Spectrogram data resolution...

[uppu]

My Data resolution is not matching the QImage size that is created in the function QwtSpectrogram::renderImage().

I need the Image that could accurately match with my data resolution, and
QRasterData(double x, double y) should always have (x,y) exactly matching my data resolution.

How to handle this situation?

Now the Spectrogram image is created incrementally and appended to the previous image.
But the image itself shows data for future it souldn't happen.

The problem is that image width that i need is too much more than the screen width itself, In otherwords, for my data, screen is too small while the image is too big .

How to handle this situation?


Please reply.

[Uwe]

I need the Image that could accurately match with my data resolution, and QRasterData(double x, double y) should always have (x,y) exactly matching my data resolution.

The pixel raster of your monitor ( something physical ) is different to the resolution of your data, that's why you have (!) to implement some sort of resampling ( f.e. next neighbor ). You can return the resolution of your data by implementing YourData::rasterHint(). Then the spectrogram might render the image in a lower resolution scaling it to the canvas later. This will speed up the image composition, but you still have to do the resampling.

If you continue with trying to align the image resolution to your data resolution - good luck, but don't expect any assistance from my side.

The problem is that image width that i need is too much more than the screen width itself, In otherwords, for my data, screen is too small while the image is too big .

O.k, your application is rendering huge images - obviously a bad idea.

Uwe

[uppu]

ok, resampling i could do in QRasterData::iniRaster()!

[Uwe]

ok, resampling i could do in QRasterData::iniRaster()!

I recommend to do it in QwtRasterData::value(). Simply round x/y to the next index ( this is next neighbor) of your data.

Uwe

[uppu]

ok, rounding to next data iteration will be done in QRasterData::value()

but, I'll load the data from the data file in the QRasterData::initRaster()...