How do we manage layers flatten etc

[mwpowellhtx]

I have what seems like perhaps a simple use case. How do I add layers? I want to do some drawing, perhaps a scale meter, another layer add some points, another layer draw a highlighted region with alpha channel color, and so on. How do I ensure i am targeting the correct layers by all that, i.e. without necessarily disrupting another layer? Second, when does the flattening happen? Thanks...

[mwpowellhtx]

Throwing a wild guess out there, perhaps Concat is analogous to "flatten" layers behavior, i.e. in a paint.net parlance, for example. i.e. when saving from the native .pdn file to something like a .png or .jpg.

[mwpowellhtx]

I got it working. Couple of nominal layers doing what I wanted them to do. Seems to work great saving the bitmap image out.

[mwpowellhtx]

Follow up question, how do I manage the BlendMode, SKPaint.BlendMode. The docs are not at all clear what the effects truly are.

More specifically, I want for what I am painting in a given layer to be what appears in the chosen colors. I do not want the colors masking the source image. Case in point, drawing a scale indicator on a map, let's say.

[mwpowellhtx]

This is what I currently have, work in progress. Colors will eventually be white foreground black background. And the offsets be adjusted accordingly as well.

However, this is what I want to draw, notice "100 meters" is clearly drawn on top of the source image. No masking or filtering going on. Examples illustrated using paint.net, not skia.

And actually including foreground and background layers, this is even closer to what I want there.

Notwithstanding that pesky lil SKBlendMode.

[mwpowellhtx]

Ah I think SKBlendMode.SrcOver sorts it properly. Also have to be aware of the layer Z order in which they are presented.