More on the Gimp

 Selections, Paths, Channels, Masks

 1) A "Path" is one of those bezier-tool shapes.

    * Paths can be manipulated interactively.
      - move pivot points
      - move handles together or individually.

    * You can save a Path (closed or open) 
      in the "Paths" part of the Layers window.
      Once there, you can add points, take away points, etc.

    * You can show/hide it by picking different tools.

    * You can convert any selection to a Path.  (Tricky.)

    * Or, you can covert a Path to a Selection (it'll close).

    * You can "stroke" a path with the current brush.

    * Paths can be "locked" to current layer so that
      transforms (perspective, rotate, scale, ...) affect path as well. 

 2) Transparency of selections
    
    * selections can be "aliased" - select transparent percent of a pixel.

    * selections can be "feathered" - fade in/out (transparency) gradually.

 3) Selections can be saved as "Channel Masks".

    * visibility (eye) toggle shows selected mask

    * paint/filter applies only to stuff in mask

    * essentially gives multiple selections in same image

    * can combine (add/subtract/intersect/...) mask with selection

    * can set color and opacity to aid in editing

    * can create/edit masks by "painting" (greyscale) in them


 4) Applications of all this :

    * colorize seperate parts of an image (masks for various parts)

    * edit paths / masks / selections in many ways to get just parts you want

 5) Examples

    (will do some of these next week, following the book)


   (a) 

    Using castle and accordian in this directory, 
    make the woman appear to a giant behind the castle.

    Then put that in a picture frame 
    ("picture frame" in Google gives www.pictureframes.com
     which gives many examples)
    and use perspective transform to put in on a wall somewhere...


   (b) 

     colorize selected parts of an aimge (pg 117)

   (c) 

     shadows and highlights convert circle to a ball (pg 182)

   (d)
    
     global color changes and levels (pg 202 and thereabouts)

   (e)

     removing part of an image (pg 212 and thereabouts

   (f)

     compositing (chapter 7)

   (e)
     
     rendering (text special effects, chapter 8)