QCustomPlot Discussion and Comments

Custom brush color from x1 to x2, x3 to x4,etcReturn to overview

As the title says, I want my graph to have my own colours(gradient) from a particular offset range.
Like 400-450 for violet, etc. (These are values on x axes of course). I looked up QLinearGradient but it is not working for me, as the gradient is relative to the screen and not "Fixed". If I zoom in or pan then the gradient also moves and its not perfect either. I don't think I need a colormap because colors have no relation with my y values. Any help would be appreciated :)
Thanks

Anyone ? is this possible ?