fix #1768

Move PerPixelAlphaForm's code into QRCodeSplashForm to avoid 2 derived class of Form in same file.

Before: QRCodeSplashForm -> PerPixelAlphaForm -> Form
After: QRCodeSplashForm -> Form

shadowsocks-csharp/View/QRCodeSplashForm.cs

@@ -12,12 +12,13 @@ using System.Diagnostics;
 
 namespace Shadowsocks.View
 {
-    public class QRCodeSplashForm : PerPixelAlphaForm
+    public class QRCodeSplashForm : Form
     {
         public Rectangle TargetRect;
 
         public QRCodeSplashForm()
         {
+            FormBorderStyle = FormBorderStyle.None;
             this.Load += QRCodeSplashForm_Load;
             this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.None;
             this.BackColor = System.Drawing.Color.White;
@@ -69,16 +70,6 @@ namespace Shadowsocks.View
             brush = new SolidBrush(Color.FromArgb(30, Color.Red));
         }
 
-        protected override CreateParams CreateParams
-        {
-            get
-            {
-                CreateParams cp = base.CreateParams;
-                cp.ExStyle |= 0x00080000; // This form has to have the WS_EX_LAYERED extended style
-                return cp;
-            }
-        }
-
         void timer_Tick(object sender, EventArgs e)
         {
             double percent = (double)sw.ElapsedMilliseconds / 1000.0 / (double)ANIMATION_TIME;
@@ -148,6 +139,69 @@ namespace Shadowsocks.View
                 flashStep++;
             }
         }
+
+        // PerPixelAlphaForm.cs
+        // http://www.codeproject.com/Articles/1822/Per-Pixel-Alpha-Blend-in-C
+        // Rui Lopes
+        protected override CreateParams CreateParams
+        {
+            get
+            {
+                CreateParams cp = base.CreateParams;
+                cp.ExStyle |= 0x00080000; // This form has to have the WS_EX_LAYERED extended style
+                return cp;
+            }
+        }
+
+        public void SetBitmap(Bitmap bitmap)
+        {
+            SetBitmap(bitmap, 255);
+        }
+
+        /// <para>Changes the current bitmap with a custom opacity level.  Here is where all happens!</para>
+        public void SetBitmap(Bitmap bitmap, byte opacity)
+        {
+            if (bitmap.PixelFormat != PixelFormat.Format32bppArgb)
+                throw new ApplicationException("The bitmap must be 32ppp with alpha-channel.");
+
+            // The idea of this is very simple,
+            // 1. Create a compatible DC with screen;
+            // 2. Select the bitmap with 32bpp with alpha-channel in the compatible DC;
+            // 3. Call the UpdateLayeredWindow.
+
+            IntPtr screenDc = Win32.GetDC(IntPtr.Zero);
+            IntPtr memDc = Win32.CreateCompatibleDC(screenDc);
+            IntPtr hBitmap = IntPtr.Zero;
+            IntPtr oldBitmap = IntPtr.Zero;
+
+            try
+            {
+                hBitmap = bitmap.GetHbitmap(Color.FromArgb(0));  // grab a GDI handle from this GDI+ bitmap
+                oldBitmap = Win32.SelectObject(memDc, hBitmap);
+
+                Win32.Size size = new Win32.Size(bitmap.Width, bitmap.Height);
+                Win32.Point pointSource = new Win32.Point(0, 0);
+                Win32.Point topPos = new Win32.Point(Left, Top);
+                Win32.BLENDFUNCTION blend = new Win32.BLENDFUNCTION();
+                blend.BlendOp = Win32.AC_SRC_OVER;
+                blend.BlendFlags = 0;
+                blend.SourceConstantAlpha = opacity;
+                blend.AlphaFormat = Win32.AC_SRC_ALPHA;
+
+                Win32.UpdateLayeredWindow(Handle, screenDc, ref topPos, ref size, memDc, ref pointSource, 0, ref blend, Win32.ULW_ALPHA);
+            }
+            finally
+            {
+                Win32.ReleaseDC(IntPtr.Zero, screenDc);
+                if (hBitmap != IntPtr.Zero)
+                {
+                    Win32.SelectObject(memDc, oldBitmap);
+                    //Windows.DeleteObject(hBitmap); // The documentation says that we have to use the Windows.DeleteObject... but since there is no such method I use the normal DeleteObject from Win32 GDI and it's working fine without any resource leak.
+                    Win32.DeleteObject(hBitmap);
+                }
+                Win32.DeleteDC(memDc);
+            }
+        }
     }
 
