GDIdemo: Delphi Version

{*****************************************************************************
*                                                                            *
*  GDIdemo.dpr                                                               *
*  GDIdemoU.pas                                                              *
*                                                                            *
*  This program shows how to use Windows GDI functions to write to a virtual *
*  buffer. It uses GDI functions to display a cross-hatched rectangle with a *
*  border, something that would require construction from several graphics   *
*  primitives if using Fastgraph for Windows drawing functions only.         *
*                                                                            *
*****************************************************************************}
unit GDIdemoU;
interface
uses
  SysUtils, WinTypes, WinProcs, Messages, Classes, Graphics, Controls,
  Forms, Dialogs, FGWin;
type
  TForm1 = class(TForm)
    procedure AppOnActivate(Sender: TObject);
    procedure FormActivate(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure FormPaint(Sender: TObject);
    procedure FormResize(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  end;
var
  Form1: TForm1;
implementation
{$R *.DFM}
var
  dc   : hDC;
  hPal : hPalette;
  hVB  : integer;
  cxClient, cyClient : integer;
procedure TForm1.AppOnActivate(Sender: TObject);
begin
  fg_realize(hPal);
  Invalidate;
end;
procedure TForm1.FormActivate(Sender: TObject);
begin
  fg_realize(hPal);
end;
procedure TForm1.FormCreate(Sender: TObject);
var
  Brush : hBrush;
  hDIB  : hDC;
  Pen   : hPen;
begin
  dc := GetDC(Form1.Handle);
  fg_setdc(dc);
  hPal := fg_defpal;
  fg_realize(hPal);
  fg_vbinit;
  hVB := fg_vballoc(320,240);
  fg_vbopen(hVB);
  fg_vbcolors;
  { use FG to fill the virtual buffer with light green pixels }
  fg_setcolor(20);
  fg_fillpage;
  { use Windows GDI functions to display a cross-hatched
    rectangle with blue border in the virtual buffer }
  hDIB := fg_getdc;
  Pen := CreatePen(PS_SOLID,3,RGB(0,0,255));
  Brush := CreateHatchBrush(HS_DIAGCROSS,RGB(255,0,0));
  SelectObject(hDIB,Pen);
  SelectObject(hDIB,Brush);
  Rectangle(hDIB,20,20,50,50);
  DeleteObject(Pen);
  DeleteObject(Brush);
  Application.OnActivate := AppOnActivate;
end;
procedure TForm1.FormPaint(Sender: TObject);
begin
  fg_vbscale(0,fg_getmaxx,0,fg_getmaxy,0,cxClient-1,0,cyClient-1);
end;
procedure TForm1.FormResize(Sender: TObject);
begin
  cxClient := ClientWidth;
  cyClient := ClientHeight;
  Invalidate;
end;
procedure TForm1.FormDestroy(Sender: TObject);
begin
  fg_vbclose;
  fg_vbfree(hVB);
  fg_vbfin;
  DeleteObject(hPal);
  ReleaseDC(Form1.Handle,dc);
end;
end.