On Oct 24, 2004, at 11:10 PM, Joseph J. Strout wrote:
At 10:09 PM -0400 10/24/04, Barrie Jones wrote:
Here is a basic question:
If I draw on a canvas with coordinates that extend beyond the window,
will the window scroll bars be set up automatically?
No, you have to handle that yourself. Any drawing beyond the bounds
of the canvas is simply clipped off. But when a scrollbar value
changes, you get a ValueChanged event (or something like that), which
you can use to redraw the canvas content -- such drawing to take into
account the current values of the scrollbars, of course.
Thanks for the starter Joe. I have found some examples and need another
guideline before I start.
My graphs could be much larger than the computer screen. They are not
too complex and draw very quickly.
1) Should I instantiate a canvas big enough for the oversize graphic
such that only part of it shows in the window with scroll bars? Then
just draw the graphs using coordinates of the oversize canvas. I then
read scroll bars etc...
or
2) Having created the big canvas, should I use NewPicture to draw
offscreen then place it on the big canvas.
or
3) Could I make a window sized canvas (locked to the window) and do my
oversize graphics in a NewPicture, apply part of the NewPicture to the
canvas and scroll the NewPicure on the smaller canvas.
Barrie
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