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POPango and FreeType -- not rendering text, just weird pixels
 

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  1. POPango and FreeType -- not rendering text, just weird pixels
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    <p>I'm trying to get Pango to control FreeType. I've successfully got FreeType to render into a bitmap but Pango doesn't seem to know what's going on, I'm obviously not doing something correctly.</p> <p>This is the code that I'm using at the moment:</p> <pre><code>font_map = pango_ft2_font_map_new(); pango_ft2_font_map_set_resolution(PANGO_FT2_FONT_MAP(font_map), 72, 72); cr = pango_font_map_create_context(PANGO_FONT_MAP(font_map)); font_description = pango_font_description_new (); pango_font_description_set_family (font_description, "Courier New"); pango_font_description_set_weight (font_description, PANGO_WEIGHT_BOLD); pango_font_description_set_absolute_size (font_description, 32 * PANGO_SCALE); layout = pango_layout_new(cr); pango_layout_set_font_description(layout, font_description); pango_layout_set_text(layout, "Some sample text!", -1); pango_context_set_font_description(cr, font_description); FT_Bitmap bitmap = { 0 }; bitmap.width = drawBitmap.get()-&gt;getWidth(); bitmap.rows = drawBitmap.get()-&gt;getHeight(); bitmap.pitch = bitmap.width * 4; bitmap.buffer = (unsigned char*)drawBitmap.get()-&gt;getDataPtr(); bitmap.num_grays = 256; bitmap.pixel_mode = FT_PIXEL_MODE_GRAY; pango_ft2_render_layout(&amp;bitmap, layout, 100, 100); </code></pre> <p><code>drawBitmap</code> is just my helper class, I know this works because I can fill it with random colours and they show up.</p> <p>This is what gets rendered:</p> <p><img src="https://i.stack.imgur.com/caLWi.png" alt="enter image description here"></p> <p>I want to try to get that text to show up properly.</p> <hr> <p>EDIT: The problem has been brought into sharper relief after fixing the bit depth of the image and switching from bare Pango FreeType to Pango Cairo with the FreeType engine.</p> <p>Using this line:</p> <pre><code>font_map = pango_cairo_font_map_new_for_font_type(CAIRO_FONT_TYPE_WIN32); </code></pre> <p>produces</p> <p><img src="https://i.stack.imgur.com/6I7nK.png" alt="enter image description here"></p> <p>and when I run through <code>pango_font_map_list_families</code>, I get a long list of the fonts installed on my system.</p> <p>However if I change it to this, to use FreeType:</p> <pre><code>font_map = pango_cairo_font_map_new_for_font_type(CAIRO_FONT_TYPE_FT); </code></pre> <p>it produces</p> <p><img src="https://i.stack.imgur.com/l2Qy3.png" alt="enter image description here"></p> <p>and then there are suddenly only 3 fonts on my system, <code>Sans</code>, <code>Serif</code> and <code>Monospace</code>.</p>
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    1. USChris Burt-Brown
    1. USChris Burt-Brown
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      1. POPango and FreeType -- not rendering text, just weird pixels
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    1. COI don't know if this is related but `pango_font_map_list_families` is only listing `Sans`, `Serif` and `Monospace` as available fonts so I wonder if Pango is understanding Windows' font structure...
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      1. POPango and FreeType -- not rendering text, just weird pixels
      1. USChris Burt-Brown
    2. CO(1) Could this be the default "Not Available" characters being drawn? In lots of fonts it is a simple rectangle such as this. (2) Zooming in, there seems to be some RGB overlapping. Are you correctly converting from grayscale (what FreeType returns) to RGb (apparently, your output format)?
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      1. POPango and FreeType -- not rendering text, just weird pixels
      1. USusr2564301
    3. CO@Jongware: You are right on both fronts, I've fixed the RGB/grayscale confusion and they now show as regular white boxes. The next step is to figure out why they are not rendering as actual text.
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      1. POPango and FreeType -- not rendering text, just weird pixels
      1. USChris Burt-Brown
 

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