Dan Walmsley
4 years ago
committed by
GitHub
GitHub
578 changed files with 8581 additions and 4345 deletions
@ -1,6 +1,7 @@ |
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<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003"> |
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<ItemGroup> |
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<ItemGroup Condition="'$(TargetFramework)' != 'net6'"> |
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<PackageReference Include="System.ValueTuple" Version="4.5.0" /> |
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<PackageReference Include="System.Threading.Tasks.Extensions" Version="4.5.4" /> |
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<PackageReference Include="System.Runtime.CompilerServices.Unsafe" Version="4.6.0" /> |
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</ItemGroup> |
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</Project> |
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|
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@ -1,5 +0,0 @@ |
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<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003"> |
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<ItemGroup> |
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<PackageReference Include="JetBrains.Annotations" Version="10.3.0" /> |
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</ItemGroup> |
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</Project> |
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@ -1,5 +1,5 @@ |
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<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003"> |
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<ItemGroup> |
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<ItemGroup Condition="'$(TargetFramework)' != 'net6'"> |
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<PackageReference Include="System.Memory" Version="4.5.3" /> |
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</ItemGroup> |
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</Project> |
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|
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@ -1,11 +1,9 @@ |
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{ |
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"sdk": { |
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"version": "7.0.100", |
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"version": "7.0.101", |
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"rollForward": "latestFeature" |
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}, |
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"msbuild-sdks": { |
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"Microsoft.Build.Traversal": "1.0.43", |
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"MSBuild.Sdk.Extras": "3.0.22", |
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"AggregatePackage.NuGet.Sdk" : "0.1.12" |
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"Microsoft.Build.Traversal": "3.2.0" |
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} |
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} |
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|
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@ -0,0 +1,13 @@ |
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{ |
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"profiles": { |
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"ControlCatalog.Browser": { |
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"commandName": "Project", |
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"launchBrowser": true, |
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"environmentVariables": { |
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"ASPNETCORE_ENVIRONMENT": "Development" |
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}, |
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"applicationUrl": "https://localhost:5001;http://localhost:5000", |
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"inspectUri": "{wsProtocol}://{url.hostname}:{url.port}/debug?browser={browserInspectUri}" |
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} |
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} |
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} |
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@ -0,0 +1,212 @@ |
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using System; |
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using System.Numerics; |
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using Avalonia; |
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using Avalonia.Controls; |
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using Avalonia.Input; |
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using Avalonia.LogicalTree; |
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using Avalonia.Markup.Xaml; |
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using Avalonia.Rendering.Composition; |
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|
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namespace ControlCatalog.Pages |
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{ |
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public class GesturePage : UserControl |
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{ |
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private bool _isInit; |
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private float _currentScale; |
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|
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public GesturePage() |
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{ |
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this.InitializeComponent(); |
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} |
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|
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private void InitializeComponent() |
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{ |
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AvaloniaXamlLoader.Load(this); |
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} |
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|
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protected override void OnAttachedToVisualTree(VisualTreeAttachmentEventArgs e) |
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{ |
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base.OnAttachedToVisualTree(e); |
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|
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if(_isInit) |
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{ |
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return; |
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} |
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|
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_isInit = true; |
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|
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SetPullHandlers(this.Find<Border>("TopPullZone"), false); |
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SetPullHandlers(this.Find<Border>("BottomPullZone"), true); |
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SetPullHandlers(this.Find<Border>("RightPullZone"), true); |
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SetPullHandlers(this.Find<Border>("LeftPullZone"), false); |
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|
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var image = this.Find<Image>("PinchImage"); |
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SetPinchHandlers(image); |
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|
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var reset = this.Find<Button>("ResetButton"); |
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|
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reset!.Click += (s, e) => |
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{ |
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var compositionVisual = ElementComposition.GetElementVisual(image); |
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|
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if(compositionVisual!= null) |
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{ |
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_currentScale = 1; |
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compositionVisual.Scale = new Vector3(1,1,1); |
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image.InvalidateMeasure(); |
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} |
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}; |
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|
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} |
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|
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private void SetPinchHandlers(Control? control) |
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{ |
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if (control == null) |
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{ |
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return; |
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} |
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|
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_currentScale = 1; |
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Vector3 currentOffset = default; |
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bool isZooming = false; |
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|
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CompositionVisual? compositionVisual = null; |
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|
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void InitComposition(Control visual) |
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{ |
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if (compositionVisual != null) |
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{ |
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return; |
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} |
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|
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compositionVisual = ElementComposition.GetElementVisual(visual); |
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} |
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|
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control.LayoutUpdated += (s, e) => |
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{ |
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InitComposition(control!); |
