1fcft_text_run_rasterize(3)           fcft           fcft_text_run_rasterize(3)
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NAME

6       fcft_text_run_rasterize - rasterize a series of glyphs for a text
7       string
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SYNOPSIS

10       #include <fcft/fcft.h>
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12       struct fcft_text_run *fcft_text_run_rasterize(
13           struct fcft_font *font, size_t len, const wchar_t text[static len],
14           enum fcft_subpixel subpixel);
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DESCRIPTION

17       fcft_text_run_rasterize() shapes and rasterizes the string text into a
18       series of glyphs using the primary font, and possibly one or more fall‐
19       back fonts, in font.
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21       subpixel allows you to specify which subpixel mode to use. See
22       fcft_glyph_rasterize() for details.
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24       The string is passed to HarfBuzz for shaping, initially using the pri‐
25       mary font. The shaping data is parsed, and when an unshaped codepoint
26       is encountered, it is retried with the first fallback font. If that
27       fails too, the next fallback font is tried. After successfully shaping
28       the failed codepoint, the primary font is used to shape the rest of the
29       string. This continues until the entire string has been shaped.
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31       There is limited support for right-to-left scripts. hb_buf‐
32       fer_guess_segment_properties() is used to guess whether to use left-to-
33       right, or right-to-left, logic, and this is done each time we try to
34       shape a part of the string.
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36       As a consequence, the result of mixed LTR and RTL strings depends on
37       the font; if the font has glyphs for all characters in the string,
38       hb_buffer_guess_segment_properties() is only called once, on the entire
39       string. Meaning the entire string is subject to either LTR, or RTL
40       logic, but not both.
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42       If the (primary) font does not have glyphs for all characters, then
43       hb_buffer_guess_segment_properties() will be called for each segment
44       where shaping failed. In this case, parts of the string may be treated
45       as LTR while others are treated as RTL.
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RETURN VALUE

48       On error, NULL is returned.
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50       On success, a pointer to a dynamically allocated text-run is returned:
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52           struct fcft_text_run {
53               const struct fcft_glyph **glyphs;
54               int *cluster;
55               size_t count;
56           };
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58       Both glyphs and cluster are arrays with count elements. cluster con‐
59       tains the character offsets (in the original string) of each corre‐
60       sponding glyph.
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62       Note that the glyphs' cols member are invalid.
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64       The text-run is not cached in fcft. The calling application may cache
65       it for as long as it likes, including after the font has been de‐
66       stroyed.
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68       The text-run must be free:d with fcft_text_run_destroy().
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SEE ALSO

71       fcft_text_run_destroy(), fcft_grapheme_rasterize(), fcft_glyph_raster‐
72       ize()
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762.5.0                             2021-11-13        fcft_text_run_rasterize(3)
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