Users are expecting LibreOffice to render fonts more faithfully and with better antialiasing, so we need to move to newer APIs. DirectWrite/Direct2D is such an API, available since Windows Vista SP2 (Platform Update) and in every newer version of Windows, replacing the obsolete GDI++.
This task could be turned into a GSoC project, maybe.
Created attachment 117991 [details]
Comparison between Direct2D (above) versus GDI+ (below): notice the smoother edges in D2D
DirectWrite rendering for Graphite to work around ExTextOut bug
Is this bug fixed?
If so, could you please close it as RESOLVED FIXED?
Could you please checking checking it with vertical text layout?
Would say DirectWrite/Direct2D was implemented to support OpenGL rendering, but not fully.
Per ESC (2017-05-24) for the 5.5/6.0 build we will fully drop XP and Vista support. That decision now provides opportunity to fully refactor Windows graphics to DirectWrite/Direct2D rendering.
Khaled completed Akash's work on HarfBuzz Common Layout (bug 89870) in 5.3 and 5.4 they've routed more of the Windows rendering through DirectWrite calls expanding on work by Tor, Tim and Martin for Graphite support.
But the DirectWrite/Direct2D implemented thus far was only a subset, it now needs refinement (bug 107521). And needs support for floating point positioning (bug 103322) to support sub-pixel rendering. While loss of grayscale mode antialiasing with our DirectWrite implementation is causing issues for non-OpenGL Windows users (bug 106990).
@Adolfo, you OK with closing this?
Adolfo, please confirm bug 107521 then.