16.9. Chalk
| 16. Alpha to Logo Filters |

### 16.9. Chalk

#### 16.9.1. Overview

图 16.358. Example for the “Chalk” filter

Original image

“Chalk” applied

This filter creates a chalk drawing effect for the active layer.

It is derived from the “Chalk” script (File → Create → Logos → Chalk in the image window), which creates a logo from a text of your choice, for instance:

The “Chalk” Script-Fu script.

| 警告
The image will always be resized to the active layer's size.

The “Chalk” filter

1. applies a Gaussian blur to the layer, spreads the pixels, and ripples the layer horizontally and vertically,

2. extracts edges using the Sobel edge detect filter, and

   | 注意
   Sometimes the sobel edge detect produces some garbage at the image sides.

3. increases the luminosity level.

Unfortunately you cannot change the tool and filter options. But you may reproduce the process step by step using the methods listed above, varying the respective options. Then you just have to add a background layer filled with any color. That's all.

#### 16.9.2. Activate the filter

You can find this filter in the image window menu under Filters → Alpha to Logo → Chalk.

#### 16.9.3. Options

图 16.359. “Chalk” option

Background color

  The background color is the color of the “blackboard” you are drawing on with chalk, and of course it's black. When you click on the color button, the color selector pops up and you may select any other color.

16.8. Bovination |  | 16.10. Chip Away