Ergebnis der Suchanfrage

• Forum: Multimedia

  Re: [GR32] How to add intensity?

    Delphi
    by Medium, 25. Jan 2010
  Mh, then there is no obvious reason for this darkening. You could use your reference output and compare a white-tinted image (= implicit conversion to grayscales) of just a pure red, green and blue area to derive the weights they used, to make your output similar to it. That is, if you approve of the reference :)
• Forum: Multimedia

  Re: [GR32] How to add intensity?

    Delphi
    by Medium, 25. Jan 2010
  This might sound old, but I learned by doing. I have a general interest in graphics, so my spare time projects often are somehow related. And every time I hit a wall, I fire up good ole oncle google and find something eventually -> *pow* knowledge enhanced :)
  I couldn't even recommend any general sources or books, since all I do is basically self-taught by doing, fiddeling around and reading...
• Forum: Multimedia

  Re: [GR32] How to add intensity?

    Delphi
    by Medium, 23. Jan 2010
  Aha! You basically want a color tint. The 100% formula for this is:
  
  Brightness := (original.R + original.G + original.B)/(3*255) // normalized to 0..1
  NewColor := RGB(tint.R*Brightness, tint.G*Brightness, tint.B*Brightness)
  
  That is what jfheins already wrote, I suppose your implementation had rounding issues or did not normalize brightness (I'm too lazy to verfy this now :)).
  
  This...
• Forum: Multimedia

  Re: [GR32] How to add intensity?

    Delphi
    by Medium, 23. Jan 2010
  As I already said, change the line
  tmp := t*a + (1-t)*b;
  to
  tmp := (1-t)*a + t*b;
  
  Another thing is, that it's not clear to me, which variable holds the original color. Color or Row? If it's Row, then change
  Row.R := Lerp(Color.R, (Color.R * Row.R) div 255, APercent / 100);
  to
  Row.R := Lerp(Row.R, (Color.R * Row.R) div 255, APercent / 100);
• Forum: Multimedia

  Re: [GR32] How to add intensity?

    Delphi
    by Medium, 22. Jan 2010
  If this is not what you get after the change, please post the whole part of your source. Otherwise we won't come far here. I won't ask for it a third time, since the code you provided had little to do with the Lerp() function, and as such can't relate to the problem. (It should work as well if you handled each channel separately, as already said.)
• Forum: Multimedia

  Re: [GR32] How to add intensity?

    Delphi
    by Medium, 22. Jan 2010
  Oops, I switched the "t" and "(1-t)". Just exchange these, and you're good to go.
  
  Regarding the code you posted: You cannot simply multiply with whole combined RGB-values. You must handle each color channel separately.
• Forum: Multimedia

  Re: [GR32] How to add intensity?

    Delphi
    by Medium, 22. Jan 2010
  :gruebel: Lerp() can be used for just this. Use the original color of a pixel as first parameter, and the color of that pixel as if the effect was applied fully as second. Pass any value between 0 and 1 as third parameter, and get a linear interpolation between the original and the fully affected color. What exactly is your problem? You might also want to provide some more of your actual code...
• Forum: Multimedia

  Re: [GR32] How to add intensity?

    Delphi
    by Medium, 22. Jan 2010
  I haven't really understood what you do with this particular filter, but it looks like you're looking for simple linear interpolation, where you can shift beween two values freely.
  
  
  function Lerp(a, b: Byte; t: Double): Byte;
  var
  tmp: Double;
  begin
  tmp := t*a + (1-t)*b;
  if tmp<0 then result := 0 else
  if tmp>255 then result := 255 else