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if (compositionVisual != null) |
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{ |
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compositionVisual.Scale = new(_currentScale, _currentScale, 1); |
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|
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if(currentOffset == default) |
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{ |
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currentOffset = compositionVisual.Offset; |
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} |
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} |
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}; |
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|
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control.AddHandler(Gestures.PinchEvent, (s, e) => |
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{ |
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InitComposition(control!); |
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isZooming = true; |
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|
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if(compositionVisual != null) |
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{ |
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var scale = _currentScale * (float)e.Scale; |
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compositionVisual.Scale = new(scale, scale, 1); |
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} |
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}); |
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|
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control.AddHandler(Gestures.PinchEndedEvent, (s, e) => |
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{ |
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InitComposition(control!); |
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|
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isZooming = false; |
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|
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if (compositionVisual != null) |
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{ |
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_currentScale = compositionVisual.Scale.X; |
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} |
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}); |
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|
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control.AddHandler(Gestures.ScrollGestureEvent, (s, e) => |
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{ |
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InitComposition(control!); |
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|
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if (compositionVisual != null && !isZooming) |
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{ |
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currentOffset -= new Vector3((float)e.Delta.X, (float)e.Delta.Y, 0); |
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|
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compositionVisual.Offset = currentOffset; |
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} |
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}); |
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} |
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|
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private void SetPullHandlers(Control? control, bool inverse) |
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{ |
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if (control == null) |
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{ |
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return; |
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} |
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|
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var ball = control.FindLogicalDescendantOfType<Border>(); |
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Vector3 defaultOffset = default; |
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CompositionVisual? ballCompositionVisual = null; |
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if (ball != null) |
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{ |
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InitComposition(ball); |
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} |
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else |
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{ |
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return; |
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} |
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|
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control.LayoutUpdated += (s, e) => |
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{ |
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InitComposition(ball!); |
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if (ballCompositionVisual != null) |
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{ |
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defaultOffset = ballCompositionVisual.Offset; |
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} |
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}; |
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|
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control.AddHandler(Gestures.PullGestureEvent, (s, e) => |
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{ |
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Vector3 center = new((float)control.Bounds.Center.X, (float)control.Bounds.Center.Y, 0); |
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InitComposition(ball!); |
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if (ballCompositionVisual != null) |
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{ |
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ballCompositionVisual.Offset = defaultOffset + new System.Numerics.Vector3((float)e.Delta.X * 0.4f, (float)e.Delta.Y * 0.4f, 0) * (inverse ? -1 : 1); |
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} |
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}); |
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|
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control.AddHandler(Gestures.PullGestureEndedEvent, (s, e) => |
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{ |
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InitComposition(ball!); |
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if (ballCompositionVisual != null) |
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{ |
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ballCompositionVisual.Offset = defaultOffset; |
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} |
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}); |
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|
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void InitComposition(Control control) |
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{ |
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if (ballCompositionVisual != null) |
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{ |
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return; |
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} |
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ballCompositionVisual = ElementComposition.GetElementVisual(ball); |
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|
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if (ballCompositionVisual != null) |
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{ |
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var offsetAnimation = ballCompositionVisual.Compositor.CreateVector3KeyFrameAnimation(); |
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offsetAnimation.Target = "Offset"; |
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offsetAnimation.InsertExpressionKeyFrame(1.0f, "this.FinalValue"); |
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offsetAnimation.Duration = TimeSpan.FromMilliseconds(100); |
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var implicitAnimations = ballCompositionVisual.Compositor.CreateImplicitAnimationCollection(); |
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implicitAnimations["Offset"] = offsetAnimation; |
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ballCompositionVisual.ImplicitAnimations = implicitAnimations; |
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} |
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} |
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} |
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} |
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} |
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@ -0,0 +1,117 @@ |
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<UserControl xmlns="https://github.com/avaloniaui" |
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xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" |
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xmlns:d="http://schemas.microsoft.com/expression/blend/2008" |
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d:DesignHeight="800" |
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d:DesignWidth="400" |
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x:Class="ControlCatalog.Pages.GesturePage"> |
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<StackPanel Orientation="Vertical" |
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Spacing="4"> |
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<TextBlock FontWeight="Bold" |
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FontSize="18" |
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Margin="5">Pull Gexture (Touch / Pen)</TextBlock> |
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<TextBlock Margin="5">Pull from colored rectangles</TextBlock> |
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<Border> |
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<DockPanel HorizontalAlignment="Stretch" |
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ClipToBounds="True" |
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Margin="5" |
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Height="200"> |
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<Border DockPanel.Dock="Top" |
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Margin="2" |
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Name="TopPullZone" |
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Background="Transparent" |
