Hello,
My hopes of getting a fade effect to work have faded away! I'm trying
to alter the palette of a bitmap stored in a TImage container in order to
achieve a "Fade Out" effect. The For loops gradually darken the original
RGB values and copy them to a Fade array (of TPallet{*word*249}try). I then
want to use AnimatePalette() API Call to set the image's current palette
to the slightly darker Fade palette. The code executes without compile
time errors or run time errors,
but it doesn't cause the bitmap image to fade! What am I doing wrong
here??
Thanks in advance,
Dave Irizarry
***** Source Code *****
The form contains a TImage object with a picture loaded and a button which
begins
the Fade effect (or is supposed to do so!)
unit Fader;
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls, ExtCtrls;
type
TForm1 = class(TForm)
Button1: TButton;
Img1: TImage;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
MyPalette, Fade: Array [0..256] of TPalet{*word*249}try; //Pallete Structure
arrays
end;
var
Form1: TForm1;
implementation
{$R *.DFM}
procedure TForm1.Button1Click(Sender: TObject);
var
BmpPal: HPALETTE;
i,j,k: integer;
begin
BmpPal:=Img1.Picture.Bitmap.Palette; //get palette handle from TImage
object
i:=GetPalet{*word*249}tries(BmpPal,0,255,MyPalette); //copy palette entries to
MyPalette
//Fade out image by slightly darkening RGB values
for k:=9 downto 0 do begin
for j:=0 to i-1 do begin
Fade[j].peRed:= ((MyPalette[j].peRed)*k) div 10;
Fade[j].peGreen:= ((MyPalette[j].peGreen)*k) div 10;
Fade[j].peBlue:= ((MyPalette[j].peBlue)*k) div 10;
Fade[j].peFlags:= PC_RESERVED;
end;
AnimatePalette(BmpPal,0,i,@Fade[0]); //Copy Fade palette structure to
Picture
Img1.Invalidate; //force
redraw of Img1
end;
end;
end.
