Delphi基本图像处理代码（一）

作者：黑客防线网安网站维护基地来源：黑客防线网安网站维护基地浏览次数：0

本篇关键词：Delphi

[图像的旋转和翻转]

以下代码用ScanLine配合指针移动实现，用于24位色！

//旋转90度
procedure Rotate90(const Bitmap:TBitmap);
var
i,j:Integer;
rowIn,rowOut:pRGBTriple;
Bmp:TBitmap;
Width,Height:Integer;
begin
Bmp:=TBitmap.Create;
Bmp.Width := Bitmap.Height;
Bmp.Height := Bitmap.Width;
Bmp.PixelFormat := pf24bit;
Width:=Bitmap.Width-1;
Height:=Bitmap.Height-1;
for j := 0 to Height do
begin
    rowIn := Bitmap.ScanLine[j];
    for i := 0 to Width do
    begin
      rowOut := Bmp.ScanLine[i];
      Inc(rowOut,Height - j);
      rowOut^ := rowIn^;
      Inc(rowIn);
    end;
end;
Bitmap.Assign(Bmp);
end;

//旋转180度
procedure Rotate180(const Bitmap:TBitmap);
var
i,j:Integer;
rowIn,rowOut:pRGBTriple;
Bmp:TBitmap;
Width,Height:Integer;
begin
Bmp:=TBitmap.Create;
Bmp.Width := Bitmap.Width;
Bmp.Height := Bitmap.Height;
Bmp.PixelFormat := pf24bit;
Width:=Bitmap.Width-1;
Height:=Bitmap.Height-1;
for j := 0 to Height do
begin
    rowIn := Bitmap.ScanLine[j];
    for i := 0 to Width do
    begin
      rowOut := Bmp.ScanLine[Height - j];
      Inc(rowOut,Width - i);
      rowOut^ := rowIn^;
      Inc(rowIn);
    end;
end;
Bitmap.Assign(Bmp);
end;

//旋转270度
procedure Rotate270(const Bitmap:TBitmap);
var
i,j:Integer;
rowIn,rowOut:pRGBTriple;
Bmp:TBitmap;
Width,Height:Integer;
begin
Bmp:=TBitmap.Create;
Bmp.Width := Bitmap.Height;
Bmp.Height := Bitmap.Width;
Bmp.PixelFormat := pf24bit;
Width:=Bitmap.Width-1;
Height:=Bitmap.Height-1;
for j := 0 to Height do
begin
    rowIn := Bitmap.ScanLine[j];
    for i := 0 to Width do
    begin
      rowOut := Bmp.ScanLine[Width - i];
      Inc(rowOut,j);
      rowOut^ := rowIn^;
      Inc(rowIn);
    end;
end;
Bitmap.Assign(Bmp);
end;

任意角度旋转就是将原图上的像素映射到新图上，以下代码为了好理解，并未进行充分优化！但速度上已经比较快了！我的另一篇文章中对优化问题进行了些简单说明，也就是尽量少用浮点运算！

