Image Scaling

I’m converting a project over from Mac, and I’m shocked at the relative quality of image scaling on Windows.

I have a large image in my project that I’m displaying in a Canvas. I scale the image down in the Paint event using the .DrawPicture method.

On a Mac, this looks great: http://i.imgur.com/29hpASs.png

But on Windows, the scaling is blocky and ugly: http://i.imgur.com/vOSPmkT.png

I’d like to use Hi-DPI in this project so some sort of scaling is necessary. Is there any way to get high-quality image downscaling on Windows like there is on Mac?

The kind of image you are downsizing is not the easiest.

There is a very interesting discussion about downscale quality at https://forum.xojo.com/9403-scale-quality-of-canvas-control/41

It was mentioned that a lot of HiDPI things don’t work correctly on Windows. If you’re using an Image Set, try to see what happens if you do it the pre 2016R1 -way.
So turn off HiDPI and drag in your picture. This way it won’t end up as an Image Set but as a regular picture. After that, turn on HiDPI again.

[quote=264717:@Michel Bujardet]The kind of image you are downsizing is not the easiest.

There is a very interesting discussion about downscale quality at https://forum.xojo.com/9403-scale-quality-of-canvas-control/41[/quote]

Thanks for that link, after going through the thread I tried doing the downscaling with GDI+ and it looks acceptable.

@Marco Hof I did this too! Hopefully these problems are fixed in future versions.