On Saturday 31 of March 2012 15:35:32 Bernd Kreuss wrote: > Hello widgetset and Qt experts, I need some explanations to better > understand what is going on. I recently posted a thread > "TCanvas.TextRect, subpixel antialiasing with Qt4" that also included a > small demo application and screenshots to demonstrate my problem. > > I have tried to step through the LCL and widgetset code to see what is > actually going on, the problem is when outputting text to some offscreen > TCanvas, like for example the TCanvas of the bitmap of a TImage then it > will use different text anti-aliasing settings than when doing the same > for the TCanvas of the form during the paint event. I have observed this > with Qt on Linux. > > When painting to the canvas of the form during paint it will respect the > subpixel antialiasing settings from my .fonts.conf file and text will be > subpixel-antialiased but when outputting text to the canvas of a bitmap > it will only use "normal" antialiasing (which looks quite ugly and > inconsistent when you see such text appearing right next to the other > properly antialiased text in the same application). > > I have tried to step through it and it seems it will ask Qt to create a > bitmap(?) and a device context for the bitmap and then use Qt to paint > on this bitmap and I tried to patch some of the Qt units trying to > change font settings and dc settings and renderhints immediately before > QPainter_drawText() is called but nothing has the desired effect but I > also did not see any obvious flags or constants whose names would > suggest that they have anything to do with it. > > What is going on here and is it even *possible* to solve this problem? > The main reason for me is to use the html panel from turbopower_ipro > which seems to be rendering its content to such an offscreen canvas and > is producing really really ugly font rendering compared to the rest of > the application. > > The problem does *not* occur with GTK2. I have not tried Windows yet.
No idea, maybe best would be to open an issue about it and attach good example, so I can take a look into. zeljko
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