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TrueType subsetting: embed a cmap for latin subsets
To support latin subsets in PDF, TrueType fonts require a cmap to map unicode to glyph indices for all characters in the winansi encoding.
This commit is contained in:
Adrian Johnson
parent
7c268bc838
commit
85c25d79f7
3 changed files with 92 additions and 37 deletions
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@ -460,6 +460,9 @@ _cairo_truetype_subset_init (cairo_truetype_subset_t *truetype_subset,
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cairo_private void
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_cairo_truetype_subset_fini (cairo_truetype_subset_t *truetype_subset);
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cairo_private int
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_cairo_unicode_to_winansi (unsigned long unicode);
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cairo_private const char *
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_cairo_winansi_to_glyphname (int glyph);
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@ -343,7 +343,8 @@ static unsigned int _winansi_0x80_to_0x9f[] = {
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0x02dc, 0x2122, 0x0161, 0x203a, 0x0153, 0x0000, 0x017e, 0x0178
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};
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static int _unicode_to_winansi (unsigned long unicode)
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int
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_cairo_unicode_to_winansi (unsigned long unicode)
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{
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int i;
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@ -618,7 +619,7 @@ _cairo_sub_font_map_glyph (cairo_sub_font_t *sub_font,
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if (sub_font->parent->use_latin_subset &&
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(! _cairo_font_face_is_user (sub_font->scaled_font->font_face)))
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{
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latin_character = _unicode_to_winansi (font_unicode);
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latin_character = _cairo_unicode_to_winansi (font_unicode);
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if (latin_character > 0 ||
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(latin_character == 0 && sub_font->num_glyphs_in_latin_subset > 0))
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{
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@ -1184,7 +1185,7 @@ _cairo_scaled_font_subset_create_glyph_names (cairo_scaled_font_subset_t *subset
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}
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if (utf16_len == 1) {
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int ch = _unicode_to_winansi (utf16[0]);
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int ch = _cairo_unicode_to_winansi (utf16[0]);
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if (ch > 0)
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strncpy (buf, _cairo_winansi_to_glyphname (ch), sizeof (buf));
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else
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@ -393,51 +393,98 @@ cairo_truetype_font_check_boundary (cairo_truetype_font_t *font,
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return CAIRO_STATUS_SUCCESS;
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}
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typedef struct _cmap_unicode_range {
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unsigned int start;
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unsigned int end;
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} cmap_unicode_range_t;
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static cmap_unicode_range_t winansi_unicode_ranges[] = {
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{ 0x0020, 0x007f },
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{ 0x00a0, 0x00ff },
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{ 0x0152, 0x0153 },
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{ 0x0178, 0x0178 },
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{ 0x017d, 0x017e },
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{ 0x0192, 0x0192 },
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{ 0x02c6, 0x02c6 },
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{ 0x02dc, 0x02dc },
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{ 0x2013, 0x2026 },
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{ 0x2030, 0x2030 },
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{ 0x2039, 0x203a },
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{ 0x2122, 0x2122 },
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};
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static cairo_status_t
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cairo_truetype_font_write_cmap_table (cairo_truetype_font_t *font,
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unsigned long tag)
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{
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unsigned int i;
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int i;
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unsigned int j;
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int range_offset;
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int num_ranges;
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int entry_selector;
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int length;
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num_ranges = ARRAY_LENGTH (winansi_unicode_ranges);
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length = 16 + (num_ranges + 1)*8;
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for (i = 0; i < num_ranges; i++)
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length += (winansi_unicode_ranges[i].end - winansi_unicode_ranges[i].start + 1)*2;
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entry_selector = 0;
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while ((1 << entry_selector) <= (num_ranges + 1))
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entry_selector++;
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entry_selector--;
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cairo_truetype_font_write_be16 (font, 0); /* Table version */
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cairo_truetype_font_write_be16 (font, 2); /* Num tables */
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cairo_truetype_font_write_be16 (font, 1); /* Num tables */
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cairo_truetype_font_write_be16 (font, 3); /* Platform */
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cairo_truetype_font_write_be16 (font, 0); /* Encoding */
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cairo_truetype_font_write_be32 (font, 20); /* Offset to start of table */
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cairo_truetype_font_write_be16 (font, 1); /* Encoding */
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cairo_truetype_font_write_be32 (font, 12); /* Offset to start of table */
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cairo_truetype_font_write_be16 (font, 1); /* Platform */
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cairo_truetype_font_write_be16 (font, 0); /* Encoding */
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cairo_truetype_font_write_be32 (font, 52); /* Offset to start of table */
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/* Output a format 4 encoding table. */
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/* Output a format 4 encoding table for the winansi encoding */
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cairo_truetype_font_write_be16 (font, 4); /* Format */
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cairo_truetype_font_write_be16 (font, 32); /* Length */
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cairo_truetype_font_write_be16 (font, length); /* Length */
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cairo_truetype_font_write_be16 (font, 0); /* Version */
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cairo_truetype_font_write_be16 (font, 4); /* 2*segcount */
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cairo_truetype_font_write_be16 (font, 4); /* searchrange */
