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;