<![CDATA[Custom QQuickPaintedItem looks bad on Raspberry Pi]]>Hello all,
I wrote a QtQml-based application for a Raspberry Pi 2B+ earlier this year, with plenty of help from these forums :) It's a data recorder for sampling electric values.

I'm expanding its capabilities, and have run into a problem. It can now support over 240 separate values. Originally I used a custom QQuickPaintedItem, and put in a Flickable so users could scroll through the values. When I run the new version with 240 values, the text becomes blurry, like it's been resized.

I have some screenshots that show what I mean: https://imgur.com/a/w1LWQ

My QQuickPaintedItem draws onto a QImage. It appears that when the QImage's height is greater than 2048 pixels, it gets blurry/resized. I wonder if this is related to the Pi's maximum texture size of 2048?

Can anyone point me in the right direction for making my images not look like a blurry mess?

]]>https://forum.qt.io/topic/83954/custom-qquickpainteditem-looks-bad-on-raspberry-piRSS for NodeSat, 24 Oct 2026 02:17:37 GMTFri, 06 Oct 2017 21:51:03 GMT60<![CDATA[Reply to Custom QQuickPaintedItem looks bad on Raspberry Pi on Tue, 10 Oct 2017 21:20:07 GMT]]>Sorry i´m just using the QImage generated by poppler. I have no control about the generator.

]]>https://forum.qt.io/post/420003https://forum.qt.io/post/420003Tue, 10 Oct 2017 21:20:07 GMT<![CDATA[Reply to Custom QQuickPaintedItem looks bad on Raspberry Pi on Tue, 10 Oct 2017 14:09:48 GMT]]>@sneubert Wow that's pretty big. Do you have any other tips for getting good quality? Like maybe the format used for QImage?

]]>https://forum.qt.io/post/419940https://forum.qt.io/post/419940Tue, 10 Oct 2017 14:09:48 GMT<![CDATA[Reply to Custom QQuickPaintedItem looks bad on Raspberry Pi on Tue, 10 Oct 2017 04:25:56 GMT]]>I rendered pdf DIN A4 pages with 600 dpi via poppler

]]>https://forum.qt.io/post/419767https://forum.qt.io/post/419767Tue, 10 Oct 2017 04:25:56 GMT<![CDATA[Reply to Custom QQuickPaintedItem looks bad on Raspberry Pi on Mon, 09 Oct 2017 17:43:22 GMT]]>@sneubert How big were your images? I tried setting the GPU memory to 256M, but it didn't make any difference.

]]>https://forum.qt.io/post/419720https://forum.qt.io/post/419720Mon, 09 Oct 2017 17:43:22 GMT<![CDATA[Reply to Custom QQuickPaintedItem looks bad on Raspberry Pi on Mon, 09 Oct 2017 07:13:42 GMT]]>Just a guess, but I also had some issues displaying QQuickPaintedItem with
large images and it turned out, that the memory split was at a low value.
After changing it to e.g. 256 M, the Images got displayed correctly.

]]>https://forum.qt.io/post/419530https://forum.qt.io/post/419530Mon, 09 Oct 2017 07:13:42 GMT<![CDATA[Reply to Custom QQuickPaintedItem looks bad on Raspberry Pi on Sun, 08 Oct 2017 01:44:30 GMT]]>I had considered a listview, and cannot recall now why I decided against using it. I will investigate it again.

]]>https://forum.qt.io/post/419376https://forum.qt.io/post/419376Sun, 08 Oct 2017 01:44:30 GMT<![CDATA[Reply to Custom QQuickPaintedItem looks bad on Raspberry Pi on Fri, 06 Oct 2017 22:05:37 GMT]]>Hi! Not sure what causes it, but your texture-size guess sounds reasonable. For the solution: Wouldn't it be easier anyway to replace the huge image with a listview?

]]>https://forum.qt.io/post/419261https://forum.qt.io/post/419261Fri, 06 Oct 2017 22:05:37 GMT