DWD Structured @ CERN

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After a seeming eternity the unthinkable has finally happened; DWD has been discussed formally on an implementation level and it’s exciting to say that some parts are now under development. Thanks to the CERN Sprint we’ve had Martin Gräßlin, Sebastian Kügler, a couple others, and myself in one room able to make final decisions on how it will all come together.

Dare I say DWD is officially real, entering development, and coming? Yes!

Previously I’ve made two posts about DWD concepts, this post will summarize the basics of DWD as it has been finalized. Some parts of both designs previously posted have been used and I’ll make another post later including mockups with more detailed information, but for new here’s an overview of DWD basics;

Low-Level IPC

DWD will use D-Bus as its IPC, being implemented via the KWin Window Metadata Tier 1 Framework. This is for Qt/KDE driven implementations, but anyone can implement DWD via D-Bus.

Core Structure

At its core DWD will work with ‘Semantic Objects’ and ‘Priority Groups’. Semantic objects refer to things like ‘media player controls’, ‘navigation’, and ‘actions’. Applications bundle Semantic Objects into Priority Groups, then push those groups to the window manager.

The window manager will tell the app whether a group was accepted or rejected; a group is rejected if any single semantic object in that group is denied for any reason. Higher priority groups get first swing at embedding their controls, and it may affect widget placement in certain situations, such as phone controls.

From there applications just hide their own elements in response to what groups were accepted. There will be some events and flags as well, but we won’t get into that yet.

Customisation

One aspect to note is that DWD will offer no customisation on the client-side. I had gone down that rabbit-hole in an early draft and we all deemed it overcomplicated. Ultimately what applications need to know is that the controls are being served – not how or where they’ve been served.

One thing we did was look at is Gnome CSDs which offered all the craziness applications could possibly want, and we noticed they weren’t actually being all that crazy with it. Generally the same controls made repeat appearances and when it really comes down to it in practice there’s not much of a value in extreme customisation. As we said previously if you need extreme customisation and weirdness this may not be the method for you – which is fine. At the same time we would recommend application authors examine why they would need exotic controls, and why they specifically need them in the windeco.

Stewarding the Protocol

One thing that was discussed was who and how to steward the protocol. When I first posted about DWD there was backlash about KDE being a ‘protocol gatekeeper’. Afterwards I proposed an extension-based design which also had backlash because it could make the protocol technologically ‘complex and messy’.

Ultimately we decided to steward the protocol and simply work with anyone who wants to be included in the design process directly. We will accept input into where the protocol will go and provide any resources we can.

One thing that was made clear was that some groups are uninterested in considering the DWD approach after being asked. We all agreed it’s not worth making a convoluted extension system just to cater to groups which probably won’t participate, instead focusing on making the best protocol we can for those who want DWD. For those environments that will not support DWD I’m glad to say that it’s still 100% compatible and applications using it will continue to work as normal, they just won’t have content in the decoration. We will not be breaking other environments.

Again, we’ll be open and welcoming to anyone who wants to join us in working on and implementing DWD.

The Implementation Plan

Right now early work is being done on our existing frameworks to move them into position to implement DWDs. Once that is done we’ll implement the protocol with a minimal number of Semantic Objects, and using the low-level API port a small number of simple applications as a beta. Applications being considered for initial DWD tests include Konsole, Kate, KCalc, and similarly small apps with basic requirements.

After the API has proven itself on smaller-scale applications we would move up to heavier applications. KDevelop was mentioned specifically as a candidate as its relatively heavy UI could benefit from space-saving DWDs while developers could very quickly give us high-quality feedback. This may be where we move to higher-level classes which will hide away the group/object system as well.

Designs & Reference Material Incoming

I’ll be making another post later with designs which should be mostly accurate to what the final protocol will produce; accurate enough to place in the Wiki as design references for how applications should look when using the final DWDs.

While Martin will continue focusing down Wayland and making excellent progress, he also had a rough timeline for when we can expect basic DWDs make an appearance. I won’t quote him as it was an off-the-cuff estimate, but it’s exciting to know there’s light at the end of the tunnel, and that we’re out of the conceptual phase.