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cairo_truetype_font_write_be16 (font, 1); /* entry selector */
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cairo_truetype_font_write_be16 (font, 0); /* rangeshift */
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cairo_truetype_font_write_be16 (font, 0xf000 + font->base.num_glyphs - 1); /* end count[0] */
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cairo_truetype_font_write_be16 (font, 0xffff); /* end count[1] */
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cairo_truetype_font_write_be16 (font, num_ranges*2 + 2); /* 2*segcount */
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cairo_truetype_font_write_be16 (font, (1 << (entry_selector + 1))); /* searchrange */
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cairo_truetype_font_write_be16 (font, entry_selector); /* entry selector */
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cairo_truetype_font_write_be16 (font, num_ranges*2 + 2 - (1 << (entry_selector + 1))); /* rangeshift */
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for (i = 0; i < num_ranges; i++)
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cairo_truetype_font_write_be16 (font, winansi_unicode_ranges[i].end); /* end count[] */
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cairo_truetype_font_write_be16 (font, 0xffff); /* end count[] */
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cairo_truetype_font_write_be16 (font, 0); /* reserved */
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cairo_truetype_font_write_be16 (font, 0xf000); /* startCode[0] */
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cairo_truetype_font_write_be16 (font, 0xffff); /* startCode[1] */
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cairo_truetype_font_write_be16 (font, 0x1000); /* delta[0] */
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cairo_truetype_font_write_be16 (font, 1); /* delta[1] */
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cairo_truetype_font_write_be16 (font, 0); /* rangeOffset[0] */
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cairo_truetype_font_write_be16 (font, 0); /* rangeOffset[1] */
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/* Output a format 6 encoding table. */
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for (i = 0; i < num_ranges; i++)
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cairo_truetype_font_write_be16 (font, winansi_unicode_ranges[i].start); /* startCode[] */
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cairo_truetype_font_write_be16 (font, 0xffff); /* startCode[] */
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cairo_truetype_font_write_be16 (font, 6);
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cairo_truetype_font_write_be16 (font, 10 + 2 * font->base.num_glyphs);
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cairo_truetype_font_write_be16 (font, 0);
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cairo_truetype_font_write_be16 (font, 0); /* First character */
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cairo_truetype_font_write_be16 (font, font->base.num_glyphs);
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for (i = 0; i < font->base.num_glyphs; i++)
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cairo_truetype_font_write_be16 (font, i);
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for (i = 0; i < num_ranges; i++)
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cairo_truetype_font_write_be16 (font, 0x0000); /* delta[] */
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cairo_truetype_font_write_be16 (font, 1); /* delta[] */
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range_offset = num_ranges*2 + 2;
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for (i = 0; i < num_ranges; i++) {
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cairo_truetype_font_write_be16 (font, range_offset); /* rangeOffset[] */
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range_offset += (winansi_unicode_ranges[i].end - winansi_unicode_ranges[i].start + 1)*2 - 2;
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}
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cairo_truetype_font_write_be16 (font, 0); /* rangeOffset[] */
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for (i = 0; i < num_ranges; i++) {
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for (j = winansi_unicode_ranges[i].start; j < winansi_unicode_ranges[i].end + 1; j++) {
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int ch = _cairo_unicode_to_winansi (j);
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int glyph;
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if (ch > 0)
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glyph = font->scaled_font_subset->latin_to_subset_glyph_index[ch];
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else
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glyph = 0;
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cairo_truetype_font_write_be16 (font, glyph);
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}
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}
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return font->status;
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}
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@ -985,8 +1032,9 @@ cairo_truetype_font_add_truetype_table (cairo_truetype_font_t *font,
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* The tables in the table directory must be listed in alphabetical
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* order. The "cvt", "fpgm", and "prep" are optional tables. They
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* will only be embedded in the subset if they exist in the source
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* font. The pos parameter of cairo_truetype_font_add_truetype_table()
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* specifies the position of the table in the table directory.
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* font. "cmap" is only embedded for latin fonts. The pos parameter of
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* cairo_truetype_font_add_truetype_table() specifies the position of
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* the table in the table directory.
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*/
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static void
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cairo_truetype_font_create_truetype_table_list (cairo_truetype_font_t *font)
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@ -1016,7 +1064,9 @@ cairo_truetype_font_create_truetype_table_list (cairo_truetype_font_t *font)
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has_prep = TRUE;
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font->num_tables = 0;
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pos = 1;
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pos = 0;
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if (font->scaled_font_subset->is_latin)
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pos++;
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if (has_cvt)
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pos++;
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if (has_fpgm)
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@ -1024,7 +1074,8 @@ cairo_truetype_font_create_truetype_table_list (cairo_truetype_font_t *font)
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cairo_truetype_font_add_truetype_table (font, TT_TAG_glyf, cairo_truetype_font_write_glyf_table, pos);
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pos = 0;
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cairo_truetype_font_add_truetype_table (font, TT_TAG_cmap, cairo_truetype_font_write_cmap_table, pos++);
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if (font->scaled_font_subset->is_latin)
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cairo_truetype_font_add_truetype_table (font, TT_TAG_cmap, cairo_truetype_font_write_cmap_table, pos++);
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if (has_cvt)
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cairo_truetype_font_add_truetype_table (font, TT_TAG_cvt, cairo_truetype_font_write_generic_table, pos++);
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if (has_fpgm)
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