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List:       kde-kafka
Subject:    Re: Writing the selection code
From:       Thomas <zander () xs4all ! nl>
Date:       2000-11-23 17:48:01
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> Hello all,
> 
> Over the pas few days I have been getting to grips with DOM, and I have 
> it straight, I can begin writing some of the selection methods.
> 
> What we need are the following methods:
> 
>  - To be able to click in the view and select an object
>  - To be able to click inthe view and select where to write some text
>  - To be able to highlight some text
>  - To be able to highlight objects

I understand that the DOM allows the editing of object via api calls,
this means selecting, changing, adding.

I would suggest a cursor object that can point to a dom object and the text
in there.
So the cursor could for example point to a specific <p> tag, character 10. 
The <p> tag should be referenced, meaning that moving the <p> tag to a <td>
tag should not invalidate the cursor (I want it to remember where I was typing).
The pointer should also save a position (in pixels) for the undo mechanism.
For every undo a cursor would be saved so the cursor placement is remembered
through undo/redos. But that is pretty advanced.
Don't know if the QCursor can be used here..

Highlighting text/objects means having 2 object references, a start 
object and an end object. Within these objects you could have a start/end
position.

For example:
 <p>line1</p>
  <hr>
 <p>line2</p>

selectionStart is firstP, character 3
selectionEnd is lastP, character 5

Remember that there are only 2 <P> objects in the above example, not 4 ;)

Selecting on objects basis is the same, minus the character offsets. We just
need a way to calculate which objects are between the first and last object. 
I think we need coordinates to calculate that..

Basically you have 2 objects in your doc object for text
selection and 2 objects for object selection. If you can use a <p>-type
object for this; great!
 
>  - Update the DOM tree with what the user does. If for example we want 
> to type text in it would find the node where the mouse is, take in 
> keyboard input for one letter, update the DOM, move the cursor 
> (keyboard) right one letter and repeat. For updating the DOM we can use 
> the KHTML DOM calls, and there is also a method which returns the DOM 
> node the user clicks on. This could be reimplemented.

ehh, reimplemented?? Why not just use that?
Read some of the earlier emails Schimmy wrote about this stuff.

> If anyone has suggestions on a better way, or would like to get their 
> hands dirty, please speak up.

Just  passing along some things, hope it helps.

-- 
Thomas Zander                                            zander@earthling.net
The only thing worse than failure is the fear of trying something new
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