本文以实例讲述了Delphi实现图像文本旋转特效的解决方法，在本程序中利用的控件主要是Panel 控件、Image 控件、Edit 控件、Label 控件和Button 控件。本程序的关键是利用Delphi 的bmp_rotate()函数来实现旋转图像的功能。并巧妙地调用相关Windows API 函数来实现对文本的旋转特效。
完整的实例代码如下：
unit Unit1;
interfaceusesWindows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,math,StdCtrls, ExtCtrls;
typeTForm1 = class(TForm)Edit1: TEdit;
Image1: TImage;
bmprotate: TButton;
Label1: TLabel;
Panel1: TPanel;
Image2: TImage;
Panel2: TPanel;
Image3: TImage;
Edit2: TEdit;
RotatedText: TButton;
Label2: TLabel;
procedure bmprotateClick(Sender: TObject);
procedure RotatedTextClick(Sender: TObject);
procedure FormCreate(Sender: TObject);
private{
Private declarations }
public{
Public declarations }
procedure bmp_rotate(src,dst:Tbitmap;
angle:extended);
Procedure DrawRotatedText(TheCanvas : TCanvas;
TheAngle : Integer;
TheText : String);
end;
varForm1: TForm1;
implementation{
$R *.DFM}
procedure TForm1.bmp_rotate(src,dst:Tbitmap;
angle:extended);
//图像旋转varc1x,c1y,c2x,c2y:integer;
p1x,p1y,p2x,p2y:integer;
radius,n:integer;
alpha:extended;
c0,c1,c2,c3:tcolor;
beginangle := (angle / 180) * pi;
//将文本框内的内容转换角度c1x := src.Width div 2;
c1y := src.Height div 2;
c2x := dst.Width div 2;
c2y := dst.Height div 2;
if c2x < c2y thenn := c2yelsen := c2x;
dec (n,1);
//使n 值减少1,n:=n-1for p2x := 0 to n do beginfor p2y := 0 to n do beginif p2x = 0 thenalpha:= pi/2elsealpha := arctan2(p2y,p2x);
radius := round(sqrt((p2x*p2x)+(p2y*p2y)));
//设置旋转时的半径大小p1x := round(radius * cos(angle+alpha));
//设置旋转时的圆心横坐标p1y := round(radius * sin(angle+alpha));
//设置旋转时的圆心纵坐标c0 := src.Canvas.pixels[c1x+p1x,c1y+p1y];
//替换图像相关坐标处的像素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;
//置换不同位置的像素点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 //响应其他的消息请求end;
end;
procedure TForm1.bmprotateClick(Sender: TObject);
VarRAngle : Extended;
beginRAngle := StrToFloat(Edit1.Text);
//设置旋转的角度bmp_rotate(Image1.Picture.bitmap,Image2.Picture.bitmap, RAngle);
//运行旋转函数，旋转图形end;
Procedure TForm1.DrawRotatedText(TheCanvas : TCanvas;
TheAngle : Integer;
TheText : String);
varlf : TLogFont;
tf : TFont;
beginImage3.Canvas.refresh;
with TheCanvas do beginFont.Name:='Arial';
Font.Size:=18;
Brush.Style:= bsClear;
tf:= TFont.Create;
trytf.Assign(Font);
GetObject(tf.Handle, Sizeof(lf), @lf);
//将当前实例句柄赋给tf 这个Font 对象lf.lfEscapement:=TheAngle*10;
lf.lfOrientation := TheAngle * 10;
//使输入时的横坐标线与水平线呈所指定的角度tf.Handle := CreateFontIndirect(lf);
//创建一个Font 具体对象Font.Assign(tf);
//使这个对象运用到程序中finallytf.Free;
//释放对象end;
TextOut(Image3.left, Image3.top+20 , TheText);
//绘制文本到指定区域end;
end;
procedure TForm1.RotatedTextClick(Sender: TObject);
VarTheAngle : Integer;
beginTheAngle := StrToInt(Edit2.Text);
//将文本框中的文本转换角度DrawRotatedText(Image3.Canvas, TheAngle, 'Delphi图形工作室');
//调用旋转文本函数end;
procedure TForm1.FormCreate(Sender: TObject);
vartf : TFont;
theText:string;
begintheText:='Delphi图形工作室';
//设置文本with Image3.Canvas dobeginFont.Name := 'Arial';
//设置字体Font.Size := 18;
//设置字体大小Brush.Style := bsClear;
//设置笔刷样式tf:= TFont.Create;
//创建一个Font 具体对象TextOut(Image3.left, Image3.top+20 , TheText);
//绘制文本到指定区域end;
end;
end.
