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Thread: QWT Spectrogram

  1. #1
    Join Date
    Feb 2012
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    Unix/X11

    Default QWT Spectrogram

    I have an array of byte data, such that each element of the array is a pixel value (0..255), where 0 is black and 255 is white. I started with the QWT Spectrogram example and quickly I was able to display the image. In my application I have removed all scales and other adornments; all I want is the image in the frame.
    I am failing to figure out how to do the following:
    My image data is W pixels wide and H pixels high. I want the image on the computer screen be "true" size, that is not be scaled. What I see is that qwt routines try to fit the image into the plot frame. When the window is stretched, the image gets distorted. To put it differently, I want my image always have the aspect ratio of the data (W x H pixels) and each data pixel coincide exactly with a computer screen pixel.

    Thank you in advance,
    Zen

  2. #2
    Join Date
    Feb 2006
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    Default Re: QWT Spectrogram

    See QwtPlotRescaler - the navigation example shows how to use it.

    Uwe

  3. #3
    Join Date
    Feb 2012
    Posts
    6
    Qt products
    Qt4
    Platforms
    Unix/X11

    Default Re: QWT Spectrogram

    Thanks a lot Uwe,
    I see now how to use it and how it works.
    Zen

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