🚀 go-pugleaf

**> On Tue, 12 Jan 1993 22:53:00 GMT, piggy@hilbert.cc.utas.edu.au (La Monte Yarroll) said:

  piggy> I'm writing a user interface based on epoch in which I need to use
  piggy> multiple mouse clicks for alternate functionality.

Great!

  piggy> If anyone has already solved this problem, I'd like to know--in any
  piggy> case I'll be coding my proposed solution today.

Try looking in the various emacs lisp archives.  The ones that have
epoch code are likely to have epoch mouse handling for multiple
clicks. IMOUSE is one such package that did useful stuf: one click to
set point, doubleclick to select word, triple click to select
sentence.

Information on emacs lisp archives for epoch code can be found in the
FAQ.  Look for the faq tomorrow.

  piggy> I invite comments on this proposal.  Counter-proposals are welcome.

Here come some comments.

  piggy> Version:
  piggy> 	Epoch 4.2, mouse.el revision 1.12--multiple click detection
  piggy> 	based on code by Brian L. Kahn.


  piggy> BUG:
  piggy> 	Epoch calls the mouse handlers on each up and down click.  It
  piggy> 	should only call an event handler once for a given type of
  piggy> 	click.  I.e. a double click should not first call the code for
  piggy> 	a single click. 

Okay. To start with, I don't consider this a BUG.  Nor, do I doubt, do
the Epoch developers, or any number of people who have written mouse
code for epoch.  Or, for that matter, mouse code under _ANY_
reasonably modern user interface toolkit (e.g., Motif, XView, Athena,
Garnet, Mac Toolkit, Windows, etc. etc.).

Why is this not a bug? Well, let's look at your proposed solution:

  piggy> Proposed solution:
  piggy> 	Extra modifiers mouse-single-... mouse-quintuple-... will be
  piggy> 	added to the valid modifiers which can be passed to routines
  piggy> 	such as define-mouse.  Note that this allows for notions such
  piggy> 	as mouse-double-down and mouse-triple-up.  The default is to
  piggy> 	assume a single click.

  piggy> 	No mouse handler will be called until mouse-interval ms have
  piggy> 	elapsed since a mouse event has been reported by X.

Alright, so there's a big problem: LAG.  We're talking about lots of
lag.  Whenever you click the mouse button, epoch would always have to
stall for mouse-interval ms, waiting to see if this click was really a
double-click.  This would make using epoch's mouse abilities feel like
wading through putty.  For example, suppose mouse-interval is an
entire second. Every time you use the mouse, epoch would freeze for a
second.

[example code deleted]

Wanting to do radically different things on single and double-clicks
is generally a bad thing.  I'd suggest looking at books on ui style
(e.g., the Mac style guide) and considering what gets selected in a
mac text field when you click some number of times.

Brook

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Brown Computer Graphics	| Fortune sez: Brook's Law -- Adding manpower to a late
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