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| author | Jan Djärv <jan.h.d@swipnet.se> | 2011-01-29 11:36:16 +0100 |
|---|---|---|
| committer | Jan Djärv <jan.h.d@swipnet.se> | 2011-01-29 11:36:16 +0100 |
| commit | 481ae0855fbeadb5817ea3ffa7d5dbf3723000ac (patch) | |
| tree | 72de5f18e26f21eb1c7b0610cb35d74efcd8eace /src/nsfont.m | |
| parent | e52f87a1c0ac9e6f04c1047d2b4828744e83f7ba (diff) | |
| download | emacs-481ae0855fbeadb5817ea3ffa7d5dbf3723000ac.tar.gz | |
Handle floating point errors in ns-fonts (Bug#7887).
* nsfont.m (nsfont_open): Ensure that fonts with inexact
descenders would not become one pixel too tall (Bug#7887).
Diffstat (limited to 'src/nsfont.m')
| -rw-r--r-- | src/nsfont.m | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/src/nsfont.m b/src/nsfont.m index b8848525f21..68cd19da70e 100644 --- a/src/nsfont.m +++ b/src/nsfont.m @@ -809,6 +809,14 @@ nsfont_open (FRAME_PTR f, Lisp_Object font_entity, int pixel_size) const char *fontName = [[nsfont fontName] UTF8String]; int len = strlen (fontName); + /* The values specified by fonts are not always exact. For + * example, a 6x8 font could specify that the descender is + * -2.00000405... (represented by 0xc000000220000000). Without + * adjustment, the code below would round the descender to -3, + * resulting in a font that would be one pixel higher than + * intended. */ + CGFloat adjusted_descender = [sfont descender] + 0.0001; + #ifdef NS_IMPL_GNUSTEP font_info->nsfont = sfont; #else @@ -830,7 +838,7 @@ nsfont_open (FRAME_PTR f, Lisp_Object font_entity, int pixel_size) brect = [sfont boundingRectForFont]; full_height = brect.size.height; - min_height = [sfont ascender] - [sfont descender]; + min_height = [sfont ascender] - adjusted_descender; hd = full_height - min_height; /* standard height, similar to Carbon. Emacs.app: was 0.5 by default. */ @@ -845,10 +853,10 @@ nsfont_open (FRAME_PTR f, Lisp_Object font_entity, int pixel_size) /* max bounds */ font_info->max_bounds.ascent = lrint (hshrink * [sfont ascender] + expand * hd/2); - /* [sfont descender] is usually negative. Use floor to avoid + /* Descender is usually negative. Use floor to avoid clipping descenders. */ font_info->max_bounds.descent = - -lrint (floor(hshrink* [sfont descender] - expand*hd/2)); + -lrint (floor(hshrink* adjusted_descender - expand*hd/2)); font_info->height = font_info->max_bounds.ascent + font_info->max_bounds.descent; font_info->max_bounds.width = lrint (font_info->width); @@ -884,7 +892,7 @@ nsfont_open (FRAME_PTR f, Lisp_Object font_entity, int pixel_size) /* set up metrics portion of font struct */ font->ascent = lrint([sfont ascender]); - font->descent = -lrint(floor([sfont descender])); + font->descent = -lrint(floor(adjusted_descender)); font->min_width = ns_char_width(sfont, '|'); font->space_width = lrint (ns_char_width (sfont, ' ')); font->average_width = lrint (font_info->width); |