sdk/samples/WPFSamples/StickyNotes/csharp/form.cs

   1 using System;
   2 using System.Drawing;
   3 using System.Drawing.Imaging;
   4 using System.Runtime.InteropServices;
   5 using System.Windows.Forms;
   6
   7 namespace StickyNotes
   8 {
   9         // This only works with Windows 2000/XP
  10         class Splash : Form
  11         {
  12                 public Splash(Bitmap bitmap)
  13                 {
  14                         // Window settings
  15                         this.TopMost = true;
  16                         this.ShowInTaskbar = false;
  17                         this.Size = bitmap.Size;
  18                         this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;
  19                         this.Show();
  20             // Must be called before setting bitmap
  21                         this.SelectBitmap(bitmap);
  22             this.BackColor = Color.Red;
  23             this.Click += new EventHandler(Splash_Click);
  24             this.MouseClick += new MouseEventHandler(Splash_MouseClick);
  25                 }
  26
  27         void Splash_MouseClick(object sender, MouseEventArgs e)
  28         {
  29             this.Close();
  30         }
  31
  32         void Splash_Click(object sender, EventArgs e)
  33         {
  34
  35         }
  36
  37                 // Sets the current bitmap
  38                 public void SelectBitmap(Bitmap bitmap)
  39                 {
  40                         // Does this bitmap contain an alpha channel?
  41                         if (bitmap.PixelFormat != PixelFormat.Format32bppArgb)
  42                         {
  43                                 throw new ApplicationException("The bitmap must be 32bpp with alpha-channel.");
  44                         }
  45
  46                         // Get device contexts
  47                         IntPtr screenDc = APIHelp.GetDC(IntPtr.Zero);
  48                         IntPtr memDc = APIHelp.CreateCompatibleDC(screenDc);
  49                         IntPtr hBitmap = IntPtr.Zero;
  50                         IntPtr hOldBitmap = IntPtr.Zero;
  51
  52                         try
  53                         {
  54                                 // Get handle to the new bitmap and select it into the current device context
  55                                 hBitmap = bitmap.GetHbitmap(Color.FromArgb(0));
  56                                 hOldBitmap = APIHelp.SelectObject(memDc, hBitmap);
  57
  58                                 // Set parameters for layered window update
  59                                 APIHelp.Size newSize = new APIHelp.Size(bitmap.Width, bitmap.Height);   // Size window to match bitmap
  60                                 APIHelp.Point sourceLocation = new APIHelp.Point(0, 0);
  61                                 APIHelp.Point newLocation = new APIHelp.Point(this.Left, this.Top);             // Same as this window
  62                                 APIHelp.BLENDFUNCTION blend = new APIHelp.BLENDFUNCTION();
  63                                 blend.BlendOp             = APIHelp.AC_SRC_OVER;                                                // Only works with a 32bpp bitmap
  64                                 blend.BlendFlags          = 0;                                                                                  // Always 0
  65                                 blend.SourceConstantAlpha = 255;                                                                                // Set to 255 for per-pixel alpha values
  66                                 blend.AlphaFormat         = APIHelp.AC_SRC_ALPHA;                                               // Only works when the bitmap contains an alpha channel
  67
  68                                 // Update the window
  69                                 APIHelp.UpdateLayeredWindow(Handle, screenDc, ref newLocation, ref newSize,
  70                                         memDc, ref sourceLocation, 0, ref blend, APIHelp.ULW_ALPHA);
  71                         }
  72                         finally
  73                         {
  74                                 // Release device context
  75                                 APIHelp.ReleaseDC(IntPtr.Zero, screenDc);
  76                                 if (hBitmap != IntPtr.Zero)
  77                                 {
  78                                         APIHelp.SelectObject(memDc, hOldBitmap);
  79                                         APIHelp.DeleteObject(hBitmap);                                                                          // Remove bitmap resources
  80                                 }
  81                                 APIHelp.DeleteDC(memDc);
  82                         }
