Writing custom canvas items

Deriving from the Item
Redrawing
Grid-fitting

This chapter leads you through the process of creating your first custom canvas item.

Deriving from the Item

Redrawing

Once your item changed in a way that a part of it needs to be redrawn, just call cc_item_dirty() to tell other items and all the renderers that the item changed. If your item doesn't update after changes it usually doesn't call cc_item_dirty().