[metrics] Add a private tag for Italic correction, Ital #2378
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| @@ -107,6 +107,7 @@ _get_gasp (hb_face_t *face, float *result, hb_ot_metrics_tag_t metrics_tag) | |||
| #define _HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER_HHEA HB_TAG ('H','d','s','c') | |||
| #define _HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP_OS2 HB_TAG ('O','l','g','p') | |||
| #define _HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP_HHEA HB_TAG ('H','l','g','p') | |||
| #define _HB_OT_METRICS_TAG_ITALIC_CORRECTION HB_TAG ('I','t','a','l') | |||
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Feel free to suggest something better
ebraminio
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| g_assert_cmpint (value, ==, 426); | ||
| int x_scale; | ||
| hb_font_get_scale (font, &x_scale, NULL); | ||
| g_assert_cmpint ((int) roundf (-asinf ((float) value / x_scale) * 180.f / (float) M_PI), ==, -12); |
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How to get post->italicDegree back, can be done by HB_OT_METRICS_TAG_HORIZONTAL_CARET_RUN / HB_OT_METRICS_TAG_HORIZONTAL_CARET_RISE right now also of course
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I don't understand this. "Italic correction" is a specific TeX-related concept that is not the same as "italic angle", and cannot be directly computed from it; it's a per-glyph metric that is up to the font designer to specify. In XeTeX (for example), we do synthesize a "fake" value for italic correction -- using italic angle as one of the inputs -- but that's just a fallback heuristic to make up for the lack of this glyph metric in OpenType fonts. I don't think harfbuzz should be attempting to do anything like that; it's purely an application-level function. |
#1890 is what I suggest but nobody shows any interest and Behdad says no client will use that (but I believe a font manager easily can take advantage of it, don't you know any other client willing to use it?) so the only remained option will be providing one |
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Another doomed attempt :/ let's agree on having hb-style or a |
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let's take another look later |
Fixes #1880 (or, it can be considered for)
Compare https://github.com/harfbuzz/harfbuzz/pull/2378/files#diff-3e0886e0824e462dddb236ac6d8b2fbbR78 to https://github.com/harfbuzz/harfbuzz/pull/2374/files#diff-3e0886e0824e462dddb236ac6d8b2fbbR67 (-426 vs 430)