On Friday 01 Aug 2008 4:23:49 am Scott Wallace wrote:
Therefore, when a child wanted to drag a Sketch, just moving the mouse pointer over it brought up a halo, and that halo always included the "center of rotation" handle, typically right at the center of Sketch, right where the child was likely to grab it if intending to "pick it up."
mouse over halos are useful when the pointer has a single button only (e.g. handhelds with touch stylus.
Pick-on-click changes the z-order and I have seen children getting flustered when many minutes of careful stacking gets changed by a casual click. Treating click-drag as a move may be a better option.
How about the following for handling mouse events?
if mouse-over-halos is true then on hover bring up halo. bring up direction handles based on pref if bluebutton is pressed bring up halo with direction handles always. and then if halo is on ignore mouse clicks outside of halo buttons and dir handles. allow dir handle to be moved/rotated using direct drag. else allow morph to be moved using direct drag.
Nowadays, however, we operate with mouse-over-halos turned off, and with the showDirectionForSketches preference turned off as well.
If direction handles are always shown, kids learn to anticipate its appearance. I introduce it to them as "legs" (arrow is the big toe) around which the morph can turn or leave a trail. This metaphor goes well with the overall theme of costumes and players.
Subbu