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

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This commit is contained in:
Paul Davis 2014-11-05 16:57:37 -05:00
parent 857719f2e1
commit ecd618c343
1 changed files with 6 additions and 21 deletions
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27
libs/canvas/rectangle.cc
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@ -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.
*/