BGRA Bilinear Zoom
lazarus / 39-Graphics

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Gigatron · 2024-06-20 17:42

Hi,

In this Haujobb - Megademo 2000 - Amiga Demo (AGA), a cool fx is what
i would like to remake ; Bilinear zoom from Optima the coder
of the demo.

https://www.youtube.com/watch?v=woMBJhQoi9E&t=176s

Picture is from JCS;

here is the code with trilinear zoom for better than demo ; no math
function used; maybe there are some complex filtering method with
anisotropic etc..;

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i unit
Unit1; {$mode objfpc}{$H+} interface uses  Classes, SysUtils, Forms,
Controls, Graphics, Dialogs, ExtCtrls,  BGRAVirtualScreen, BGRABitmap,
BGRABitmapTypes; type   { TForm1 }   TForm1 = class(TForm)   
BGRAVirtualScreen1: TBGRAVirtualScreen;    Timer1: TTimer;   
procedure BGRAVirtualScreen1Redraw(Sender: TObject; Bitmap:
TBGRABitmap);    procedure FormCreate(Sender: TObject);    procedure
Timer1Timer(Sender: TObject);  private   public   end; var  Form1:
TForm1;  bm : TBGRABitmap;  alpha,z : integer;    //
zoom  implementation {$R *.lfm} { TForm1 }   procedure
TForm1.FormCreate(Sender: TObject);begin      bm :=
TBGRABitmap.Create('girls2.png');      alpha := 255;end; procedure
TForm1.BGRAVirtualScreen1Redraw(Sender: TObject; Bitmap:
TBGRABitmap);var  bw: TBGRABitmap;  bw2: TBGRABitmap;  bw3:
TBGRABitmap;begin      bw := bm.FilterGrayScale as TBGRABitmap;     
bw2:= bm.FilterGrayScale as TBGRABitmap;      bw3:= bm.FilterGrayScale
as TBGRABitmap;       bitmap.StretchPutImage(Rect(0-z,0-
z,0+640+z,0+400+z),bm,dmSet,alpha);       // Trilinear zoom test ;   
 bitmap.StretchPutImage(Rect(0-z,0-
z,0+640+z,0+400+z),bw2,dmFastBlend,-alpha);      if(alpha=1) then    
begin       
bitmap.StretchPutImage(Rect(2-z,2-z,2+640+z,2+400+z),bw,dmFastBlend,
150);        bitmap.StretchPutImage(Rect(4-z,4-
z,4+640+z,4+400+z),bw3,dmFastBlend,100);       endend; procedure
TForm1.Timer1Timer(Sender: TObject);begin          dec(alpha);       
 if(alpha <1) then          begin            alpha :=1;            inc
(z,1);             if (z>655) then            begin            z  :=
0;             end;           end;         
BGRAVirtualScreen1.RedrawBitmap;end; end.