Added a progress spinner control that should work on top of WinForms even with its poor transparent control support

git-svn-id: file:///srv/devel/repo-conversion/nuwi@50 d2e56fa2-650e-0410-a79f-9358c0239efd

Source/Controls/ProgressSpinner.cs

@@ -0,0 +1,176 @@
+using System;
+using System.Data;
+using System.Drawing;
+using System.Linq;
+using System.Windows.Forms;
+
+namespace Nuclex.Windows.Forms.Controls {
+
+  /// <summary>Displays a progress spinner to entertain the user while waiting</summary>
+  public partial class ProgressSpinner : UserControl {
+
+    /// <summary>Number of dots the progress spinner will display</summary>
+    private const int DotCount = 8;
+    /// <summary>Size of a normal dot (only ever assumed by the trailing dot)</summary>
+    private const int DotRadius = 4;
+    /// <summary>
+    ///   The leading dot will be DotCount times this larger than a normal dot
+    /// </summary>
+    private const int ScaleFactor = 1;
+
+    /// <summary>Initializes a new progress spinner</summary>
+    public ProgressSpinner() {
+      SetStyle(
+        (
+          ControlStyles.AllPaintingInWmPaint |
+          ControlStyles.OptimizedDoubleBuffer |
+          ControlStyles.ResizeRedraw | ControlStyles.UserPaint |
+          ControlStyles.SupportsTransparentBackColor
+        ),
+        true
+      );
+
+      InitializeComponent();
+
+      Disposed += new EventHandler(OnDisposed);
+
+      if(!DesignMode) {
+        StartSpinner();
+      }
+    }
+
+    /// <summary>Releases all resources owned by the control when it is destroyed</summary>
+    /// <param name="sender">Control that is being destroyed</param>
+    /// <param name="arguments">Not used</param>
+    private void OnDisposed(object sender, EventArgs arguments) {
+      if(this.dotOutlinePen != null) {
+        this.dotOutlinePen.Dispose();
+        this.dotOutlinePen = null;
+      }
+      if(this.dotFillBrush != null) {
+        this.dotFillBrush.Dispose();
+        this.dotFillBrush = null;
+      }
+    }
+
+    /// <summary>Starts the spinner's animation</summary>
+    public void StartSpinner() {
+      this.spinnerRunning = true;
+      this.animationUpdateTimer.Enabled = true;
+    }
+
+    /// <summary>Stops the spinner's animation</summary>
+    public void StopSpinner() {
+      this.animationUpdateTimer.Enabled = false;
+      this.spinnerRunning = false;
+    }
+
+    /// <summary>Color used to fill the dots</summary>
+    public Color DotFillColor {
+      get { return this.dotFillColor; }
+      set {
+        if(value != this.dotFillColor) {
+          this.dotFillColor = value;
+          if(this.dotFillBrush != null) {
+            this.dotFillBrush.Dispose();
+            this.dotFillBrush = null;
+          }
+        }
+      }
+    }
+
+    /// <summary>Color used for the dots' outline</summary>
+    public Color DotOutlineColor {
+      get { return this.dotOutlineColor; }
+      set {
+        if(value != this.dotOutlineColor) {
+          this.dotOutlineColor = value;
+          if(this.dotOutlinePen != null) {
+            this.dotOutlinePen.Dispose();
+            this.dotOutlinePen = null;
+          }
+        }
+      }
+    }
+
+    /// <summary>Called when the control is hidden or shown</summary>
+    /// <param name="arguments">Not used</param>
+    protected override void OnVisibleChanged(EventArgs arguments) {
+      base.OnVisibleChanged(arguments);
+
+      this.animationUpdateTimer.Enabled = this.spinnerRunning && Visible;
+    }
+
+    /// <summary>Called when the control should redraw itself</summary>
+    /// <param name="arguments">Provides access to the drawing surface and tools</param>
+    protected override void OnPaint(PaintEventArgs arguments) {
+      if(Parent != null && this.BackColor == Color.Transparent) {
+        using(var bmp = new Bitmap(Parent.Width, Parent.Height)) {
+          Parent.Controls.Cast<Control>()
+                .Where(c => Parent.Controls.GetChildIndex(c) > Parent.Controls.GetChildIndex(this))
+                .Where(c => c.Bounds.IntersectsWith(this.Bounds))
+                .OrderByDescending(c => Parent.Controls.GetChildIndex(c))
+                .ToList()
+                .ForEach(c => c.DrawToBitmap(bmp, c.Bounds));
+
+          arguments.Graphics.DrawImage(bmp, -Left, -Top);
+        }
+      }
+
+      if(this.dotOutlinePen == null) {
+        this.dotOutlinePen = new Pen(this.dotOutlineColor);
+      }
+      if(this.dotFillBrush == null) {
+        this.dotFillBrush = new SolidBrush(this.dotFillColor);
+      }
+
+      //e.Graphics.SmoothingMode = SmoothingMode.HighQuality;
+
+      int diameter = Math.Min(Width, Height);
+      PointF center = new PointF(diameter / 2.0f, diameter / 2.0f);
+
+      int bigRadius = diameter / 2 - DotRadius - (DotCount - 1) * ScaleFactor;
+
+      float unitAngle = 360 / DotCount;
+
+      for(int index = 0; index < DotCount; ++index) {
+        int dotIndex = (index + leadingDotIndex) % DotCount;
+
+        var dotPosition = new PointF(
+          center.X + (float)(bigRadius * Math.Cos(unitAngle * dotIndex * Math.PI / 180)),
+          center.Y + (float)(bigRadius * Math.Sin(unitAngle * dotIndex * Math.PI / 180))
+        );
+
+        int currentDotRadius = DotRadius + index * ScaleFactor;
+
+        PointF c1 = new PointF(dotPosition.X - currentDotRadius, dotPosition.Y - currentDotRadius);
+        arguments.Graphics.FillEllipse(this.dotFillBrush, c1.X, c1.Y, 2 * currentDotRadius, 2 * currentDotRadius);
+        arguments.Graphics.DrawEllipse(this.dotOutlinePen, c1.X, c1.Y, 2 * currentDotRadius, 2 * currentDotRadius);
+      }
+
+    }
+
+    /// <summary>Called when the animation timer ticks to update the animation state</summary>
+    /// <param name="sender">Animation timer that has ticked</param>
+    /// <param name="arguments">Not used</param>
+    private void animationTimerTicked(object sender, EventArgs arguments) {
+      this.leadingDotIndex = (this.leadingDotIndex + 1) % DotCount; // Advance the animation
+      Invalidate(); // Request a redraw at the earliest opportune time
+    }
+
+    /// <summary>Whether the spinner has been started</summary>
+    private bool spinnerRunning;
+    /// <summary>Color in which the dots will be filled</summary>
+    private Color dotFillColor = Color.RoyalBlue;
+    /// <summary>Color that will be used for the dots' outline</summary>
+    private Color dotOutlineColor = Color.White;
+    /// <summary>Brush used to fill the dots</summary>
+    private Brush dotFillBrush;
+    /// <summary>Brush used for the dots' outline</summary>
+    private Pen dotOutlinePen;
+    /// <summary>Index of the currently leading dot</summary>
+    private int leadingDotIndex = 0;
+
+  }
+
+} // namespace Nuclex.Windows.Forms.Controls