add function codes

src/Shared/HandyControl_Shared/Data/GlowWindow/GlowBitmap.cs

@@ -0,0 +1,113 @@
+using System;
+using System.Runtime.InteropServices;
+using System.Windows.Media;
+using System.Windows.Media.Imaging;
+using HandyControl.Tools.Interop;
+
+namespace HandyControl.Data
+{
+    internal class GlowBitmap : DisposableObject
+    {
+        internal const int GlowBitmapPartCount = 16;
+
+        private const int BytesPerPixelBgra32 = 4;
+
+        private static readonly CachedBitmapInfo[] _transparencyMasks = new CachedBitmapInfo[GlowBitmapPartCount];
+
+        private readonly InteropValues.BITMAPINFO _bitmapInfo;
+
+        private readonly IntPtr _pbits;
+
+        internal GlowBitmap(IntPtr hdcScreen, int width, int height)
+        {
+            _bitmapInfo.biSize = Marshal.SizeOf(typeof(InteropValues.BITMAPINFOHEADER));
+            _bitmapInfo.biPlanes = 1;
+            _bitmapInfo.biBitCount = 32;
+            _bitmapInfo.biCompression = 0;
+            _bitmapInfo.biXPelsPerMeter = 0;
+            _bitmapInfo.biYPelsPerMeter = 0;
+            _bitmapInfo.biWidth = width;
+            _bitmapInfo.biHeight = -height;
+
+            Handle = InteropMethods.CreateDIBSection(
+                hdcScreen,
+                ref _bitmapInfo,
+                0u,
+                out _pbits,
+                IntPtr.Zero,
+                0u);
+        }
+
+        internal IntPtr Handle { get; }
+
+        internal IntPtr DIBits => _pbits;
+
+        internal int Width => _bitmapInfo.biWidth;
+
+        internal int Height => -_bitmapInfo.biHeight;
+
+        protected override void DisposeNativeResources() => InteropMethods.DeleteObject(Handle);
+
+        private static byte PremultiplyAlpha(byte channel, byte alpha) => (byte)(channel * alpha / 255.0);
+
+        internal static GlowBitmap Create(GlowDrawingContext drawingContext, GlowBitmapPart bitmapPart, Color color)
+        {
+            var orCreateAlphaMask =
+                GetOrCreateAlphaMask(bitmapPart);
+
+            var glowBitmap =
+                new GlowBitmap(
+                    drawingContext.ScreenDC,
+                    orCreateAlphaMask.Width,
+                    orCreateAlphaMask.Height);
+
+            for (var i = 0; i < orCreateAlphaMask.DIBits.Length; i += BytesPerPixelBgra32)
+            {
+                var b = orCreateAlphaMask.DIBits[i + 3];
+                var val = PremultiplyAlpha(color.R, b);
+                var val2 = PremultiplyAlpha(color.G, b);
+                var val3 = PremultiplyAlpha(color.B, b);
+                Marshal.WriteByte(glowBitmap.DIBits, i, val3);
+                Marshal.WriteByte(glowBitmap.DIBits, i + 1, val2);
+                Marshal.WriteByte(glowBitmap.DIBits, i + 2, val);
+                Marshal.WriteByte(glowBitmap.DIBits, i + 3, b);
+            }
+
+            return glowBitmap;
+        }
+
+        private static CachedBitmapInfo GetOrCreateAlphaMask(GlowBitmapPart bitmapPart)
+        {
+            if (_transparencyMasks[(int)bitmapPart] == null)
+            {
+                var bitmapImage = new BitmapImage(new Uri($"pack://application:,,,/HandyControl;Component/Resources/Images/GlowWindow/{bitmapPart}.png"));
+
+                var array = new byte[BytesPerPixelBgra32 * bitmapImage.PixelWidth * bitmapImage.PixelHeight];
+                var stride = BytesPerPixelBgra32 * bitmapImage.PixelWidth;
+                bitmapImage.CopyPixels(array, stride, 0);
+
+                _transparencyMasks[(int)bitmapPart] =
+                    new CachedBitmapInfo(
+                        array,
+                        bitmapImage.PixelWidth,
+                        bitmapImage.PixelHeight);
+            }
+
+            return _transparencyMasks[(int)bitmapPart];
+        }
+
+        private sealed class CachedBitmapInfo
+        {
+            internal readonly byte[] DIBits;
+            internal readonly int Height;
+            internal readonly int Width;
+
+            internal CachedBitmapInfo(byte[] diBits, int width, int height)
+            {
+                Width = width;
+                Height = height;
+                DIBits = diBits;
+            }
+        }
+    }
+}