C# 实现渐变透明图片

C# 实现渐变透明图片 使用方式 Bitmap _Bitmap = (Bitmap)Image.FromFile(@"c:\1.jpg"); pictureBox3.Image = _Bitmap; Bitmap _NewBitmap1 = Zgke.MyImage.Panit.Impression.BothAlpha(_Bitmap, false, false); pictureBox1.SizeMode = PictureBoxSizeMode.AutoSize; pictureBox1.Image = _NewBitmap1; Bitmap _NewBitmap2 = Zgke.MyImage.Panit.Impression.BothAlpha(_Bitmap, false, true); pictureBox2.SizeMode = PictureBoxSizeMode.AutoSize; pictureBox2.Image = _NewBitmap2; 效果图 下面是全部代码 ///

/// 设置图形边缘半透明 zgke@sina.com qq:116149 ///

/// 图形 /// true中心透明 false边缘透明 /// true横 false纵 /// public static Bitmap BothAlpha(Bitmap p_Bitmap, bool p_CentralTransparent, bool p_Crossdirection) { Bitmap _SetBitmap = new Bitmap(p_Bitmap.Width, p_Bitmap.Height); Graphics _GraphisSetBitmap = Graphics.FromImage(_SetBitmap); _GraphisSetBitmap.DrawImage(p_Bitmap, new Rectangle(0, 0, p_Bitmap.Width, p_Bitmap.Height)); _GraphisSetBitmap.Dispose(); Bitmap _Bitmap = new Bitmap(_SetBitmap.Width, _SetBitmap.Height); Graphics _Graphcis = Graphics.FromImage(_Bitmap); Point _Left1 = new Point(0, 0); Point _Left2 = new Point(_Bitmap.Width, 0); Point _Left3 = new Point(_Bitmap.Width, _Bitmap.Height / 2); Point _Left4 = new Point(0, _Bitmap.Height / 2); if (p_Crossdirection) { _Left1 = new Point(0, 0); _Left2 = new Point(_Bitmap.Width / 2, 0); _Left3 = new Point(_Bitmap.Width / 2, _Bitmap.Height); _Left4 = new Point(0, _Bitmap.Height); } Point[] _Point = new Point[] { _Left1, _Left2, _Left3, _Left4 }; PathGradientBrush _SetBruhs = new PathGradientBrush(_Point, WrapMode.TileFlipY); _SetBruhs.CenterPoint = new PointF(0, 0); _SetBruhs.FocusScales = new PointF(_Bitmap.Width / 2, 0); _SetBruhs.CenterColor = Color.FromArgb(0, 255, 255, 255); _SetBruhs.SurroundColors = new Color[] { Color.FromArgb(255, 255, 255, 255) }; if (p_Crossdirection) { _SetBruhs.FocusScales = new PointF(0, _Bitmap.Height); _SetBruhs.WrapMode = WrapMode.TileFlipX; } if (p_CentralTransparent) { _SetBruhs.CenterColor = Color.FromArgb(255, 255, 255, 255); _SetBruhs.SurroundColors = new Color[] { Color.FromArgb(0, 255, 255, 255) }; } _Graphcis.FillRectangle(_SetBruhs, new Rectangle(0, 0, _Bitmap.Width, _Bitmap.Height)); _Graphcis.Dispose(); BitmapData _NewData = _Bitmap.LockBits(new Rectangle(0, 0, _Bitmap.Width, _Bitmap.Height), ImageLockMode.ReadOnly, _Bitmap.PixelFormat); byte[] _NewBytes = new byte[_NewData.Stride * _NewData.Height]; Marshal.Copy(_NewData.Scan0, _NewBytes, 0, _NewBytes.Length); _Bitmap.UnlockBits(_NewData); BitmapData _SetData = _SetBitmap.LockBits(new Rectangle(0, 0, _SetBitmap.Width, _SetBitmap.Height), ImageLockMode.ReadWrite, _SetBitmap.PixelFormat); byte[] _SetBytes = new byte[_SetData.Stride * _SetData.Height]; Marshal.Copy(_SetData.Scan0, _SetBytes, 0, _SetBytes.Length); int _WriteIndex = 0; for (int i = 0; i != _SetData.Height; i++) { _WriteIndex = i * _SetData.Stride + 3; for (int z = 0; z != _SetData.Width; z++) { _SetBytes[_WriteIndex] = _NewBytes[_WriteIndex]; _WriteIndex += 4; } } Marshal.Copy(_SetBytes, 0, _SetData.Scan0, _SetBytes.Length); _SetBitmap.UnlockBits(_SetData); return _SetBitmap; }