[Interest] About copying the image buffer with alpha blending

song.7.liu at nokia.com song.7.liu at nokia.com
Wed Aug 29 17:02:38 CEST 2012


After using the QPixmap, the pixel format now is Format_ARGB32_Premultiplied, and the performance looks better.

But one question is about the background image, as this case the alpha channel info can be dropped,
is there a way to discard this alpha info to accelerate drawing background image ?


-----Original Message-----
From: interest-bounces+song.7.liu=nokia.com at qt-project.org [mailto:interest-bounces+song.7.liu=nokia.com at qt-project.org] On Behalf Of Rodal Samuel (Nokia-MP/Oslo)
Sent: Wednesday, August 29, 2012 6:43 PM
To: interest at qt-project.org
Subject: Re: [Interest] About copying the image buffer with alpha blending

On 08/29/2012 12:05 PM, ext song.7.liu at nokia.com wrote:
> QImage(const QString &fileName, const char *format = 0);
> If I want to use Format_ARGB8565_Premultiplied, so what's the format 
> string in above constructor ?
> Thanks,
> Song

Why not use QPixmap? It should pick the best format for blitting and blending automatically.


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