How to stop flickering in layered image animation - delphi

Question

i used 30 png pictures on a transplanted from to make a simple animation, a Timer make an event every 33 Millisecond to change the visibility of the TImage Components which have the png images, i tried all the method suggested in other posts to stop flickering but could not solve the problem.
unit Animation;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, AdvShaper, pngimage, ExtCtrls, StdCtrls;
type
TAnimation_Form = class(TForm)
Image1: TImage;
Timer: TTimer;
Image2: TImage;
Image3: TImage;
Image4: TImage;
Image5: TImage;
Image6: TImage;
Image7: TImage;
Image8: TImage;
Image9: TImage;
Image10: TImage;
Image11: TImage;
Image12: TImage;
Image13: TImage;
Image14: TImage;
Image15: TImage;
Image16: TImage;
Image17: TImage;
Image18: TImage;
Image19: TImage;
Image20: TImage;
Image21: TImage;
Image22: TImage;
Image23: TImage;
Image24: TImage;
Image25: TImage;
Image26: TImage;
Image27: TImage;
Image28: TImage;
Image29: TImage;
Image30: TImage;
Exit: TButton;
procedure TimerTimer(Sender: TObject);
procedure ExitClick(Sender: TObject);
private
{ Private declarations }
Image_Counter:Integer;
procedure ChooseImage(I:Integer);
procedure Init();
public
{ Public declarations }
end;
procedure Run_Animation_Form();
procedure Finish_Animation_Form();
implementation
var
Animation_Form: TAnimation_Form;
{$R *.dfm}
procedure Finish_Animation_Form();
Begin
Animation_Form.Close;
End;
procedure Run_Animation_Form();
Begin
Animation_Form := TAnimation_Form.Create(nil);
Try
Animation_Form.Init();
Animation_Form.ShowModal();
Finally
Animation_Form.Free;
End;
End;
{ TAnimation_Form }
procedure TAnimation_Form.ChooseImage(I: Integer);
begin
TwinControl(FindComponent(Format('Image%d',[I]))).Visible := False;
TwinControl(FindComponent(Format('Image%d',[I+1]))).Visible := True;
end;
procedure TAnimation_Form.ExitClick(Sender: TObject);
begin
Close;
end;
procedure TAnimation_Form.Init;
begin
TransparentColor := True;
TransparentColorValue := Color;
Image1.Visible := True;
Image_Counter:=1;
ControlStyle:=ControlStyle - [csOpaque];
BorderWidth := 10;
Anchors := [akLeft, akTop, akBottom, akRight];
end;
procedure TAnimation_Form.TimerTimer(Sender: TObject);
begin
if Image_Counter >= 30 then
Begin
Image30.Visible := False;
Image1.Visible := True;
Image_Counter:=1;
End
else
Begin
ChooseImage(Image_Counter);
Inc(Image_Counter);
End;
end;
end.
Thanks for your help and sorry for my bad English

