XDrawLine(3) XLIB FUNCTIONS XDrawLine(3)

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

X Version 11 libX11 1.8.10 XDrawLine(3)