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List:       kfm-devel
Subject:    Re: khtml/khtmlw and getSelected()/getSelectedText()
From:       Waldo Bastian <bastian () ens ! ascom ! ch>
Date:       1999-06-17 13:30:13
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Dawit Alemayehu wrote:
> 
> On Wed, 16 Jun 1999, Waldo Bastian wrote:
> [snipped]
> > I had a look at this the other day. The problem seems to be that select() isn't
> > working correctly for HTMLText objects. You might have noted that Ctrl-A
> > does select all other objects (e.g. images, links) on a page.
> 
> Correct.  This is what I actually meant.  It does not select the text objects
> at all.  But what is wierd is that HTMLLinkText inherts from HTMLText and
> does not override the select() method at all.  Why would it then work for
> hyper-links and not regular text objects.

Well... We have several text classes... there is a README about that I guess.

Most text is not actually a HTMLText but a HTMLTextMaster.
This HTMLTextMaster spawns of HTMLTextSlaves during layout.

The HTMLTextMaster contains the actual text as well as selection 
start and end. The HTMLTextSlave contains a pointer to the Master and
info about where which part of the text should be drawn.

> > I think that we should add a select(...) method to HTMLText which takes into
> > account the selStart and selEnd fields of the HTMLText object.
> 
> >From one of the select() methods in HTMLText :
> 
> void HTMLText::select( KHTMLWidget *_htmlw, HTMLChain *_chain,
>     bool _select, int _tx, int _ty )
> {
>     const char *u = getURL();
>     if ( (u == 0) || (*u == '\0') || (_select == isSelected()) )
>         return;
> 
>     setSelected( _select );
> 
>         selStart = 0;
>         selEnd = strlen( text );
> 
>     _chain->push( this );
>     _htmlw->paint(_chain, x + _tx, y - ascent + _ty, width, ascent+descent);
>     _chain->pop();
> }
> 
> setStart and selEnd values that contain the length of the text within the
> HTMLText object are indeed already in both select methods, but they are not used
> at all in these methods.  Could this be the problem ?? 

Unlikely. They are used in the paint methods of the object.
(htmlw->paint descents the object tree to paint the object)

> The reason
> I am unsure is because HTMLLinkText inherts from HTMLText and does not override
> the select() methods, however the select() function works okay for it.

The problem most likely doesn't lie in HTMLText but in HTMLTextMaster/Slave.
(Sorry for stating otherwise)

Basically there are two clases of HTMLText functions:

HTMLText and HTMLTextMaster/HTMLTextSlave.

Derived from these is HTMLLinkText and (I guess) HTMLLinkTextMaster 
(used for links)

The difference between HTMLText and HTMLTextMaster/Slave is that HTMLText 
is used for words without any spaces or with only non-breaking spaces.

HTMLTextMaster is a specialized object which can contain a whole paragraph 
of text and which can fit itself into a flow thereby breaking itself up into
HTMLTextSlaves for each line.

This is done to reduce the number of objects needed to render text.

Having a paragraph consisting of text with 100 words which needs to be
spread across 5 lines would take 100 HTMLText objects. Using HTMLTextMaster/
Slave objects, we only need 1 HTMLTextMaster and 5 HTMLTextSlaves.

Unfortunately these Master/Slaves objects are slightly more complex than 
the other objects in KHTML(W).

Cheers,
Waldo
-- 
KDE, A New Millenium, A New Desktop                      http://www.kde.org

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