On a complete aside it was a complete pleasure meeting everyone. Great to see some of the friends I met last year again, fantastic to make many more new ones, and I wanted to thank everyone in the Sprint as well as those who supported it for making such a great event happen.

Special thanks to CERN for hosting this Sprint! Be awesome and support future Sprints by clicking the links below;
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DWD: Protocol U-Turn

Since Martin posted his Wayland progress I’ve noticed an uptick in questions about CSD, so I figure now is a good time to upload this post I’ve had sitting around, as for the past month I’ve been closely examining the concept of “Dynamic Window Decorations”, or “DWDs” and how to better implement them.

When Last We Saw Our Heroes

For those who need a primer or reminder, DWD is the sister of “Client Side Decorations”, or “CSD”s. Both CSD and DWD are methods for placing widgets in the frame area of windows to save vertical space, look cleaner, and either make applications feel unique or more integrated.

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Indeed, DWDs would be themeable like traditional decorations, fully supporting transparency effects.

CSD charges the application with drawing the whole window including the frame, instructing the window manager to discard the provided frame. This is the method used on Windows, OSX, and GTK. DWD is aiming for the opposite approach; the window manager continues to draw the window frame, but the application can request certain widgets to replace the window title. Martin Gräßlin plans to keep as much as possible on the server-side as there are many important advantages including customisation, stability, trust, and integration.

DWD “1.0” Was Getting Complicated

One thing CSD will always have over DWD is customisation; when an application has free reign over the whole window it can literally do anything; it can make windows round if it wants to, it can invent crazy widgets and put em’ in the title area, and more. DWD isn’t suited to this, and while designing the first iteration of the protocol I tried to bang a square peg into the round hole by providing those many possibilities.

In my infinite wisdom I re-invented X, with a sprawling protocol that covered dozens of edge-cases which would likely never be used. Even with that, people still complained about the fact that many customisations would still impossible. People also didn’t like the KDE crew being the stewards of this protocol, as different environments want to do different things.

DWD, as originally envisioned, had to change – it was just too complicated and inflexible. Listening to the feedback it was clear the protocol had to be simple, flexible, and tractable. A large requirement was also making it able to grow outside of KDE with or without our ‘approval’.

DWDs New Approach

DWD, as I have drafted it, has been boiled down to a discovery service whose sole purpose is getting apps and window managers to figure out compatible protocols, and specify some standard UI controls which will use those protocols.

Here’s the quick overview on the current core “DWD Protocol”, again, as of my current draft (which could totally be rejected):

  • DWD will be organised into “extensions”. Extensions are just blueprints listing required D-Bus specifications, widgets/controls, and options.
  • Applications and the Window Manager handshake for compatible extensions.
  • Applications tell the Window Manager what controls from those extensions it should display, and how it wants them laid out.
  • Applications hide their native controls.
  • DWD is done and gets out of the way at this point. Control is handed to specifications like MPRIS2, and Window Managers (or Plasma) control the app through those protocols using the requested controls.

That’s it, DWD “2.0” in a nutshell.

KDE will need to create some reference extensions (plus some D-Bus specs) and hopefully everyone will be happy enough to standardise on the basics. From there any environment can create specialised extensions for DWD, we can work with extensions we like, and maybe standardise on the really useful ones (much like libinput has been folded into many environments). If someone makes an awesome extension that handles admin access requests, we could use it. If we make an extension that handles progress charts, someone else could adopt it. I’d like us to develop two reference extensions: a basic toolbar extension, and an MPRIS2 extension.

Advantages over “1.0”

Security is the biggest upside to offloading work on other protocols. DWD doesn’t care how the standards are implemented, so they can be as secure (or insecure) as they choose to be. Security issues or weaknesses in the protocol itself will be mitigated, as the protocol is much smaller. Patches for applications or changes to functional protocols can be made without breaking DWD.

Integration is also another bonus. Parts of the desktop can integrate the protocols extensions use, without DWD needing to explicitly support it. The best example is MPRIS2, which already exists and has amazing support everywhere. The idea behind DWD is that we create more MPRIS-type extensions as we need them.

