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Re: [ft] bitmap_left description
From: |
Phil Endecott |
Subject: |
Re: [ft] bitmap_left description |
Date: |
Sat, 27 Sep 2014 15:55:33 +0100 |
Hi Werner & others,
Werner LEMBERG wrote:
The docs for bitmap_left say:
This is the bitmap's left bearing expressed in integer
pixels. Of course, this is only valid if the format is
FT_GLYPH_FORMAT_BITMAP.
I'm rendering individual glyphs from a TrueType font using
FT_Load_Glyph() followed by FT_Render_Glyph(). Having done that I
had been struggling to work out the metrics for the result. Then I
discovered that bitmap_left and bitmap_top seem to tell me exactly
what I need to know - but I had been avoiding them because this not
a bitmap font and the description quoted above.
Well, after calling FT_Render_Glyph, `face->glyph' *does* hold a
bitmap, as specified by the `face->glyph->format' field. Please read
the documentation of its type, `FT_GlyphSlotRec'.
Is it OK to use bitmap_left/top after FT_Render_Glyph()?
Yes.
Thanks for confirming that. I'll shortly write a more general "am
I doing this right?" email, but I do seem to be getting the results
I expected now that I'm using bitmap_left/top.
Is this a documentation issue?
Obviously. Please suggest an improvement.
My "mental disconnect" was between the format of the glyph, which
I imagined to be vector (and only vector) for a glyph from a vector
font, and the presence of a bitmap in the glyph slot after rendering.
So my suggestion would be to say:
This is the bitmap's left bearing expressed in integer
pixels. This is only valid if the glyph slot contains
a bitmap.
Thanks, Phil.