100 lines
2.8 KiB
XML
100 lines
2.8 KiB
XML
<chapter id="hello-harfbuzz">
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<title>Hello, HarfBuzz</title>
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<para>
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Here's the simplest HarfBuzz that can possibly work. We will improve
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it later.
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</para>
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<orderedlist numeration="arabic">
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<listitem>
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<para>
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Create a buffer and put your text in it.
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</para>
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</listitem>
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</orderedlist>
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<programlisting language="C">
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#include <hb.h>
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hb_buffer_t *buf;
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buf = hb_buffer_create();
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hb_buffer_add_utf8(buf, text, strlen(text), 0, strlen(text));
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</programlisting>
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<orderedlist numeration="arabic">
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<listitem override="2">
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<para>
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Guess the script, language and direction of the buffer.
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</para>
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</listitem>
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</orderedlist>
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<programlisting language="C">
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hb_buffer_guess_segment_properties(buf);
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</programlisting>
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<orderedlist numeration="arabic">
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<listitem override="3">
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<para>
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Create a face and a font, using FreeType for now.
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</para>
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</listitem>
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</orderedlist>
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<programlisting language="C">
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#include <hb-ft.h>
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FT_New_Face(ft_library, font_path, index, &face)
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hb_font_t *font = hb_ft_font_create(face);
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</programlisting>
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<orderedlist numeration="arabic">
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<listitem override="4">
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<para>
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Shape!
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</para>
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</listitem>
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</orderedlist>
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<programlisting>
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hb_shape(font, buf, NULL, 0);
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</programlisting>
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<orderedlist numeration="arabic">
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<listitem override="5">
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<para>
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Get the glyph and position information.
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</para>
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</listitem>
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</orderedlist>
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<programlisting language="C">
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hb_glyph_info_t *glyph_info = hb_buffer_get_glyph_infos(buf, &glyph_count);
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hb_glyph_position_t *glyph_pos = hb_buffer_get_glyph_positions(buf, &glyph_count);
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</programlisting>
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<orderedlist numeration="arabic">
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<listitem override="6">
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<para>
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Iterate over each glyph.
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</para>
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</listitem>
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</orderedlist>
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<programlisting language="C">
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for (i = 0; i < glyph_count; ++i) {
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glyphid = glyph_info[i].codepoint;
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x_offset = glyph_pos[i].x_offset / 64.0;
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y_offset = glyph_pos[i].y_offset / 64.0;
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x_advance = glyph_pos[i].x_advance / 64.0;
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y_advance = glyph_pos[i].y_advance / 64.0;
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draw_glyph(glyphid, cursor_x + x_offset, cursor_y + y_offset);
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cursor_x += x_advance;
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cursor_y += y_advance;
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}
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</programlisting>
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<orderedlist numeration="arabic">
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<listitem override="7">
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<para>
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Tidy up.
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</para>
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</listitem>
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</orderedlist>
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<programlisting language="C">
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hb_buffer_destroy(buf);
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hb_font_destroy(hb_ft_font);
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</programlisting>
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<para>
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This example shows enough to get us started using HarfBuzz. Now we
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are going to use the remainder of HarfBuzz's API to refine that
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example and improve our text shaping capabilities.
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</para>
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</chapter>
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