Smudge

The Smudge tool mixes colors by displacing pixels, like a finger passing through wet paint. To quickly access this tool and switch between the Blur, Sharpen, and Smudge tools press R.

 

The tool's parameters will be shown in a floating box over an image (by right-clicking the mouse) and also in the Settings Panel.

To change the settings for a parameter, enter a numerical value in the parameter's field and press Enter or adjust the slider.

To spread color along a straight line, first select a starting point by clicking the left mouse button and while holding Shift, move the cursor to the desired endpoint and release Shift. If Shift is not released, then new lines will be drawn to each point where the mouse is clicked.