treats all coordinates as
relative to the origin, and
CoordModePrevious treats all coordinates
after the first as relative to the previous point.
The
XDrawSegments function draws multiple, unconnected lines. For each
segment,
XDrawSegments draws a line between (x1, y1) and (x2, y2). It
draws the lines in the order listed in the array of
XSegment structures
and does not perform joining at coincident endpoints. For any given line,
XDrawSegments does not draw a pixel more than once. If lines intersect,
the intersecting pixels are drawn multiple times.
All three functions use these GC components: function, plane-mask, line-width,
line-style, cap-style, fill-style, subwindow-mode, clip-x-origin,
clip-y-origin, and clip-mask. The
XDrawLines function also uses the
join-style GC component. All three functions also use these GC mode-dependent
components: foreground, background, tile, stipple, tile-stipple-x-origin,
tile-stipple-y-origin, dash-offset, and dash-list.
XDrawLine,
XDrawLines, and
XDrawSegments can generate
BadDrawable,
BadGC, and
BadMatch errors.
XDrawLines can also generate a
BadValue error.
STRUCTURES
The
XSegment structure contains:
typedef struct {
short x1, y1, x2, y2;
} XSegment;
All x and y members are signed integers. The width and height members are 16-bit
unsigned integers. You should be careful not to generate coordinates and sizes
out of the 16-bit ranges, because the protocol only has 16-bit fields for
these values.
DIAGNOSTICS
- BadDrawable
- A value for a Drawable argument does not name a defined
Window or Pixmap.
- BadGC
- A value for a GContext argument does not name a defined
GContext.
- BadMatch
- An InputOnly window is used as a Drawable.
- BadMatch
- Some argument or pair of arguments has the correct type and
range but fails to match in some other way required by the request.
- BadValue
- Some numeric value falls outside the range of values
accepted by the request. Unless a specific range is specified for an
argument, the full range defined by the argument's type is accepted. Any
argument defined as a set of alternatives can generate this error.
SEE ALSO
XDrawArc(3), XDrawPoint(3), XDrawRectangle(3)
Xlib - C Language X Interface