[Interest] QPixmap or QImage::scaled() crash on iOS with smoothTransformation

[maitai]

Hello again,

FYI there is no such thing as Qt::SmoothScale in QPainter::drawImage or 
QPainter::drawPixmap so I ended up with something like:

     QPixmap pixscaled(QSize(scaleX, scaleY));
     if(scaleX > pix.width() || scaleY > pix.height()) {
         pixscaled.fill(Qt::transparent);
         QPainter painter(&pixscaled);
         painter.setBackgroundMode(Qt::TransparentMode);
         painter.setRenderHints(QPainter::Antialiasing, true);
         painter.setRenderHints(QPainter::SmoothPixmapTransform, true);
         painter.drawPixmap(QRect(QPoint(0, 0), QSize(scaleX, scaleY)), 
pix);
         painter.end();
     } else {
         pixscaled = pix.scaled(scaleX, scaleY, Qt::IgnoreAspectRatio, 
Qt::SmoothTransformation);
     }

and no crash anymore...

Thanks once more
Philippe Lelong

Le 20-07-2015 05:17, maitai a écrit :
> Ok, it's good there is a workaround
> 
> Thank you very much
> 
> 
> Le 19-07-2015 23:16, Allan Sandfeld Jensen a écrit :
>> On Sunday 19 July 2015, maitai wrote:
>>> Arf...
>>> 
>>> Only solution is to go back to 5.4.2 for iOS?
>>> 
>> It should be fixed by 5.5.1, if you need smooth-scaling before then 
>> and
>> can
>> not build a new Qt binary, you can either overallocate the from image
>> by one
>> pixel or scale using the painter, something like this:
>> 
>> QImage dst(dstSize);
>> QPainter painter(&dst);
>> painter.drawImage(srcImage, dstImage, QRect(QPoint(), dstSize),
>> Qt::SmoothScale);
>> painter.end();
>> 
>> For downscaling, QImage smooth scaling is better than the qpainter
>> scaling,
>> but for upscaling they are the same.
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