winform图片旋转

01.//可以实现任意角度的旋转，旋转出现的角落空白可以选择填充的颜色。

02. 

03. 

04.using System;

05. 

06.using System.Drawing;

07.using System.Drawing.Drawing2D;

08.using System.Drawing.Imaging;

09.using System.Text;

10.using System.Windows.Forms;

11. 

12.namespace bitmaprerote

13.{

14.public partial class Form1 : Form

15.{

16.public Form1()

17.{

18.InitializeComponent();

19.}

20.public static Bitmap KiRotate(Bitmap bmp, float angle, Color bkColor)

21.{

22.int w = bmp.Width + 2;

23.int h = bmp.Height + 2;

24. 

25.PixelFormat pf;

26. 

27.if (bkColor == Color.Transparent)

28.{

29.pf = PixelFormat.Format32bppArgb;

30.}

31.else

32.{

33.pf = bmp.PixelFormat;

34.}

35. 

36.Bitmap tmp = new Bitmap(w, h, pf);

37.Graphics g = Graphics.FromImage(tmp);

38.g.Clear(bkColor);

39.g.DrawImageUnscaled(bmp, 1, 1);

40.g.Dispose();

41. 

42.GraphicsPath path = new GraphicsPath();

43.path.AddRectangle(new RectangleF(0f, 0f, w, h));

44.Matrix mtrx = new Matrix();

45.mtrx.Rotate(angle);

46.RectangleF rct = path.GetBounds(mtrx);

47. 

48.Bitmap dst = new Bitmap((int)rct.Width, (int)rct.Height, pf);

49.g = Graphics.FromImage(dst);

50.g.Clear(bkColor);

51.g.TranslateTransform(-rct.X, -rct.Y);

52.g.RotateTransform(angle);

53.g.InterpolationMode = InterpolationMode.HighQualityBilinear;

54.g.DrawImageUnscaled(tmp, 0, 0);

55.g.Dispose();

56.tmp.Dispose();

57.return dst;

58.}

59.private void button2_Click(object sender, EventArgs e)

60.{

61.Bitmap map = new Bitmap("F:\\hj.jpg");

62.this.pictureBox1.SizeMode = PictureBoxSizeMode.StretchImage;

63.map = KiRotate(map, 30, Color.Pink);

64.pictureBox1.Image = map;

65.}

66.}

67.}