ugraphicutil.~pas

简要介绍： 提供强大的图像处理功能

//****************************************************
//功能描述：图像处理函数
//创建日期: 2006-8-25
//author:  Qinc
//****************************************************
unit UGraphicUtil;

interface
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls,
  jpeg, ExtCtrls, StdCtrls,Math,Forms;


type
  TGraphicUtil = class
  private
  public
    class procedure Rotate(Srcbmp, DestBmp: Tbitmap; angle: extended);
    class procedure Zoom(Srcbmp, DestBmp: Tbitmap; zoomScale: extended);
    class procedure Rotate90(Srcbmp, DestBmp: Tbitmap);
    class procedure Rotate180(Srcbmp, DestBmp: Tbitmap);
    class procedure Rotate270(Srcbmp, DestBmp: Tbitmap);
    class function BmpToJpeg(bmp:TBitmap;scale:TJPEGQualityRange):TJPEGImage;
    class function JPGToBmp(jpg:TJPEGImage):TBitmap;
  end;

implementation

{ TGraphicUtil }

//***********************************************************
//功能：任意角度旋转
//参数：Srcbmp：源位图 DestBmp:目标位图 ；angle旋转角度
//返回值：无
class procedure TGraphicUtil.Rotate(Srcbmp, DestBmp: 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
  if SrcBmp.Width > SrcBmp.Height then
  begin
    DestBmp.width := SrcBmp.Width;
    DestBmp.height := SrcBmp.Width;
  end
  else
    DestBmp.Width := SrcBmp.Height;
  DestBmp.Height := SrcBmp.Height;
  //将角度转换为PI值
  angle := (angle / 180) * pi;
  // 计算中心点，你可以修改它
  c1x := SrcBmp.width div 2;
  c1y := SrcBmp.height div 2;
  c2x := DestBmp.width div 2;
  c2y := DestBmp.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 := SrcBmp.canvas.pixels[c1x + p1x, c1y + p1y];
      c1 := SrcBmp.canvas.pixels[c1x - p1x, c1y - p1y];
      c2 := SrcBmp.canvas.pixels[c1x + p1y, c1y - p1x];
      c3 := SrcBmp.canvas.pixels[c1x - p1y, c1y + p1x];

      DestBmp.Canvas.pixels[c2x + p2x, c2y + p2y] := c0;
      DestBmp.canvas.pixels[c2x - p2x, c2y - p2y] := c1;
      DestBmp.canvas.pixels[c2x + p2y, c2y - p2x] := c2;
      DestBmp.canvas.pixels[c2x - p2y, c2y + p2x] := c3;
    end;
    application.processmessages
  end;

end;
//***********************************************************

//***********************************************************
//功能：缩放位图
//参数：Srcbmp：源位图 DestBmp:目标位图 ；zoomScale缩放比例
//返回值：无
class procedure TGraphicUtil.Zoom(Srcbmp, DestBmp: Tbitmap;
  zoomScale: extended);
begin
  DestBmp.Width := Trunc(zoomScale * Srcbmp.Width);
  DestBmp.Height := Trunc(zoomScale * Srcbmp.Height);
  SetStretchBltMode(DestBmp.Canvas.Handle,HALFTONE);
  StretchBlt(DestBmp.Canvas.Handle,0,0,DestBmp.Width,DestBmp.Height,
              Srcbmp.Canvas.Handle,0,0,Srcbmp.Width,Srcbmp.Height,SRCCOPY);
  DestBmp.PixelFormat := pf24bit;
end;
//***********************************************************


class procedure TGraphicUtil.Rotate180(Srcbmp, DestBmp: Tbitmap);
begin

end;

class procedure TGraphicUtil.Rotate270(Srcbmp, DestBmp: Tbitmap);
begin

end;

class procedure TGraphicUtil.Rotate90(Srcbmp, DestBmp: Tbitmap);
begin

end;


//***********************************************************
//功能：bmp转换为JPG
//参数：
//返回值：无
class function TGraphicUtil.BmpToJpeg(bmp:TBitmap;scale:TJPEGQualityRange):TJPEGImage;
begin
  Result  := nil;
  if Assigned(bmp) then
  begin
    Result := TJPEGImage.Create;
    Result.Assign(bmp);
    Result.PixelFormat := jf24Bit;
    Result.CompressionQuality := scale;
    Result.JPEGNeeded;
    Result.Compress;
  end;
end;
//***********************************************************



//***********************************************************
//功能：Jpg转换为bmp
//参数：
//返回值：无
class function TGraphicUtil.JPGToBmp(jpg: TJPEGImage): TBitmap;
begin
  Result := nil;
  if Assigned(Jpg) then
  begin
    Result := TBitmap.Create;
    jpg.DIBNeeded;
    Result.Assign(jpg); 
  end;
end;
//***********************************************************




end.