Re: Questions about the font shaping tender
On 02.02.2016 11:58, Khaled Hosny wrote: > Personally I’d do a mixture of the two, a 7th (8th? I think we have 6 or > 7 SalLayout implementations already) SalLayout that uses HarfBuzz > (reusing the existing HarfBuzz integration code as much as possible) > then gradually switch existing platforms to it as it matures, so it is > an overall win not just for the sake of fixing tests. that definitely sounds like a reasonable approach--i feel we currently have more platform specific font rendering back-ends than we can handle. if harfbuzz is good enough for Firefox and Chromium on all platforms surely it can be good enough for us. ___ LibreOffice mailing list LibreOffice@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/libreoffice
Re: Questions about the font shaping tender
I’m just trying to understand what is this about for now. Regards, Khaled On Tue, Feb 02, 2016 at 07:18:28AM +1100, Chris Sherlock wrote: > This does seem a bit odd… unless we want to make AFM parsing cross-platform? > > The only thing that I’m aware implements AFM parsing is > PrintFontManager, which is only used by Unix-based platforms. > > Could we get some clarification around this? > > Oh, and also - Khaled, once this is clarified why don’t you go for the > tender? I can’t think of anyone I’d more highly recommend than > yourself, and I’m reasonably certain you have some good ideas around > how to fix the SalLayout mess... certainly you have the technical > expertise and experience to tackle this. > > Just a suggestion :-) > > Chris > > > On 1 Feb 2016, at 9:35 PM, Khaled Hosny wrote: > > > > I just came across this tender [1] and it is not quite clear to me what > > is it about. Am I right in thinking this is about having a shared > > cross-platform implementation of VCL text layout API (the dreaded > > SalLayout et all)? If so I don’t understand what AFM stuff is doing here > > since we don’t use any of this AFM stuff during text layout as far as I > > can know and I don’t see how it can even be reused for such a task. > > > > 1. > > https://blog.documentfoundation.org/blog/2015/12/16/tender-for-cross-platform-fontshaping-stubs-for-layout-tests-201512-05/ > > > > Regards, > > Khaled > > ___ > > LibreOffice mailing list > > LibreOffice@lists.freedesktop.org > > http://lists.freedesktop.org/mailman/listinfo/libreoffice ___ LibreOffice mailing list LibreOffice@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/libreoffice
Re: Questions about the font shaping tender
On Tue, Feb 02, 2016 at 10:15:07AM +0100, Miklos Vajna wrote: > Hi, > > I think the problem to solve is that we have different layout on Linux, > Windows and OS X, which means it's next to impossible to write unit > tests that assert the text is laid out correctly, since there can be > small differences today. The hope is that this is the root cause of e.g. > the chart tests which are not enabled by default today. > > As far as I know, there are two ways you can solve this: > > - use the Linux stack everywhere (fontconfig, freetype, harfbuzz? > something like that), IIRC that's what e.g. Chromium does > - create a 4th layout in VCL, which is just a stub, but gives exactly > the same results in all platforms, to allow writing unit tests that > are executed in all platforms OK, I think I see the line of reasoning behind the second option, but I still fail to understand what AFM has to do with this, using AFM to get glyph metrics to avoid using platform specific APIs? If it is just a stub implementation, why not use a fixed width font and simplify/dump things even further? Personally I’d do a mixture of the two, a 7th (8th? I think we have 6 or 7 SalLayout implementations already) SalLayout that uses HarfBuzz (reusing the existing HarfBuzz integration code as much as possible) then gradually switch existing platforms to it as it matures, so it is an overall win not just for the sake of fixing tests. Regards, Khaled signature.asc Description: PGP signature ___ LibreOffice mailing list LibreOffice@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/libreoffice
Re: Questions about the font shaping tender
Would it be helpful to look at the way that OutputDevice handles laying out text? When I was looking at this code early last year I found that I had to try to understand what OutputDevice did before I could come even *close* to understanding what SalLayout was attempting. For instance, the DX array code looks suspiciously like it was adopted from the way that EMF (and I guess Windows GDI?) handles text layout. If I were to start a Wiki page, would that be at all helpful? It would be rough, but if others wanted to correct my mistakes and misunderstandings then could this be helpful in any way? Chris > On 2 Feb 2016, at 8:15 PM, Miklos Vajna wrote: > > Hi, > > I think the problem to solve is that we have different layout on Linux, > Windows and OS X, which means it's next to impossible to write unit > tests that assert the text is laid out correctly, since there can be > small differences today. The hope is that this is the root cause of e.g. > the chart tests which are not enabled by default today. > > As far as I know, there are two ways you can solve this: > > - use the Linux stack everywhere (fontconfig, freetype, harfbuzz? > something like that), IIRC that's what e.g. Chromium does > - create a 4th layout in VCL, which is just a stub, but gives exactly > the same results in all platforms, to allow writing unit tests that > are executed in all platforms > > Regards, > > Miklos > ___ > LibreOffice mailing list > LibreOffice@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/libreoffice ___ LibreOffice mailing list LibreOffice@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/libreoffice
Re: Questions about the font shaping tender
Hi, I think the problem to solve is that we have different layout on Linux, Windows and OS X, which means it's next to impossible to write unit tests that assert the text is laid out correctly, since there can be small differences today. The hope is that this is the root cause of e.g. the chart tests which are not enabled by default today. As far as I know, there are two ways you can solve this: - use the Linux stack everywhere (fontconfig, freetype, harfbuzz? something like that), IIRC that's what e.g. Chromium does - create a 4th layout in VCL, which is just a stub, but gives exactly the same results in all platforms, to allow writing unit tests that are executed in all platforms Regards, Miklos signature.asc Description: Digital signature ___ LibreOffice mailing list LibreOffice@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/libreoffice
Re: Questions about the font shaping tender
This does seem a bit odd… unless we want to make AFM parsing cross-platform? The only thing that I’m aware implements AFM parsing is PrintFontManager, which is only used by Unix-based platforms. Could we get some clarification around this? Oh, and also - Khaled, once this is clarified why don’t you go for the tender? I can’t think of anyone I’d more highly recommend than yourself, and I’m reasonably certain you have some good ideas around how to fix the SalLayout mess... certainly you have the technical expertise and experience to tackle this. Just a suggestion :-) Chris > On 1 Feb 2016, at 9:35 PM, Khaled Hosny wrote: > > I just came across this tender [1] and it is not quite clear to me what > is it about. Am I right in thinking this is about having a shared > cross-platform implementation of VCL text layout API (the dreaded > SalLayout et all)? If so I don’t understand what AFM stuff is doing here > since we don’t use any of this AFM stuff during text layout as far as I > can know and I don’t see how it can even be reused for such a task. > > 1. > https://blog.documentfoundation.org/blog/2015/12/16/tender-for-cross-platform-fontshaping-stubs-for-layout-tests-201512-05/ > > Regards, > Khaled > ___ > LibreOffice mailing list > LibreOffice@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/libreoffice ___ LibreOffice mailing list LibreOffice@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/libreoffice
Questions about the font shaping tender
I just came across this tender [1] and it is not quite clear to me what is it about. Am I right in thinking this is about having a shared cross-platform implementation of VCL text layout API (the dreaded SalLayout et all)? If so I don’t understand what AFM stuff is doing here since we don’t use any of this AFM stuff during text layout as far as I can know and I don’t see how it can even be reused for such a task. 1. https://blog.documentfoundation.org/blog/2015/12/16/tender-for-cross-platform-fontshaping-stubs-for-layout-tests-201512-05/ Regards, Khaled ___ LibreOffice mailing list LibreOffice@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/libreoffice
