multiple layers of canvas
Use multiple layers of can canvas :
- Image Layer : contains the original image
- Region Layer : contain visual depiction of regions (rectangle, circle, polygon, etc)
- Attributes Layer : contains attribute of each region
This will enable the following features:
- render only the layer that needs update
- user drawing region -> only update the region layer
- user updating the attributes -> only update the attributes layer
- Allow users to hide and show these regions using UI control elements