Chagall Reference   Frame-/Block-mode     12.5.93
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   This mode is used to edit pictures, or a cut out
   portion of one (a 'block').

   A 'frame' here is a rectangular marking in the 
   picture which has no contents as yet. A frame
   is indicated by 'empty corners' of the marked area.
   
   A block, on the other hand, is created by cutting
   out, copying, loading etc. Block markings have 
   'filled corners'.
   
   With this mode activated, you can first of all 
   draw out a frame. If the current picture already
   contains a frame or block, then by activating this
   mode you get the possibility to move it with the
   mouse.

   Furthermore, a frame (not block!) can also be scaled: 
   By dragging any corner one can vary height and width 
   simultaneously, whereas by dragging at an edge just
   the height or the width can be altered. 
   There is also an important difference between frame
   and block in moving its position: A frame cannot be
   pushed across the borders of the current picture (of 
   which you may see only a cut-out portion in the window).
   You can draw blocks that are larger than the window, 
   but if you reach the edge of the picture then the block 
   will be limited by this and the frame will 'shrink' by 
   an appropriate amount. A block, on the other hand, 
   can also be pushed outside the visible region of the 
   window; during this the whole of the block basically 
   remains visible.
   
   If one moves the block outside the current window, then 
   this corresponds to a Drag-and-Drop..\..\..\DIV\DRAG.


