asked on

Problem with loading a Bitmap image

hi i am having trouble loading a bitmap image into a DrawGrid.
i am using the following code to load the pictures:
function GetBitmap(BitmapName: string): TBitmap;
var i: Integer;
begin
Result := nil;
for I := 1 to 20 do
if SameText(ImagePaths[i], BitmapName) then
begin
Result := Images[i].Picture.Bitmap; //CRASHES ON THIS LINE
Break;
end;
end;

i call this function during the following line:
DrawGrid1.Canvas.Draw(Rect.Left,Rect.Top,GetBitmap(xArray[ARow, ACol, c_pic]))

xArray[ARow, ACol, c_pic] contains the picture name for example 'house.bmp' and is an array of string.

Ioannis Anifantakis

Here is a very explanatory tutorial about use of DrawGrid.
I suggest you take a look

http://www.delphi-central.com/tutorials/memory_game.aspx

TheRealLoki

should it be zero based?
e.g.
for i := 0 to 19

if "images" is a list, then it usually starts at zero

OutOfLuck

ASKER

hi thankyou for the link, but it doesnt help me solve my problem becasue in their code they use a procedure to load images whilst i need to use a function.
also i changed me values to 0 as well and that also didnt fix the problem.

TheRealLoki

The problem is because you have not actually loaded the images into the Images object yet
therefore when you try to access the TImage in "Images[i]" it causes an error

You need a procedure like this :-

procedure LoadImages;var i: integer;begin For i := 0 to 19 do begin if not assigned(Images[i]) then Images[i] := TImage.Create(nil); Images[i].Picture.LoadFromFile(ImagePaths[i]); end;end;

And you need to place a call to it in your Form's create method
e.g.

procedure TfrmRooms.FormCreate(Sender: TObject);
begin
LoadImages;
// other code here...
end;

You _do_ also need to change your for loop to be 0 based, as your Images is an array [0..19] of TImage

function GetBitmap(BitmapName: string): TBitmap;
var i: Integer;
begin
Result := nil;
for I := 0 to 19 do // <-- zero based, not 1-20
if SameText(ImagePaths[i], BitmapName) then
begin
Result := Images[i].Picture.Bitmap; //CRASHES ON THIS LINE
Break;
end;
end;

Loki

OutOfLuck

ASKER

so basically you need a procedure and a function to make this work?

TheRealLoki

I was trying to work with your existing code....
Personally, I'd rewrite the whole thing ;-)

you could make it really simple by just doing this :-
function GetBitmap(BitmapName: string): TBitmap;
begin
result := nil;
if pos('.bmp', BitmapName) > 0 then
begin
result := TBitmap.Create;
result.LoadFromFile(BitmapName);
end;
end;

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TheRealLoki

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OutOfLuck

ASKER

okay well I do have another code but the problem with that is for some reason it will not load all th pictures into the grid it repeats quite a few pictures and only let's me display one picture at a time, should I post that code up?

TheRealLoki

from your other posts it appears you only show the image on click
is that right?

OutOfLuck

ASKER

yes that is correct