 
@@ -224,77 +278,4 @@ namespace Shadowsocks.View
         [DllImport("gdi32.dll", ExactSpelling = true, SetLastError = true)]
         public static extern int DeleteObject(IntPtr hObject);
     }
-
-
-    public class PerPixelAlphaForm : Form
-    {
-        // http://www.codeproject.com/Articles/1822/Per-Pixel-Alpha-Blend-in-C
-        // Rui Lopes
-
-        public PerPixelAlphaForm()
-        {
-            // This form should not have a border or else Windows will clip it.
-            FormBorderStyle = FormBorderStyle.None;
-        }
-
-        public void SetBitmap(Bitmap bitmap)
-        {
-            SetBitmap(bitmap, 255);
-        }
-
-        /// <para>Changes the current bitmap with a custom opacity level.  Here is where all happens!</para>
-        public void SetBitmap(Bitmap bitmap, byte opacity)
-        {
-            if (bitmap.PixelFormat != PixelFormat.Format32bppArgb)
-                throw new ApplicationException("The bitmap must be 32ppp with alpha-channel.");
-
-            // The idea of this is very simple,
-            // 1. Create a compatible DC with screen;
-            // 2. Select the bitmap with 32bpp with alpha-channel in the compatible DC;
-            // 3. Call the UpdateLayeredWindow.
-
-            IntPtr screenDc = Win32.GetDC(IntPtr.Zero);
-            IntPtr memDc = Win32.CreateCompatibleDC(screenDc);
-            IntPtr hBitmap = IntPtr.Zero;
-            IntPtr oldBitmap = IntPtr.Zero;
-
-            try
-            {
-                hBitmap = bitmap.GetHbitmap(Color.FromArgb(0));  // grab a GDI handle from this GDI+ bitmap
-                oldBitmap = Win32.SelectObject(memDc, hBitmap);
-
-                Win32.Size size = new Win32.Size(bitmap.Width, bitmap.Height);
-                Win32.Point pointSource = new Win32.Point(0, 0);
-                Win32.Point topPos = new Win32.Point(Left, Top);
-                Win32.BLENDFUNCTION blend = new Win32.BLENDFUNCTION();
-                blend.BlendOp = Win32.AC_SRC_OVER;
-                blend.BlendFlags = 0;
-                blend.SourceConstantAlpha = opacity;
-                blend.AlphaFormat = Win32.AC_SRC_ALPHA;
-
-                Win32.UpdateLayeredWindow(Handle, screenDc, ref topPos, ref size, memDc, ref pointSource, 0, ref blend, Win32.ULW_ALPHA);
-            }
-            finally
-            {
-                Win32.ReleaseDC(IntPtr.Zero, screenDc);
-                if (hBitmap != IntPtr.Zero)
-                {
-                    Win32.SelectObject(memDc, oldBitmap);
-                    //Windows.DeleteObject(hBitmap); // The documentation says that we have to use the Windows.DeleteObject... but since there is no such method I use the normal DeleteObject from Win32 GDI and it's working fine without any resource leak.
-                    Win32.DeleteObject(hBitmap);
-                }
-                Win32.DeleteDC(memDc);
-            }
-        }
-
-        protected override CreateParams CreateParams
-        {
-            get
-            {
-                CreateParams cp = base.CreateParams;
-                cp.ExStyle |= 0x00080000; // This form has to have the WS_EX_LAYERED extended style
-                return cp;
-            }
-        }
-    }
 }