Finally, core DWD is out of the hotpath for data passing. Window Managers don’t need to be “like X” and conform to complex drawing and customisation tasks. Hopefully as a de-stresser to Martin, this method of offering DWD will be much more easily implemented in a plugin architecture which can be gradually expanded upon. We won’t need to have the full protocol out-of gate, and environments can start with the bare basics and evolve as useful extensions are finalised. I don’t know how he might want to do it, but DWD extension plugins could be potentially be maintained entirely outside of Kwin (or other Window managers) if we play our cards right.

The Downsides

Nothing is perfect, so of course there are downsides;

Customisation.

The big elephant in the room. Going over more standard protocols (and not bloating the new specification) means applications will have no say over how content is styled in the window. I considered this for a while and ultimately decided that it’s O.K.

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We could still offer a few more standardised ways of doing common things we do today, such as passing a colour palette to sync with the window, but outside of the handshake I’ll push for an extension-over-integration policy.

 

The application doesn’t need to know how things are done, only that they’re getting done. The WM knows more about the environment it’s in than the application; functionality is what matters. The volume button on a computer might be shown as a slider, but on a touch-device it may be a larger button with a popout slider. Maybe a phone will simply use the hardware controls. It’s up to whatever is managing the control.

For people already seething with rage ready to point at me and say “Linux is about choice! Applications should choose what their UIs look like!” I will point out; applications can chose not to use DWD. They can choose to implement a CSD-based application. But lets be real here: when we find a need for speciality widgets, if they are really something useful, their host toolkits/environments can always add the extension.

Generally though, if an application is doing something really unique it’s probably doing it’s own thing anyway – like Chrome/Chromium – or breaking the local HIGs. If you absolutely need to save that 18px while also showing a one-of-a-kind rainbow-powered rocket-widget which must be in the frame… CSD is the price of needing to be that special.

Fragmentation.

With anyone able to create extensions, there’s a change we might have a situation where two environments create two similar offerings. For this, I believe it’s a chance for everyone to experiment, and then work together to standardise. The one thing this means is that applications created for another environment might take longer to get CSD-like functionality, though they should present their interfaces in their traditional application UI.

I think this is still better than CSD, as often a broken CSD is unusable vs a DWD which will simply not conserve space.

DWD

So, in the end, this is the direction DWD has gone. Keep it simple, let anyone decide how it should be used, and piggyback off of proven protocols.

MPRIS2 shows what a purpose-driven protocol can do, and already has lots of examples of “remote control” interfaces. Outside of MPRIS2 we would create missing D-Bus specifications which would hopefully make the wider applications library accessible in a similar manner. Specifications for things like progress management, search, sharing, and many others could be created which will benefit applications, and allow deeper desktop integration for everybody.

For those who saw the previous designs in my original DWD blog post, not much has actually changed visually. Everything I posted is still possible, but now we have a much more practical way to do it which I am much more confident we could reliably implement and share.

Plasma Sprint 2015

Just over 2 weeks ago I stepped off a plane, putting my heels onto Canadian soil after spending a week participating in the Plasma 2015 Sprint. The entire experience was exhausting in the best of ways, and after landing home my throughput was thoroughly trounced for some time as I settled back into normalcy. But lets rewind to the beginning;

The day of my arrival in Barcelona it would be a far cry to say I was nervous – in the moments before pressing the buzzer I was in a downright terror! These people will realise I’m an idiot! Ship me back to Canada on the next canoe! Needless to say only minutes in to the sprint not only were my worst fears completely unfounded – but I met a group as welcoming as they were brilliant.

Finally, I think I have the perspective to share my experience. I won’t try to recap the entire event, I will mainly focus on VDG work.

But first! The People of KDE

I met about a dozen dedicated and hard-working developers in the Blue Systems office during the sprint, and it needs to be said just how great these people are – each and every one passionate about their respective fields and projects. I’d really just like to give a shout-out to everyone I met in the Sprint. They’re the kind of people who make you smarter by proximity, and they welcome you to do it. For anyone invited to a Sprint I highly recommend jumping on the chance; you will be enriched for doing it.

