9. Changing brush size

Since GIMP 2.4, all brushes have a variable size that can be changed.

9.1. How to change the size of a brush

You can change the brush size in several ways:

1. Using the Size slider of the tool options. Pencil, Paintbrush, Eraser, Airbrush, Clone, Heal, Perspective Clone, Blur/Sharpen and Dodge/Burn tools have a slider to vary the brush size.

   Figure 7.20. The Size slider

   

1. By using the default shortcut keys for changing a tool’s size:

   • Decrease size by 1: [

   • Increase size by 1: ]

   • Decrease size by 10: {

   • Increase size by 10: }

2. By using the default mouse scrollwheel actions for changing a tool’s size:

   • Decrease size by 1: Ctrl+Alt+Scrollwheel Down

   • Increase size by 1: Ctrl+Alt+Scrollwheel Up

3. By programming the mouse wheel:

   1. In the main window of GIMP, click on Edit → Preferences.

   2. In the left column of the new window, select Input Devices → Input Controllers.

   3. You can see Additional Input Controllers, with two columns: Available Controllers and Active Controllers.

      In the column Active Controllers, double-click the Main Mouse Wheel button.

   4. Then, you see a new window: Configure Input Controller.

      In the left column Event, click Scroll Up to get it highlighted.

   5. Click the Edit button (at the bottom middle of the list).

   6. You can see the window Select Controller Event Action.

      Drop-down the Tools item, by clicking the small triangle on its left.

   7. In the left column Action, click Increase Brush Scale to highlight it, then click the OK button.

   8. Now, in front of Scroll Up is display tools-paint-brush-scale-increase.

   9. Close the window.

   10. With the same method, program Scroll Down with Decrease Brush Scale.

   11. Don’t forget to click the OK button of the main window of Preferences.

   After these somewhat long explanations, you can use your mouse wheel to vary size brush. For example, choose the pencil tool with the “Circle” brush. Set the pointer in the image window, use the mouse wheel, in the two directions, you can see the “Circle” shrinking or stretching.

4. You can program the “Up” and “Down” arrow keys of the keyboard.

   The method is similar to that of the mouse wheel. The only differences are:

   • In the column Active Controllers, double-click Main Keyboard.

   • In the column Event, click Cursor Up for the first key, and Cursor Down for the second key.

   • Then, use the two keys (Up arrow and Down arrow) and the result is the same as you got with the mouse wheel.