Main form takes on dimensions of loaded bitmap
lazarus / 39-Graphics

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jave · 2018-10-16 10:41

Hi all,

Me again. lol

I've made some changes to my code so that when a bitmap file is
loaded, the image displays on the 2nd form.  This works fine, however
when I click on a button to process the bitmap image, my main form
takes on the dimensions of the loaded bitmap.  What am I doing wrong?

Code:
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 procedure
TForm1.Button4Click(Sender: TObject);begin  BitMap2 :=
TBitMap.create;  BitMap2.Assign(BitMap1);  width := BitMap2.Width; 
height := BitMap2.Height;  Label3.Caption := IntToStr(width); 
Label4.Caption := IntToStr(height);  for px:= 0 to width do begin    
for py:= 0 to height do begin        // get colour        colour1 :=
BitMap2.Canvas.Pixels[px,py];        colour2 :=
BitMap2.Canvas.Pixels[px+1,py];        if (colour1 <> colour2) then
begin // if pixels do not match           BitMap2.Canvas.Pixels[px,py]
:= clRed;           // colour1 := BitMap1.Canvas.Pixels[px,py];      
end      end;  end;  for py:= 0 to height do begin      for px:= 0 to
width do begin        // get colour        colour1 :=
BitMap2.Canvas.Pixels[px,py];        colour2 :=
BitMap2.Canvas.Pixels[px,py+1];        if (colour1 <> colour2) then
begin // if pixels do not match           BitMap2.Canvas.Pixels[px,py]
:= clRed;           // colour1 := BitMap1.Canvas.Pixels[px,py];      
end      end;  end;  Label6.Caption := 'Image processed.'; 
Form3.Image1.Canvas.Draw(0,0,BitMap2);  Form3.Image1.Stretch := True
;end; 
I'm pretty sure I don't need the 2nd bitmap but added it as I was
trying a few different things.  Thanks!

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JuhaManninen · 2018-10-16 10:53

You explicitly set width and height of TForm1 at lines 5 and 6 of your
listing.

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jave · 2018-10-17 06:01

Okay, so how can I obtain the width and height of the loaded bitmap
image?

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wp · 2018-10-17 07:50

Declare width and height as local variables. But you must be aware
that these names are already defined by the form (that's the reason
why the size of the form changes in your code), fpc in mode objfpc
rejects local variables with this ambiguity. Therefore, name them "w"
and "h", or "lWidth" and "lHeight", "l" for "local":
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 procedure
TForm1.Button4Click(Sender: TObject);var  lWidth, lHeight: Integer;  
// <--- NEWbegin  BitMap2 := TBitMap.create; 
BitMap2.Assign(BitMap1);  lWidth := BitMap2.Width;  lHeight :=
BitMap2.Height;  Label3.Caption := IntToStr(lWidth);  Label4.Caption
:= IntToStr(lHeight);  for px:= 0 to lWidth do begin    ...

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jave · 2018-10-17 08:19

Ah okay.  Many thanks!!