Fill
An operation that fills a designated area with a solid color, gradient, or pattern, commonly known as the paint bucket tool.
Fill is an operation that uniformly covers a designated image area with a solid color, gradient, or pattern. In image editors, it is typically represented by a bucket icon and called the paint bucket or fill tool.
Fill behavior depends on the tolerance setting. Low tolerance fills only pixels nearly identical to the clicked color, while high tolerance extends to a broader range of similar colors. For example, setting appropriate tolerance allows filling an entire white background with red in a single click.
Creating a selection first and then filling ensures color is applied to a precise area. Using a gradient fill produces a smooth color transition instead of a flat color. Filling on a separate layer makes it easy to change or remove the fill later.