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BorderBrush="Red" |
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HorizontalAlignment="Stretch" |
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Height="50" |
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BorderThickness="1"> |
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<Border.GestureRecognizers> |
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<PullGestureRecognizer PullDirection="TopToBottom"/> |
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</Border.GestureRecognizers> |
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<Border Width="10" |
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Height="10" |
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HorizontalAlignment="Center" |
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VerticalAlignment="Center" |
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CornerRadius="5" |
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Name="TopBall" |
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Background="Green"/> |
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</Border> |
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<Border DockPanel.Dock="Bottom" |
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BorderBrush="Green" |
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Margin="2" |
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Background="Transparent" |
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Name="BottomPullZone" |
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HorizontalAlignment="Stretch" |
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Height="50" |
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BorderThickness="1"> |
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<Border.GestureRecognizers> |
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<PullGestureRecognizer PullDirection="BottomToTop"/> |
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</Border.GestureRecognizers> |
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<Border Width="10" |
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Name="BottomBall" |
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HorizontalAlignment="Center" |
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VerticalAlignment="Center" |
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Height="10" |
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CornerRadius="5" |
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Background="Green"/> |
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</Border> |
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<Border DockPanel.Dock="Right" |
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Margin="2" |
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Background="Transparent" |
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Name="RightPullZone" |
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BorderBrush="Blue" |
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HorizontalAlignment="Right" |
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VerticalAlignment="Stretch" |
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Width="50" |
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BorderThickness="1"> |
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<Border.GestureRecognizers> |
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<PullGestureRecognizer PullDirection="RightToLeft"/> |
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</Border.GestureRecognizers> |
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<Border Width="10" |
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Height="10" |
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Name="RightBall" |
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HorizontalAlignment="Center" |
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VerticalAlignment="Center" |
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CornerRadius="5" |
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Background="Green"/> |
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|
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</Border> |
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<Border DockPanel.Dock="Left" |
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Margin="2" |
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Background="Transparent" |
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Name="LeftPullZone" |
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BorderBrush="Orange" |
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HorizontalAlignment="Left" |
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VerticalAlignment="Stretch" |
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Width="50" |
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BorderThickness="1"> |
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<Border.GestureRecognizers> |
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<PullGestureRecognizer PullDirection="LeftToRight"/> |
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</Border.GestureRecognizers> |
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<Border Width="10" |
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Height="10" |
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Name="LeftBall" |
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HorizontalAlignment="Center" |
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VerticalAlignment="Center" |
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CornerRadius="5" |
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Background="Green"/> |
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|
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</Border> |
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</DockPanel> |
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</Border> |
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|
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<TextBlock FontWeight="Bold" |
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FontSize="18" |
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Margin="5">Pinch/Zoom Gexture (Multi Touch)</TextBlock> |
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<Border ClipToBounds="True"> |
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<Image Stretch="UniformToFill" |
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Margin="5" |
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Name="PinchImage" |
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Source="/Assets/delicate-arch-896885_640.jpg"> |
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<Image.GestureRecognizers> |
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<PinchGestureRecognizer/> |
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<ScrollGestureRecognizer CanHorizontallyScroll="True" CanVerticallyScroll="True"/> |
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</Image.GestureRecognizers> |
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</Image> |
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</Border> |
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<Button HorizontalAlignment="Center" Name="ResetButton">Reset</Button> |
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</StackPanel> |
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</UserControl> |
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@ -0,0 +1,26 @@ |
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using System; |
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using System.Runtime.InteropServices; |
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|
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namespace Avalonia.Compatibility |
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{ |
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internal sealed class OperatingSystemEx |
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{ |
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#if NET6_0_OR_GREATER
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public static bool IsWindows() => OperatingSystem.IsWindows(); |
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public static bool IsMacOS() => OperatingSystem.IsMacOS(); |
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public static bool IsLinux() => OperatingSystem.IsLinux(); |
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public static bool IsAndroid() => OperatingSystem.IsAndroid(); |
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public static bool IsIOS() => OperatingSystem.IsIOS(); |
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public static bool IsBrowser() => OperatingSystem.IsBrowser(); |
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public static bool IsOSPlatform(string platform) => OperatingSystem.IsOSPlatform(platform); |
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#else
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public static bool IsWindows() => RuntimeInformation.IsOSPlatform(OSPlatform.Windows); |
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public static bool IsMacOS() => RuntimeInformation.IsOSPlatform(OSPlatform.OSX); |
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public static bool IsLinux() => RuntimeInformation.IsOSPlatform(OSPlatform.Linux); |
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public static bool IsAndroid() => IsOSPlatform("ANDROID"); |
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public static bool IsIOS() => IsOSPlatform("IOS"); |
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public static bool IsBrowser() => IsOSPlatform("BROWSER"); |
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public static bool IsOSPlatform(string platform) => RuntimeInformation.IsOSPlatform(OSPlatform.Create(platform)); |
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#endif
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} |
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} |
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@ -1,34 +0,0 @@ |
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using System; |
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using System.Runtime.CompilerServices; |
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using JetBrains.Annotations; |
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|
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namespace Avalonia |
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{ |
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/// <summary>
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/// A stub of Code Contract's Contract class.
