Indexing a Timage component in delphi 5

You can also do as follows

var
  c : TComponent;
begin
 c := FindComponent('Image1');
 if Assigned(c) then
   if c is TImage then
     (c as TImage).Left := 1;  // do whatever want

type
  TForm1 = class(TForm)
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    FImages:TList;
  public
    function AddImage:TImage;
    procedure RemoveImage(const Index:Integer);
    function GetImage(const Index:Integer):TImage;
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

function TForm1.AddImage:TImage;
begin
  Result:=TImage.Create(Self);
  Result.Parent:=Self;
  FImages.Add(Result);
end;

procedure TForm1.RemoveImage(const Index:Integer);
begin
  GetImage(Index).Free;
  FImages.Delete(Index);
end;

function TForm1.GetImage(const Index:Integer):TImage;
begin
  Result:=FImages[Index];
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  FImages:=TList.Create;
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  FImages.Free;
end;

>>Extase:
>>try to use an ImageList component
>>(TImageList) instead.

I have a ImageList component to store  and access the images(bitmaps) I am using.

I still need to be able to draw the image to a certain place on my form which I have
designated as a series of timage components.

In VB I would use an array of
images each accesible by an image Index.

By your responses it seems there is no 'internal' property to do this and one must resort to code to find the appropriate
component.

>>Paul_UK  
Nice code, I  ran it and it works.() Seems like a lot of processing though seeing as I have 100 images to cycle through each time I want to access one image..
Pehaps this is the only way it can be done.

Also, I would have to manually set the tag properties of all the components.
This is the solution I will use if none
better arises...


>>mokule

Your procedure looks like it would work fine but the  the logic processing will envlove integer representaions of the
picture elements and converting back and forth using text arguements would be cumbersome :) That is the program will
select ,say the number 4 and I would want to access the element using the integer value...
 

I will leave the question open to see if there
are any more responses...thanks all for your help, (Us VB programmers really need it :)..

>I have a ImageList component to store  and access the images(bitmaps)
>I am using.

>I still need to be able to draw the image to a certain place on my form
>which I have
>designated as a series of timage components.

as you have a imagelist in use, then you have also an index
-> the imagelist can accessed like an array

to paint it on your form you've multiple possibilties
- using windows-api (bitBlt for ex)
- using vcl (canvas Stretchdraw for ex)

use the forms onPaint-event to keep your formpainting/display consistent

what is your problem?

meikl ;-)

Or, if you don't need to stretch the images, you could just use the Draw method of the ImageList, e.g.

  ImageList1.Draw(Canvas, Left, Top, ImageIndex);

Where ImageIndex is the index number of the required image in the ImageList.

Cheers,
Paul

>kretzschmar

>use the forms onPaint-event to keep your >formpainting/display consistent

>what is your problem ?

Thanks for the response kreztschmar. My problem perhaps
is two fold. Being new to delphi programming its difficult not to think in terms of VB. I was looking for a way
to access the Timage element because the properties and methods of that component really suit well the model I
am trying to construct.

I do realize the TImageList is an array and the elements
contained can be accessed as such. I also realize that contents of the list can be wriiten to the form (or to any element for that matter). However, not only would it be more tedious to draw all the elements using x and y co-ordinates,the images would also lack the event handling methods that I utilize as the user clicks on an image.

I can use the TImageList control to select the particuliar picture that will be drawn onto the Timage . However, I still have to find the location to draw to , which, using my model
would be an integer value repesenting the component.

Thanks again for your input. I am sure there would be many
other ways to accomplish the same task, however I find it easier to manipulate the code using the timage object. I will use Paul_UK ' s  solution . I do think though that the image control index of VB is a superior system for this type of project and I am surprised that the delphi VCL does not support it. (Spoken like a true VB programmer eh :).

Thanks again,
Tandy
 

>(Spoken like a true VB programmer eh :).

no not really,
but delphi didn't support control-arrays at designtime,
but you can do it at runtime of course

for ex

  imageArr : Array[0..11] of TImage; //12 images just for example

now you could drop 12 TImage-components on the form
and do you desired layout and assign the events you need

to transport the 12 TImages into the array,
just write a onFormCreate-event handler,
where you transfer the references into the array like

imageArr[0] := Image1;
imageArr[1] := Image2;
imageArr[2] := Image3;
imageArr[3] := Image4;
imageArr[4] := Image5;
imageArr[5] := Image6;
imageArr[6] := Image7;
imageArr[7] := Image8;
imageArr[8] := Image9;
imageArr[9] := Image10;
imageArr[10] := Image11;
imageArr[11] := Image12;

i personally would prefer a tlist (IList : TList)    rather than an array,
like extase suggested, in this the tranfer in the formcreate-event would be

IList := TList.Create;
Ilist.Add(Image1);
Ilist.Add(Image1);
Ilist.Add(Image2);
Ilist.Add(Image3);
Ilist.Add(Image4);
Ilist.Add(Image5);
Ilist.Add(Image6);
Ilist.Add(Image7);
Ilist.Add(Image8);
Ilist.Add(Image9);
Ilist.Add(Image10);
Ilist.Add(Image11);
Ilist.Add(Image12);
 
a tlist has some benefits
- is dynamic
- has some good methods

if you now assign a general onClick-event to all TImages for ex,
and you want to know which image is now clicked, then its became easy

procedure GeneralImageClick(sender : TObject);
var
  i : Integer;  
begin
  i := IList.IndexOf(sender);
  if i > - 1 then  //is the sender a TImage from the list
    TImage(IList[i]).Visible := false;  //just as sample
end;

well,
anyway glad that paul helped you,
have a nice time with delphi,
hoping you will like delphi in future as you like vb now

good luck again

meikl ;-)


 

Thanks for the extra comments after
the answer was accepted kretzschmar.

Your code looks very sophistcated and will add value to
this question as a PAQ. I will have a look at it again when I
get more comfortable with the basics of Delphi. I really do
like Delphi but for many of the small projects I work on, the
methods such as you describe are really beyond the scope of
what I need to produce. The biggest reason I switched to Delphi was because my VB(4.0) is outdated and it seems to have so many dependencies on support files. Delphi(5.0) seems to generate smaller code and is more portable.
 
 Thanks to all,
Happy Coding :)
Tandy

example using a TImageList component.

type
  TForm1 = class(TForm)
    ImageList1: TImageList;
    Image1: TImage;
    Button1: TButton;
    Edit1: TEdit;
    Button2: TButton;
  private
  public
    procedure DrawImage(const Index:Integer);
  end;

implementation

{$R *.dfm}

procedure TForm1.DrawImage(const Index:Integer);
begin
  with Image1.Picture do
  begin
    with Bitmap do
    begin
      Height:=0;
      Width:=0;
    end;
    ImageList1.GetBitmap(Index, Bitmap);
  end;
end;