> -----Original Message----- > From: development-bounces+kai.koehne=digia....@qt-project.org > [mailto:development-bounces+kai.koehne=digia....@qt-project.org] On > Behalf Of John Layt > Sent: Thursday, March 07, 2013 9:55 PM > To: development@qt-project.org > Subject: Re: [Development] ICU and Windows > > On Thursday 07 Mar 2013 16:16:05 Koehne Kai wrote: > > >> On 02/06/2013 11:20 PM, Koehne Kai wrote: > > >> > [...] > > >> > That is what we should do indeed. I learned from > > >> > > > >> > http://userguide.icu-project.org/icudata > > >> > > > >> > that one can also ship the ICU data in separate .data files, > > >> > located in a "ICU>> > > >> data directory" that can be specified e.g. at compilation time. So > > >> how about creating a bare minimum icudt.dll, and rather ship .data > > >> files in a well-known place ($$[QT_INSTALL_ICU])? This would allow > > >> anyone with enough knowledge to tailor what exactly they want to > > >> ship, while reducing the footprint of "I don't care about > > >> localization for hello world" types of applications. > > > > > >Alright, this is what I found out so far: You can configure ICU to > > >either place all the data in the icudt49 library, >or in one big .dat > > >file at a specified location, or as individual files. Having multiple > > >.dat files is supported >too, but that requires someone deciding how > > >they should be split up. > > > > > >Shipping the library is what we have right now, which is IMO not > > >acceptable. Just check out the comments on the >5.0.1 release blog, > > >there are people still caring about 20 MB overhead :) Shipping the > > >default .dat file would mean >hat either your app doesn't have any > > >codec support etc at all, or has everything. If we ship individual > > >files we'd >need to ship > > >2345 files... that gives full flexibility, but good luck for the poor > > >developer trying to find out >what he needs :) > > > > > >So the bottom line for me is: _We_ have to come up with an ICU > > >profile that contains what we consider important, and >which we want > > >to ship in our default icudt library. If someone needs additional > > >things he could add it by just >shipping e.g. an additional .dat > > >file. [...] > > > Thoughts? Comments? Praises? ;) > > This is an issue that will only get worse if/when we hard require ICU for all > the localization data, so we do need to work out an acceptable solution. > > One of the ideas behind moving to ICU was to allow embedded devs to > decide what locales they wanted to ship to save space, rather than having > them all embedded in QtCore. It's obviously a feature that the Windows > devs would appreciate too, although 20MB really doesn't seem that much to > me :-).
That depends on the viewpoint, I guess :) It's a lot if you have to add it to a minimal console app just using QtCore. > I assume the idea of your patch is to use the http://apps.icu- > project.org/datacustom/ to create the minimal .dat file and include that in Qt > along with the empty dll? No, actually not. The patch is just about being able to use an ICU that is compiled with '--with-data-packaging=archive'. That is, icudt library is empty, and all the contents are in a separate .dat file. The tricky part is however to make sure we find the .dat file at runtime ... > One option to note is that according to http://userguide.icu- > project.org/icudata in the "Reducing the Size of ICU's Data" sections you can > modify the ICU build to put less data in the dll simply by removing the mk > files for the conversion tables and locale and collation data you don't need. > Keeping only the core conversion tables apparently reduces the data to > about 5MB. This would also save any messing with having to load a .dat file. Sure, but the question is whether we can come up with a sensible default for the ICU libs in the official installer. There seems to be some data that current Qt / Webkit API's do not use, e.g. Collators. But if I de-select e.g. "Collators", "Rule Based Number Format", "Transliterators" from http://apps.icu-project.org/datacustom/ it's still 15,5 MB :( > It's clear that we can't require devs to know how to pick and choose what ICU > resources they do and don't need, as they won't know what ones are > needed and which are optional. Perhaps we need to write a tool or build > script that helps devs with choosing what resources to include, and then > deletes the mk files and builds ICU for them. In this way we avoid having to > build or ship ICU ourselves, but still make life easier for devs. If the > script > could also tell qmake what features to enable/disable in Qt as a result then > even better. ICU has these tools already: It's http://apps.icu-project.org/datacustom/, icupkg, and gencmn . What's missing is IMO mainly some documentation which Qt modules / API's use which data. > The first step is obviously to compile the list of all the resources we > currently > need and don't need, and the conversion tables are the obvious main target > for reducing the size. True. > I'll make sure when I do the QLocale changes that devs can choose to only > use the system locale resources on the understanding that they won't have > custom locales or advanced features like collation available. Sounds good :) Regards Kai _______________________________________________ Development mailing list Development@qt-project.org http://lists.qt-project.org/mailman/listinfo/development