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/// </summary>
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/// <remarks>
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/// It would be nice to use Code Contracts on Avalonia but last time I tried it slowed things
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/// to a crawl and often crashed. Instead use the same signature for checking preconditions
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/// in the hope that it might become usable at some point.
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/// </remarks>
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public static class Contract |
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{ |
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/// <summary>
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/// Specifies a precondition.
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/// </summary>
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/// <typeparam name="TException">
|
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/// The exception to throw if <paramref name="condition"/> is false.
|
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/// </typeparam>
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/// <param name="condition">The precondition.</param>
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[MethodImpl(MethodImplOptions.AggressiveInlining)] |
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[ContractAnnotation("condition:false=>stop")] |
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public static void Requires<TException>(bool condition) where TException : Exception, new() |
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{ |
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if (!condition) |
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{ |
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throw new TException(); |
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} |
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} |
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} |
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} |
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@ -0,0 +1,128 @@ |
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using Avalonia.Input.GestureRecognizers; |
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|
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namespace Avalonia.Input |
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{ |
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public class PinchGestureRecognizer : StyledElement, IGestureRecognizer |
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{ |
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private IInputElement? _target; |
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private IGestureRecognizerActionsDispatcher? _actions; |
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private float _initialDistance; |
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private IPointer? _firstContact; |
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private Point _firstPoint; |
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private IPointer? _secondContact; |
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private Point _secondPoint; |
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private Point _origin; |
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|
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public void Initialize(IInputElement target, IGestureRecognizerActionsDispatcher actions) |
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{ |
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_target = target; |
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_actions = actions; |
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} |
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|
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private void OnPointerPressed(object? sender, PointerPressedEventArgs e) |
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{ |
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PointerPressed(e); |
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} |
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private void OnPointerReleased(object? sender, PointerReleasedEventArgs e) |
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{ |
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PointerReleased(e); |
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} |
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|
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public void PointerCaptureLost(IPointer pointer) |
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{ |
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RemoveContact(pointer); |
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} |
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|
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public void PointerMoved(PointerEventArgs e) |
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{ |
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if (_target != null && _target is Visual visual) |
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{ |
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if(_firstContact == e.Pointer) |
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{ |
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_firstPoint = e.GetPosition(visual); |
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} |
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else if (_secondContact == e.Pointer) |
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{ |
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_secondPoint = e.GetPosition(visual); |
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} |
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else |
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{ |
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return; |
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} |
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|
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if (_firstContact != null && _secondContact != null) |
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{ |
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var distance = GetDistance(_firstPoint, _secondPoint); |
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|
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var scale = distance / _initialDistance; |
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|
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_target?.RaiseEvent(new PinchEventArgs(scale, _origin)); |
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} |
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} |
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} |
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|
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public void PointerPressed(PointerPressedEventArgs e) |
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{ |
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if (_target != null && _target is Visual visual && (e.Pointer.Type == PointerType.Touch || e.Pointer.Type == PointerType.Pen)) |
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{ |
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if (_firstContact == null) |
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{ |
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_firstContact = e.Pointer; |
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_firstPoint = e.GetPosition(visual); |
