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			323 lines
		
	
	
		
			6.4 KiB
		
	
	
	
		
			ObjectPascal
		
	
	
	
	
	
			
		
		
	
	
			323 lines
		
	
	
		
			6.4 KiB
		
	
	
	
		
			ObjectPascal
		
	
	
	
	
	
//
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// AggPas 2.4 RM3 Demo application
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// Note: Press F1 key on run to see more info about this demo
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//
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// Paths: src;src\ctrl;src\svg;src\util;src\platform\win;expat-wrap
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//
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program
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 gamma_correction ;
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{$DEFINE AGG_BGR24 }
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{DEFINE AGG_RGB24 }
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{DEFINE AGG_RGB565 }
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{DEFINE AGG_RGB555 }
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uses
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 agg_basics ,
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 agg_platform_support ,
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 agg_ctrl ,
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 agg_slider_ctrl ,
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 agg_rasterizer_scanline_aa ,
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 agg_scanline ,
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 agg_scanline_u ,
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 agg_renderer_base ,
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 agg_renderer_scanline ,
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 agg_render_scanlines ,
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 agg_gamma_lut ,
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 agg_gamma_functions ,
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 agg_path_storage ,
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 agg_conv_stroke ,
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 agg_ellipse
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{$I pixel_formats.inc } 
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{$I agg_mode.inc }
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const
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 flip_y = true;
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type
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 the_application = object(platform_support )
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   m_thickness ,
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   m_gamma     ,
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   m_contrast  : slider_ctrl;
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   m_rx ,
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   m_ry : double;
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   constructor Construct(format_ : pix_format_e; flip_y_ : boolean );
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   destructor  Destruct;
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   procedure on_init; virtual;
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   procedure on_draw; virtual;
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   procedure on_mouse_move       (x ,y : int; flags : unsigned ); virtual;
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   procedure on_mouse_button_down(x ,y : int; flags : unsigned ); virtual;
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   procedure on_key(x ,y : int; key ,flags : unsigned ); virtual;
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  end;
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{ CONSTRUCT }
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constructor the_application.Construct;
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begin
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 inherited Construct(format_ ,flip_y_ );
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 m_thickness.Construct(5 ,5 ,400 - 5 ,11 ,not flip_y_ );
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 m_gamma.Construct    (5 ,5 + 15 ,400 - 5 ,11 + 15 ,not flip_y_ );
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 m_contrast.Construct (5 ,5 + 30 ,400 - 5 ,11 + 30 ,not flip_y_ );
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 add_ctrl(@m_thickness );
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 add_ctrl(@m_gamma );
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 add_ctrl(@m_contrast );
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 m_thickness.label_('Thickness=%3.2f' );
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 m_gamma.label_    ('Gamma=%3.2f' );
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 m_contrast.label_ ('Contrast' );
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 m_thickness.range_(0.0 ,3.0 );
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 m_gamma.range_    (0.5 ,3.0 );
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 m_contrast.range_ (0.0 ,1.0 );
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 m_thickness.value_(1.0 );
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 m_gamma.value_    (1.0 );
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 m_contrast.value_ (1.0 );
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end;
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{ DESTRUCT }
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destructor the_application.Destruct;
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begin
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 inherited Destruct;
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 m_thickness.Destruct;
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 m_gamma.Destruct;
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 m_contrast.Destruct;
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end;
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{ ON_INIT }
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procedure the_application.on_init;
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begin
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 m_rx:=_width / 3.0;
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 m_ry:=_height / 3.0;
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end;
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{ ON_DRAW }
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procedure the_application.on_draw;
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var
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 g ,dark ,light ,x ,y ,v ,gval ,dy : double;
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 i : unsigned;
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 gamma : gamma_lut;
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 pixf  : pixel_formats;
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 renb : renderer_base;
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 ren  : renderer_scanline_aa_solid;
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 ras : rasterizer_scanline_aa;
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 sl  : scanline_u8;
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 rgba : aggclr;
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 path : path_storage;
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 gm_pw : gamma_power;
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 gpoly ,
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 poly  : conv_stroke;
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 ell   : ellipse;
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begin
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// Initialize structures
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 g:=m_gamma._value;
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 gamma.Construct(g );
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 pixfmt_gamma(pixf ,rbuf_window ,@gamma );
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 renb.Construct(@pixf );
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 ren.Construct (@renb );
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 rgba.ConstrDbl(1 ,1 ,1 );
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 renb.clear    (@rgba );
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 dark :=1.0 - m_contrast._value;
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 light:=m_contrast._value;
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 rgba.ConstrDbl(dark ,dark ,dark );
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 renb.copy_bar (0 ,0 ,trunc(_width ) div 2 ,trunc(_height ) ,@rgba );
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 rgba.ConstrDbl(light ,light ,light );
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 renb.copy_bar (trunc(_width ) div 2 + 1 ,0 ,trunc(_width ) ,trunc(_height ) ,@rgba );
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 rgba.ConstrDbl(1.0 ,dark ,dark );
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 renb.copy_bar (0 ,trunc(_height ) div 2 + 1 ,trunc(_width ) ,trunc(_height ) ,@rgba );
