UI(17)——使用GDI+實作圖像旋轉的2種簡單方法

方法一：旋轉畫圖區，以90度旋轉為例

private void btnRotate90_Click(object sender, EventArgs e)
        {
            Graphics gs = pictureBox1.CreateGraphics();
            string strFile = @"E:\p.jpg";
            Bitmap bmp = new Bitmap(strFile);
            gs.FillRectangle(Brushes.White, pictureBox1.ClientRectangle);
            Point[] destinationPoints = { new Point(ClientRectangle.Width, 0), new Point(ClientRectangle.Width, ClientRectangle.Height), new Point(0, 0) };
            gs.DrawImage(bmp, destinationPoints);
        }
           

方法二：旋轉圖像自身，以90度旋轉為例

private void btnRotate90_Click(object sender, EventArgs e)
        {
            Graphics gs = pictureBox1.CreateGraphics();
            string strFile = @"E:\p.jpg";
            Image img = Image.FromFile(strFile);
            img.RotateFlip(RotateFlipType.Rotate90FlipNone);
            gs.DrawImage(img, pictureBox1.ClientRectangle);

        }