RGB to Gray Scale Conversion Using Delphi

We can code an RGB to Gray scale conversion directly in the main unit of our color inversion project. It is easy, as easy as our color inversion project.

1. Open our previous color inversion project.
2. Double click the main menu component, and add a menu item 'Convert to Gray Scale' under Image menu (see figure 1).
3. Double click on the menu item, and you'll be directed to the event handler, edit as shown below:
   

   
   procedure TMainForm.ConverttoGrayScale1Click(Sender: TObject);
   var
   i,j:integer;
   ptr:PByteArray;
   begin
   try
    ImageForm:=TImageForm(ActiveMDIChild);
    for i:=0 to (ImageForm.Image1.Height-1) do
    begin
      ptr:=ImageForm.Image1.Picture.Bitmap.ScanLine[i];
      for j:=0 to (ImageForm.Image1.Width-1) do
      begin
        if ImageForm.Image1.Picture.Bitmap.PixelFormat
          =pf24bit then
        begin
          ptr[3*j]:=round(0.114* ptr[3*j]
            +0.587*ptr[3*j+1] + 0.299*ptr[3*j+2]);
          ptr[3*j+1]:=ptr[3*j];
          ptr[3*j+2]:=ptr[3*j];
        end;
      end;
      ImageForm.Image1.Refresh;
    end;
    except
      ShowMessage('Cannot complete the operation');
    end
   end;

4. Save all files, and now you can compile/run the project. The execution looks like shown in figure 2.
   

Figure 1. RGB to Gray Scale Conversion Menu

Figure 2. RGB to Gray Scale Conversion

Source Code Download
You can download the Delphi 7 source code here, and the Turbo Delphi Explorer source code here.