text2skin & Performance

Hi there,


Finally I think I found the bug which eats my CPU time.


It's a bit complicated, and I'm not sure how this is fixed best. The bug
is not within VDR, the hundred thousands calls dsyslog() were just a
symtom, not the real cause.


Let me explain:


As I already suspected, it's related to the channel logos of the
DeepBlue skin. I added some debug statements to the file bitmap.c from
the text2skin plugin, and found out that the skin renders all channel
logos with a size of 506x616 pixels, which is *far* too big, leads to an
absolutely useless scaling of the image, and calls DrawPixel() and
therefore cPalette::Index() about 300.000 times, requesting far too much
colors, and therefore triggered the dsyslog() call.


But why the hell 506x616 pixels? Well, it took me some time to
understand this one: The reason is not the rendering of the bitmap
(which is *never* used!), but the call to cText2SkinBitmap::Available(),
which is used by the file() expression from the XML skin processor.


Available() simply tries to load the bitmap and returns !NULL if
successful. It is called with the size of the object, which seems to be
unknown in the <block condition="file(...)"> case, using the whole size
of the OSD.


All this takes *a lot of* useless CPU time! I did some quick&dirty
hacks, the results are impressive! No more CPU peaks in the "Channels"
menu, and much faster!


Now, how can this be fixed?


First, we could change the cText2SkinBitmap::Available() function:
cText2SkinBitmap *bmp = Load(Filename, Alpha, height, width, colors, true);
to
cText2SkinBitmap *bmp = Load(Filename, Alpha, 0, 0, colors, true);


Second, we could change the cxFunction::FunFile() from xml/function.c
and remove the mObject->Size().* parameters, setting them to zero.


But, I'd prefer another solution: The Reference doc from the Text2Skin
plugin reads:


> 3.10 file
> --------
> Returns the parameter, if the file exists in the skin directory.


It says "if the file exists", but in fact it checks if it's a valid
bitmap! Maybe someone wants to check for a non-bitmap file????


I's suggest replacing the call to cText2SkinBitmap::Available() with a
simple call to stat(), checking for file existance, and nothing more.




Any comments?




bye, Michael