From: Simon Tatham <[EMAIL PROTECTED]> "ahmad khalifa" <[EMAIL PROTECTED]> wrote:
> im guessing that simon is moving the Shaping/Bidi calls to a less frequently
> called function. i.e Bidi/Shaping is called only when the Actual text buffer
> changes. that would be more efficient.
That's certainly something I want to do. Currently, the bidi and shaping routines are called for the whole window on _every_ call to do_paint(), and since those happen on a timer, they really need to be doing less when there's no change.
I'm not sure how best to do that in the current architecture. I suspect it's going to be necessary to cache each line of the terminal both before _and_ after doing bidi, so that the `before' cache tells you whether you need to run the bidi algorithm at all, and the `after' cache tells you precisely which characters on the line actually need redrawing.
instead of that, cant you just call bidi/shaping on buffer change ? i.e on WM_KEYDOWN and on 'receive()' ? or maybe a separate timer with a bigger interval ? but some flickering would occur.
ofcourse your expertise on putty would be best for tackling this issue, but if you want i could look into it...
> i dont convert the whole string to unicode and then back, i lookup > the unicode value for each char as needed,
Yes. The trouble is that PuTTY _already_ does character set conversion code, so doing your own entirely separately is a complete waste of space (not to mention that your implementation used a global variable in minibidi.h, which is a serious portability hazard).
What _should_ be happening is that minibidi.c shouldn't be directly handling an array of wchar_t. Instead, it should be handling an array of structures containing both a wchar_t and an index back into the original ldata array. Those wchar_t are set up before calilng do_bidi(), using PuTTY's own character set conversion (so it doesn't just work in UTF-8, CP1256 and CP1255 - it also works in ISO-8859-6 and ISO-8859-8, and any other character set we might later support in PuTTY).
This allows the maximum amount of information to be preserved from the original ldata. In particular, it allows the bidi algorithm to move the character attributes (bold, underline, colours etc) along with the displayed character, because for every bidi_char output from the bidi routine there is an index parameter pointing back to the original ldata entry which contains all the attribute data.
I've prepared my own version of the patch which demonstrates this. You can download it at
http://www.tartarus.org/~simon/arabic-putty/patch.arabic.20040501.simon
Alongside that is a demonstration text file, which I downloaded from the Web and added colour escape sequences to. You can download this test file, in three different character sets, from:
http://www.tartarus.org/~simon/arabic-putty/buniya.utf http://www.tartarus.org/~simon/arabic-putty/buniya.win1256 http://www.tartarus.org/~simon/arabic-putty/buniya.iso88596
You should find that my patch supports ISO-8859-6 as well as Win1256 and UTF-8. You should also find that two words near the top of the file are highlighted red and blue, and that the red and blue highlights move _with_ the text when you turn bidi on and off.
I'm still not ready to check this patch in, because I haven't yet fixed the speed problem caused by running the bidi algorithm all the time. But I'd like to know what you think of the changes so far.
Great, i think you just finished Phase-2 !! and you also gave me a good idea of how to deal with cursors inside bidi. anything we can do to speed up the process ? as i said if you're busy i can look into the On-Buffer-Change.
ak.
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