6.3 Drawing Points

The draw-point and draw-points functions make use of the following graphics context components: function, plane-mask, foreground, subwindow-mode, clip-x, clip-y, clip-ordering, clip-region and clip-mask.

The draw-point function uses the foreground pixel and function components of the graphics context to draw a single point into the specified drawable, while draw-points draws multiple points into the specified drawable. These functions are not affected by the tile or stipple in the graphics context.

draw-point

drawable gcontext x y

Function

drawable: The destination drawable.
gcontext: The graphics context for drawing the point.
x, y: The x and y coordinates of the point drawn. Type is int16.

Combines the foreground pixel in the gcontext with the pixel in the drawable specified by the x and y coordinates.

draw-points

drawable gcontext points &optional relative-p

Function

drawable: The destination drawable.
gcontext: The graphics context for drawing the points.
points: A list of points to be drawn in the order listed. The first point is always relative to the drawable's origin; if relative-p, the rest of the points are drawn relative to the previous point, else they are drawn relative to the drawable's origin. Type is point-seq.
relative-p: Specifies the coordinate mode used for drawing the pixels either relative to the origin or to the previous point. Type boolean.

Combines the foreground pixels in the graphics context with the pixels at each point in the drawable. The points are drawn in the order listed.

draw-points requires a mode argument, relative-p that indicates whether the points are relative to the destination origin or to the previous point. In either case, the first point is always relative to the destination origin. The rest of the points are relative either to the drawable's origin or to the previous point, depending on the value of relative-p.