regarding ymacs caret
Jason Wang
i was trying to understand how the code is structured. i read the pdf
regarding your style of programming, but i still couldn't figure out
how you did your caret at this point.
Basically, when i click on a character anywhere, you can detect which
character precisely i've clicked and move the caret there. How did you
detect which character i clicked? Where did you handle to the event?
thank you very much for any pointers!
Jason
Mihai Călin Bazon
It's one of the tricky parts. :-) But the algorithm is quite simple — look in ymacs-frame.js, function "_on_mouseDown".
1. determine the (x, y) of the click in pixels relative to the editor (that is, point (0, 0) is the top-left corner of the editor area). This is done by ev.computePos(element) (DynarchLIB function).
2. translate coordinates into (line, column) with coordinatesToRowCol(x, y) (look for this function in Ymacs_Frame).
This second function is the tricky one. It defines two helper functions, findLine and findCol. They are recursive and work the same, although for column is a bit more work. They start from the middle, and search that line/column which is closest to the mouse click.
Another helper is the coordinates(line, column) function (also in Ymacs_Frame) which returns the (x, y) in pixels of a certain character in the buffer. To accomplish this it inserts an empty SPAN tag at that position and then looks up its coordinates.
Inserting the SPAN is a story in itself, and it's implemented in the insertInText function (again, in ymacs-frame.js).
Hope this helps.
Cheers,
-Mihai
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Mihai Bazon,
http://mihai.bazon.net/blog
Jason Wang
I am trying to look through the DlEvent library, but i can't figure
out what the DOM argument (where your D and P are) is. As well, for
clarification, the difference between event and eventproxy is that
event is for native events in javascript and eventproxy is for user
defined events?
Another question, i noticed that in the docs it says for EventProxy
you need to call callHooks to pass in parameters and such. Is the ev
in _on_mouseDown(ev) an instance of DlEvents?
Thank you very much for all your help!
Jason
On Apr 14, 2:29 am, Mihai Călin Bazon <mihai.ba...@gmail.com> wrote:
> Hi Jason,
>
> It's one of the tricky parts. :-) But the algorithm is quite simple -- look
> >www.ymacs.com- AJAX code editor