Newsgroups: comp.lang.smalltalk
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From: forcieri@ERE.UMontreal.CA (Forcier Isabelle)
Subject: How to make graphical objects blink in VW 1.0 ?
Message-ID: <forcieri.792253141@alize.ERE.UMontreal.CA>
Sender: news@cc.umontreal.ca (Administration de Cnews)
Organization: Universite de Montreal
Date: Wed, 8 Feb 1995 14:19:01 GMT
Lines: 37

I have a view that is composed of many graphical objects (to be more 
specific, a gantt with a lot of operations in it) and I want to make the 
emphasis on some of those operations witch are represented by a 
rectangle, a border and a textual ID inside.

An easy way to do this is by drawing a thicker border for those 
operations. I would prefer to make those operations blink on the screen 
to get the attention of the user. I have an idea on a way I could 
implement this, but i'm afraid it will be very slow. Anyway, here's my idea:

1- Create an idependent process for the "blink" of the operations so the 
user can work while the operations are blinking.

2- The "blink" are simulated by constantly redrawing the operations, 
using 2 different colors.

Since the time spent to draw something is quite long, i'm not shure this 
would be a good implementation. Note also that the graphical objects on 
the gantt (the operations) can be moved at any time by the user and that the 
gantt is inside a scrolling view.

For now, my best shot is to try to accelerate the time to redraw an 
object on the gantt.

If you think of something else, let me know...

(Somebody told me that on those old computers, you could set a pixel to 
blink and forget about it... I think it was by setting a particular color 
and the system knows that the character in that color should blink. He 
was pretty surprised when I told him that I didn't know anything about 
making something blink within visual works --otherwise than constantly 
redrawing the object that should blink with an independent process--)


Philippe Marier
forcieri@ERE.UMontreal.CA

