Displaying a Full View Bitmap Image in a VCL Forms Application

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Go Up to How To Build a VCL Forms Application with Graphics

This procedure loads a bitmap image from a file and displays it in its entirety to a VCL form. The procedure uses the Height and Width properties of the Bitmap object to display a full view of the image.

  1. Create a VCL form with a button control.
  2. Provide a bitmap image.
  3. Code the button's onClick event handler to load and display a bitmap image.
  4. Build and run the application.

To create a VCL form and button

  1. Choose File > New > Other > Delphi Projects or C++Builder Projects and double-click the VCL Forms Application icon.The VCL Forms Designer is displayed.
  2. From the Standard page of the Tool Palette, place a button component on the form.
  3. In the Object Inspector, enter Full View for the Caption property and FullView for the name property.

To provide a bitmap image

  1. Create a directory in which to store your project files.
  2. Locate a bitmap image on your local drive, and copy it to your project directory.
  3. Save all files in your project to your project directory.

To write the OnClick event handler

  1. In the Object Inspector, double-click the Button1 OnClick event on the Events tab. The Code Editor displays with the cursor in the TForm1.FullViewClick (Delphi) or TForm1::FullViewClick (C++) event handler block.
  2. Enter the following event handling code, replacing MyFile.bmp with the name of the bitmap image in your project directory:
      Bitmap := TBitmap.Create;
        Form1.Canvas.Brush.Bitmap := Bitmap;
        Form1.Canvas.Brush.Bitmap := nil;
Graphics::TBitmap Bitmap = new Graphics::TBitmap();
try {
  Bitmap->LoadFromFile( "..\\MyFile.bmp" );
  Form1->Canvas->Brush->Bitmap = Bitmap;
    Rect( 0, 0, Bitmap->Width, Bitmap->Height ) );
} __finally {
  Form1->Canvas->Brush->Bitmap = NULL;

Note: For C++ projects, the code assumes the target output directory is located in the project directory.

  1. For Delphi, add the following variable declaration in the var block:
Bitmap : TBitmap;

To run the program

  1. Choose Run > Run .
  2. Click the button to display the image bitmap in a rectangle in the upper left corner of the form.

See Also