Using cCairoSurface drawing while preserving current image

Hello!

I would like to draw a cCairoSurface image onto a DC while preserving what is there.

Here is an example of what that looked like when I used c32bppdib.

Attachment 192656

However, what I get when just using the .DrawToDC function of cCairoSurface, is that:

Attachment 192657

Can you advise me on how to achieve my goal while being as performant as my previous approach c32bppdib approach?

Quote:

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Originally Posted by tmighty2

I would like to draw a cCairoSurface image onto a DC while preserving what is there.

Here is an example of what that looked like when I used c32bppdib.

Attachment 192656

However, what I get when just using the .DrawToDC function of cCairoSurface, is that:

Attachment 192657

Can you advise me on how to achieve my goal while being as performant as my previous approach c32bppdib approach?

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I think that kind of question was answered in different examples already...

The ideal Rendering-call for "Sub-Images" (Sub-Surfaces) is:

CC.RenderSurfaceContent SubSurface_Or_ImageListKey, OffsX, OffsY

Whereas the Surface.DrawToDC-call should be reserved for the "bigger Containers" -
like one or two PicBoxes on your Form - or ideally, the entire Form itself...
(and used as sparsely as possible).

That in turn means, you will have to create "Pixelsize-matching ParentSurface-CairoContext-Objects"
for these Containers first (to apply the above mentioned .RenderSurfaceContent to).

...BTW, you now have 3 questions already in the CodeBank-section -
(which is for code-examples and -demos).

Olaf