Hi *According to conclusion above, we will plan how to migrate to Cairo.* We will need help with Pango.
Cheers, Alex On 26 January 2017 at 23:45, Aliaksei Syrel <alex.sy...@gmail.com> wrote: > Hi > > (My previous email was not a joke, I don't try to troll anyone. Let tolls > do their job in other places) > *Let's forget Moz2D for a moment :) Imagine that it does not exist. *It > was done just for fun and is even not in pharo repo. ( > https://github.com/syrel/Moz2D). We needed something that works and it > was made investing just a few months of time of a single anonymous student > during summer exams session and vacations. > > I would like to start maybe one of the most important discussion that will > influence Pharo and will dictate how system will look like in a few years. > I invite everyone to join this discussion, especially board and consortium > members. Because here is where business starts. > > There are some real questions: > > 1. Do we need Bloc or Morphic2 or %name your favourite framework%? > 2. How advanced and modern do you want it to be? > 3. What technology stack do we want to use for our new graphical > framework? > 4. What platforms and operating systems do we want to support? > 5. How flexible technology stack should be? (some parts may change in > the future) > 6. Who will pay for it? > 7. How many engineers can community afford? > 8. Do you know how much other systems invest in graphical frameworks? > 9. It is not a science project, isn't it? > > Let me first put my two cents in. > > Low-level UI framework (without widgets) consists of multiple parts: > > 1. Vector graphics library to render shapes (fill, stroke, path > builder, composition and blending operators) > 2. Font service library (to support different font formats and collect > information about local fonts installed in the system) > 3. Text layout engine (this is where glyph positioning magic happens, > link above too) > 4. Text shaping engine (for high quality text rendering, to understand > the problem => http://behdad.org/text/) > 5. Complex script library (to support ligatures, split glyphs and > other UTF8 stuff, remember https://github.com/mi > nimaxir/big-list-of-naughty-strings > <https://github.com/minimaxir/big-list-of-naughty-strings>) > 6. Image processing library (for various image effects, like gaussian > blur, morphology filter, gamma, displacement map, just to name a few) > 7. Hardware acceleration. Software rendering is nice, however, modern > UIs are full of fancy stuff that require hardware acceleration. > 8. Window and Event management library. With support of borderless and > semi-transparent windows + good support of touchpad. > 9. Custom written "Glue" library that allows all components to work > together. Since modern libs are implemented in C++ we would need to > implement C wrapper and a lot of integration tests. > 10. Make the whole beast cross platform. > > > Did I miss something? > > Here are some modern technologies commonly used for mentioned parts: > > 1. Skia, Direct2D, CoreGraphics, Cairo > 2. Fontconfig, Freetype2 > 3. HarfBuzz > 4. Pango, OpenType > 5. Graphite2, FriBidi > 6. Imagemagic, SVG filters libraries > 7. Vulkan, OpenGL > 8. wxWidgets, QT, GTK, SDL2 > 9. todo > 10. todo > > Luckily Pango covers bullets 2 - 5. It indeed sounds like a great idea! > > Let's assume that we stop on Cairo + Pango. According to pango.com > > The integration of Pango with Cairo (http://cairographics.org/) provides >> a complete solution with high quality text handling and graphics rendering. > > > According to the this potential technology stack we will have: > > - Cairo for vector graphics and rendering of basic shapes > - Pango for text rendering > - SDL2 for window and events management > > What we will not get: > > - Support of filters; Cairo does not support gaussian blur. 3D > transformations, we will not be able to not implement card flip animation. > Never reach the same performance if using platform native frameworks (e.g. > Direct2D on windows). Cairo will not die, but there is zero progress. > - Vulkan support. Never with cairo. Pure OpenGL too (try to compile > cairo-gl on mac, good luck!) There is a way to compile it with quartz > support. As of version 2.7.9, *XQuartz does not provide support for > high-resolution Retina displays to X11 apps*, which run in > pixel-doubled mode on high-resolution displays. ( > https://bugs.freedesktop.org/show_bug.cgi?id=92777 > <https://bugs.freedesktop.org/show_bug.cgi?id=92777>). > - Borderless or transparent window with SDL2. Also, did you notice > that sdl2 window turns black/white while resizing? There is no way to get a > continuous window resize event with SDL2 (https://bugzilla.libsdl.org/s > how_bug.cgi?id=2077). The issue is that events stop firing while user > is resizing a window because main thread is blocked. *Bug is already 3 > years old. *Indeed SDL2 is used for games, however how often do gamers > resize game window? > - Stateless API. Must have for a graphical framework like Bloc where > canvas state is not shared between visual elements. It means that while > rendering users must not clean the state of a canvas after every draw call. > > Bloc is not my or Glenn's or Doru's personal property. We suggest, you > decide. It would be great if community could invest money and time in a > working and appropriate solution. > > P.S. If we would not care, we would agree with you instantly and even not > bothered ourselves trying to spend time on finding cheap solution for such > a complex problem. > > P.P.S Sorry for a long email :) > > Cheers, > Alex > > On 26 January 2017 at 21:10, Aliaksei Syrel <alex.sy...