On 20 Feb, Sven Neumann wrote:
>> Finally I don't understand what the healing tool has to do
>> with a 'brush' (as it is currently implemented)
> Painting with a brush is just a way to select an area. And a very nice
> and intuitive one also. The problem with the current implementation is
> however that it tries to heal while you are painting. This doesn't quite
> work. I think it would be better if, while you are painting, the tool
> would work like the clone tool. Then, when the mouse is released, the
> healing algorithm should be applied on the area selected by the paint
> stroke.

This has two disadvantages. First, you won't see the real effect until
you're finished anyway.
Second, this might give many disjoint sets of points,
which is difficult to handle in the algorithm.
There are a bunch of selection tools including the quick mask. Using
these it's much easier and quicker to select a region than painting it
with a brush. In most cases the lasso tool would do.
Since the healing tool is of more 'global' nature, being forced to
use a local tool like a brush seems misleading.
What could make sense would be to use a selection (one in the
destination area and a translated one in the source area) first,
compute the 'healed' area without pasting it into the destination
area, yet. Now the brush could be optionally used to copy parts
of the healed area into the destination area.

>> A bug has been reported when source and destination areas are of
>> different depth. Since, IHMO, the healing tool doesn't make sense
>> in that case, I'd suggest to simply abort with an informative
>> error message.
> Why does it not make sense to heal a region in an image using a texture
> from another image, or from another layer in the same image? The clone
> tool supports this nicely, so it seems to make some sense that the heal
> tool supports it as well.

The main difference between the cloning tool and the healing tool relies
on first computing the quotient of the pixel values in the destination
area by those in the source area. Then, these factors are 'smoothed out'
by solving a Poisson equation. Finally the source pixel values are
multiplied by these factors before they are put into the destination
area. Currently the R,G,B values of the destination and source area
are divided by each other. How can this be done if there are, say 3
values in the destination area but only 1 value in the source area.

What's the quickest way to get accustomed to Gimp's internals?


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