Qt : imagesc simple code

I am very interested with imagesc function in matlab. We can plot our data and plot image with user defined colormap. I have try to create a Qt: imagesc simple code using QPainter. This is a simple idea how to create Qt imagesc simple code. You can modified this code like your problem.

This code create a random data with size wdata(width) and hdata(height). I am create a winter colormap using colormap matlab function. You can get other colormap with looking at colormap matlab function. This is a code how to create winter colormap :

//create winter colormap
int **drawingWidget::Winter()
    int **cmap = array2int(m_colorMapLength, 4);
    float *winter = new float[m_colorMapLength];
    for (int i = 0; i < m_colorMapLength; i++)
        winter[i] = 1.0f * i / (m_colorMapLength - 1);
        cmap[i][0] = 255;
        cmap[i][1] = 0;
        cmap[i][2] = (int)(255 * winter[i]);
        cmap[i][3] = (int)(255 * (1.0f - 0.5f * winter[i]));

    delete [] winter;
    return cmap;

We can convert our data to colormap using this function :

//convert our data to colormap color
QRgb drawingWidget::GetColor(float f)
    int r, g, b, a;
    float tmp1 = (m_colorMapLength * (f - minData) + (maxData - f));
    float tmp2 = (maxData - minData);
    int cindex = (int) round( tmp1/tmp2 );

    if (cindex < 1)
        cindex = 1;
    if (cindex > m_colorMapLength)
        cindex = m_colorMapLength;

    //int alpha = cmap[cindex - 1, 0];
    r = cmap[cindex - 1][1];
    g = cmap[cindex - 1][2];
    b = cmap[cindex - 1][3];
    a = 255;
    QRgb value = qRgba(r, g, b, a);

    return value;

You will get more information after reading my code. This is an output when running this Qt imagesc simple code :

You can download the full Qt imagesc simple code at here

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