大侠帮忙看看，为什么不行？？在线等

Question

我的意图是 将image1图像的奇数行的偶数点 复制到image2看看这段代码，为什么不行？
提议 可先屏蔽“if i mod 2=1 then”和“if j mod 2=0 then”
procedure TForm1.Button1Click(Sender: TObject);
var
bmp:Tbitmap;
pArray:PByteArray;
i,j,RGBvalue:integer;
Rvalue,Gvalue,Bvalue:Byte;
begin
    bmp:=Tbitmap.Create;
    bmp.Width:=image1.Width;
    bmp.Height:=image1.Height;
    for i:=0 to image1.Height-1 do
        if i mod 2=1 then
        begin
            pArray:=image1.Picture.Bitmap.ScanLine[i];
            for j:=0 to image1.Width-1 do
                if j mod 2=0 then
                begin
                    RGBvalue:=pArray[j];
                    Rvalue:=GetRvalue(RGBvalue);
                    Gvalue:=GetGvalue(RGBvalue);
                    Bvalue:=GetBvalue(RGBvalue);
                    bmp.Canvas.Pixels[j,i]:=RGB(Rvalue,Gvalue,Bvalue);
                end;
        end;    image2.Picture.Bitmap.Assign(bmp);
end;

Answer 1

为什么用rgb转换？
procedure TForm1.Button1Click(Sender: TObject);
var
  bmp:Tbitmap;
  i,j:integer;
begin
    bmp:=Tbitmap.Create;
    bmp.Width:=image1.Width;
    bmp.Height:=image1.Height;
    for i:=0 to image1.Height-1 do
      if i mod 2=1 then begin
          for j:=0 to image1.Width-1 do
              if j mod 2=0 then
                  bmp.Canvas.Pixels[j,i]:=Image1.Canvas.Pixels[j,i];
      end;
    image2.Picture.Bitmap.Assign(bmp);
end;