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Drawing Konquis

After arriving mid-day Jens Reuterberg headed the idea to begin creating and stockpiling promotional graphics. Essentially we wanted vector artwork which could be used easily for things like release announcements, large print materials, web pages, etc. Jens dove head-first into logotypes, and I splintered off into doing up a pair of vector Katie and Konqui graphics during my half-day; Konqui being a direct trace, and Katie being new. You can view the original graphics by the talented Tyson Tan here.

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Download KatieDownload Konqui

VDG ❤ Developers

There was a great deal discussed during a pair of review and planning sessions in the first two official Sprint days. One of the biggest things (for Jens and I) was helping the VDG and developers interoperate better; for those who don’t know, the VDG communicates very differently than mainline developers.

Devs tend to focus on bug reports, mailing lists, reviewboards, and IRC. Members of the VDG tend to use Forums, Hangouts, and to a limited extent IRC. Immediately there’s very little overlap, which means at this point developers have to go to the forums to wield the VDG.

The problem lies in how forums operate; where the VDG design processes benefits from the relative chaos, it’s not good for developers looking for the ‘final word’ of the design discussion. It’s further impacted by forum conversations which don’t have definitive conclusions, or discussions which can get muddled down. When developers go to the forums they need a solid final product to build around – but on multiple occasions they end with a half dozen different designs and no clear answer on what they should do.

It was a short discussion during the Sprint, but Jens and I both immediately agreed that this is an area where the VDG must step up and refine our process.

The current idea will be sticking with the forums threads as the main creative area, but changing the way they spin down. Once we feel a design discussion has gestated, the VDG aims to have a member pull the ‘final’ design from the conversation, at which point they’ll put together a coherent deliverable developers can understand and act on, on a channel they are comfortable with.

There are still details we are ferreting out before we more formally put this into motion, but the essential aim is to move the VDG into a position where we can reliably ship usable deliverable design, on a channel developers can comfortably handle.

Breeze Applications

This only came up briefly during the Sprint as well, but is something which has been brewing for a while now – so it might be worth mentioning ‘for realsies’, essentially since I don’t think anyone pointed out that this is a ‘thing’;

KDE and Plasma have a bit of a history with names, and for many core applications we’ve been wanting a more consistent scheme for it all. At the same time, with every major tookit release (i.e. Qt4 -> Qt5) many applications need to be ported or re-written. Finally, on these major releases, visual/workflow trends have usually shifted meaning the experience of applications will also shift.

So, all this stuff going on, we figure it’s time to put a bow on it and turn this cavalcade of factors into one cohesive event, so we’ve come up with the concept of Breeze Applications.

The idea is that, coinciding with frameworks, trend, and design changes we will name a subset of the bundled applications after the current design. So for Plasma 5 we will have ‘Breeze’, for some future plasma version many moons from now we may have ‘Gust’ or ‘Wind’ applications.

What does this mean? The biggest thing is that we intend to use these ‘Breeze’ applications as standards bearers, which we hope to see other applications follow. It’s much the same way Google treats ‘Holo’ and ‘Material’, along with their base applications: This is the design, these are the examples. Ideally we intend to focus on only a few applications, which developers will be able to dissect and say ‘oh, this is the plan’. In addition, as new technologies and techniques land, we hope Breeze applications will be the frontrunners in adopting cutting-edge KDE/Plasma technologies.

Does this mean every Plasma or KF5 app will be named “Breeze X”? No. We only plan on Breeze-ifying the more simple core applications which can be easily maintained, kept up to date, and streamlined enough that the code could easily be used for reference material.

Fun fact: The bathrooms in Frankford are powered by Ubuntu!
Fun fact: The bathrooms in Frankford are powered by Ubuntu!

Dynamic Window Decorations

Before I even get started on this, I must give props to David Edmonston. The man is a trooper, and I feel almost as if I tortured the poor gentleman throughout the sprint.

During the sprint I presented some of my DWD plans; technical details were discussed, implementation questions were raised, and concerns were were round-tabled. The discussion was extremely positive and productive, and real issues were ferreted out.

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One of the larger questions was ‘what IPC protocol should be used?’; I personally was educated about the Wayland protocol, and that it could be used even on ‘non-wayland’ systems – since it is just a protocol and not an installed library. Ultimately, the developers present agreed that D-Bus was the way to go, the general consensus being that the protocol is known and familiar, mature, battle-tested, and isn’t going to shift or break.

