Runtime Canvas 
Runtime Canvas block is used to pass instruction information back to Sonolus.
Identifier 
ts
const RuntimeCanvasId = 1001Values 
| Index | Initial Value | Description | 
|---|---|---|
| 0 | 0 | Scroll: 0= Left to right,1= Top to bottom,2= Right to left,3= Bottom to top | 
| 1 | 0 | Size | 
Access 
| Callback | Read | Write | 
|---|---|---|
| preprocess | ✔ | ✔ | 
| render | ✔ | ❌ | 
Remarks 
Scroll controls the scrolling direction and starting position, while size controls the size in the scrolling direction.