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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Make Widget.useblit robust against underlying canvas changes","articleBody":"As noted in https://github.com/matplotlib/matplotlib/pull/30490#discussion_r2312635485 (and #30485, the original issue, also #25075), Widget.canvas, which is typically initialized as `self.useblit = useblit and canvas.supports_blit`, is fragile against changes in the underlying canvas (the most common case in practice being a temporarily switch from a canvas that supports blitting to one that doesn't, when saving to vector output).\n@tacaswell wrote some code to handle that in #25085, but some further fixes were necessary in #30490 which uses a different approach; a unified way of handling the issue would be nice to have.\n\n**Status:**\n\n- [x] Button\n- [x] _SelectorWidget\n- [x] SpanSelector\n- [x] ToolLineHandles\n- [x] ToolHandles\n- [x] RectangleSelector\n- [x] LassoSelector\n- [x] PolygonSelector\n\nNot supported yet:\n\n- [ ] CheckButtons\n- [ ] RadioButtons\n- [ ] Cursor\n- [ ] MultiCursor\n- [ ] Lasso\n","author":{"url":"https://github.com/anntzer","@type":"Person","name":"anntzer"},"datePublished":"2025-09-02T09:26:54.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":8},"url":"https://github.com/30503/matplotlib/issues/30503"}