TBitmap.TransparentMode Property

Determines whether the TransparentColor property's value is automatically calculated or stored with the bitmap object.

Pascal

property TransparentMode: TTransparentMode;

C++

__property TTransparentMode TransparentMode;

Description

When TransparentMode is set to tmAuto (the default), the TransparentColor property returns the color of the bottom-leftmost pixel of the bitmap image. When TransparentMode is set to tmFixed, the TransparentColor property refers to the color stored in the bitmap object.

C++ Examples:

Copy Code

/*
An examples of TBitmap Color, TGraphic Transparent, TBitmap
TransparentMode, TBitmap TransparentColor and TCanvas Draw.
*/

#include <memory>       //for STL auto_ptr class

void __fastcall TForm1::Button1Click(TObject *Sender)
{
  std::auto_ptr<Graphics::TBitmap> bitmap(new Graphics::TBitmap);
  try
  {
    bitmap->LoadFromFile("..\\FACTORY.BMP ");
    bitmap->Transparent = true;
    bitmap->TransparentColor = bitmap->Canvas->Pixels[50][50];
    Form1->Canvas->Draw( 0, 0, bitmap.get());
    bitmap->TransparentMode = tmAuto;
    Form1->Canvas->Draw(50, 50, bitmap.get());
  }
  catch (...)
  {
    ShowMessage("Could not load or display bitmap");
  }
}

Delphi Examples:

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procedure TForm1.Button1Click(Sender: TObject);
var
  Bitmap : TBitMap;
begin
  Bitmap := TBitmap.Create;
  try
    with Bitmap do begin
      LoadFromFile('factory.bmp');
      Transparent := True;
      TransParentColor := BitMap.canvas.pixels[50,50];
      Form1.Canvas.Draw(0,0,BitMap);
      TransparentMode := tmAuto;
      Form1.Canvas.Draw(50,50,BitMap);
    end;
  finally
    Bitmap.Free;
  end;
end;