How to use wxGraphicContext to draw on a wxBitmap?

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Parduz
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How to use wxGraphicContext to draw on a wxBitmap?

Post by Parduz »

I'm building a component which shows a vertical bar chart, using wxGraphicContext to get a nice antialiasing.

The "draft" works, but it needs some optimization. One of them is to draw the fixed part of the chart (axis, labels, grid, etc) on a bitmap each time the component changes size, and then always using that bitmap as a background and redraw only the bars when needed.
chart.jpg
chart.jpg (45.75 KiB) Viewed 14112 times
What i don't get is how to use wxGraphicContext to draw on a bitmap.

Could i get a little code showing how to do so?
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doublemax
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Re: How to use wxGraphicContext to draw on a wxBitmap?

Post by doublemax »

https://docs.wxwidgets.org/trunk/classw ... 2dc0686e2e

FWIW: When the background has only little content, i don't think this optimization is worth the effort (yet).
Use the source, Luke!
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Parduz
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Re: How to use wxGraphicContext to draw on a wxBitmap?

Post by Parduz »

Oh... that's the way. Thanks.
doublemax wrote: Thu Jul 27, 2023 2:08 pm FWIW: When the background has only little content, i don't think this optimization is worth the effort (yet).
Well, the bars needs to be updated the fastest i can, and the program will run on an embedded linux PC, so not a really fast machine: i don't have yet a comparison, but i think that drawing that background (and computing each line and label position) at each refresh takes some relevant time.
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