TÉMA:

 
unit Unit1; 
 
{$mode objfpc}{$H+}
 
interface
 
uses
  Classes, SysUtils, LResources, Forms, Controls, Graphics, Dialogs,
  glib2, gdk2, gtk2, gtkdef, cairo, ExtCtrls;
 
type
 
  { TForm1 }
 
  TForm1 = class(TForm)
    Image1: TImage;
    procedure FormCreate(Sender: TObject);
    procedure Image1ChangeBounds(Sender: TObject);
  private
    { private declarations }
  public
    { public declarations }
  end; 
//ha már nincs a Free Pascalban, hát beleteszem a gdk_cairo_create-t
function gdk_cairo_create(drawable: PgdkDrawable):Pcairo_t; cdecl; external gdklib;
 
var
  Form1: TForm1; 
  ct: Pcairo_t;
  gdio: PGDIObject;
implementation
 
{ TForm1 }
 
procedure TForm1.FormCreate(Sender: TObject);
begin
  image1.Picture.Bitmap.Canvas.Brush.Color:= clWhite;
  image1.Picture.Bitmap.Width:= 300;
  image1.Picture.Bitmap.Height:=300;
  image1.Picture.Bitmap.Canvas.FillRect(0,0,300,300);
 
end;
 
procedure TForm1.Image1ChangeBounds(Sender: TObject);
begin
  image1.Picture.Bitmap.Canvas.FillRect(0,0,300,300);
  gdio:= PGDIObject(image1.Picture.Bitmap.Handle);
  ct:= gdk_cairo_create(gdio^.GDIBitmapObject);
 
  cairo_move_to (ct, 128.0, 25.6);
  cairo_line_to (ct, 230.4, 230.4);
  cairo_rel_line_to (ct, -102.4, 0.0);
  cairo_curve_to (ct, 51.2, 230.4, 51.2, 128.0, 128.0, 128.0);
  cairo_close_path (ct);
 
  cairo_move_to (ct, 64.0, 25.6);
  cairo_rel_line_to (ct, 51.2, 51.2);
  cairo_rel_line_to (ct, -51.2, 51.2);
  cairo_rel_line_to (ct, -51.2, -51.2);
  cairo_close_path (ct);
 
  cairo_set_line_width (ct, 10.0);
  cairo_set_source_rgb (ct, 0, 0, 1);
  cairo_fill_preserve (ct);
  cairo_set_source_rgb (ct, 0, 0, 0);
  cairo_stroke (ct);
 
  cairo_destroy(ct);
end;
 
 
initialization
  {$I unit1.lrs}
 
end.          

procedure TForm1.Form1Paint(Sender: TObject);
var
  cs: Pcairo_surface_t;
  ct: Pcairo_t;
  dpy: PDisplay;
  window: TWindow;
  screenid: LongInt;
  scr: PScreen;
begin
  dpy := GDK_WINDOW_XDISPLAY(Pointer(PGtkWidget(Form1.Handle)^.window));
  window := GDK_WINDOW_XWINDOW(Pointer(PGtkWidget(Form1.Handle)^.window));
  scr := XDefaultScreenOfDisplay(dpy);
  screenid := XScreenNumberOfScreen(scr);
  cs:= cairo_xlib_surface_create(dpy, window, DefaultVisual(dpy, screenid), 300, 300);
  ct:= cairo_create(cs);
  cairo_set_source_rgb (ct, 0, 1, 1);
 
  cairo_move_to (ct, 128.0, 25.6);
  cairo_line_to (ct, 230.4, 230.4);
  cairo_rel_line_to (ct, -102.4, 0.0);
  cairo_curve_to (ct, 51.2, 230.4, 51.2, 128.0, 128.0, 128.0);
  cairo_close_path (ct);
  cairo_stroke(ct);
 
  cairo_move_to (ct, 64.0, 25.6);
  cairo_rel_line_to (ct, 51.2, 51.2);
  cairo_rel_line_to (ct, -51.2, 51.2);
  cairo_rel_line_to (ct, -51.2, -51.2);
  cairo_close_path (ct);
 
  cairo_set_line_width (ct, 10.0);
  cairo_set_source_rgb (ct, 0, 0, 1);
  cairo_fill_preserve (ct);
  cairo_set_source_rgb (ct, 0, 0, 0);
  cairo_stroke (ct);
 
  cairo_destroy(ct);
  cairo_surface_destroy(cs);
end;