/*
This example creates a region and selects this region as the
clipping rectangle for the Image component's canvas. It then
sets the canvas's brush color to red and calls FillRect 
using the ClipRect as the area to fill. Lastly, the ClipRect
is reset to the original value that it contained by calling
SelectClipRect with nil as the second parameter and deletes
the region.  Place a TImage object in the form.
*/
void __fastcall TForm1::Button1Click(TObject *Sender)
{
    HRGN MyRgn;

    MyRgn = ::CreateRectRgn(100,100,200,200);
    ::SelectClipRgn(Image1->Canvas->Handle,MyRgn);
    Image1->Canvas->Brush->Color = clRed;
    Image1->Canvas->FillRect(Image1->Canvas->ClipRect);
    Image1->Invalidate();
    ::SelectClipRgn(Image1->Canvas->Handle,NULL);
    ::DeleteObject(MyRgn);
}

/*
This example converts a specified icon to a bitmap. To run 
this example, add an image, a button, and an Open dialog to 
a form. Name the button ConvertIcon2Bitmap, and add the 
following code as its OnClick event handler.
*/

#include <memory>       //for STL auto_ptr class

void __fastcall TForm1::ConvertIcon2BitmapClick(TObject *Sender)
{
  OpenDialog1->DefaultExt = ".ICO";
  OpenDialog1->Filter = "icons (*.ico)|*.ICO";
  OpenDialog1->Options << ofOverwritePrompt << ofFileMustExist << ofHideReadOnly;
  if (OpenDialog1->Execute())
  {
    std::auto_ptr<TIcon> pi(new Graphics::TIcon);
    AnsiString as;
    pi->LoadFromFile(OpenDialog1->FileName);
    as = ChangeFileExt(OpenDialog1->FileName,".BMP");
    Image1->Width = pi->Width;
    Image1->Height = pi->Height;
    Image1->Canvas->Draw(0, 0, pi.get());
    Image1->Picture->SaveToFile(as);
    ShowMessage(OpenDialog1->FileName + " Saved to " + as);
  }
}

/*
The following code uses ClientRect to find and draw a line
from the top left to the bottom right of the current
control.  Select a TControl in the ListBox list.  This
example assumes that the current object is a descendent of
TControl and has a public Canvas property.
*/
{
  TPoint APoint = Point(X, Y);
  int Index = ListBox1->ItemAtPos(APoint, True);
  TImage *myImage;
  TClass ClassRef = ListBox1->Items->Objects[Index]->ClassType();
  if (String(ClassRef->ClassName()) == "TImage")
  {
    myImage = dynamic_cast<TImage *>(ListBox1->Items->Objects[Index]);
    // make sure we are using the TControls canvas and not the from's!
    myImage->Canvas->MoveTo(myImage->ClientRect.Left, myImage->ClientRect.Top);
    myImage->Canvas->LineTo(myImage->ClientRect.Right, myImage->ClientRect.Bottom);
    myImage = NULL;
  }
}

/*
The following example paints a cross-hatched ellipse onto 
Image1 which is a TImage on the form when the user clicks on
Button1.
*/
void __fastcall TForm1::Button1Click(TObject *Sender)
{
  TCanvas *pCanvas = Image1->Canvas;
  pCanvas->Brush->Color = clRed;
  pCanvas->Brush->Style = bsDiagCross;
  pCanvas->Ellipse(0, 0, Image1->Width, Image1->Height);
}

{
This example creates a region and selects this region as the
clipping rectangle for the Image component's canvas. It then
sets the canvas's brush color to red and calls FillRect 
using the ClipRect as the area to fill. Lastly, the ClipRect
is reset to the original value that it contained by calling
SelectClipRect with nil as the second parameter and deletes
the region.  Place a TImage object in the form.
}
procedure TForm1.Button1Click(Sender: TObject);
var
    MyRgn: HRGN;
begin
    MyRgn := CreateRectRgn(100,100,200,200);
    SelectClipRgn(Image1.Canvas.Handle,MyRgn);
    Image1.Canvas.Brush.Color := clRed;
    Image1.Canvas.FillRect(Image1.Canvas.ClipRect);
    Image1.Invalidate;
    SelectClipRgn(Image1.Canvas.Handle, HRGN(nil));
    DeleteObject(MyRgn);
end;

{
This example converts a specified icon to a bitmap. To run 
this example, add an image, a button, and an Open dialog to 
a form. Name the button ConvertIcon2Bitmap, and add the 
following code as its OnClick event handler.
} 
procedure TForm1.ConvertIcon2BitmapClick(Sender: TObject);
var 
  s : string;
  Icon: TIcon;
begin
  OpenDialog1.DefaultExt := '.ICO';
  OpenDialog1.Filter := 'icons (*.ico)|*.ICO';
  OpenDialog1.Options := [ofOverwritePrompt, ofFileMustExist, ofHideReadOnly ];
  if OpenDialog1.Execute then
  begin
    Icon := TIcon.Create;
    try
      Icon.Loadfromfile(OpenDialog1.FileName);
      s:= ChangeFileExt(OpenDialog1.FileName,'.BMP');
      Image1.Width := Icon.Width;
      Image1.Height := Icon.Height;
      Image1.Canvas.Draw(0,0,Icon);
      Image1.Picture.SaveToFile(s);
      ShowMessage(OpenDialog1.FileName + ' Saved to ' + s);
    finally
      Icon.Free;
    end;
  end;
end; 

{
The following code uses ClientRect to find and draw a line
from the top left to the bottom right of the current
control.  Select a TControl in the ListBox list.  This
example assumes that the current object is a descendent of
TControl and has a public Canvas property.
}
  if (ListBox1.Items.Objects[Index] is TImage) then
  begin
    myImage:= (ListBox1.Items.Objects[Index] as TImage);
    with myImage.ClientRect do
    begin // make sure we are using the TControl's canvas and not the form's!
      myImage.Canvas.MoveTo(Left, Top);
      myImage.Canvas.LineTo(Right, Bottom);
    end;
  myImage:= nil;
  end;

{
The following example paints a cross-hatched ellipse onto 
Image1 which is a TImage on the form when the user clicks on
Button1.
}
procedure TForm1.Button1Click(Sender: TObject);
begin
  with Image1 do begin
    Canvas.Brush.Color := clRed;
    Canvas.Brush.Style := bsDiagCross;
    Canvas.Ellipse(0, 0, Image1.Width, Image1.Height);
  end;
end;