2.8. Foreground Select
| 2. Selectie Gereedschappen |

### 2.8. Foreground Select

Afbeelding 14.34. The “Foreground Select” tool in the Toolbox

This tool lets you extract the foreground from the active layer or from a selection. With GIMP-2.10, selection refinement has been improved. After the selection is made, with its marching ants, you can copy-paste or click-and-drag it to another image used as background,and, inverting the selection, you can can make changes in background.

#### 2.8.1. Activating the Tool

You can activate the Foreground Select tool in two ways:

- by clicking on the tool icon in the Toolbox,

- through Tools → Selection Tools → Foreground Select in the image menu.

- This tool has no shortcut, but you can set one using Edit → Preferences → Interface → Configure Keyboard Shortcuts → Tools → Foreground Select

#### 2.8.2. Directions for use

Let us start with an object distinctly different from background, not needing to be refined.

1. Roughly select the foreground you want to extract. When you select this tool, the mouse pointer goes with the lasso icon. It actually works like the Fuzzy Select tool. Select as little as possible from the background.

   When the mouse pointer comes over line beginning, a small yellow circle appears: release mouse button to close selection. While selecting, click-and-drag draws a fuzzy line, drag only draws a straight line.

   The selection is closed.

   As soon you click to start drawing, a small window pops up:

   There you have:

   - A Preview checkbox that toggles displaying a preview of the foreground extraction status. Esc key also toggles this preview.

   - A little cross to quit: returns to the original image.

   - A Select button: not active for the moment.

2. Press Enter to create the mask:

   The mouse pointer goes now with the Paint-brush icon. The dark blue area (this color can be changed) is for background. The light blue area covers the zone you have selected, on which you will paint to extract foreground. Between foreground area and background is a zone you have selected belonging to background named Unknown pixels area.

3. Draw a line through the foreground: using the paintbrush, whose size can be changed in options, draw a continuous line in the selected foreground going over colors which will be kept for the extraction. The color used to draw the line is of no importance; not using the same color as foreground is better. Be careful not painting background pixels.

   With this one-color object distinctly different from background, a few strokes are enough:

4. Toggle preview to verify result.

   | Opmerking
   This Preview mask is a mask: you can draw directly on it and see result immediately.

5. Try Matting Levin engine that may improve result.

6. When you are satisfied with result, click on Select button to get the selection of the foreground with its marching ants.

#### 2.8.3. Options

Afbeelding 14.35. “Foreground Select” tool options

Normally, tool options are displayed in a window attached under the Toolbox as soon as you activate a tool. If they are not, you can access them from the image menu bar through Windows → Dockable Windows → Tool Options which opens the option window of the selected tool.

Mode; Feather edges

  | Opmerking
  See Selection Tools for help with options that are common to all these tools. Only options that are specific to this tool are explained here.

Draw mode

  Draw foreground: to draw what will be foreground.

  Draw background: to draw what will be background.

  Draw unknown: to add to your selection pixels that are in background.

Stroke width

  The size of the brush.

Preview mask

  You can adapt the color of the preview to your image.

Engine

  Work with Matting global(default) and improve result with Matting Levin.

Iterations

  Default is 1. Repeating algorithm may improve result.

#### 2.8.4. Refining Foreground Extraction

In most images, foreground is not distinctly different from background. Refining selection allows you now to extract these foregrounds. Procedure steps are the same as above, but, during drawing foreground, you will often toggle Preview, use Zoom (+ key), Draw background to delete unwanted background extraction areas. You can also work directly on Preview mask.

Afbeelding 14.36. Example for Draw background

On the left: drawing foreground ill-advisedly went over unknown pixels area: a part of background will be included in foreground selection!

In middle: Draw background option is checked: draw on inclusion and unwanted pixels.

On the right: unwanted selected pixels in background are no longer in foreground selection.

You will often have to reduce the unknown pixels zone with Draw background.

Afbeelding 14.37. Example for Draw unknown

On the left: the selection left a small part of foreground unselected, in unknown pixels area.

On the right: with Draw unknown option checked, draw on unselected pixels. They are now selected in foreground.

2.7. Intelligent Scissors |  | 3. Paint Tools

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