OK, although I know the whole mosaic thing has been discussed a lot over the years...I've looked and I can't see an answer to my question.
Imagine I am trying to create a mosaic using a folder of images of fruit to do something like the Archimboldo image below.
I create my folder of PNG images of fruit, just fruit against an alpha background.
Now I want to paint a collage using these PNG images...
So, my question is; how do I get the actual images/shapes of the fruit to collage together and not the background shape.
So just the actual organic shapes collage/mosaic together, with computer working out the best shape and colour fit.
I've tried drawing into an alpha layer with a folder of PNG's..
I hope this isn't too confusing.
Just to be clear:
Are you asking how you get the paint synthesizer to only draw in the face and not the background?
Or are you asking how to generate an alpha-masked image brush in the paint synthesizer?
I am trying to create an alpha masked image brush: a folder of alpha masked images, like the banana. I want these images to collage together, not the backgrounds collage together.
I get this when I make an image brush fig.1 below
but I am trying to achieve this; where the alpha background is ignored and the actual images/bananas are mosaiced closely together ignoring the square alpha background.
see below, fig. 2
I hope this makes sense
So it sounds like you don't want to use a tiling option for path start or path application. You want something like a smooth random path start. Then you want to setup the path start panel so that it doesn't draw on where you have already drawn. If you are using a white background, then you can use the white only option (Inhibitor).
Or you can enable brush blanking, turn on reset blanking, and then use Skip Blanking.
You will get some overlap with this approach. We should probably add a blanking radius option to brush size modulation.
You might try turning on the Not White option for If Canvas in Path End, and then set End Calc to Cur Brush Radius. This might help a little bit.
You could also play around with the Grow Region from Start Point option for Path Type in the Path Shape control panel.
OK thanks John, I will work my way through these suggestions