Initial import

2021-07-05 21:44:43 +02:00 · 2021-07-05 21:44:43 +02:00 · 6a08490c61
--- a/NuGet.Config
+++ b/NuGet.Config
@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="utf-8"?>
+<configuration>
+  <packageSources>
+    <clear />
+    <add key="api.nuget.org" value="https://api.nuget.org/v3/index.json" />
+    <add key="avalonia-all" value="https://nuget.avaloniaui.net/repository/avalonia-all/index.json" />
+  </packageSources>
+</configuration>
--- a/PerspectiveDemo.sln
+++ b/PerspectiveDemo.sln
@ -0,0 +1,16 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "PerspectiveDemo", "PerspectiveDemo\PerspectiveDemo.csproj", "{B17E0F8D-B865-48B7-BE2D-5CFE8FB26289}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{B17E0F8D-B865-48B7-BE2D-5CFE8FB26289}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{B17E0F8D-B865-48B7-BE2D-5CFE8FB26289}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{B17E0F8D-B865-48B7-BE2D-5CFE8FB26289}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{B17E0F8D-B865-48B7-BE2D-5CFE8FB26289}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+EndGlobal
--- a/PerspectiveDemo/App.axaml
+++ b/PerspectiveDemo/App.axaml
@ -0,0 +1,7 @@
+<Application xmlns="https://github.com/avaloniaui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             x:Class="PerspectiveDemo.App">
+    <Application.Styles>
+        <FluentTheme Mode="Light"/>
+    </Application.Styles>
+</Application>
--- a/PerspectiveDemo/App.axaml.cs
+++ b/PerspectiveDemo/App.axaml.cs
@ -0,0 +1,24 @@
+using Avalonia;
+using Avalonia.Controls.ApplicationLifetimes;
+using Avalonia.Markup.Xaml;
+
+namespace PerspectiveDemo
+{
+    public class App : Application
+    {
+        public override void Initialize()
+        {
+            AvaloniaXamlLoader.Load(this);
+        }
+
+        public override void OnFrameworkInitializationCompleted()
+        {
+            if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop)
+            {
+                desktop.MainWindow = new MainWindow();
+            }
+
+            base.OnFrameworkInitializationCompleted();
+        }
+    }
+}
--- a/PerspectiveDemo/MainWindow.axaml
+++ b/PerspectiveDemo/MainWindow.axaml
@ -0,0 +1,28 @@
+<Window xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+        mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
+        x:Class="PerspectiveDemo.MainWindow"
+        Title="PerspectiveDemo">
+    <Panel>
+        <Canvas Name="Canvas" Width="300" Height="300" Background="LightGray" HorizontalAlignment="Center" VerticalAlignment="Center">
+            <Canvas.Styles>
+                <Style Selector="Thumb">
+                    <Setter Property="Template">
+                        <Setter.Value>
+                            <ControlTemplate>
+                                <Rectangle Margin="-5,-5,0,0" Width="10" Height="10" Fill="Black"/>
+                            </ControlTemplate>
+                        </Setter.Value>
+                    </Setter>
+                </Style>
+            </Canvas.Styles>
+            <Rectangle Name="Rectangle" Canvas.Left="0" Canvas.Top="0" Width="100" Height="100" Fill="Blue"/>
+            <Thumb Name="UL" Canvas.Left="100" Canvas.Top="100" DragDelta="OnDragDelta" ClipToBounds="False"/>
+            <Thumb Name="UR" Canvas.Left="200" Canvas.Top="100" DragDelta="OnDragDelta" ClipToBounds="False"/>
+            <Thumb Name="LL" Canvas.Left="100" Canvas.Top="200" DragDelta="OnDragDelta" ClipToBounds="False"/>
+            <Thumb Name="LR" Canvas.Left="200" Canvas.Top="200" DragDelta="OnDragDelta" ClipToBounds="False"/>
+        </Canvas>
+    </Panel>
+</Window>
--- a/PerspectiveDemo/MainWindow.axaml.cs
+++ b/PerspectiveDemo/MainWindow.axaml.cs
@ -0,0 +1,117 @@
+// https://github.com/AvaloniaUI/Avalonia/pull/6192
+// https://docs.microsoft.com/en-us/xamarin/xamarin-forms/user-interface/graphics/skiasharp/transforms/non-affine
+// http://www.charlespetzold.com/blog/2007/08/250638.html
+using System.Diagnostics;
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Controls.Primitives;
+using Avalonia.Controls.Shapes;
+using Avalonia.Input;
+using Avalonia.Markup.Xaml;
+using Avalonia.Media;
+
+namespace PerspectiveDemo
+{
+    public partial class MainWindow : Window
+    {
+        public MainWindow()
+        {
+            InitializeComponent();
+#if DEBUG
+            this.AttachDevTools();
+#endif
+            UpdateTransform();
+        }
+
+        private void InitializeComponent()
+        {
+            AvaloniaXamlLoader.Load(this);
+        }
+
