XDrawLine(3X11) XLIB FUNCTIONS 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 speci-
fied GC to draw a line between the specified set of points
(x1, y1) and (x2, y2). It does not perform joining at
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XDrawLine(3X11) XLIB FUNCTIONS XDrawLine(3X11)
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 speci-
fied 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 coordi-
nates 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, stip-
ple, 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.
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XDrawLine(3X11) XLIB FUNCTIONS XDrawLine(3X11)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 cor-
rect 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 spe-
cific 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 ALSOXDrawArc(3X11), XDrawPoint(3X11), XDrawRectangle(3X11)
Xlib - C Language X Interface
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