# Scrawl-canvas v8 - Filters test 104

## Compound filters: Use a white-transparent gradient as a filter input

### To change image, drag-and-drop an image file over the canvas

Filter effect
Final filter opacity
Pattern gradient
Gradient easing
Blend filter
Displace filter scaling
Scale X:
Scale Y:
Filter dimensions
Width:
Height:
Filter offset
Offset X:
Offset Y:
Pattern dimensions
Width:
Height:
Pattern matrix
Shift X:
Skew X:
Stretch X:
Shift Y:
Skew Y:
Stretch Y:

#### Test purpose

- Create a test Picture entity
- Create a set of transparent-white gradients to be loaded into the example filters
- Create the example filters:

- Glass bars/rings - super-imposes a set of bars (or rings) over the image, using: 'process-image (linear gradient); blend (multiply)
- Displace bars/rings - use the gradient to displace parst of the image, using: process-image (radial gradient); displace
- Etching - create a black-white rough drawing effect, as seen in old books with illustrations, using: process-image (linear gradient); grayscale; gaussian-blur; matrix; invert-channels; threshold; blend (screen)
- Green monitor - create a late-20th-century computer green-screen monitor effect, using: process-image (linear gradient); grayscale; modulate-channels; blend (luminosity)

- Manipulate the gradient Cell size, matrix, and easing settings to change the appearance of the output.
- Manipulate the filter settings to change the appearance of the output.

Touch test: not required

Annotated code