使图片任意转动的编程例子

unit unitImage; 
 
interface 
 
uses 
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs, 
  StdCtrls, ExtCtrls, math; 
 
type 
  TForm1 = class(TForm) 
    Image1: TImage; 
    Image2: TImage; 
    Image3: TImage; 
    Button2: TButton; 
    Button3: TButton; 
    Button4: TButton; 
    Image4: TImage; 
    Button1: TButton; 
    procedure Button2Click(Sender: TObject); 
    procedure Button3Click(Sender: TObject); 
    procedure Button4Click(Sender: TObject); 
  private 
    { Private declarations } 
    procedure bmp_rotate(src, dst: tbitmap; angle: extended); 
  public 
    { Public declarations } 
  end; 
 
var 
  Form1: TForm1; 
 
implementation 
 
{$R *.DFM} 
 
{ TForm1 } 
 
procedure TForm1.bmp_rotate(src, dst: tbitmap; angle: extended); 
var 
  c1x, c1y, c2x, c2y: integer; 
  p1x, p1y, p2x, p2y: integer; 
  radius, n: integer; 
  alpha: extended; 
  c0, c1, c2, c3: tcolor; 
begin 
  //将角度转换为PI值 
  angle := (angle / 180) * pi; 
  // 计算中心点，你可以修改它 
  c1x := src.width div 2; 
  c1y := src.height div 2; 
  c2x := dst.width div 2; 
  c2y := dst.height div 2; 
 
  // 步骤数值number 
  if c2x < c2y then 
    n := c2y 
  else 
    n := c2x; 
  dec(n, 1); 
 
  // 开始旋转 
  for p2x := 0 to n do begin 
      for p2y := 0 to n do begin 
          if p2x = 0 then 
            alpha := pi / 2 
          else 
            alpha := arctan2(p2y, p2x); 
          radius := round(sqrt((p2x * p2x) + (p2y * p2y))); 
          p1x := round(radius * cos(angle + alpha)); 
          p1y := round(radius * sin(angle + alpha)); 
 
          c0 := src.canvas.pixels[c1x + p1x, c1y + p1y]; 
          c1 := src.canvas.pixels[c1x - p1x, c1y - p1y]; 
          c2 := src.canvas.pixels[c1x + p1y, c1y - p1x]; 
          c3 := src.canvas.pixels[c1x - p1y, c1y + p1x]; 
 
          dst.canvas.pixels[c2x + p2x, c2y + p2y] := c0; 
          dst.canvas.pixels[c2x - p2x, c2y - p2y] := c1; 
          dst.canvas.pixels[c2x + p2y, c2y - p2x] := c2; 
          dst.canvas.pixels[c2x - p2y, c2y + p2x] := c3; 
        end; 
      application.processmessages 
    end; 
end; 
 
 
procedure TForm1.Button2Click(Sender: TObject); 
var 
  i, j: integer; 
begin 
  //确定旋转后位图的大小 
  image2.Picture.Bitmap.Height := image1.picture.width; 
  image2.Picture.Bitmap.Width := image1.picture.height; 
  for i := 0 to image1.Height do 
    for j := 0 to image1.Width do 
      image2.canvas.Pixels[(-i + image1.Height), 
        j] := image1.canvas.Pixels[j, i]; 
end; 
 
 
procedure TForm1.Button3Click(Sender: TObject); 
var 
  i, j: integer; 
begin 
  //确定旋转后位图的大小 
  image3.Picture.Bitmap.Height := image1.picture.Height; 
  image3.Picture.Bitmap.Width := image1.picture.Width; 
  for i := 0 to image1.Height do 
    for j := 0 to image1.Width do 
      image3.canvas.Pixels[(image1.Width 
        - j), (image1.Height - i)] := image1.canvas.Pixels[j, i]; 
end; 
 
 
procedure TForm1.Button4Click(Sender: TObject); 
var 
  i, j: integer; 
begin 
  //确定旋转后位图的大小 
  image4.Picture.Bitmap.Height := image1.picture.Width; 
  image4.Picture.Bitmap.Width := image1.picture.Height; 
  for i := 0 to image1.Height do 
    for j := 0 to image1.Width do 
      image4.canvas.Pixels[i, (image1.Width-j)] := image1.canvas.Pixels[j, i]; 
end; 
 
 
 
end.