[GSoC] Subpixel glyph positioning - Looking for a mentor

Alexander Farrow alexanderfarrow at tutanota.com
Fri Mar 29 16:06:10 UTC 2019

For GSoC 2019 I would love to work on the "Sub-pixel and stable glyph positioning" project from the
list of ideas without a mentor:
https://bugs.documentfoundation.org/show_bug.cgi?id=103322 <https://bugs.documentfoundation.org/show_bug.cgi?id=103322>

I'm particularly interested in this project as I experience poor glyph positioning quite often as a
LibreOffice user.

To achieve the required skills for this project I read the "State of text rendering" paper  by Behdad
Esfahbod to further my understanding of text rendering. I've also followed the HarfBuzz tutorial to
develop a primitive text rendering program.

I've been familiarising myself with the LibreOffice text rendering code particularly CommonSalLayout.
I've written a very small patch for this file, changing a variable from tools::Point to basegfx::B2DPoint
to add support for floating point values.

I've followed the Bugzilla comments and I'm now looking into what changes will need to be made
throughout the code-base to store the glyph positions in a floating point variable. Specifically, I'm
currently looking into how to make the following code changes:

1. DeviceCoordinate -  Change from a long to a double.
2. GlyphItem - Change m_aLinearPos from tools::Point to basegfx::B2DPoint. Change m_nOrigWidth
from an int to a double. Change m_nXOffset from an int to a double.

I am hoping that somebody would like to be my mentor for this project.

With many thanks,
Alexander Farrow (IRC: AlexanderFarrow)

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