From 29bc310563d4c8c728adfa78e18af9e4d3c89116 Mon Sep 17 00:00:00 2001 From: Werner Lemberg Date: Thu, 13 Jan 2011 12:22:55 +0100 Subject: [PATCH] [raster] Handle drop-outs at glyph borders according to Microsoft. If a drop-out rule would switch on a pixel outside of the glyph's bounding box, use the right (or top) pixel instead. This is an undocumented feature, but some fonts like `Helvetica Neue LT Com 65 Medium' heavily rely on it. Thanks to Greg Hitchcock who explained this behaviour. * src/raster/ftraster.c (Vertical_Sweep_Drop, Horizontal_Sweep_Drop): Implement it. --- ChangeLog | 14 ++++++++++++++ src/raster/ftraster.c | 10 ++++++++++ 2 files changed, 24 insertions(+) diff --git a/ChangeLog b/ChangeLog index 79869402a..5d25d78be 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,17 @@ +2011-01-13 Werner Lemberg + + [raster] Handle drop-outs at glyph borders according to Microsoft. + + If a drop-out rule would switch on a pixel outside of the glyph's + bounding box, use the right (or top) pixel instead. This is an + undocumented feature, but some fonts like `Helvetica Neue LT Com 65 + Medium' heavily rely on it. + + Thanks to Greg Hitchcock who explained this behaviour. + + * src/raster/ftraster.c (Vertical_Sweep_Drop, + Horizontal_Sweep_Drop): Implement it. + 2011-01-09 suzuki toshiya [cache] Fix Savannah bug #31923, patch drafted by Harsha. diff --git a/src/raster/ftraster.c b/src/raster/ftraster.c index 9638dfb02..a6d3179b1 100644 --- a/src/raster/ftraster.c +++ b/src/raster/ftraster.c @@ -2403,6 +2403,11 @@ return; /* no drop-out control */ } + /* undocumented but confirmed: If the drop-out would result in a */ + /* pixel outside of the bounding box, use the right pixel instead */ + if ( pxl < 0 ) + pxl = e1; + /* check that the other pixel isn't set */ e1 = pxl == e1 ? e2 : e1; @@ -2579,6 +2584,11 @@ return; /* no drop-out control */ } + /* undocumented but confirmed: If the drop-out would result in a */ + /* pixel outside of the bounding box, use the top pixel instead */ + if ( pxl < 0 ) + pxl = e1; + /* check that the other pixel isn't set */ e1 = pxl == e1 ? e2 : e1;