# Scrawl-canvas v8 - Filters test 102

## Filter blend operation

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

Line IN
Line MIX
Blend operation
Opacity
Offset - X
Offset - Y

#### Test purpose

- Create two Cells which we can use to generate images for the filter
- Load an additional image from the DOM
- For each of our assets, create an image filter to load the assets into the filter pipeline
- Create a blend filter
- Create a Block entity, using a gradient for its fill, and apply the blend filter to it
- Update the filter's lineIn and lineMix attributes and note the effect
- Update the blend operation, check that the choice changes the display appropriately
- In particular make sure the lineMix asset moves when the filter offset values are updated

Note that filter memoization would provide no benefit in this demo because of the way we include the (rotating) cell-based wheel image filter in the display block filters array, even though that filter will only be displayed (as part of the compositing filter) if selected. Moral: only load process-image filters into a filter array if you intend to use them!

Touch test: not required

Annotated code