Image property "smooth: false" not working properly

There is a rendering bug since Qt 5.2 beta where scaled images with 'smooth' turned off are actually rendered with smoothing turned on (looking blurry). Whether the property applies properly depends on the state of other items in the scene.

Long story:

We write a small 2D MMORPG client. In this client we scale up the entire UI if the resolution is larger than a specific value. However since we have pixel art graphics we use smooth: false for all Image {} elements to keep the pixel look.

This worked great in Qt 5.1.1 and below. However since Qt 5.2 beta in certain situations turning off the smooth rendering does not seem to work.

You can reproduce it reliably using our client:

• Checkout and compile https://github.com/tales/tales-client
• Log into game (you can use some garbage email address, we do not validate them. ("aaa@aaaa.aa" works as sane email)).

Now if you are in the game and you have the window larger than 959x959 to make the UI scale up.

Now you should realize that the joystick in lower left and the buttons in lower right are blurred even though their images have "smooth: false" set.

Other strange issues happening since Qt 5.2 beta that may be related: Once you "open" the inventory or status page by clicking the tabs at the sides of the screen (or press 'c' or 'i') the blurring suddenly goes away.

The pages we open are basically only items which are over the main game. However opening the windows has an effect on the scrolling of the map. This is related to hiding the contents of these pages when they are entirely offscreen.

I attached two screenshots which show the bug. I did not do anything but opening the side window.