What's our metaphor - a whiteboard, or a bulletin board?
The display area contains regions with distinct appearances - "Whiteboard", "Cork", and "Hazard Stripes". The distinct appearances are visual cues for what the region does:
Post-it's are rectangular surfaces containing information. They can be placed over a whiteboard area, or stored in a corkboard area. Corkboard areas also function as zoomscape regions for postits; postits placed over a corkboard area are reduced in size; their former size is restored when they are removed from the corkboard area.
The FlowMenu is used for all actions other than drawing/painting.
The primary action in the whiteboard and in postit areas is drawing/painting, as if with a pen.
When the user draws on a whiteboard or postit, and the stroke goes under another postit, the overlapping postit temporarily turns semitransparent.
When the user draws on a postit, and the stroke reaches or exceeds the postit's current bounds, the postit grows in size dynamically to accommodate the stroke.
(Problem: If the user draws on a postit that is in a zoomscape, and the drawing stretches the bounds of the zoomscape, that might cause the zoom level of the postit to suddenly change. This must be handled in a way that's as non-jarring as possible.)
Other actions in the whiteboard and postit areas include:
choose pen color pen thickness
choose to erase (freehand scribble eraser)
Chunks of drawn information on the whiteboard area can be "lifted" off the board to create a new postit that contains and encloses that information.
This process can be done destructively (remove the original copy of the information) or non-destructively (copy, without disturbing the original)
The process can be done freehand or with a rectangular "rubber-band" select.
The user can also create new blank post-it, using a rectangular "rubber-band" action to define its size.
When the user interacts with a postit, it is brought to the fore of the z-ordering. Thus, postits are z-ordered with most-recently-used on top, while least-recently used ones are on the bottom.
Postits can be moved, resized, destroyed, and made transparent.
Postits can have one of a number of pastel shades, just like paper postits.
The user can copy the postit's drawn content to the whiteboard, either destructively or non-destructively. In this way, a frequently used symbol or picture can be "stamped" - draw the picture on the whiteboard, make a postit out of it, move the postit into position and non-destructively "stamp" the image onto the whiteboard.
Various ways to "cleanup" the workspace:
The whiteboard can have all it's drawings cleared off
A "Delete All" command destroys all postits and removes all drawn information.
A "Tidy-up postits" command would be worthwhile, but some thought needs to be put into coming up with reasonable behavior for it.
Saving vs. Storing: What happens when you restore a save in a different physical environment than it was originally made?
When the SketchClient sends over a sketch, it appears in a brand new postit note. The user of the SketchClient can "post", "revise", or "clear" that note. Sketchclient can send variable color notes to variable locations Real-time drawing in sketch-client? Possibly.
You can have arbitrary islands of zoom or send; even a roomapplet-like arrangement!
Transitional areas; shrinks from a direction to a direction, or shrink from out-to-in
Would you have to specify lots of different shrink directions to avoid discontinuities?