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Re: [ft-devel] [cairo] FT_Bitmap_Convert, and FreeType's bitmap format v
From: |
Bill Spitzak |
Subject: |
Re: [ft-devel] [cairo] FT_Bitmap_Convert, and FreeType's bitmap format vs Cairo's |
Date: |
Tue, 25 Apr 2017 09:51:35 -0700 |
> Also I am wondering about a little drawing issue I have - I want to scale a
> freetype bitmap up and draw a larger version of it (useful for illustrations
> for rasterization issues...) but it seems that cairo always anti-alias the
> edges at the original resolution, and I haven't figured out how to turn it
> off yet.
> Let's say, I have rendered a glyph to a 24x24 grid in FreeType, and want to
> draw that in cairo to 480 x 480 . I'd like cairo to render at the destination
> resolution - i.e. do whatever at the 1-pixel boundary in 480x480, but it
> seems that it is doing it in the original grid, which blows up to be extra
> blurry at ~20 pixels wide in 480x480. Here is how it looks (the corner S is
> original resolution drawn as is):
>
> http://htl10.users.sourceforge.net/tmp/S.png
>
> This is from a word-in-progress rewrite of freetype-py's
> glyph-alpha/glyph-monochrome examples which uses numpy and matplotlib, to
> using pycairo for drawing.
Possibly you want to do cairo_patter_set_filter(source,
CAIRO_FILTER_BEST) or CAIRO_FILTER_NEAREST (the difference is that
BEST will actually antialias the boundaries between the pixels which
looks nicer if the image is rotated or scaled by a non-integer).