correct the rendering of Rectangle outlines, and the computation of their bounding box

diff --git a/libs/canvas/rectangle.cc b/libs/canvas/rectangle.cc
index 232da178935b083720b8db64d2334087ee993eff..a4540ccbacfb8bc32c7103be09ae8fe762fc239d 100644 (file)
--- a/libs/canvas/rectangle.cc
+++ b/libs/canvas/rectangle.cc
@@ -98,20 +98,13 @@ Rectangle::render_self (Rect const & area, Cairo::RefPtr<Cairo::Context> context
                 * thick, it will precisely align with the corner
                 * coordinates of the rectangle. So if the rectangle
                 * has a left edge at 0 and a right edge at 10, then
-                * the left edge must span -0.5..+0.5, the right edge
-                * must span 9.5..10.5 (i.e. the single full color
-                * pixel is precisely aligned with 0 and 10
-                * respectively).
-                *
-                * we have to shift left/up in all cases, which means
-                * subtraction along both axes (i.e. edge at
-                * N, outline must start at N-0.5). 
-                *
-                * see the cairo FAQ on single pixel lines to see why we do
-                * the 0.5 pixel additions.
+                * the left edge must span 0..1, the right edge
+                * must span 9..10 because the first and final pixels
+                * to be colored are actually "at" 0.5 and 9.5 (midway
+                * between the integer coordinates.
                 */
 
-               self = self.translate (Duple (0.5, 0.5));
+               self = self.shrink (0.5);
 
                if (_outline_what == What (LEFT|RIGHT|BOTTOM|TOP)) {
                        
@@ -155,13 +148,6 @@ Rectangle::compute_bounding_box () const
 {
        if (!_rect.empty()) {
                Rect r = _rect.fix ();
-
-               /* take into acount the 0.5 addition to the bounding
-                  box for the right and bottom edges, see ::render() above
-               */
-
-               r = r.expand (1.0);
-
                _bounding_box = r;
        }
 
@@ -273,8 +259,7 @@ void
 TimeRectangle::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const
 {
        Rect self = get_self_for_render ();
-
-
+       
        /* This is a TimeRectangle, so its right edge is drawn 1 pixel beyond
         * (larger x-axis coordinates) than a normal Rectangle.
         */