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|
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return; |
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} |
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else if (_secondContact == null && _firstContact != e.Pointer) |
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{ |
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_secondContact = e.Pointer; |
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_secondPoint = e.GetPosition(visual); |
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} |
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else |
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{ |
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return; |
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} |
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|
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if (_firstContact != null && _secondContact != null) |
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{ |
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_initialDistance = GetDistance(_firstPoint, _secondPoint); |
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|
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_origin = new Point((_firstPoint.X + _secondPoint.X) / 2.0f, (_firstPoint.Y + _secondPoint.Y) / 2.0f); |
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|
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_actions!.Capture(_firstContact, this); |
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_actions!.Capture(_secondContact, this); |
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} |
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} |
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} |
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|
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public void PointerReleased(PointerReleasedEventArgs e) |
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{ |
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RemoveContact(e.Pointer); |
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} |
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|
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private void RemoveContact(IPointer pointer) |
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{ |
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if (_firstContact == pointer || _secondContact == pointer) |
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{ |
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if (_secondContact == pointer) |
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{ |
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_secondContact = null; |
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} |
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|
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if (_firstContact == pointer) |
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{ |
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_firstContact = _secondContact; |
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|
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_secondContact = null; |
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} |
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_target?.RaiseEvent(new PinchEndedEventArgs()); |
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} |
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} |
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|
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private float GetDistance(Point a, Point b) |
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{ |
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var length = _secondPoint - _firstPoint; |
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return (float)new Vector(length.X, length.Y).Length; |
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} |
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} |
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} |
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@ -0,0 +1,375 @@ |
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// Code in this file is derived from
|
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// https://github.com/flutter/flutter/blob/master/packages/flutter/lib/src/gestures/velocity_tracker.dart
|
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|
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using System; |
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using System.Diagnostics; |
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using Avalonia.Utilities; |
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|
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namespace Avalonia.Input.GestureRecognizers |
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{ |
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// Possible enhancement: add Flutter's 'IOSScrollViewFlingVelocityTracker' and 'MacOSScrollViewFlingVelocityTracker'?
|
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|
|||
internal readonly record struct Velocity(Vector PixelsPerSecond) |
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{ |
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public Velocity ClampMagnitude(double minValue, double maxValue) |
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{ |
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Debug.Assert(minValue >= 0.0); |
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Debug.Assert(maxValue >= 0.0 && maxValue >= minValue); |
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double valueSquared = PixelsPerSecond.SquaredLength; |
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if (valueSquared > maxValue * maxValue) |
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{ |
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double length = PixelsPerSecond.Length; |
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return new Velocity(length != 0.0 ? (PixelsPerSecond / length) * maxValue : Vector.Zero); |
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// preventing double.NaN in Vector PixelsPerSecond is important -- if a NaN eventually gets into a
|
|||
// ScrollGestureEventArgs it results in runtime errors.
|
|||
} |
|||
if (valueSquared < minValue * minValue) |
|||
{ |
|||
double length = PixelsPerSecond.Length; |
|||
return new Velocity(length != 0.0 ? (PixelsPerSecond / length) * minValue : Vector.Zero); |
|||
} |
|||
return this; |
|||
} |
|||
} |
|||
|
|||
/// A two dimensional velocity estimate.
|
|||
///
|
|||
/// VelocityEstimates are computed by [VelocityTracker.getVelocityEstimate]. An
|
|||
/// estimate's [confidence] measures how well the velocity tracker's position
|
|||
/// data fit a straight line, [duration] is the time that elapsed between the
|
|||
/// first and last position sample used to compute the velocity, and [offset]
|
|||
/// is similarly the difference between the first and last positions.
|
|||
///
|
|||
/// See also:
|
|||
///
|
|||
/// * [VelocityTracker], which computes [VelocityEstimate]s.
|
|||
/// * [Velocity], which encapsulates (just) a velocity vector and provides some
|
|||
/// useful velocity operations.
|
|||
internal record VelocityEstimate(Vector PixelsPerSecond, double Confidence, TimeSpan Duration, Vector Offset); |
|||
|
|||
internal record struct PointAtTime(bool Valid, Vector Point, TimeSpan Time); |
|||
|
|||
/// Computes a pointer's velocity based on data from [PointerMoveEvent]s.
|
|||
///
|
|||
/// The input data is provided by calling [addPosition]. Adding data is cheap.
