[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [ft] Render differences on embedded ARM vs other platforms
From: |
Werner LEMBERG |
Subject: |
Re: [ft] Render differences on embedded ARM vs other platforms |
Date: |
Thu, 30 Nov 2017 06:52:34 +0100 (CET) |
> Recently, we moved from an RGBT 5551 internal color configuration to
> an RGBA 8888 configuration. There is a shared “core” application
> with a platform specific hardware abstraction layer. The code is
> compiled for windows, mac, linux, android, ios, and an embedded ARM
> hardware system (mix of 32 and 64 bit versions).
This mix might be the culprit.
> 2. Could this be some sort of a floating point rounding behavior
> issue? (hw float on the ARM rounding differently than hw/sw on the
> other systems for example)
No, since FreeType doesn't use floating point numbers.
> Basically, I am hoping for a start on where to even begin trying to
> track this down. The goal would be for rendering to be identical
> across all platforms.
I suggest that you start with the current git version of FreeType and
create a small C code file that renders exactly one of the problematic
glyphs into a buffer, using the same load flags as in your real
application. You should compile the code with debugging activated,
then set the environment variable
FT2_DEBUG=any:7
and redirect your program's stderr output to a file. If you compare
the output compiled on different platforms you get some first hints
where the (important) differences are.
Werner