When we display data on spectrogram we often do not see this peak high value. Slow plotting of spectrogram Hello, i am new in qwt. As I know, the objects in QGraphicsView are stored individually and drawing a huge amount of dots might impact performance. Spectrogram data See also: Bounding rect of the data See also: Slow plotting of spectrogram Hello Uwe! Slow plotting of spectrogram Thank you for your quick response Uwe!

When drawing on the full screen the speed of data rendering on spectrogram decreases even more. Over 90 percent of questions asked here gets answered. How to set the return value in an overloaded method? I’ve done program that could be an example after some changes. I looked at the topic http: I have a question about displaying plotting data. My task is plotting data on the spectrogram that come by timer. Return the levels of the contour lines.

ContourMode The data is displayed using contour lines When both modes are enabled the contour lines are painted on top of the spectrogram.

Slow plotting of spectrogram A spectrogram creates an image from your data, by iterating over all pixels of the image, requesting the spectfogram from the data object and mapping it to a RGB value using a QwtColorMap. For example, I have a spectrogram, filling from left to right by columns. The schedule is spectrohram drawn with the necessary speed. ExcludeMaximum ; setInterval Qt:: Slow plotting of spectrogram Hello Uwe!

Sign up using Email and Password. If the spectrogram has a valid default contour pen a contour line is painted using the default contour pen. I have a question about displaying plotting data. By spectrrogram our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.


I also want to be able to select regions of the graph and edit them, as well as scrolling and zooming around. Thank you in advance. For each pixel of this rect the intensity is mapped into a color.

I would suggest you to use either QCustomPlot or Qwt for this purpose. Poot display mode controls how the raster data will be represented. Change the color map Often it is useful to display the mapping between intensities and colors as an additional plot axis, showing a color bar. Sarid 3, 2 15 Regardless of any further optimization I recommend to speed this pllot up.

Bookmarks Bookmarks Digg del. The area is translated into a rect of the paint device. QPixmap is designed and optimized for showing images on screen.

I am considering QGraphicsView class but not sure about its performance. I’ve done program that could be an example after some changes.

QwtPlotSpectrogram Class Reference

I am using Qt to draw a spectrogram like this: My computer have parameters i CPU 3. So it is about the spectrohram of pixels and of course what happens for each pixel. NoPen the pen is calculated for each contour level using contourPen. For this purpose, I used the example “realtime” in qwt. Slow plotting of spectrogram Hello!


I do not understand how to properly reimplement plit QwtPlotSpectrogram:: Tomas Tomas 1, 5 ConrecAttributebool on.

QCustomPlot Discussion and Comments

Spectrogram By Ronayn in forum Qwt. Sign up using Facebook. It helped me to solve the problem with the performance. How to set the return value in an overloaded method?

As it is called for every pixel it is worth to spend some time on writing it in a performant way. The time now is Size of plot is points on x-axis by on y-axis but size can be points on x-axis by on y-axis. Resolution of the data is much higher then the resolution of the screen. Over 90 percent of questions asked here gets answered.

MantidPlot: Image and Contour Line Plots (Spectrograms) – Mantid Project

Email Required, but never shown. The following user says thank you to Uwe for this useful post: Is it possible to do not lose these single maximums on the spectrogram? Sign up or log in Sign up using Google.