Fill Tool

The Fill Tool lets you fill connected regions of similar color in an input image with solid colors of your choice. One very simple example of using the fill tool might be to color a scanned pattern from a coloring book. The black lines in a scanned coloring book page define regions with white interiors. The Fill Tool works by defining one or more fill points each of which marks a location within a region. Each fill point has an associated fill threshold and fill color -- the transformation starts at each fill point expands the surrounding region until it hits pixels that differ from the initial fill point by more than the fill threshold. The smaller the threshold, the closer surrounding pixels have to match to be included in the region. Once the region has been expanded as far as it will go, it is filled with the fill color for that region. You can create up to 256 different fill points, each with its own fill threshold and fill color.

Input Image Overlay

Fill points are displayed on the input image as small circles. The current fill point, if any, is marked with a cross also.

To insert a new fill point: shift-click on the input image. The initial threshold and color of the new fill point are set from the Threshold slider and the Color control. As soon as you create the new fill point, its region is filled and the result is displayed on the output image.

To remove a fill point: ctrl-click near the control point.

To make a fill point the current fill point: click near the fill point on the input image. The current fill point's threshold and fill color are displayed by the Threshold slider and Color control (see below).

To deselect a fill point: click on the input image, but not close to any of the existing fill points.

To move a fill point: click and drag the fill point on the input image;

Amount

The amount control lets you scale back the fill overall or you can create a mask to restrict speck removal to specific parts of the image.

Threshold

This slider lets you control the fill threshold. If there is a current fill point, the threshold of that fill point is updated when you change the threshold. The threshold determines how closely surrounding pixels must match the pixel at the fill point to be included in the filled region. The smaller the threshold, the closer they have to match, and the small the region.

Color

This control lets you select the fill color. If there is a current fill point, its color is updated when you change colors.

Tips

If the input image is black and white, fill colors are interpreted as neutral grays whose brightness is equal to the luminance of the fill color, so the output image remains black and white. If you want to apply colored fill to a black and white image, convert it to color before using the Fill Tool.