前面为判断部分，如果是90,180,270这类特殊角度，将调用上面的代码，这样效率更高！

//任意角度
function RotateBitmap(Bitmap:TBitmap;Angle:Integer;BackColor:TColor):TBitmap;
var
i,j,iOriginal,jOriginal,CosPoint,SinPoint : integer;
RowOriginal,RowRotated : pRGBTriple;
SinTheta,CosTheta : Extended;
AngleAdd : integer;
begin
Result:=TBitmap.Create;
Result.PixelFormat := pf24bit;
Result.Canvas.Brush.Color:=BackColor;
Angle:=Angle Mod 360;
if Angle<0 then Angle:=360-Abs(Angle);
if Angle=0 then
    Result.Assign(Bitmap)
else if Angle=90 then
begin
    Result.Assign(Bitmap);
    Rotate90(Result);//如果是旋转90度，直接调用上面的代码
end
else if (Angle>90) and (Angle<180) then
begin
    AngleAdd:=90;
    Angle:=Angle-AngleAdd;
end
else if Angle=180 then
begin
    Result.Assign(Bitmap);
    Rotate180(Result);//如果是旋转180度，直接调用上面的过程
end
else if (Angle>180) and (Angle<270) then
begin
    AngleAdd:=180;
    Angle:=Angle-AngleAdd;
end
else if Angle=270 then
begin
    Result.Assign(Bitmap);
    Rotate270(Result);//如果是旋转270度，直接调用上面的过程
end
else if (Angle>270) and (Angle<360) then
begin
    AngleAdd:=270;
    Angle:=Angle-AngleAdd;
end
else
    AngleAdd:=0;
if (Angle>0) and (Angle<90) then
begin
SinCos((Angle + AngleAdd) * Pi / 180, SinTheta, CosTheta);
if (SinTheta * CosTheta) < 0 then
begin
    Result.Width := Round(Abs(Bitmap.Width * CosTheta - Bitmap.Height * SinTheta));
    Result.Height := Round(Abs(Bitmap.Width * SinTheta - Bitmap.Height * CosTheta));
end
else
begin
    Result.Width := Round(Abs(Bitmap.Width * CosTheta + Bitmap.Height * SinTheta));
    Result.Height := Round(Abs(Bitmap.Width * SinTheta + Bitmap.Height * CosTheta));
end;
CosTheta:=Abs(CosTheta);
SinTheta:=Abs(SinTheta);
if (AngleAdd=0) or (AngleAdd=180) then
begin
    CosPoint:=Round(Bitmap.Height*CosTheta);
    SinPoint:=Round(Bitmap.Height*SinTheta);
end
else
begin
    SinPoint:=Round(Bitmap.Width*CosTheta);
    CosPoint:=Round(Bitmap.Width*SinTheta);
end;
for j := 0 to Result.Height-1 do
begin
    RowRotated := Result.Scanline[j];
    for i := 0 to Result.Width-1 do
    begin
      Case AngleAdd of
        0:
        begin
          jOriginal := Round((j+1)*CosTheta-(i+1-SinPoint)*SinTheta)-1;
          iOriginal := Round((i+1)*CosTheta-(CosPoint-j-1)*SinTheta)-1;
        end;
        90:
        begin
          iOriginal := Round((j+1)*SinTheta-(i+1-SinPoint)*CosTheta)-1;
          jOriginal := Bitmap.Height-Round((i+1)*SinTheta-(CosPoint-j-1)*CosTheta);
        end;
        180:
        begin
          jOriginal := Bitmap.Height-Round((j+1)*CosTheta-(i+1-SinPoint)*SinTheta);
          iOriginal := Bitmap.Width-Round((i+1)*CosTheta-(CosPoint-j-1)*SinTheta);
        end;
        270:
        begin
          iOriginal := Bitmap.Width-Round((j+1)*SinTheta-(i+1-SinPoint)*CosTheta);
          jOriginal := Round((i+1)*SinTheta-(CosPoint-j-1)*CosTheta)-1;
        end;
      end;
      if (iOriginal >= 0) and (iOriginal <= Bitmap.Width-1)and
         (jOriginal >= 0) and (jOriginal <= Bitmap.Height-1)
      then
      begin
        RowOriginal := Bitmap.Scanline[jOriginal];
        Inc(RowOriginal,iOriginal);
        RowRotated^ := RowOriginal^;
        Inc(RowRotated);
      end
      else
      begin
        Inc(RowRotated);
      end;
    end;
end;
end;
end;

虽然这已经实现了图像任意角度的旋转，但注意看看上面的代码，都是用Round取整，也就是在原图中找最近的像素填充到新图中，这样在边缘会产生锯齿！如果想效果更好，应该是用四个像素的值运算后得到新像素的值！

如对应到原图的坐标是(6.3,8.6)，用第一种方法可能就用(6,9)填充了该像素，但如果想消除边缘锯齿，就应该用(6,8)、(6,9)、(7,8)、(7,9)运算得出新点的像素，而边缘就用颜色等于背景色的点代替！

感兴趣的朋友可以找些二次线性插值资料看看，或者以后再讨论，这里就不多说了！

后面的浮雕滤镜效果其实就用到了线性插值的思想！

//水平翻转
procedure FlipHorz(const Bitmap:TBitmap);
var
i,j:Integer;
rowIn,rowOut:pRGBTriple;
Bmp:TBitmap;
Width,Height:Integer;
begin
Bmp:=TBitmap.Create;
Bmp.Width := Bitmap.Width;
Bmp.Height := Bitmap.Height;
Bmp.PixelFormat := pf24bit;
Width:=Bitmap.Width-1;
Height:=Bitmap.Height-1;
for j := 0 to Height do
begin
    rowIn := Bitmap.ScanLine[j];
    for i := 0 to Width do
    begin
      rowOut := Bmp.ScanLine[j];
      Inc(rowOut,Width - i);
      rowOut^ := rowIn^;
      Inc(rowIn);
    end;
end;
Bitmap.Assign(Bmp);
end;

//垂直翻转
procedure FlipVert(const Bitmap:TBitmap);
var
i,j:Integer;
rowIn,rowOut:pRGBTriple;
Bmp:TBitmap;
Width,Height:Integer;
begin
Bmp:=TBitmap.Create;
Bmp.Width := Bitmap.Height;
Bmp.Height := Bitmap.Width;
Bmp.PixelFormat := pf24bit;
Width:=Bitmap.Width-1;
Height:=Bitmap.Height-1;
for j := 0 to Height do
begin
    rowIn := Bitmap.ScanLine[j];
    for i := 0 to Width do
    begin
      rowOut := Bmp.ScanLine[Height - j];
      Inc(rowOut,i);
      rowOut^ := rowIn^;
      Inc(rowIn);
    end;
end;
Bitmap.Assign(Bmp);
end;