I also gave my personal thoughts on how applications might access/implement DWDs, and while there’s still considerable room for discussion, it seems to be on the right track. I was cautioned by developers and I feel the need to point out: even when the DWD protocol does pick up steam it will still be years before it’s available in any meaningful way.

During the development portion of the Sprint I managed to rope David into doing some DWD work on a proof-of-concept level. Through his efforts we now have a much better idea of what obstacles we will face integrating widgets into server-side decorations, such as ensuring the draw code runs correctly/efficiently. He heroically managed to get window decorations to draw usable sliders, so we do know window decorations are capable of drawing server-side widgets.

Sadly, the proof did nearly cost David his sanity. It probably didn’t help that I was giggling like an imbecile. Sorry about that, David. I hope the tea made up for it. :/

UI Feedback

Throughout the Sprint Jens and I were able to lend our services in helping to design and streamline interfaces. Towards he end of the Sprint we also did a walkthrough of the Plasma desktop and several components to identify surface-level bugs and weak areas.

This included an extensive review of the system settings utility and its KCMS.

I also managed to chip in some light advice with a new power-manager tool, and an upcoming redesign of the Baloo settings manager with Vishesh Handa.

And a Great Deal more!

As I mentioned at the start of the post, and can only mention again; There were a lot of really great people at the Sprint – and all of them had their own projects, goals, plans, and feedback. It was really impressive to meet people who had such a deep understanding of KDE Frameworks and Plasma, able to talk about extremely complex technologies in detail over a coffee.

I, personally, learned a great deal from everyone. From being unable to compile a package to now comfortably hacking, simply rubbing shoulders with the outstanding individuals was absolutely my privilege.

There’s a great deal not in this post, but I imagine other posts will fill in the rest… So on a closing note I will say again; if you are ever invited to a Sprint, don’t hesitate to say yes – it’s an amazing experience which is beyond worth it!

I drank this. I still don't know what it was.
I drank this. I still don’t know what it was.

DWD – a FAQ for questions around the Web

Don’t know what DWDs are? Click the link below to find out!

https://kver.wordpress.com/2014/10/25/presenting-dwd-a-candidate-for-kde-window-decorations/

It seems about the right time to post some common questions and misconceptions about DWDs I’ve seen around the web, so here’s a general FAQ about DWDs; If I missed any questions about DWD, please post them!

Window decorations would be responsible for widgets. Here's 3 potential window decorations using DWDs.
Window decorations would be responsible for widgets. Here’s 3 potential window decorations using DWDs. Note that the decoration dictates style – and users dictate the decorations. Complete control of your personal preference.

DWDs are going to make my windows inconsistent and ugly! Application widgets might clash with my window decoration!

DWDs are not CSDs, and all theming and drawing is handled by the window manager and decoration. In addition, applications only export the structure of their widgets, they do not pre-draw or draw the widgets themselves. Applications would have little or no say in how their decorations look, just like traditional SSDs.

That being said, we don’t want DWDs to be absolutly rigid, we are looking at ‘safe’ ways applications can do basic branding on themselves in a reasonable manner, which decorations could potentially integrate without excessive effort. The main thing we are looking at is allowing applications to offer a colour pallet which decorations could use to tweak their appearance, but DWD ultimately would put the power in your hands and options would also be provided to disable unwanted hints and effects for more consistency. A primary sentiment with DWDs is that the user would be completely in control of all aspects DWDs would provide.

Will I lose my current customizations, or ability to customise? Will I lose the ability to customise my windows in the future?

No! DWDs will actually give you more options – at least in KDE.

The only change to your existing configuration might be the switch from standard SSDs to DWDs when the option is initially added (or deemed stable). If you wanted your current setup to reign supreme, you could simply disable DWD-based widgets, and your desktop would be remain identical to how it is today.

I want features like controls on my phone, or controls in the panel, but I don’t like widgets in window decorations. Can I have one but not the other?

Yes. Since DWD is just a protocol, we could potentially build DWDs to be enabled/disabled on a per-service basis. You disable it in kwin, but keep device integration, or vice-versa.

