# vtkcharxy with rectangles
**URL:** https://discourse.vtk.org/t/vtkcharxy-with-rectangles/11026
**Category:** Support
**Created:** [March 23, 2023, 12:46am UTC](https://discourse.vtk.org/t/vtkcharxy-with-rectangles/11026 "2023-03-23T00:46:55Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@antoine1](https://discourse.vtk.org/u/antoine1)
#### Post date: [March 23, 2023, 12:46am UTC](https://discourse.vtk.org/t/vtkcharxy-with-rectangles/11026/1 "2023-03-23T00:46:55Z")
Hello,
I have a plot on vtkcharXY and i have a qslider (from qt).
the slider is a double slider ( or a range slider).
The idea is the user can set the double slider to select a window on the plot. To show this window on the plot i would like to put two rectangles( one from 0 to the minimum of the window and one from the maximum of the window to the extremity of the chart.) with grey color and little bit transparent.
I checked the pain function from vtkcharxy and vtkContext2D but i have a problem with vtkContextDevice2D which is not initialize.
I don’t really know what is vtkContextDevice2D. i don’t even know if this is the good way to put transparent rectangles.
what is the best way to do this?
thank you in advance!
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### Author:  [@antoine1](https://discourse.vtk.org/u/antoine1)
#### Post date: [March 27, 2023, 6:19pm UTC](https://discourse.vtk.org/t/vtkcharxy-with-rectangles/11026/2 "2023-03-27T18:19:01Z")
no one?