HarfBuzz text shaping engine
http://harfbuzz.github.io/
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136 lines
4.6 KiB
136 lines
4.6 KiB
/* |
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* Copyright © 2019 Ebrahim Byagowi |
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* |
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* This is part of HarfBuzz, a text shaping library. |
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* |
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* Permission is hereby granted, without written agreement and without |
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* license or royalty fees, to use, copy, modify, and distribute this |
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* software and its documentation for any purpose, provided that the |
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* above copyright notice and the following two paragraphs appear in |
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* all copies of this software. |
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* |
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* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR |
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* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES |
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* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN |
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* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH |
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* DAMAGE. |
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* |
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* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, |
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* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND |
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* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS |
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* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO |
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* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. |
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*/ |
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#include "hb.hh" |
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#ifndef HB_NO_STYLE |
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#ifdef HB_EXPERIMENTAL_API |
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#include "hb-ot-var-avar-table.hh" |
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#include "hb-ot-var-fvar-table.hh" |
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#include "hb-ot-stat-table.hh" |
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#include "hb-ot-os2-table.hh" |
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#include "hb-ot-head-table.hh" |
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#include "hb-ot-post-table.hh" |
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#include "hb-ot-face.hh" |
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/** |
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* hb_style_tag_t: |
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* @HB_STYLE_TAG_ITALIC: Used to vary between non-italic and italic. |
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* A value of 0 can be interpreted as "Roman" (non-italic); a value of 1 can |
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* be interpreted as (fully) italic. |
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* @HB_STYLE_TAG_OPTICAL_SIZE: Used to vary design to suit different text sizes. |
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* Non-zero. Values can be interpreted as text size, in points. |
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* @HB_STYLE_TAG_SLANT: Used to vary between upright and slanted text. Values |
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* must be greater than -90 and less than +90. Values can be interpreted as |
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* the angle, in counter-clockwise degrees, of oblique slant from whatever the |
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* designer considers to be upright for that font design. |
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* @HB_STYLE_TAG_WIDTH: Used to vary width of text from narrower to wider. |
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* Non-zero. Values can be interpreted as a percentage of whatever the font |
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* designer considers “normal width” for that font design. |
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* @HB_STYLE_TAG_WEIGHT: Used to vary stroke thicknesses or other design details |
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* to give variation from lighter to blacker. Values can be interpreted in direct |
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* comparison to values for usWeightClass in the OS/2 table, |
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* or the CSS font-weight property. |
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* |
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* Defined by https://docs.microsoft.com/en-us/typography/opentype/spec/dvaraxisreg |
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* |
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* Since: EXPERIMENTAL |
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**/ |
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typedef enum { |
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HB_STYLE_TAG_ITALIC = HB_TAG ('i','t','a','l'), |
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HB_STYLE_TAG_OPTICAL_SIZE = HB_TAG ('o','p','s','z'), |
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HB_STYLE_TAG_SLANT = HB_TAG ('s','l','n','t'), |
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HB_STYLE_TAG_WIDTH = HB_TAG ('w','d','t','h'), |
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HB_STYLE_TAG_WEIGHT = HB_TAG ('w','g','h','t'), |
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/*< private >*/ |
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_HB_STYLE_TAG_MAX_VALUE = HB_TAG_MAX_SIGNED /*< skip >*/ |
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} hb_style_tag_t; |
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/** |
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* hb_style_get_value: |
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* @font: a #hb_font_t object. |
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* @style_tag: a style tag. |
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* |
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* Searches variation axes of a hb_font_t object for a specific axis first, |
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* if not set, then tries to get default style values from different |
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* tables of the font. |
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* |
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* Returns: Corresponding axis or default value to a style tag. |
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* |
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* Since: EXPERIMENTAL |
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**/ |
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float |
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hb_style_get_value (hb_font_t *font, hb_tag_t tag) |
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{ |
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hb_style_tag_t style_tag = (hb_style_tag_t) tag; |
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hb_face_t *face = font->face; |
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#ifndef HB_NO_VAR |
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hb_ot_var_axis_info_t axis; |
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if (hb_ot_var_find_axis_info (face, style_tag, &axis)) |
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{ |
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if (axis.axis_index < font->num_coords) return font->design_coords[axis.axis_index]; |
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/* If a face is variable, fvar's default_value is better than STAT records */ |
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return axis.default_value; |
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} |
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#endif |
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if (style_tag == HB_STYLE_TAG_OPTICAL_SIZE && font->ptem) |
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return font->ptem; |
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/* STAT */ |
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float value; |
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if (face->table.STAT->get_value (style_tag, &value)) |
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return value; |
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switch ((unsigned) style_tag) |
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{ |
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case HB_STYLE_TAG_ITALIC: |
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return face->table.OS2->is_italic () || face->table.head->is_italic () ? 1 : 0; |
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case HB_STYLE_TAG_OPTICAL_SIZE: |
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{ |
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unsigned int lower, upper; |
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return face->table.OS2->v5 ().get_optical_size (&lower, &upper) |
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? (float) (lower + upper) / 2.f |
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: 12.f; |
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} |
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case HB_STYLE_TAG_SLANT: |
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return face->table.post->table->italicAngle.to_float (); |
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case HB_STYLE_TAG_WIDTH: |
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return face->table.OS2->has_data () |
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? face->table.OS2->get_width () |
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: (face->table.head->is_condensed () ? 75 : 100); |
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case HB_STYLE_TAG_WEIGHT: |
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return face->table.OS2->has_data () |
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? face->table.OS2->usWeightClass |
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: (face->table.head->is_bold () ? 700 : 400); |
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default: |
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return 0; |
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} |
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} |
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#endif |
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#endif
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