The convolve tool uses the current brush to blur or sharpen your image.
See also: Brush Selection .
Convolve Settings
The Pressure Sensitivity section sets whether hardness, rate or size will be effected by pressure for input devices that support this option.
The rate slider sets the strength of the convolve effect.
Blur mode blurs the image colours into each other. The result will be a smooth transition between colours, but will always be darker than the original colours.
Sharpen mode causes neighbouring pixels with similar colours to converge. Used judiciously, blurry edges can be sharpened somewhat, but if applied repeatedly it can produce unusual results.
See also: Sharpen Filter
Default Keyboard Shortcut: V
The key modifier: Shift places the convolve tool into straight line mode. Holding Shift while clicking Button1 will convolve in a straight line. Consecutive clicks will continue convolving in straight lines that originate from the end of the last line.
The key combination: Ctrl-Button1 will switch between blur and sharpen modes. The mode will change back when Button1 is released.