d05337b719
See AccessibleCaretEventHub.h for the class description. Both TouchCaret and SelectionCarets have their event handling mechanism, which lead to a lot of code duplication. Now AccessibleCaretEventHub serves as the single entry point for all events and callbacks. We also encountered performance issues in SelectionCarets because many unnecessary events might be dispatched to Gaia driven by the selection changed events. SelectionCarets did not have clear internal states to avoid this. To solve it, AccessibleCaretEventHub implements state classes, and rely on the current states to call the CopyPasteManager's handler only when it's needed. For example, when dragging a caret, we do not interest in NotifySelectionChanged() for updating the carets. Since we've known a caret is being dragging, we can call UpdateCarets() directly. Hence DragCaretState does not override OnSelectionChanged().
38 lines
1.3 KiB
Plaintext
38 lines
1.3 KiB
Plaintext
// Steps to generate AccessibleCaretEventHubStates.png
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// 1. Install Graphviz
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// 2. dot -T png -o AccessibleCaretEventHubStates.png AccessibleCaretEventHubStates.dot
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digraph event_hub_states {
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node [style=filled];
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edge [color="gray30", fontcolor="gray20", fontsize=12]
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NoAction [label="NoAction\n(Initial)"color="#96FF2F"];
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NoAction -> PressCaret [label="Press & on a caret"];
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NoAction -> PressNoCaret [label="Press & not on a caret"];
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NoAction -> Scroll [label="Scroll start"];
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PressCaret [color="#84D8FF"];
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PressCaret -> DragCaret [label="Move & distance is large"];
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PressCaret -> NoAction [label="Release (synthesizing a tap)"];
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DragCaret [color="#84D8FF"];
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DragCaret -> DragCaret [label="Move"];
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DragCaret -> NoAction [label="Release"];
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PressNoCaret [color="#E8C516"];
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PressNoCaret -> NoAction [label="Move & distance is large or\nRelease or\nBlur"];
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PressNoCaret -> LongTap [label="Long tap"];
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PressNoCaret -> Scroll [label="Scroll start", constraint=false];
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LongTap [color="#E8C516"]
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LongTap -> NoAction;
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Scroll [color="#FF9022"]
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Scroll -> PostScroll [label="Scroll end"];
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Scroll -> NoAction [label="Blur"];
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PostScroll [color="#FF9022"]
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PostScroll -> Scroll [label="Scroll start"];
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PostScroll -> NoAction [label="Blur or\nWait 300ms"];
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PostScroll -> NoAction [label="Press (forward to NoAction)", constraint=false];
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}
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