CODEWITHSUNDEEP
wxwidgets
mad
mad

Reputation: 3503

wxWidgets multi layer transparency-enabled drawing

I am using wxWidgets to design a GUI that draws multiple layers with transparency on top of each other. Therefore I have one method for each layer that draws with wxGraphicsContext onto the "shared" wxImage, which is then plotted to the wxWindow in the paintEvent method.

I have the layer data in arrays exactly of the same dimension as my wxImage and therefore I need to draw/manipulate pixel-wise, of course. Currently I am doing that with the drawRectangle-routine. My guess is that this is quite inefficient.

Is there a clever way to manipulate wxImage's pixel data directly, enabling me to still use transparency of each separate layer in the resulting image? Or is the 1x1 pixel drawing with drawRectangle sufficient?

Thanks for any thoughts on this!

Upvotes: 1

Views: 513

Answers (1)

VZ.
VZ.

Reputation: 22688

You can efficiently manipulate wxImage pixels by just directly accessing them, they are stored in two contiguous RGB and alpha arrays which you can work with directly.

The problem is usually converting this wxImage to wxBitmap which can be displayed -- this is the expensive operation, and to avoid it raw bitmap access can be used to manipulate wxBitmap directly instead.

Upvotes: 1

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