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| author | Po Lu <luangruo@yahoo.com> | 2022-01-03 13:57:13 +0000 |
|---|---|---|
| committer | Po Lu <luangruo@yahoo.com> | 2022-01-03 13:57:13 +0000 |
| commit | ab5ee3e29e916d4009b301841e9780aad564a6a0 (patch) | |
| tree | 87aba92dd6fa03dd496b23e366618d9d7b15a958 /src/haiku_font_support.cc | |
| parent | c7768382cc08c6861ed514316a27050b4104fbf4 (diff) | |
| download | emacs-ab5ee3e29e916d4009b301841e9780aad564a6a0.tar.gz emacs-ab5ee3e29e916d4009b301841e9780aad564a6a0.tar.bz2 emacs-ab5ee3e29e916d4009b301841e9780aad564a6a0.zip | |
* src/haiku_font_support.cc (BFont_char_bounds): Fix bearings.
Diffstat (limited to 'src/haiku_font_support.cc')
| -rw-r--r-- | src/haiku_font_support.cc | 31 |
1 files changed, 25 insertions, 6 deletions
diff --git a/src/haiku_font_support.cc b/src/haiku_font_support.cc index 298bc73f29e..6ea10b2e47c 100644 --- a/src/haiku_font_support.cc +++ b/src/haiku_font_support.cc @@ -126,9 +126,28 @@ BFont_have_char_block (void *font, int32_t beg, int32_t end) return ft->IncludesBlock (beg, end); } -/* Compute bounds for MB_STR, a character in multibyte encoding, - used with font. The width (in pixels) is returned in ADVANCE, - the left bearing in LB, and the right bearing in RB. */ +/* Compute bounds for MB_STR, a character in multibyte encoding, used + with FONT. The distance to move rightwards before reaching to the + next character's left escapement boundary is returned in ADVANCE, + the left bearing in LB, and the right bearing in RB. + + The left bearing is the amount of pixels from the left escapement + boundary (origin) to the left-most pixel that constitutes the glyph + corresponding to mb_str, and RB is the amount of pixels from the + origin to the right-most pixel constituting the glyph. + + Both the left and right bearings are positive values measured + towards the right, which means that the left bearing will only be + negative if the left-most pixel is to the left of the origin. + + The bearing values correspond to X11 XCharStruct semantics, which + is what Emacs code operates on. Haiku itself uses a slightly + different scheme, where the "left edge" is the distance from the + origin to the left-most pixel, where leftwards is negative and + rightwards is positive, and the "right edge" is the distance (where + leftwards is similarly negative) between the right-most pixel and + the right escapement boundary, which is the left escapement + boundary plus the advance. */ void BFont_char_bounds (void *font, const char *mb_str, int *advance, int *lb, int *rb) @@ -140,9 +159,9 @@ BFont_char_bounds (void *font, const char *mb_str, int *advance, ft->GetEdges (mb_str, 1, &edge_info); ft->GetEscapements (mb_str, 1, &escapement); - *advance = std::lrint (escapement * size); - *lb = std::lrint (edge_info.left * size); - *rb = *advance + std::lrint (edge_info.right * size); + *advance = std::ceil (escapement * size); + *lb = std::ceil (edge_info.left * size); + *rb = *advance + std::ceil (edge_info.right * size); } /* The same, but for a variable amount of chars. */ |