[C#] 濾鏡筆記 – 漣漪效果 | 當麻許的超技八

[C#] 濾鏡筆記 – 漣漪效果

2012-12-04

最近一些需求我要用到漣漪效果，讓文字變得讓機器人看不懂..

就是要歪七扭八，也就是要將圖片給液態化..

其中會用到比較多的數學跟演算方法

整理過上述網站的Code 寫成一隻function 給有需要的人..

/// <summary>

/// 水波紋效果

/// </summary>

/// <param name="src"></param>

/// <param name="nWave">坡度</param>

/// <returns></returns>

public Bitmap AdjustRippleEffect(Bitmap src, short nWave)

    int nWidth = src.Width;

    int nHeight = src.Height;

   // 透過公式進行水波紋的採樣

    FloatPoint[,] fp = new FloatPoint[nWidth, nHeight];

    Point[,] pt = new Point[nWidth, nHeight];

    Point mid = new Point();

    mid.X = nWidth / 2;

    mid.Y = nHeight / 2;

    double newX, newY;

    double xo, yo;

   //先取樣將水波紋座標跟RGB取出

    for (int x = 0; x < nWidth; ++x)

        for (int y = 0; y < nHeight; ++y)

            xo = ((double)nWave * Math.Sin(2.0 * 3.1415 * (float)y / 128.0));

            yo = ((double)nWave * Math.Cos(2.0 * 3.1415 * (float)x / 128.0));

            newX = (x + xo);

            newY = (y + yo);

            if (newX > 0 && newX < nWidth)

                fp[x, y].X = newX;

                pt[x, y].X = (int)newX;

            else

                fp[x, y].X = 0.0;

                pt[x, y].X = 0;

            if (newY > 0 && newY < nHeight)

                fp[x, y].Y = newY;

                pt[x, y].Y = (int)newY;

            else

                fp[x, y].Y = 0.0;

                pt[x, y].Y = 0;

    //進行合成

    Bitmap bSrc = (Bitmap)src.Clone();

    // 依照 Format24bppRgb 每三個表示一 Pixel 0: 藍 1: 綠 2: 紅

    BitmapData bitmapData = src.LockBits(new Rectangle(0, 0, src.Width, src.Height), ImageLockMode.ReadWrite,

                                   PixelFormat.Format24bppRgb);

    BitmapData bmSrc = bSrc.LockBits(new Rectangle(0, 0, bSrc.Width, bSrc.Height), ImageLockMode.ReadWrite,

                                     PixelFormat.Format24bppRgb);

    int scanline = bitmapData.Stride;

    IntPtr Scan0 = bitmapData.Scan0;

    IntPtr SrcScan0 = bmSrc.Scan0;

    unsafe

        byte* p = (byte*)(void*)Scan0;

        byte* pSrc = (byte*)(void*)SrcScan0;

        int nOffset = bitmapData.Stride - src.Width * 3;

        int xOffset, yOffset;

        for (int y = 0; y < nHeight; ++y)

            for (int x = 0; x < nWidth; ++x)

                xOffset = pt[x, y].X;

                yOffset = pt[x, y].Y;

                if (yOffset >= 0 && yOffset < nHeight && xOffset >= 0 && xOffset < nWidth)

                    p[0] = pSrc[(yOffset * scanline) + (xOffset * 3)];

                    p[1] = pSrc[(yOffset * scanline) + (xOffset * 3) + 1];

                    p[2] = pSrc[(yOffset * scanline) + (xOffset * 3) + 2];

                p += 3;

            p += nOffset;

    src.UnlockBits(bitmapData);

    bSrc.UnlockBits(bmSrc);

    return src;

public struct FloatPoint

    public double X;

    public double Y;

原圖:

效果:

Bitmap bmpSrc = new Bitmap(Server.MapPath("sample.png"));

var result = AdjustRippleEffect(bmpSrc, 5);

Bitmap bmpSrc = new Bitmap(Server.MapPath("sample.png"));

var result = AdjustRippleEffect(bmpSrc, 10);