Axis not aligning with Spectrogram image

[Ronayn]

Obviously your data bins cover squares with a size of 1, f.e one square is from 5-6, 10-11. So if you want to have a ticks centered its positions need to be 5.5, 10.5.

But I guess what you really want is a square at 4.5-5-5, 9.5.10.5 - probably by using qRound() instead of floor ( = casting to int ) in YourRasterData::value().

Uwe

PS: If the resolutions of your data is 1x1 don't forget to implement YourRasterData::rasterHint(). It will make the rendering process much faster.

Thanks for your reply Uwe. I modified my code to use qRound -- I also had to change the axis and the spectrograms bounding rect. The attached plot shows the result (it looks good!).

I dont quite understand your advice about rasterHint -- very much a graphics novice here. I am going to look through the examples to see if I can figure out what you mean. Btw, each data point (bin) of my data should be square (though I can live with rectangles!).