Compute screen proportion

[Furtbichler]

Do you know the difference between display resolution and aspect ratio? Why do you name your thread 'screen proportion' but you refer to images?
Did you bother using google?
I found all answers.

But what the heck:

Most modern screen resulutions are not exactly 16:9, 4:3 etc.

I would recommend using a list of standard ratios, e.g. (4:3, 5:4, 16:9, 16:10), compare the screen dimension (widht / height) with the entries in the list and return the closest candidate or 'none' if the difference is out of tolerance.

Delphi-Quellcode:

Function AspectRatio (aWidth, aHeight : Integer) : String;
Const
  RatioX : Array [0..3] of integer = (4,5,16,16);
  RatioY : Array [0..3] of integer = (3,4,10, 9);

  tolerance = 1E-2;

Var
  diff,dmin, ratio : Double;
  i,j : Integer;

Begin
  ratio := aWidht/aHeight;
  dmin := 999;
  j:=-1;
  for i:=0 to High(RatioX) do begin
    diff := abs(RatioX[i]/RatioY[i] - ratio);
    if diff < dmin then begin
      j := i;
      dmin := diff;
    end
  end;

  if diff<tolerance then
     result := Format('%d:%d',[RatioX[j], RatioY[j]])
  else
     result := 'nonstandard';
End;