Effect Composition

[BoltBait]

I know how to call the Gaussian Blur function to blur from the source canvas to the destination canvas.

this.blurEffect.Render(blurToken, dstArgs, srcArgs, rois, startIndex, length);

This always does a replacement on the destination canvas.

Is there a way to do this AND specify a blending operation?

For example, could I call the Gaussian Blur function from the source canvas to the desintation canvas and specify the "Darken" blending operation so that the destination canvas would be the result of blending the image already on the destination canvas with the gaussian blur of the source canvas (using the specified blending op, obviously)?

[pyrochild]

Look into the (PaintDotNet.Data?).UserBlendOps.MultiplyBlendOp and its Apply() methods... If you still have the source code from my Outline Object plugin in your inbox, then you can look at the way I use the UserBlendOps.NormalBlendOp class.

[BoltBait]

No, I know how to use blend ops. What I want to do is blur from the source canvas to the destination canvas (and other effects) and apply a blend op on the way--without having to create another canvas as an intermediate step.

[pyrochild]

No, you can't, as far as I know, even so much as run Gaussian Blur via code without providing it with a destination Surface. Whether that Surface is your final destination Surface, or an intermediate one that you create, is up to you.

[Rick Brewster]

Remember how I said the rendering architecture is very limiting right now? If you had a 3rd surface to work with, everything would be possible. But, memory usage makes that prohibitive.

As is, we must wait for the retained-mode, tile-based rendering of Paint.NET v4.0 ...

[Ed Harvey]

If you had a 3rd surface to work with, everything would be possible. But, memory usage makes that prohibitive.

Given the huge amount of memory on modern PCs, wouldn't this would only be a problem far very large images?

IIRC, your resize code allocates extra surfaces to accomplish its processing...

[Simon Brown]

Just render from the destination canvas onto itself.

[pyrochild]

Just render from the destination canvas onto itself.

That can't always work, depending on what you're doing.

Oh, and this topic is 2 months old. Let it die in peace.