Re: PangoGlyphString + PangoLayout?

[Behdad Esfahbod <behdad behdad org>]

You have a better luck just copying basic-fc.c and modifying it, and either
installing your module on the system or register it using pango_module_register().

behdad

On 03/01/2012 08:28 AM, Mindaugas Jaunius wrote:
> Hi,
> 
> To be able to fully control open type font features (liga, smcp, ssup)
> I ended up using PangoOTBuffer not just PangoLayout. No the problem I
> run into is that the output of PangoOTBuffer is PangoGlyphString. The
> only function I found to show it is pango_cairo_show_glyph_string(cr,
> font, glyphString), but this function shows the full PangoGlyphString
> in one line and does not create a wraping paragraph on PangoLayout. No
> is there a way to give my PangoGlyphString from PangoOTBuffer to
> PangoLayout?
> 
> Below is some code of how I am using PangoOTBuffer now. Mainly I used
> code from pango modules class basic-fc.c as an example. Any comments
> and critiques on the code are welcomed.
> 
> const char foo[] = "ffi ff fl Wa VA";
> 
> static const PangoOTFeatureMap gsub_features[] =
> {
>   {"ccmp", PANGO_OT_ALL_GLYPHS},
>   {"locl", PANGO_OT_ALL_GLYPHS},
>   {"liga", PANGO_OT_ALL_GLYPHS},
>   {"clig", PANGO_OT_ALL_GLYPHS}
> };
> 
> static const PangoOTFeatureMap gpos_features[] =
> {
>   {"kern", PANGO_OT_ALL_GLYPHS},
>   {"mark", PANGO_OT_ALL_GLYPHS},
>   {"mkmk", PANGO_OT_ALL_GLYPHS}
> };
> 
> cairo_t *cr = cairo_create(surface);
> cairo_set_source_rgb(cr, 1.0, 1.0, 1.0); // sets the background color to white
> cairo_paint(cr);
> 
> PangoLayout *layout; // layout for a paragraph of text
> layout = pango_cairo_create_layout(cr);
> 
> PangoFontDescription *descFont;
> pango_layout_set_text(layout, foo, -1);
> pango_layout_set_width(layout, width * PANGO_SCALE);
> descFont = pango_font_description_from_string("Fedra Serif Pro A Book 20");
> pango_layout_set_font_description(layout, descFont);
> pango_font_description_free(descFont);
> 
> cairo_move_to(cr, 20, 40);
> cairo_set_line_width(cr, 1.0); // sets the line width, default is 2.0
> 
> cairo_set_source_rgb(cr, 0.0, 0.0, 0.0); // set the colour to black
> 
> pango_cairo_update_layout(cr, layout); // update layout
> 
> PangoLayoutIter *iter = NULL;
> iter = pango_layout_get_iter(layout);
> 
> PangoLayoutRun *run = NULL;
> run = pango_layout_iter_get_run_readonly(iter);
> 
> PangoFont *font = run->item->analysis.font; // get PangoFont of Fedra Serif
> 
> PangoFcFont *fc_font = PANGO_FC_FONT(font);
> 
> PangoOTBuffer *otBuffer;
> otBuffer = pango_ot_buffer_new(fc_font);
> 
> glong n_chars = g_utf8_strlen(foo, strlen(foo));
> PangoGlyphString *glyphs = pango_glyph_string_new();
> 
> const char *p = foo;
> int cluster = 0;
> int i;
> FT_Face face;
> PangoOTRulesetDescription desc;
> const PangoOTRuleset *ruleset;
> 
> face = pango_fc_font_lock_face(fc_font);
> if (!face) {
> LOGE("Can not lock fc font face");
> }
> 
> // add all glyphs to otBuffer
> for (i = 0; i < n_chars; i++) {
> gunichar wc;
> PangoGlyph glyph;
> 
> wc = g_utf8_get_char(p);
> 
> if (g_unichar_type(wc) != G_UNICODE_NON_SPACING_MARK)
> 	cluster = p - foo1;
> 
> if (pango_is_zero_width(wc))
> 	glyph = PANGO_GLYPH_EMPTY;
> else {
> 	gunichar c = wc;
> 
> 	if (run->item->analysis.level % 2)
> 		g_unichar_get_mirror_char(c, &c);
> 
> 	glyph = pango_fc_font_get_glyph(fc_font, c);
> }
> 
> if (!glyph)
> 	glyph = PANGO_GET_UNKNOWN_GLYPH(wc);
> 
> pango_ot_buffer_add_glyph(otBuffer, glyph, 0, cluster);
> 
> p = g_utf8_next_char(p);
> }
> 
> // apply open type features
> desc.script = run->item->analysis.script;
> desc.language = run->item->analysis.language;
> desc.n_static_gsub_features = G_N_ELEMENTS(gsub_features);
> desc.static_gsub_features = gsub_features;
> desc.n_static_gpos_features = G_N_ELEMENTS(gpos_features);
> desc.static_gpos_features = gpos_features;
> desc.n_other_features = 0;
> desc.other_features = NULL;
> 
> ruleset = pango_ot_ruleset_get_for_description(pango_ot_info_get(face), &desc);
> 
> pango_ot_ruleset_substitute(ruleset, otBuffer);
> pango_ot_ruleset_position(ruleset, otBuffer);
> 
> // output from otBuffer to PangoGlyphString
> pango_ot_buffer_output(otBuffer, glyphs);
> 
> pango_cairo_show_glyph_string(cr, font, glyphs);
> 
> -mindaugas
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