Philipp Reichmuth wrote:
>>> What forbid us from loading the bitmaps all at once when they are
>>> generated? Will it be very slow or very memory consuming? If this is not
>>> possible, can we use bitmaps directly when displaying a new page instead
>>> of drawing lyx formulas and then replace them with bitmaps?
>
> KB> If you would have hundreds of formulas , you would know the answer.
> KB> Having a slower processor is a pain on startup.
>
> Would it be possible to generate bitmaps ahead while the user does
> nothing, just to utilize idle periods?
>
Sorry for bringing up again this old thread (I wasn't paying attention :). I
also find the current behaviour also somewhat annoying. I think that there
is some misunderstanding, and I'd like to contribute to it :)
This is more or less what I understand from reading the code and doing a bit
of experimentation. Please correct me if I'm wrong.
1) Right now all previews are converted to ppm on a first shot at startup
(including latex, dvips and ps->ppm), in non-blocking mode (you can type
while it's doing it). This is obviously the most time-consuming operation.
Then these bitmaps (which can be loaded natively by both frontends) are
loaded un screeful at a time, this time in blocking mode.
2) On my 1Ghz i686 the loading operation of all snippets is aceptable (like
10 sec), on a normal-sized document (35 pages) with lots of formulas. Of
course, on a large book it can be annoyingly worse.
I've checked this by removing the check for heigh < bv_height on
for (int height = 0; row && height < bv_height; row = row->next()) {
On getVisibleParagraphs, located on graphics/GraphicsSupport.C
Maybe an easy way to improve things would be to load more than one screenful
at a time (say two or more). I suppose that this can be achieved by adding
a look-ahead factor F, somethig like
for (int height = 0; row && height < F*bv_height; row = row->next())
Does this makes sense?
3) I don't know if a smarter way of loading bitmaps (like the one suggested
by Andrè) would improve things that much: bitmap loading is still
"blocking"... I think that the ultimate solution is still to make it
non-blocking, i.e. to load on idle time, like Bo Peng suggested.
Sorry if I've misunderstood everything...
Bye, Alfredo
