C# 实现渐变透明图片

最新推荐文章于 2025-05-14 11:22:39 发布

原创最新推荐文章于 2025-05-14 11:22:39 发布 · 7.5k 阅读

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#c# #byte #图形 #qq #c

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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

/// <summary>
        /// 设置图形边缘半透明 zgke@sina.com qq:116149
        /// </summary>
        /// <param name="p_Bitmap">图形</param>
        /// <param name="p_CentralTransparent">true中心透明 false边缘透明</param>
        /// <param name="p_Crossdirection">true横 false纵</param>
        /// <returns></returns>
        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;

}