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    No Undo for RGB Swap

    I checked Image/Swap Colors. An option rarely used, I suppose.
    After applying a RGB switch, no 'undo' is possible. I think it should be.
    0.6180339887
    Rest In Peace, Sam!

    #2
    This would be easier, though it is not difficult to undo if you know how.

    RGB -> RBG repeat to undo
    RGB -> BGR repeat to undo
    RGB -> BRG use RGB -> GBR to undo
    RGB -> GRB repeat twice to undo
    RGB -> GBR use RGB -> BRG to undo

    Whichever of the first two options you used last time, just use it again.
    If you used the 3rd option use the 5th option to undo it.
    If you used the 5th option use the 3rd option to undo it.
    If you used the 4th option, use it again twice to undo it.
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      #3
      A very nice workaround of course, but I keep wondering, why this isn't a bitmap change which activates the 'undo' function.
      0.6180339887
      Rest In Peace, Sam!

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        #4
        I have found it awkward too, to have to rearrange my thinking for this function. My poor little brain! It's a bad time for the phone to ring. LOL
        Its: Belongs to "It"
        It's: Shortened form of "It is"
        ---------------------
        Lose: Fail to keep
        Loose: Not tight

        ---------------------
        Plurals do not require apostrophes

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          #5
          Much easier way to undo a color swap selection

          Originally posted by Bhikkhu Pesala View Post
          This would be easier, though it is not difficult to undo if you know how.

          RGB -> RBG repeat to undo
          RGB -> BGR repeat to undo
          RGB -> BRG use RGB -> GBR to undo
          RGB -> GRB repeat twice to undo
          RGB -> GBR use RGB -> BRG to undo

          Whichever of the first two options you used last time, just use it again.
          If you used the 3rd option use the 5th option to undo it.
          If you used the 5th option use the 3rd option to undo it.
          If you used the 4th option, use it again twice to undo it.
          The 5 RGB swap options, along with another that is not listed RGB -> RGB, represent the 6 ways of permuting 3 objects. These 6 permutations form a group (in the mathematical sense). In a group with a finite number of elements, multiplying any element by itself repeatedly will eventually result in the identity element of the group. In this case, applying the same color swap at most 2 or 3 times will result in the original colors. So for someone trying to undo a particular color swap, this means they only need repeat that same color swap choice another 1 or 2 times before getting back the original colors. This of course assumes the user remembers the original colors.

          If you used any of these color swap choices
          -------------------------------------------------
          __RGB -> RBG
          __RGB -> GRB
          __RGB -> BGR
          Repeat the same choice once to undo


          If you used any of these color swap choices
          -------------------------------------------------
          __RGB -> GBR
          __RGB -> BRG
          Repeat the same choice twice to undo


          Cheers!
          "Never do today what you can put off until tomorrow" -- Bizarro Ben Franklin

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            #6
            There is a good reason why an undo step is not created. Undo space is expensive: we only have one and unlike pro graphics editors it is stored in the very finite Random Access Memory.

            Without mentioning mathematics I'd simply say that color swap is a lossless process. The simple rotate commands also do not build an undo.

            The advantage is clear: You can perform color swaps or rotates all day and still have your previous undo at hand.

            I have noticed this behaviour a long time ago and said to myself: “how clever Irfan is!” Unlike Matera I found this aproach very intuitive. In my audio editor (Sound Forge) I frequently have to change the sampling rate to play sound slower or faster. This is similar to zooming. And after such playing with the "speed slider" a long list of undos appear. It then takes an unknown number of clicks on the Undo button to revert to the actual previous state.
            Last edited by j7n; 29.08.2008, 10:12 PM.

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