STR #1742

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STR #1742

Application:FLTK Library
Status:5 - New
Priority:2 - Low, e.g. a documentation error or undocumented side-effect
Scope:3 - Applies to all machines and operating systems
Subsystem:Core Library
Summary:Fl_Browser: Inconsistent behavior of value()
Created By:vedran
Assigned To:matt
Fix Version:Unassigned (SVN: v5952)
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#1 vedran
04:53 Jul 18, 2007
The method int value() returns the row that has keyboard focus. This is inconsistent with void value(int) which selects the row (nothing to do with keyboard focus).

Looking at int value() implementation one can see this:
int Fl_Icon_Browser::value() const {
  return lineno(selection());
It seems ok, but actually the Fl_Browser_::selection() method in context of Fl_Browser returns the line with focus, not the selected line.

One suggestion is to fix Fl_Browser_::selection() to work as advertised, but then there would be no way to detect which line has focus, not to mention the many people that subclassed Fl_Browser_ in their projects that would now have problems.

IMHO it is much better to just fix int Fl_Browser::value() to something like this:
int Fl_Icon_Browser::value() const {
  for (int i=1; i<=size(); i++)
    if (selected(i)==1) return i;
  return -1;
And also update documentation for Fl_Browser_::selection().

This is related to my STR #1740 which propose adding separate methods for focus handling.
#2 matt
11:43 Oct 07, 2007
I updated the documentation accordingly. I am more than hesitant to change the actual behavior at this point, but I understand that the return values are useless and unexpected. Unfortunatly, the strive for binary compatibility does not allow for a new pointer in Fl_Browser_ which would hold the *focused* item as opposed to the *selected* item.

Then again, returning a single value from a browser that allows an arbitrary number of selections would be wrong anyways. Even return the first selected value would be wrong - that would be like claiming that a broken watch is right twice a day is a feature.

Anyway, I upped this to 1.2 in the hope of finding a good API there.
#3 matt
15:09 Dec 28, 2008
upped to 1.3  
bottom left image   bottom right image

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