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 *seg-
              ments, 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 inter-
       secting 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 Win-
                 dow or Pixmap.

       BadGC     A value for a GContext argument does not name a defined GCon-
                 text.

       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

X Version 11                     libX11 1.1.1                     XDrawLine(3)