Most graphics tools these days provide a facility to fill areas using a gradient; an area filled with colour which gradually morphs from one colour to another. However, once an area’s filled, there’s rarely much functionality to work with these areas. Useful tools could be:
- Tolerance Filter: When using tolerance filters, traditionally you can specify that a change is detected when the colour being analysed is a given value away from the selected colour. A more useful tolerance detection would use the tolerance value to compare each step & detect a border where this step is significant. As an example, say the tolerance value is 3 and the selected value is 10, in the following sequence, the area in quotes would be selected: 1,2,4,5,9,10,11,12,10,9,8,7,6,5,4. On the other hand, using the stepped tolerance filter would select the following: 1,2,4,5,9,10,11,12,10,9,8,7,6,5,4.
- Colour Replace: Building on the above, when pasting an area with a gradient, it would be good to maintain the tone of the colour at the various points, so when pasting red over a blue gradient, the blue is replaced with red, but the shading remains the same (e.g. dark in one corner and light in another).