|
|||
///
|
|||
/// To obtain a velocity, call [getVelocity] or [getVelocityEstimate]. This will
|
|||
/// compute the velocity based on the data added so far. Only call these when
|
|||
/// you need to use the velocity, as they are comparatively expensive.
|
|||
///
|
|||
/// The quality of the velocity estimation will be better if more data points
|
|||
/// have been received.
|
|||
internal class VelocityTracker |
|||
{ |
|||
private const int AssumePointerMoveStoppedMilliseconds = 40; |
|||
private const int HistorySize = 20; |
|||
private const int HorizonMilliseconds = 100; |
|||
private const int MinSampleSize = 3; |
|||
private const double MinFlingVelocity = 50.0; // Logical pixels / second
|
|||
private const double MaxFlingVelocity = 8000.0; |
|||
|
|||
private readonly PointAtTime[] _samples = new PointAtTime[HistorySize]; |
|||
private int _index = 0; |
|||
|
|||
/// <summary>
|
|||
/// Adds a position as the given time to the tracker.
|
|||
/// </summary>
|
|||
/// <param name="time"></param>
|
|||
/// <param name="position"></param>
|
|||
public void AddPosition(TimeSpan time, Vector position) |
|||
{ |
|||
_index++; |
|||
if (_index == HistorySize) |
|||
{ |
|||
_index = 0; |
|||
} |
|||
_samples[_index] = new PointAtTime(true, position, time); |
|||
} |
|||
|
|||
/// Returns an estimate of the velocity of the object being tracked by the
|
|||
/// tracker given the current information available to the tracker.
|
|||
///
|
|||
/// Information is added using [addPosition].
|
|||
///
|
|||
/// Returns null if there is no data on which to base an estimate.
|
|||
protected virtual VelocityEstimate? GetVelocityEstimate() |
|||
{ |
|||
Span<double> x = stackalloc double[HistorySize]; |
|||
Span<double> y = stackalloc double[HistorySize]; |
|||
Span<double> w = stackalloc double[HistorySize]; |
|||
Span<double> time = stackalloc double[HistorySize]; |
|||
int sampleCount = 0; |
|||
int index = _index; |
|||
|
|||
var newestSample = _samples[index]; |
|||
if (!newestSample.Valid) |
|||
{ |
|||
return null; |
|||
} |
|||
|
|||
var previousSample = newestSample; |
|||
var oldestSample = newestSample; |
|||
|
|||
// Starting with the most recent PointAtTime sample, iterate backwards while
|
|||
// the samples represent continuous motion.
|
|||
do |
|||
{ |
|||
var sample = _samples[index]; |
|||
if (!sample.Valid) |
|||
{ |
|||
break; |
|||
} |
|||
|
|||
double age = (newestSample.Time - sample.Time).TotalMilliseconds; |
|||
double delta = Math.Abs((sample.Time - previousSample.Time).TotalMilliseconds); |
|||
previousSample = sample; |
|||
if (age > HorizonMilliseconds || delta > AssumePointerMoveStoppedMilliseconds) |
|||
{ |
|||
break; |
|||
} |
|||
|
|||
oldestSample = sample; |
|||
var position = sample.Point; |
|||
x[sampleCount] = position.X; |
|||
y[sampleCount] = position.Y; |
|||
w[sampleCount] = 1.0; |
|||
time[sampleCount] = -age; |
|||
index = (index == 0 ? HistorySize : index) - 1; |
|||
|
|||
sampleCount++; |
|||
} while (sampleCount < HistorySize); |
|||
|
|||
if (sampleCount >= MinSampleSize) |
|||
{ |
|||
var xFit = LeastSquaresSolver.Solve(2, time.Slice(0, sampleCount), x.Slice(0, sampleCount), w.Slice(0, sampleCount)); |
|||
if (xFit != null) |
|||
{ |
|||
var yFit = LeastSquaresSolver.Solve(2, time.Slice(0, sampleCount), y.Slice(0, sampleCount), w.Slice(0, sampleCount)); |
|||
if (yFit != null) |
|||
{ |
|||
return new VelocityEstimate( // convert from pixels/ms to pixels/s
|
|||
PixelsPerSecond: new Vector(xFit.Coefficients[1] * 1000, yFit.Coefficients[1] * 1000), |
|||
Confidence: xFit.Confidence * yFit.Confidence, |
|||
Duration: newestSample.Time - oldestSample.Time, |
|||
Offset: newestSample.Point - oldestSample.Point |
|||
); |
|||
} |
|||
} |
|||
} |
|||
|
|||
// We're unable to make a velocity estimate but we did have at least one
|
|||
// valid pointer position.
