set-smoothing in dc<%>
Enables or disables anti-aliased smoothing of lines, curves,
rectangles, rounded rectangles, ellipses, polygons, paths, and clear
operations. (Text smoothing is not affected by this method, and is
instead controlled through the
font% object.)
Smoothing is supported under Windows only when Microsoft's gdiplus.dll is installed (which is always the case for Windows XP). Smoothing is supported under Mac OS X always. Smoothing is supported under X only when Cairo is installed when MrEd is compiled. Smoothing is never supported for black-and-white contexts. Smoothing is always supported (and cannot be disabled) for PostScript output.
The smoothing mode is either 'unsmoothed, 'smoothed,
or 'aligned. Both 'aligned and 'smoothed
are smoothing modes.
In 'smoothed mode for a canvas or bitmap drawing context,
integer drawing coordinates correspond to the boundary between
pixels, and pen-based drawing is centered over a given line or
curve. Thus, drawing with pen width 1 from (0, 10) to
(10, 10) draws a 2-pixel wide line with 50% opacity.
The 'aligned smoothing mode is like 'smoothed, but it
paints pixels more like 'unsmoothed mode. Since it aligns
shapes to pixel boundaries, 'aligned mode often produces
better results than 'smoothed, but the results depend on the
application. The 'aligned mode is defined in terms of
'smoothed mode, except that drawing coordinates are rounded
down (via floor, after scaling and origin translation). For
line drawing, coordinates are then shifted right and down by the
floor of half a pen width. In addition, for pen drawing
through
draw-rectangle,
draw-ellipse,
draw-rounded-rectangle, and
draw-arc, the given width and height are each decreased by 1.0.
In either smoothing mode, brush and pen stipples are ignored (except
for PostScript drawing), and 'hilite and 'xor drawing
modes are treated as 'solid. If smoothing is not supported,
then attempting to set the smoothing mode to 'smoothed or
'aligned will have no effect, and
get-smoothing will always return 'unsmoothed. Similarly,
get-smoothing for a post-script-dc% always returns 'smoothed.
(-> voidsenda-dcset-smoothingmode)
mode: symbol in'(unsmoothed smoothed aligned)Sets the smoothing mode for the drawing context.