How to Flood Fill

1Choose Flood Fill Tool

On the Main Ribbon Bar, switch to the "Edit" category. Find the "Flood Fill Tool" tool button on the "Edit Tools" panel. Click to select it. As shown below.

2Choose the most Suitable Filling Options

The so-called Flood Fill is to start from a certain point (usually this point is also called the seed point. Generally, the user clicks the mouse on the canvas to confirm the position), and find all the pixels connected to the point around the seed point. Then use the new color to fill all connected pixels.

When the Flood Fill Tool is used as the current editing tool, a series of related options will appear on the right control panel. As shown below.

• Threshold: The enclosed area is composed of pixels directly or indirectly connected to the seed point. How to define whether a pixel is connected to a seed point? It is by comparing the color difference between these two points. If the difference is greater than the given threshold, then the pixel is not connected to the seed point and is not in the filled area. The opposite is the opposite. The threshold varies from 0-100. Among them, the larger the threshold, the more connected pixels and the larger the filled area.
• Fill By: Specify which color channels to use when comparing colors.
  • Visible Colors: When comparing the colors of two pixels, the differences in red, green, and blue components are comprehensively investigated.
  • Red: When comparing the color difference between two pixels, only the red difference is used as an evaluation indicator.
  • Green: When comparing the color difference between two pixels, only the green difference is used as an evaluation indicator.
  • Blue: When comparing the color difference between two pixels, only the blue difference is used as an evaluation indicator.
  • Hue: When comparing the color difference between two pixels, only hue difference is used as an evaluation indicator.
  • Saturation: When comparing the color difference between two pixels, only saturation difference is used as an evaluation indicator.
  • Lightness: When comparing the color difference between two pixels, only lightness difference is used as an evaluation indicator.
  • Alpha: When comparing the color difference between two pixels, only alpha difference is used as an evaluation indicator.
• Close Gaps: Close Gaps essentially defines the size of a square block. When it is determined that a certain pixel is connected to the seed point, then all the points in the square area where the point is the center are connected to the seed point.
  • None: Directly represented as a single pixel.
  • Small: Block size is 2 x 2.
  • Medium: Block size is 4 x 4.
  • Large: Block size is 6 x 6.
• Grow/Shrink: The amount to grow (positive) or shrink (negative) the created fill path.

  Original Shape	Grow/shrink = -0.5
  Grow/shrink = -5.0	Grow/shrink = 3.0

3Fill with Solid Color by Clicking

Move the mouse on the canvas to the position to be filled with color and click the left mouse button.