|
|||
return new VelocityEstimate( |
|||
PixelsPerSecond: Vector.Zero, |
|||
Confidence: 1.0, |
|||
Duration: newestSample.Time - oldestSample.Time, |
|||
Offset: newestSample.Point - oldestSample.Point |
|||
); |
|||
} |
|||
|
|||
/// <summary>
|
|||
/// Computes the velocity of the pointer at the time of the last
|
|||
/// provided data point.
|
|||
///
|
|||
/// This can be expensive. Only call this when you need the velocity.
|
|||
///
|
|||
/// Returns [Velocity.zero] if there is no data from which to compute an
|
|||
/// estimate or if the estimated velocity is zero.///
|
|||
/// </summary>
|
|||
/// <returns></returns>
|
|||
internal Velocity GetVelocity() |
|||
{ |
|||
var estimate = GetVelocityEstimate(); |
|||
if (estimate == null || estimate.PixelsPerSecond.IsDefault) |
|||
{ |
|||
return new Velocity(Vector.Zero); |
|||
} |
|||
return new Velocity(estimate.PixelsPerSecond); |
|||
} |
|||
|
|||
internal virtual Velocity GetFlingVelocity() |
|||
{ |
|||
return GetVelocity().ClampMagnitude(MinFlingVelocity, MaxFlingVelocity); |
|||
} |
|||
} |
|||
|
|||
/// An nth degree polynomial fit to a dataset.
|
|||
internal class PolynomialFit |
|||
{ |
|||
/// Creates a polynomial fit of the given degree.
|
|||
///
|
|||
/// There are n + 1 coefficients in a fit of degree n.
|
|||
internal PolynomialFit(int degree) |
|||
{ |
|||
Coefficients = new double[degree + 1]; |
|||
} |
|||
|
|||
/// The polynomial coefficients of the fit.
|
|||
public double[] Coefficients { get; } |
|||
|
|||
/// An indicator of the quality of the fit.
|
|||
///
|
|||
/// Larger values indicate greater quality.
|
|||
public double Confidence { get; set; } |
|||
} |
|||
|
|||
internal class LeastSquaresSolver |
|||
{ |
|||
private const double PrecisionErrorTolerance = 1e-10; |
|||
|
|||
/// <summary>
|
|||
/// Fits a polynomial of the given degree to the data points.
|
|||
/// When there is not enough data to fit a curve null is returned.
|
|||
/// </summary>
|
|||
public static PolynomialFit? Solve(int degree, ReadOnlySpan<double> x, ReadOnlySpan<double> y, ReadOnlySpan<double> w) |
|||
{ |
|||
if (degree > x.Length) |
|||
{ |
|||
// Not enough data to fit a curve.
|
|||
return null; |
|||
} |
|||
|
|||
PolynomialFit result = new PolynomialFit(degree); |
|||
|
|||
// Shorthands for the purpose of notation equivalence to original C++ code.
|
|||
int m = x.Length; |
|||
int n = degree + 1; |
|||
|
|||
// Expand the X vector to a matrix A, pre-multiplied by the weights.
|
|||
_Matrix a = new _Matrix(m, stackalloc double[n * m]); |
|||
for (int h = 0; h < m; h += 1) |
|||
{ |
|||
a[0, h] = w[h]; |
|||
for (int i = 1; i < n; i += 1) |
|||
{ |
|||
a[i, h] = a[i - 1, h] * x[h]; |
|||
} |
|||
} |
|||
|
|||
// Apply the Gram-Schmidt process to A to obtain its QR decomposition.
|
|||
|
|||
// Orthonormal basis, column-major order Vector.
|
|||
_Matrix q = new _Matrix(m, stackalloc double[n * m]); |
|||
// Upper triangular matrix, row-major order.
|
|||
_Matrix r = new _Matrix(n, stackalloc double[n * n]); |
|||
for (int j = 0; j < n; j += 1) |
|||
{ |
|||
for (int h = 0; h < m; h += 1) |
|||
{ |
|||
q[j, h] = a[j, h]; |
|||
} |
|||
for (int i = 0; i < j; i += 1) |
|||
{ |
|||
double dot = Multiply(q.GetRow(j), q.GetRow(i)); |
|||
for (int h = 0; h < m; h += 1) |
|||
{ |
|||
q[j, h] = q[j, h] - dot * q[i, h]; |
|||
} |
|||
} |
|||
|
|||
double norm = Norm(q.GetRow(j)); |
|||
if (norm < PrecisionErrorTolerance) |
|||
{ |
|||
// Vectors are linearly dependent or zero so no solution.
