57 lines
1.7 KiB
Markdown
57 lines
1.7 KiB
Markdown
## WPF Pointer-Based Touch Stack
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### Scope
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Edge
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### Version Introduced
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4.7
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### Source Analyzer Status
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NotPlanned
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### Change Description
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This change adds the ability to enable an optional WM_POINTER based WPF touch/stylus stack. Developers that do not explicitly enable this should see no change in WPF touch/stylus behavior.
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Current Known Issues With optional WM_POINTER based touch/stylus stack:
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- No support for real-time inking.
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- While inking and StylusPlugins will still work, they will be processed on the UI Thread which can lead to poor performance.
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- Behavioral changes due to changes in promotion from touch/stylus events to mouse events
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- Manipulation may behave differently
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- Drag/Drop will not show appropriate feedback for touch input
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- This does not affect stylus input
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- Drag/Drop can no longer be initiated on touch/stylus events
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- This can potentially hang the application until mouse input is detected.
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- Instead, developers should initiate drag and drop from mouse events.
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- [X] Quirked
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- [ ] Build-time break
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### Recommended Action
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Developers who wish to enable this stack can add/merge the following to their application's App.config file:
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```xml
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<configuration>
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<runtime>
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<AppContextSwitchOverrides value="Switch.System.Windows.Input.Stylus.EnablePointerSupport=true"/>
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</runtime>
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</configuration>
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```
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Removing this or setting the value to false will turn this optional stack off.
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Please note that this stack is available only on Windows 10 Creators Update and above.
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### Affected APIs
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Not detectable via API analysis
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### Category
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Windows Presentation Foundation (WPF)
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<!--
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# Original bug
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197685
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-->
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<!-- breaking change id: 172 -->
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