@gmail.com> wrote: > >> Hi, >> >> Then we will need Cairo + SDL2 (that does not work for us) + Freetype2 >> (for fonts) + Graphite (glyphs shaping technology in order to use them >> within vector graphics engine) + cross platform OpenGL / Vulkan >> context/device provider for hardware acceleration + implement Filters for >> effects (blur, lights, color matrix filters, etc...). >> >> Without all those technologies bloc WILL progress, from 80's to 00's. >> Still decades behind :) >> >> Cheers >> >> On Jan 26, 2017 20:40, "stepharong" <stephar...@free.fr> wrote: >> >>> I think that instead of investigating gtk (yet another library to bind >>> and carry around), >>> it would be smarter to have Sparta back-end using an accelerated Cairo + >>> pango. >>> Why? Because >>> - For example Cairo will not disappear in the future (here you >>> will tell me that it does not have all the full >>> features.... I think that Bloc should deliver Brick first and >>> focus on this because else it will stay a nice >>> experiment.) >>> - We do not have bench with an accelerated compiled version so >>> no idea if this is good enough. >>> - Cairo is about 1.5 mb vs 20Mb and it is packaged. >>> >>> I share the concerns of Esteban about the maintenance of such Mozz2d >>> bundling and he was pretty >>> clear with me, he will not maintain it nor take any responsibility about >>> pharo using it. >>> >>> So having a Cairo Sparta back-end would be a smart move. >>> Stef >>> >>> >>> >>> >>> >>> Hi, >>>> >>>> Thank you for the intensive set of issues you raised during the Bloc >>>> presentation. I think it is worthwhile addressing them more thoroughly, so >>>> let me start with the issue that seemed to have caused the most worries: >>>> Sparta & Moz2D. >>>> >>>> Please keep in mind that while I am involved to some extent in Bloc, >>>> the real credits for the current state go to Glenn and Alex. >>>> >>>> Moz2D (https://github.com/mozilla/moz2d, https://wiki.mozilla.org/Platf >>>> orm/GFX/Moz2D) offers an advanced backend and using it puts us on par >>>> with the rendering speed of a web browser, which is a significant added >>>> value over what we have now. >>>> >>>> However, as it was noted, it does come with a cost due to the fact that >>>> it is not available as standalone with only the features we are interested >>>> in. The vector graphics part is actually buildable out of the box. However, >>>> the text support needs to be extracted out of Moz2D, and this is where the >>>> patching scripts are used. The patches are there only for compilation >>>> purposes and not for features and they are applied automatically. You can >>>> see it here: >>>> https://github.com/syrel/Moz2D >>>> >>>> Alex updated recently the Moz2D version and it worked without problems. >>>> Of course, future changes in Moz2D might imply changes in this script as >>>> well, and this implies that we will need to maintain that script. And we >>>> could imagine applying these patches on the trunk of Moz2D to see if they >>>> work, and we can also imagine engaging with the Moz2D owners to see if we >>>> can find a middle ground. >>>> >>>> Now, let’s put this into perspective. We are currently using Athens and >>>> the Cairo backend. While Cairo is provided as a standalone library it has >>>> not seen significant advances since Mozzila shifted its focus towards >>>> Moz2D. So, sticking with it might not be an ideal strategy either. >>>> >>>> Furthermore, just like Athens, Sparta is an abstraction that allows us >>>> to switch the underlying backend should we need to. Until now we did not >>>> find a cross-platform backend that is as advanced and complete as Moz2D, >>>> but there is no reason to think that none other will appear in the future. >>>> Skia is an alternative but it is only a vector graphic engine without text >>>> support, so using it would imply to have another library for the text >>>> support. >>>> >>>> Sparta also comes with a reasonable set of tests that is aimed at >>>> testing the basic Moz2D functionality to make sure that the assumptions on >>>> top of which Sparta is built are correct. >>>> >>>> All in all, I think that the current situation is not ideal, but there >>>> is already enough engineering in place to actually make it work. And I >>>> definitely think that the potential it opens is rather significant. >>>> >>>> And, if more people look at the scripts, we might find even better and >>>> cheaper ways to express it. >>>> >>>> Cheers, >>>> Doru >>>> >>>> >>>> -- >>>> www.tudorgirba.com >>>> www.feenk.com >>>> >>>> "We cannot reach the flow of things unless we let go." >>>> >>>> >>>> >>>> >>>> >>>> >>> >>> -- >>> Using Opera's mail client: http://www.opera.com/mail/ >>> >>> >