|
|||
return null; |
|||
} |
|||
|
|||
double inverseNorm = 1.0 / norm; |
|||
for (int h = 0; h < m; h += 1) |
|||
{ |
|||
q[j, h] = q[j, h] * inverseNorm; |
|||
} |
|||
for (int i = 0; i < n; i += 1) |
|||
{ |
|||
r[j, i] = i < j ? 0.0 : Multiply(q.GetRow(j), a.GetRow(i)); |
|||
} |
|||
} |
|||
|
|||
// Solve R B = Qt W Y to find B. This is easy because R is upper triangular.
|
|||
// We just work from bottom-right to top-left calculating B's coefficients.
|
|||
// "m" isn't expected to be bigger than HistorySize=20, so allocation on stack is safe.
|
|||
Span<double> wy = stackalloc double[m]; |
|||
for (int h = 0; h < m; h += 1) |
|||
{ |
|||
wy[h] = y[h] * w[h]; |
|||
} |
|||
for (int i = n - 1; i >= 0; i -= 1) |
|||
{ |
|||
result.Coefficients[i] = Multiply(q.GetRow(i), wy); |
|||
for (int j = n - 1; j > i; j -= 1) |
|||
{ |
|||
result.Coefficients[i] -= r[i, j] * result.Coefficients[j]; |
|||
} |
|||
result.Coefficients[i] /= r[i, i]; |
|||
} |
|||
|
|||
// Calculate the coefficient of determination (confidence) as:
|
|||
// 1 - (sumSquaredError / sumSquaredTotal)
|
|||
// ...where sumSquaredError is the residual sum of squares (variance of the
|
|||
// error), and sumSquaredTotal is the total sum of squares (variance of the
|
|||
// data) where each has been weighted.
|
|||
double yMean = 0.0; |
|||
for (int h = 0; h < m; h += 1) |
|||
{ |
|||
yMean += y[h]; |
|||
} |
|||
yMean /= m; |
|||
|
|||
double sumSquaredError = 0.0; |
|||
double sumSquaredTotal = 0.0; |
|||
for (int h = 0; h < m; h += 1) |
|||
{ |
|||
double term = 1.0; |
|||
double err = y[h] - result.Coefficients[0]; |
|||
for (int i = 1; i < n; i += 1) |
|||
{ |
|||
term *= x[h]; |
|||
err -= term * result.Coefficients[i]; |
|||
} |
|||
sumSquaredError += w[h] * w[h] * err * err; |
|||
double v = y[h] - yMean; |
|||
sumSquaredTotal += w[h] * w[h] * v * v; |
|||
} |
|||
|
|||
result.Confidence = sumSquaredTotal <= PrecisionErrorTolerance ? 1.0 : |
|||
1.0 - (sumSquaredError / sumSquaredTotal); |
|||
|
|||
return result; |
|||
} |
|||
|
|||
private static double Multiply(Span<double> v1, Span<double> v2) |
|||
{ |
|||
double result = 0.0; |
|||
for (int i = 0; i < v1.Length; i += 1) |
|||
{ |
|||
result += v1[i] * v2[i]; |
|||
} |
|||
return result; |
|||
} |
|||
|
|||
private static double Norm(Span<double> v) |
|||
{ |
|||
return Math.Sqrt(Multiply(v, v)); |
|||
} |
|||
|
|||
private readonly ref struct _Matrix |
|||
{ |
|||
private readonly int _columns; |
|||
private readonly Span<double> _elements; |
|||
|
|||
internal _Matrix(int cols, Span<double> elements) |
|||
{ |
|||
_columns = cols; |
|||
_elements = elements; |
|||
} |
|||
|
|||
public double this[int row, int col] |
|||
{ |
|||
get => _elements[row * _columns + col]; |
|||
set => _elements[row * _columns + col] = value; |
|||
} |
|||
|
|||
public Span<double> GetRow(int row) => _elements.Slice(row * _columns, _columns); |
|||
} |
|||
} |
|||
} |
|||
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Reference in new issue