[Interest] QPainter::drawImage() is terrible at smooth scaling?

Allan Sandfeld Jensen kde at carewolf.com
Fri May 17 09:06:40 CEST 2019

On Freitag, 17. Mai 2019 06:48:20 CEST David M. Cotter wrote:
> is this a bug?
> https://forum.qt.io/topic/102637/qpainter-drawimage-is-terrible-at-smooth-sc
> aling
Likes like you are downscaling more than 2x. QPainter is doing bilinear 
sampling when smooth scaling, and that produces bad results at 2x downscaling. 
QImage::smoothScaled() uses a slower box scaling algorithm that works at even 
the most aggressive downscaling.


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