kev/Drawer/UCDraw/SegyReader/BitmapRotation.cs

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Imaging;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Unplugged.Segy
{
    public class BitmapRotation
    {
        #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]</param>
        /// <returns></returns>
        public static Bitmap Rotate(Bitmap b, float 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.Clear(Color.White);
            g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
            g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
            //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

        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;
        }

        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;
        }
    }
}