diff options
| author | Paul Davis <paul@linuxaudiosystems.com> | 2014-10-30 09:05:27 -0400 |
|---|---|---|
| committer | Paul Davis <paul@linuxaudiosystems.com> | 2014-10-31 10:56:08 -0400 |
| commit | a942493565666e159d50b26e1e53a44109ecbd4b (patch) | |
| tree | 47fa3d1278de6748fc295d9231be726b11eadf6c /libs/canvas/rectangle.cc | |
| parent | f7ce57e5b2880a42fe5238235b4d55a8204a0e52 (diff) | |
comment fix and expansion re: Canvas::Rectangle outline
Diffstat (limited to 'libs/canvas/rectangle.cc')
| -rw-r--r-- | libs/canvas/rectangle.cc | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/libs/canvas/rectangle.cc b/libs/canvas/rectangle.cc index 4afdfbacd4..d79518e7f6 100644 --- a/libs/canvas/rectangle.cc +++ b/libs/canvas/rectangle.cc @@ -98,13 +98,14 @@ Rectangle::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) con * 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 right edge must span -0.5..+0.5, the left edge + * 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. + * 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. |