By the way, when I write "bitmap" I mean "BMP file format", not glBitmap()
format, which does use lower-left origin.



On Fri, Sep 23, 2011 at 2:58 PM, Patrick Baggett
<[email protected]>wrote:

> The baseline is a point you give. The coordinates for the glyph are
> relative to an origin. So the punctuation should be just a small bit off
> from the baseline. If you set your baseline to be (0,0), then it *bitmap* 
> space,
> you're in the upper left. Increasing Y moves you down, but in font terms it
> moves you up (Cartesian coords). Maybe the difference there has something to
> do with it. The baseline for your font really should be lower, say for 16px
> font, at (x,15).
>
> In other words, if you render a 16pt glyph at (0,0), move over say, 12
> pixels to (12,0), render another 16pt glyph, and so on, you get this:
>
> (0,0)                  +X
> 0----------
> | G1| G2|
> |   |---+
> |---+
> |
> +Y
>
>
> You need to make sure that you actually copy the rendered glyphs to some
> position on the bitmap so the bottom of the rect of th glyph is always on
> teh baseline, and the baseline should always start at FONT_PIXELS_HEIGHT
> below 0, i.e. if your largest font glyph can be 16 pixels tall, you need to
> use 15 as a baseline Y so that [0,15] can be filled.
>
> Patrick
>
>
> http://www.freetype.org/freetype2/docs/glyphs/glyphs-3.html
>
> On Fri, Sep 23, 2011 at 12:12 PM, Farmer, Anthony <
> [email protected]> wrote:
>
>>  Hello.****
>>
>> ** **
>>
>> I’m trying to load a font into a bitmap, then into an OpenGL texture for
>> rendering, and have encountered a problem with the font baseline that I’m
>> unable to resolve via online documentation or Google search.  Attached is a
>> small bitmap showing what happens, which hopefully obviates what I’m doing
>> wrong and how it can be corrected.****
>>
>> ** **
>>
>> Briefly, I convert all the glyphs to bitmap glyphs then extract them
>> sequentially into an OpenGL texture.  Later I use the X-offset into that
>> texture for rendering text.  Unfortunately all the punctuation is being
>> placed at the TOP of the GL texture, as if the baseline were there instead
>> of along the bottom.  I don’t believe that’s the case, but that’s the
>> behavior.****
>>
>> ** **
>>
>> If there were some way I could extract the vertical location of the face’s
>> BASELINE, I could adjust everything accordingly as glyphs are extracted.
>> But I see no way to get that baseline value.****
>>
>> ** **
>>
>> Or perhaps there’s another approach altogether that I should be taking?**
>> **
>>
>> ** **
>>
>> Thanks,****
>>
>> Anthony Farmer****
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