+        private void UpdateTransform()
+        {
+            var canvas = this.FindControl<Canvas>("Canvas");
+            var rectangle = this.FindControl<Rectangle>("Rectangle");
+
+            var width = rectangle.Width;
+            var height = rectangle.Height;
+
+            var ul = this.FindControl<Thumb>("UL");
+            var ur = this.FindControl<Thumb>("UR");
+            var ll = this.FindControl<Thumb>("LL");
+            var lr = this.FindControl<Thumb>("LR");
+
+            var ptUL = new Point(Canvas.GetLeft(ul), Canvas.GetTop(ul));
+            var ptUR = new Point(Canvas.GetLeft(ur), Canvas.GetTop(ur));
+            var ptLL = new Point(Canvas.GetLeft(ll), Canvas.GetTop(ll));
+            var ptLR = new Point(Canvas.GetLeft(lr), Canvas.GetTop(lr));
+
+            var result = ComputeMatrix(new Size(width, height), ptUL, ptUR, ptLL, ptLR);
+
+            rectangle.RenderTransformOrigin = RelativePoint.Center;
+            rectangle.RenderTransform = new MatrixTransform(result);
+        }
+
+        static Point MapPoint(Matrix matrix, Point point)
+        {
+            return new Point(
+                (point.X * matrix.M11) + (point.Y * matrix.M21) + matrix.M31,
+                (point.X * matrix.M12) + (point.Y * matrix.M22) + matrix.M32);
+        }
+
+        static Matrix ComputeMatrix(Size size, Point ptUL, Point ptUR, Point ptLL, Point ptLR)
+        {
+            // Scale transform
+            var S = Matrix.CreateScale(1 / size.Width, 1 / size.Height);
+
+            // Affine transform
+            var A = new Matrix(
+                ptUR.X - ptUL.X,
+                ptUR.Y - ptUL.Y, 
+                0,
+                ptLL.X - ptUL.X,
+                ptLL.Y - ptUL.Y, 
+                0, 
+                ptUL.X,
+                ptUL.Y,
+                1);
+
+            // Non-Affine transform
+            //A.TryInvert(out var inverseA);
+            //var abPoint = MapPoint(inverseA, ptLR);
+            //var a = abPoint.X;
+            //var b = abPoint.Y;
+            double den = A.M11 * A.M22 - A.M12 * A.M21;
+            double a = (A.M22 * ptLR.X - A.M21 * ptLR.Y + A.M21 * A.M32 - A.M22 * A.M31) / den;
+            double b = (A.M11 * ptLR.Y - A.M12 * ptLR.X + A.M12 * A.M31 - A.M11 * A.M32) / den;
+
+            var scaleX = a / (a + b - 1);
+            var scaleY = b / (a + b - 1);
+
+            var N = new Matrix(
+                scaleX,
+                0,
+                scaleX - 1,
+                0,
+                scaleY,
+                scaleY - 1,
+                0,
+                0,
+                1);
+
+            // Multiply S * N * A
+            var result = S * N * A;
+            return result;
+        }
+
+        private void OnDragDelta(object? sender, VectorEventArgs e)
+        {
+            if (sender is Thumb thumb)
+            {
+                Canvas.SetLeft(thumb, Canvas.GetLeft(thumb) + e.Vector.X);
+                Canvas.SetTop(thumb, Canvas.GetTop(thumb) + e.Vector.Y);
+                UpdateTransform();
+            }
+        }
+    }
+}
--- a/PerspectiveDemo/PerspectiveDemo.csproj
+++ b/PerspectiveDemo/PerspectiveDemo.csproj
@ -0,0 +1,12 @@
+<Project Sdk="Microsoft.NET.Sdk">
+    <PropertyGroup>
+        <OutputType>WinExe</OutputType>
+        <TargetFramework>net5.0</TargetFramework>
+        <Nullable>enable</Nullable>
+    </PropertyGroup>
+    <ItemGroup>
+        <PackageReference Include="Avalonia" Version="0.10.999-cibuild0014847-beta"/>
+        <PackageReference Include="Avalonia.Desktop" Version="0.10.999-cibuild0014847-beta"/>
+        <PackageReference Include="Avalonia.Diagnostics" Version="0.10.999-cibuild0014847-beta"/>
+    </ItemGroup>
+</Project>
--- a/PerspectiveDemo/Program.cs
+++ b/PerspectiveDemo/Program.cs
@ -0,0 +1,22 @@
+using System;
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Controls.ApplicationLifetimes;
+
+namespace PerspectiveDemo
+{
+    class Program
+    {
+        // Initialization code. Don't use any Avalonia, third-party APIs or any
+        // SynchronizationContext-reliant code before AppMain is called: things aren't initialized
+        // yet and stuff might break.
+        public static void Main(string[] args) => BuildAvaloniaApp()
+            .StartWithClassicDesktopLifetime(args);
+
+        // Avalonia configuration, don't remove; also used by visual designer.
+        public static AppBuilder BuildAvaloniaApp()
+            => AppBuilder.Configure<App>()
+                .UsePlatformDetect()
+                .LogToTrace();
+    }
+}