  83                 }
  84
  85                 protected override CreateParams CreateParams
  86                 {
  87                         get
  88                         {
  89                                 // Add the layered extended style (WS_EX_LAYERED) to this window
  90                                 CreateParams createParams = base.CreateParams;
  91                                 createParams.ExStyle |= APIHelp.WS_EX_LAYERED;
  92                                 return createParams;
  93                         }
  94                 }
  95
  96                 // Let Windows drag this window for us (thinks its hitting the title bar of the window)
  97                 protected override void WndProc(ref Message message)
  98                 {
  99                         if (message.Msg == APIHelp.WM_NCHITTEST)
 100                         {
 101                                 // Tell Windows that the user is on the title bar (caption)
 102                                 message.Result= (IntPtr)APIHelp.HTCAPTION;
 103                         }
 104                         else
 105                         {
 106                                 base.WndProc(ref message);
 107                         }
 108                 }
 109         }
 110
 111         // Class to assist with Win32 API calls
 112         class APIHelp
 113         {
 114                 // Required constants
 115                 public const Int32      WS_EX_LAYERED   = 0x80000;
 116                 public const Int32      HTCAPTION               = 0x02;
 117                 public const Int32      WM_NCHITTEST    = 0x84;
 118                 public const Int32      ULW_ALPHA               = 0x02;
 119                 public const byte       AC_SRC_OVER             = 0x00;
 120                 public const byte       AC_SRC_ALPHA    = 0x01;
 121
 122                 public enum Bool
 123                 {
 124                         False = 0,
 125                         True = 1
 126                 }
 127
 128                 [StructLayout(LayoutKind.Sequential)]
 129                 public struct Point
 130                 {
 131                         public Int32 x;
 132                         public Int32 y;
 133
 134                         public Point(Int32 x, Int32 y) { this.x = x; this.y = y; }
 135                 }
 136
 137                 [StructLayout(LayoutKind.Sequential)]
 138                 public struct Size
 139                 {
 140                         public Int32 cx;
 141                         public Int32 cy;
 142
 143                         public Size(Int32 cx, Int32 cy) { this.cx = cx; this.cy = cy; }
 144                 }
 145
 146                 [StructLayout(LayoutKind.Sequential, Pack = 1)]
 147                 struct ARGB
 148                 {
 149                         public byte Blue;
 150                         public byte Green;
 151                         public byte Red;
 152                         public byte Alpha;
 153                 }
 154
 155                 [StructLayout(LayoutKind.Sequential, Pack = 1)]
 156                 public struct BLENDFUNCTION
 157                 {
 158                         public byte BlendOp;
 159                         public byte BlendFlags;
 160                         public byte SourceConstantAlpha;
 161                         public byte AlphaFormat;
 162                 }
 163
 164                 [DllImport("user32.dll", ExactSpelling = true, SetLastError = true)]
 165                 public static extern Bool UpdateLayeredWindow(IntPtr hwnd, IntPtr hdcDst, ref Point pptDst, ref Size psize, IntPtr hdcSrc, ref Point pprSrc, Int32 crKey, ref BLENDFUNCTION pblend, Int32 dwFlags);
 166
 167                 [DllImport("gdi32.dll", ExactSpelling = true, SetLastError = true)]
 168                 public static extern IntPtr CreateCompatibleDC(IntPtr hDC);
 169
 170                 [DllImport("user32.dll", ExactSpelling = true, SetLastError = true)]
 171                 public static extern IntPtr GetDC(IntPtr hWnd);
 172
 173                 [DllImport("user32.dll", ExactSpelling = true)]
 174                 public static extern int ReleaseDC(IntPtr hWnd, IntPtr hDC);
 175
 176                 [DllImport("gdi32.dll", ExactSpelling = true, SetLastError = true)]
 177                 public static extern Bool DeleteDC(IntPtr hdc);
 178
 179                 [DllImport("gdi32.dll", ExactSpelling = true)]
 180                 public static extern IntPtr SelectObject(IntPtr hDC, IntPtr hObject);
 181
 182                 [DllImport("gdi32.dll", ExactSpelling = true, SetLastError = true)]
 183                 public static extern Bool DeleteObject(IntPtr hObject);
 184         }
 185 }