XDrawLine(3X11) X Version 11 (Release 5) XDrawLine(3X11)
NAME
XDrawLine, XDrawLines, XDrawSegments, XSegment - draw lines,
polygons, and line structure
SYNTAX
XDrawLine(display, d, gc, x1, y1, x2, y2)
Display *display;
Drawable d;
GC gc;
int x1, y1, x2, y2;
XDrawLines(display, d, gc, points, npoints, mode)
Display *display;
Drawable d;
GC gc;
XPoint *points;
int npoints;
int mode;
XDrawSegments(display, d, gc, segments, nsegments)
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
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XDrawLine(3X11) X Version 11 (Release 5) XDrawLine(3X11)
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
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XDrawLine(3X11) X Version 11 (Release 5) XDrawLine(3X11)
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(3X11), XDrawPoint(3X11), XDrawRectangle(3X11)
Xlib - C Language X Interface
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