***一个奇怪的小问题！！

Question

我在作图像处理，遇到一个奇怪的问题。对图像进行对比度、亮度的调节时，如果设断点，就一只能执行，若不设断点，则只能执行一次。这是为什么呢？？

Answer 1

单步执行时会执行如timer,message等条件触发的事件,看上去程序在永远执行

Answer 2

procedure bmpbright(mybitmap: tbitmap; // 用来处理的BITMAP，要求24BIT
    brightness: integer; // 亮度，范围：0-255
                    contrast: integer; // 对比度，范围：-255-255
                    displayingray: boolean; // 是否显示为灰度，TRUE为灰度
                    reversedisplay: boolean; // 是否显示负片效果，TRUE为负片
                    colorfilter: byte; // 颜色过滤：1=滤赤色，2=荧光色
                    x1,y1,x2,y2: integer); // 处理区域
var
  thew,theh: integer;
  i,j: integer;
  p: pbytearray;
  colorlevel: int64;
  sty,stx,eny,enx: integer;
  bripos,conpos: integer;
  sum1,sum2,sum3: int64;
  ave1,ave2,ave3: integer;
  times: integer;
  rlevel,glevel,blevel: integer;
  maxnum,minnum: integer;
begin
  mybitmap.PixelFormat :=pf24bit;
  conpos:=contrast+100;
  times:=conpos;
  if conpos>100 then times:=conpos*conpos div 100;
  with mybitmap do
  begin
    thew:=width;
    theh:=height;
    if (x1=x2) or (y1=y2) then
    begin
      x1:=1;
      y1:=1;
      x2:=thew-1;
      y2:=theh-1;
    end
    else
    begin
      minnum:=min(y1,y2);
      maxnum:=max(y1,y2);
      y1:=minnum;
      y2:=maxnum;
      minnum:=min(x1,x2);
      maxnum:=max(x1,x2);
      x1:=minnum;
      x2:=maxnum;
    end;
    if x1<1 then x1:=1;
    if y1<1 then y1:=1;
    if x2>thew-1 then x2:=thew-1;
    if y2>theh-1 then y2:=theh-1;
    sum1:=0;
    sum2:=0;
    sum3:=0;
    for i:=y1 to y2 do
    begin
      p:=scanline[i];
      for j:=x1 to x2 do
      begin
        sum1:=sum1+p[j*3+2];
        sum2:=sum2+p[j*3+1];
        sum3:=sum3+p[j*3];
      end;
    end;
    ave1:=sum1 div ((y2-y1+1)*(x2-x1+1));
    ave2:=sum2 div ((y2-y1+1)*(x2-x1+1));
    ave3:=sum3 div ((y2-y1+1)*(x2-x1+1));
    for i:=y1 to y2 do
    begin
      p:=scanline[i];
      for j:=x1 to x2 do
      begin
        colorlevel:=((p[j*3+2]-ave1)*times div 100)+ave1+brightness;
        if colorlevel>255 then colorlevel:=255;
        if colorlevel<0 then colorlevel:=0;
        p[j*3+2]:=colorlevel;
        colorlevel:=((p[j*3+1]-ave2)*times div 100)+ave2+brightness;
        if colorlevel>255 then colorlevel:=255;
        if colorlevel<0 then colorlevel:=0;
        p[j*3+1]:=colorlevel;
        colorlevel:=((p[j*3]-ave3)*times div 100)+ave3+brightness;
        if colorlevel>255 then colorlevel:=255;
        if colorlevel<0 then colorlevel:=0;
        p[j*3]:=colorlevel;
        if colorfilter=1 then
          p[j*3+2]:=0;
        if colorfilter=2 then
        begin
          p[j*3+2]:=0;
          p[j*3]:=0;
        end;
        if displayingray then
        begin
          rlevel:=p[j*3+2];
          glevel:=p[j*3+1];
          blevel:=p[j*3];
          colorlevel:=rlevel*rlevel+glevel*glevel+blevel*blevel;
          colorlevel:=colorlevel div (rlevel+glevel+blevel+1);
          p[j*3]:=colorlevel;
          p[j*3+1]:=colorlevel;
          p[j*3+2]:=colorlevel;
        end;
        if reversedisplay then
        begin
          p[j*3]:=$ff-p[j*3];
          p[j*3+1]:=$ff-p[j*3+1];
          p[j*3+2]:=$ff-p[j*3+2];
        end;
      end;
    end;
  end;
end;
放了一个trackbar
procedure TForm1.TrackBar1Change(Sender: TObject);
begin
  bmpbright(imagej[0].picture.Bitmap,trackbar1.Position,trackbar2.Position,true,true,1,0,0,imagej[0].picture.Bitmap.width,imagej[0].Picture.Bitmap.Height);
end;

Answer 3

你在跟踪时，由于Delphi的IDE和你的应用程序窗口相互切换，会导致不断触发你的程序窗口的重画事件。也就是WM_PAINT消息！