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 ras.Construct;
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 sl.Construct;
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// Graph line
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 path.Construct;
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 x:=(_width - 256.0 ) / 2.0;
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 y:=50.0;
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 for i:=0 to 255 do
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  begin
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   v:=i / 255.0;
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   gm_pw.Construct(g );
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   gval:=gm_pw.func_operator_gamma(v );
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   dy  :=gval * 255.0;
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   if i = 0 then
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    path.move_to(x + i ,y + dy )
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   else
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    path.line_to(x + i ,y + dy );
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  end;
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 gpoly.Construct(@path );
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 gpoly.width_   (2.0 );
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 ras.reset;
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 ras.add_path(@gpoly );
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 rgba.ConstrInt(80 ,127 ,80 );
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 ren.color_    (@rgba );
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 render_scanlines(@ras ,@sl ,@ren );
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// Ellipses
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 ell.Construct (_width / 2 ,_height / 2 ,m_rx ,m_ry ,150 );
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 poly.Construct(@ell );
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 poly.width_   (m_thickness._value );
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 ras.reset;
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 ras.add_path(@poly );
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 rgba.ConstrInt(255 ,0 ,0 );
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 ren.color_    (@rgba );
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 render_scanlines(@ras ,@sl ,@ren );
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 ell.init(_width / 2 ,_height / 2 ,m_rx - 5.0 ,m_ry - 5.0 ,150 );
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 ras.reset;
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 ras.add_path(@poly );
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 rgba.ConstrInt(0 ,255 ,0 );
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 ren.color_    (@rgba );
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 render_scanlines(@ras ,@sl ,@ren );
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 ell.init(_width / 2 ,_height / 2 ,m_rx - 10.0 ,m_ry - 10.0 ,150 );
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 ras.reset;
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 ras.add_path(@poly );
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 rgba.ConstrInt(0 ,0 ,255 );
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 ren.color_    (@rgba );
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 render_scanlines(@ras ,@sl ,@ren );
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 ell.init(_width / 2 ,_height / 2 ,m_rx - 15.0 ,m_ry - 15.0 ,150 );
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 ras.reset;
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 ras.add_path(@poly );
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 rgba.ConstrInt(0 ,0 ,0 );
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 ren.color_    (@rgba );
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 render_scanlines(@ras ,@sl ,@ren );
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 ell.init(_width / 2 ,_height / 2 ,m_rx - 20.0 ,m_ry - 20.0 ,150 );
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 ras.reset;
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 ras.add_path(@poly );
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 rgba.ConstrInt(255 ,255 ,255 );
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 ren.color_    (@rgba );
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 render_scanlines(@ras ,@sl ,@ren );
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// Render the controls
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 render_ctrl(@ras ,@sl ,@ren ,@m_thickness );
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 render_ctrl(@ras ,@sl ,@ren ,@m_gamma );
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 render_ctrl(@ras ,@sl ,@ren ,@m_contrast );
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// Free AGG resources
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 ras.Destruct;
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 sl.Destruct;
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 path.Destruct;
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 gamma.Destruct;
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 gpoly.Destruct;
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 poly.Destruct;
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end;
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{ ON_MOUSE_MOVE }
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procedure the_application.on_mouse_move;
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begin
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 on_mouse_button_down(x ,y ,flags );
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end;
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{ ON_MOUSE_BUTTON_DOWN }
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procedure the_application.on_mouse_button_down;
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begin
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 if flags and mouse_left <> 0 then
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  begin
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   m_rx:=Abs(_width / 2 - x );
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   m_ry:=Abs(_height / 2 - y );
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   force_redraw;
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  end;
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end;
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{ ON_KEY }
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procedure the_application.on_key;
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begin
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 if key = key_f1 then
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  message_(
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   'Anti-Aliasing is very tricky because everything depends. Particularly, having '#13 +
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   'straight linear dependence "pixel coverage" -> "brightness" may be not the best. '#13 +
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   'It depends on the type of display (CRT, LCD), contrast, black-on-white vs '#13 +
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   'white-on-black, it even depends on your personal vision. There are no linear '#13 +
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   'dependencies in this World. This example demonstrates the importance of so called '#13 +
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   'Gamma Correction in Anti-Aliasing. There a traditional power function is used, '#13 +
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   'in terms of C++ it''s brighness = pow(brighness, gamma). Note, that if you improve '#13 +
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   'the quality on the white side, it becomes worse on the black side and vice versa.'#13 +
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   #13#13 +
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   'How to play with:'#13#13 +
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   'Change "Gamma" and see how the quality changes.'#13 +
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   'Use the left mouse button to resize the circles.' +
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   #13#13'Note: F2 key saves current "screenshot" file in this demo''s directory.  ' );
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end;
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VAR
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 app : the_application;
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BEGIN
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 app.Construct(pix_format ,flip_y );
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 app.caption_ ('AGG Example. Thin red ellipse (F1-Help)' );
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 if app.init(400 ,320 ,0 ) then
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  app.run;
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 app.Destruct;
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END. |