C# 图像旋转代码

方法一：

public static Bitmap rotateImage(Bitmap b, float angle)

{

    //create a new empty bitmap to hold rotated image

    Bitmap returnBitmap = new Bitmap(b.Width, b.Height);

    //make a graphics object from the empty bitmap

    Graphics g = Graphics.FromImage(returnBitmap);

    g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.NearestNeighbor;

    //move rotation point to center of image

    g.TranslateTransform((float)b.Width / 2, (float)b.Height / 2);

    //rotate

    g.RotateTransform(angle);

    //move image back

    g.TranslateTransform(-(float)b.Width / 2, -(float)b.Height / 2);

    //draw passed in image onto graphics object

    g.DrawImage(b, new Point(0, 0));

    return returnBitmap;

}

方法二：

public static Bitmap RotateImage(Bitmap image, float rotateAtX, float rotateAtY, float angle, bool bNoClip)

{

    int W, H, X, Y;

    if (bNoClip)

    {

        double dW = (double)image.Width;

        double dH = (double)image.Height;

        double degrees = Math.Abs(angle);

        if (degrees <= 90)

        {

            double radians = 0.0174532925 * degrees;

            double dSin = Math.Sin(radians);

            double dCos = Math.Cos(radians);

            W = (int)(dH * dSin + dW * dCos);

            H = (int)(dW * dSin + dH * dCos);

            X = (W - image.Width) / 2;

            Y = (H - image.Height) / 2;

        }

        else

        {

            degrees -= 90;

            double radians = 0.0174532925 * degrees;

            double dSin = Math.Sin(radians);

            double dCos = Math.Cos(radians);

            W = (int)(dW * dSin + dH * dCos);

            H = (int)(dH * dSin + dW * dCos);

            X = (W - image.Width) / 2;

            Y = (H - image.Height) / 2;

        }

    }

    else

    {

        W = image.Width;

        H = image.Height;

        X = 0;

        Y = 0;

    }

    //create a new empty bitmap to hold rotated image

    Bitmap bmpRet = new Bitmap(W, H);

    bmpRet.SetResolution(image.HorizontalResolution, image.VerticalResolution);

    //make a graphics object from the empty bitmap

    Graphics g = Graphics.FromImage(bmpRet);

    //Put the rotation point in the "center" of the image

    g.TranslateTransform(rotateAtX + X, rotateAtY + Y);

    //rotate the image

    g.RotateTransform(angle);

    //move the image back

    g.TranslateTransform(-rotateAtX - X, -rotateAtY - Y);

    //draw passed in image onto graphics object

    g.DrawImage(image, new PointF(0 + X, 0 + Y));

    return bmpRet;

}

方法三：

#region 图片旋转函数

        /// <summary>

        /// 以逆时针为方向对图像进行旋转

        /// </summary>

        /// <param name="b">位图流</param>

        /// <param name="angle">旋转角度[0,360](前台给的)</param>

        /// <returns></returns>

        public static Bitmap Rotate(Bitmap b, int angle)

        {

            angle = angle % 360;

            //弧度转换

            double radian = angle * Math.PI / 180.0;

            double cos = Math.Cos(radian);

            double sin = Math.Sin(radian);

            //原图的宽和高

            int w = b.Width;

            int h = b.Height;

            int W = (int)(Math.Max(Math.Abs(w * cos - h * sin), Math.Abs(w * cos + h * sin)));

            int H = (int)(Math.Max(Math.Abs(w * sin - h * cos), Math.Abs(w * sin + h * cos)));

            //目标位图

            Bitmap dsImage = new Bitmap(W, H);

            System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(dsImage);

            g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.Bilinear;

            g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

            //计算偏移量

            Point Offset = new Point((W - w) / 2, (H - h) / 2);

            //构造图像显示区域：让图像的中心与窗口的中心点一致

            Rectangle rect = new Rectangle(Offset.X, Offset.Y, w, h);

            Point center = new Point(rect.X + rect.Width / 2, rect.Y + rect.Height / 2);

            g.TranslateTransform(center.X, center.Y);

            g.RotateTransform(360 - angle);

            //恢复图像在水平和垂直方向的平移

            g.TranslateTransform(-center.X, -center.Y);

            g.DrawImage(b, rect);

            //重至绘图的所有变换

            g.ResetTransform();

            g.Save();

            g.Dispose();

            //dsImage.Save("yuancd.jpg", System.Drawing.Imaging.ImageFormat.Jpeg);

            return dsImage;

        }

        #endregion 图片旋转函数

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C# 图像旋转代码

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