How will I move the window if everything is interactive?

There are a few things we can do to address this issue.

The first is by looking at individual widgets and checking to see if they could conceivably be dragged. For example, buttons could easily be considered draggable surface. Progress bars are a draggable surface. About the only things that can’t really be dragged (which we would include in the specification) are tabs, text inputs, and sliders. Sliders take very little vertical room, they are less of an issue.

Next, we’ll recommend decorations insert generous area of padding in parts of the frame, which would provide grabbable area to drag from. Of course, if you have something against padding and would rather drag a window by holding alt – I’m sure an ultra-compact theme will accommodate you.

Lastly, we’ll also look at how widgets are configured, and potentially we could offer alternate behaviours for widgets. If users didn’t care about the order/arrangement of their tabs, we could easily have an option to just make tabs another draggable surface (and disable rearranging). Sliders could have an option to require users specifically use the knob. Text inputs could be set to require focus before a drag->select can occur. There are many options.

Overall, we want to assume that at least one or two apps will “abuse” DWDs, so I’d want to build ‘safety’ on the decoration level.

DWDs are complicated / CSDs would be simpler.

For applications developers DWD should be similar in complexity to CSD but will have extended options available and additional features, while omitting APIs for complex styling. DWDs will not impose default structures or layouts, or make assumptions about your layouts. Overall, DWD should be roughly equal to CSD for applications developers; they’ll likely just have a different API focus.

On a system/library level CSDs may be simple when you look at them in face-value; a simple library lets a program draw its own more functional header. But when you look at the grand scheme of things CSD libraries by nature don’t care to integrate with all environments, causing massive headaches and complexity to all other developers outside the targets of the CSD library; if the CSD library did attempt target target all environments, the CSD library itself would be *insanely* complex. Simply put you’ll never, ever, ever hear about a CSD library that supports KDE, Gnome, Windows, Mac, Unity, etc etc. DWD also forgoes the need for complex hacks and workarounds that desktop environments have had to kludge together; such as enabling corner-dragging in the toolkit because there’s no window manager support on frameless windows.

With DWD, environments can choose to support or not support DWDs, and provide incredible amounts of integration which CSDs simply cannot offer. Environment-specific integrations applications are doing (such as menubars) is primarily done through kludges and duct-tape, and even then they still don’t properly support every environment. Unity/Mac-style menubars are so broken in so many places it’s silly; support for the same applications and desktop environments vary from distro to distro. Gnome is moving towards eliminating them completely, with Gnome devs expressing that it’s one of their goals.

Lastly, the look and feel is also less susceptible to breakage; it’s been noted that GTK will often break themes, meaning theme developers constantly have to keep up with CSDs. With DWDs, the window manager doesn’t even know or care about the toolkit – it just follows the standardised instructions.

In other words once you step outside a face-value glance, DWD eliminates huge amounts of complexity – and more importantly breakage – through consistency. And support, while initially about as bad as CSD, actually has a chance of propagating across multiple desktop environments and toolkits reliably.

The buttons are too big! I hate this big button trend! (aka, I don’t like the look! It should look like this!)

I agree! DWD applications should absolutely fit and feel exactly how you want them to. If DWDs are implemented, it would be up to the window decorator and decoration to provide options like spacing, sizing, look and feel. So aside from the options decorations themselves might be able to provide, being able to completely change the decoration or decoration engine is an option. You could use minimal themes, fancy themes, ultra-compact themes or even embed the controls elsewhere and use a minimal wire-frame. DWDs would give you *more* control over the look of your applications than you’ve ever had before. So if you think one style is ugly, you aren’t ever stuck with it.

I don’t like DWD or CSD! Just keep SSD! Keep my titlebars clean!

Depending on the window manager using DWDs, buttons in titlebars could be disabled; resulting in traditional SSDs. The DWD specification is aiming to be completely backwards compatible, which means we also get a traditional SSD mode for free. That being said, DWD is still mostly conceptual at this point, so you’re still ‘safe’ from the evils of UI changes for a while.

Could my toolbar menus be placed in the window frame if DWDs aren’t supplied?