Answer 1

Rather than using multiple overlapping TImage objects and swapping their Visible property, I would suggest you create an array of 30 TPNGImage objects and then either:
use a single TImage that is always visible and assign the desired PNG to its TImage.Picture property whenever the TTimer elapses:
unit Animation;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, AdvShaper, pngimage, ExtCtrls, StdCtrls;
type
TAnimation_Form = class(TForm)
Image1: TImage;
Timer: TTimer;
Exit: TButton;
procedure FormCreate(Sender: TObject);
procedure FormDestroy(Sender: TObject);
procedure TimerTimer(Sender: TObject);
procedure ExitClick(Sender: TObject);
private
{ Private declarations }
Image_Counter: Integer;
Images: array[0..29] of TPNGImage;
public
{ Public declarations }
end;
procedure Run_Animation_Form();
procedure Finish_Animation_Form();
implementation
var
Animation_Form: TAnimation_Form = nil;
{$R *.dfm}
procedure Finish_Animation_Form();
Begin
if Animation_Form <> nil then
Animation_Form.Close;
End;
procedure Run_Animation_Form();
Begin
Animation_Form := TAnimation_Form.Create(nil);
Try
Animation_Form.ShowModal();
Finally
FreeAndNil(Animation_Form);
End;
End;
{ TAnimation_Form }
procedure TAnimation_Form.FormCreate(Sender: TObject);
var
I: Integer;
begin
for I := Low(Images) to High(Images) do
begin
Images[I] := TPNGImage.Create;
// load PNG image into Images[I] as needed...
end;
// FYI, these properties can be set at design time...
TransparentColor := True;
TransparentColorValue := Color;
Image1.Visible := True;
BorderWidth := 10;
Anchors := [akLeft, akTop, akBottom, akRight];
Image_Counter := 0;
Image1.Picture := Images[0];
ControlStyle := ControlStyle - [csOpaque];
end;
procedure TAnimation_Form.FormDestroy(Sender: TObject);
var
I: Integer;
begin
for I := Low(Images) to High(Images) do
Images[I].Free;
end;
procedure TAnimation_Form.ExitClick(Sender: TObject);
begin
Close;
end;
procedure TAnimation_Form.TimerTimer(Sender: TObject);
begin
Inc(Image_Counter);
if Image_Counter > High(Images) then
Image_Counter := 0;
Image1.Picture := Images[Image_Counter];
end;
end.
use a single TPaintBox and assign an OnPaint event handler to it that draws the current PNG onto the TPaintBox.Canvas, and then have the TTimer simply update the current PNG and call TPaintBox.Invalidate() to trigger a repaint:
unit Animation;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, AdvShaper, pngimage, ExtCtrls, StdCtrls;
type
TAnimation_Form = class(TForm)
PaintBox1: TPaintBox;
Timer: TTimer;
Exit: TButton;
procedure FormCreate(Sender: TObject);
procedure FormDestroy(Sender: TObject);
procedure TimerTimer(Sender: TObject);
procedure ExitClick(Sender: TObject);
procedure PaintBox1Paint(Sender: TObject);
private
{ Private declarations }
Image_Counter: Integer;
Images: array[0..29] of TPNGImage;
public
{ Public declarations }
end;
procedure Run_Animation_Form();
procedure Finish_Animation_Form();
implementation
var
Animation_Form: TAnimation_Form = nil;
{$R *.dfm}
procedure Finish_Animation_Form();
Begin
if Animation_Form <> nil then
Animation_Form.Close;
End;
procedure Run_Animation_Form();
Begin
Animation_Form := TAnimation_Form.Create(nil);
Try
Animation_Form.ShowModal();
Finally
FreeAndNil(Animation_Form);
End;
End;
{ TAnimation_Form }
procedure TAnimation_Form.FormCreate(Sender: TObject);
var
I: Integer;
begin
for I := Low(Images) to High(Images) do
begin
Images[I] := TPNGImage.Create;
// load PNG image into Images[I] as needed...
end;
// FYI, these properties can be set at design time...
TransparentColor := True;
TransparentColorValue := Color;
Image1.Visible := True;
BorderWidth := 10;
Anchors := [akLeft, akTop, akBottom, akRight];
Image_Counter := 0;
ControlStyle := ControlStyle - [csOpaque];
end;
procedure TAnimation_Form.FormDestroy(Sender: TObject);
var
I: Integer;
begin
for I := Low(Images) to High(Images) do
Images[I].Free;
end;
procedure TAnimation_Form.ExitClick(Sender: TObject);
begin
Close;
end;
procedure TAnimation_Form.TimerTimer(Sender: TObject);
begin
Inc(Image_Counter);
if Image_Counter > High(Images) then
Image_Counter := 0;
PaintBox1.Invalidate;
end;
procedure TAnimation_Form.PaintBox1Paint(Sender: TObject);
begin
PaintBox1.Canvas.Draw(0, 0, Images[Image_Counter]);
// or:
// PaintBox1.Canvas.StretchDraw(Rect(0, 0, PaintBox1.Width, PaintBox1.Height), Images[Image_Counter]);
end;
end.