Hi all,
These days I am doing the work to improve the speed of openning a .ppt file
which contains many jpg or bmp pictures.
I found use MS Powerpoint and OOo impress to open the same .ppt file(contains
many jpg or bmp pictures),OOo impress
is much more slower than MS Powerpoint.In my test,MS Powerpoint open my test
.ppt file in 3-4 seconds, but for OOo
it is 1-2 minutes.
I have tracked the process of importing a .ppt file, here is the process:
......
ImplSdPPTImport::Import()
SdrPowerPointImport::ImportPage(...)
SvxMSDffManager::ImportObj(...)
SvxMSDffManager::ImportGraphic(...)
SvxMSDffManager::GetBLIP(...)
SvxMSDffManager::GetBLIPDirect(...)
GraphicFilter::ImportGraphic(...)
Graphic::SetLink(...) // ********* here save picture
data into a temp file
SdrGrafObj::ForceSwapOut()
GraphicObject::FireSwapOutRequest()
GraphicObject::ImplAutoSwapOutHdl(...)
GraphicObject::SwapOut() // ******** here again swap out picture
data to temp file
......
To my opinion, OOo impress opens .ppt file slower because of:
1. It imports all contents before displays, but MS Powerpoint only imports
those needed;
2. It create too many temp files for those pictures embeded in slide pages,
but MS Powerpoint do nothing about this.
Then I do some tests, first I omit the function Graphic::SetLink(...). In the
case open my .ppt file(contains many jpg or
bmp picture), the speed raise 30%-40% and only several temp files created.
Everything looks ok except the peak memory
is twice. Maybe too many picture data in memory?
So my question is:
1. Why we must import all things before to display it? Maybe operation speed
will fast but load speed is too slow;
2. Can I maintain the input sream( .ppt file stream ) all the time? So I can
import any thing when I real need it;
Thank you to read my question, and I need your help. Any comment and hint are
welcome.
best regards,
jiangdongjin
