I made sure my code conforms to the standards set in the HACKING file.

I made sure my commits build individually and have good descriptions as per KDE guidelines.

(If not possible, don't hesitate to ask for help!)

I tested the relevant unit tests and can confirm they are not broken.

I confirmed Krita ran and the relevant functions work.

The linear burn mode looks fine but the result would be as the subtract mode with the texture inverted, so I didn't include it.

For an example of the ugly effect choose a brush with no texture and select masked brush with a very large tip. In the case of the masked brush it can work because the mask can be smaller than the tip, but in the case of texturing the mask extends indefinitelly.

I didn't include the linear dodge mode since the results are not great.

I find this method more pleasant for brushes. Maybe it could be used in the masked brush also. It is a variant that doesn't produce super hard, aliased, edges, as explained in the task.

For the hard mix mode I use a method that approximates the one used by Photoshop in the texturing of brushes.

See ColorBurnBlendStrategy::apply for an example of simplification. Maybe it would be better to modify that function and then it could be used here.

I use a custom color dodge because the one in krita ( cfColorDodge) seems to produce more speckles, maybe due to the 0/0 case.

But in almost all the cases the strength is just multiplied with the dab so there is room for integration.

Since these modes use the strength I didn't try to integrate them with for example the masking brush ones.

In the task it is explained how the strength parameter could be applied in three different ways, I chose the second one in which the strength weights the dab contribution. This MR implements the texturing modes explained in T14345.

Ps blending brush