I personally would not fold this in to be a part of the DWD specification – but developers might decide otherwise. In my designs I had DWDs placing the application menubar into an overflow portion of the command menu; I should elaborate on that:

Ideally menubars in DWD command buttons would be an application-specific option and not part of the core DWD specification. Not all applications use menubars, and in some cases (such as productivity or professional applications) the application *needs* those menubars front-and-center – not behind a button. The DWD client library would likely just include a convenience function that would allow easy menubar embedding into the command menu’ putting it into the applications’ control.

In other words, I think this should be a Kwin-specific thing, and not a DWD-specific thing. The goal of DWD isn’t to ‘take over’ the window, merely to extend it.

Could DWDs fall back to CSDs?

Yes, they could! But no, KDE won’t!

One of the few things about KDEs’ implementation would be that we would not use CSDs as a fallback ourselves. DWDs could conceivably fall back to either CSD or SSD, but it would be an application/toolkit decision. KDE sentiments are falling back to SSD if DWD became a thing, and I personally agree with that choice. KDE/Qt technologies are designed to be used in a cross-platform cross-environment manner, and CSDs are probably the least portable thing you can integrate into a program for a number of reasons.

That being said, other environments/toolkits – if they decided to pick up DWDs for other potential benefits – could use or switch to CSD as their fallback.

Could other toolkits & programs be ported to DWD? Or is this just going to be KDE/Qt?

DWD, being a protocol, is highly portable. Native implementations in various toolkits should be possible; not just Qt and Gtk, but wxWidgets, Java, or others could implement it. In addition, toolkits would not need to worry about their environment in DWD, so a GTK application with DWD could fit right in with KDE, and vice-versa (if a Gtk environment hopped on board the DWD train). That being said, we don’t know who is interested in DWD outside of KDE, and even if they were it would likely be a while before it started propagating around.

Some applications which offer plugin support could implement DWD by using their API by hiding native widgets – Firefox being a prime example. There may be limitations to customization from implementation to implementation, but it is possible. Some applications (such as Google Chrome) are more questionable as to whether or not this approach would work, but it’s still better than nothing (its known chrome has ways of hiding the tab bar, but I personally don’t know enough about the chrome addon API to know if it’s possible in that context).

Gtk programs using CSD are a much tougher question to answer. I don’t know much about the Gtk-based “headerbar” CSD library, but if *any* solution were to bring DWD to Gtk it would be in that library. From what I’ve been told there are likely significant hurdles, and if DWDs were to be implemented it would be for feature-oriented reasons, meaning early cooperation or adoption is unlikely. Either way, DWD is being designed to be toolkit and environment agnostic, so there won’t be hard KDE/Qt-driven requirements in the implementation. Also, I need to stress that I’ve heard of no interest for DWDs from Gnome or Gtk developers – Gtk may ever use DWDs.

Will the DWD protocol use DBus?

DWD will likely be DBus-based. This likely means DWD features will be disabled on Windows unless a windows-specific utility library is written using QtWinExtras (for Qt applications); If such a library were to be implemented, it would offer a truly cross-platform way to use many currently windows-specific features, such as thumbnail toolbars, icon overlays, and Glass.

For external use (like networking or bluetooth) it depends entirely on how developers want to approach it, whether or not they would be in the core protocol, or use external plugins/services to extend the base functionality of the specification. I simply don’t know the optimal solutions or how developers might approach DWDs from a technical standapoint.

Could I have my decorations on the side or bottoms of my windows?

That would be up to the decorator, theme engine, and system; applications won’t get to know how their DWDs would actually be implemented, nor would they get get ‘final say’. The DWD protocol will provide applications with the chance to provide hints and metadata to how they believe they would optimally be displayed.

KDE developers are leaning towards consistency in the UI, so that consistency is being built in to an extent; There are ‘hints’ I’d like to see specified that the default KDE setup would not use, but we do need to consider the fact that other decoration engines or environments might want those hints. If a hint was of significant and immense value our applications would readily want to request, I will seek to have those hints included. Once a specification is made, it gets much harder to extend over time (and then get new feature adoption) so I feel it’s important to have obvious specifications included, even if we ourselves won’t use them in our default setup.

Things like position hints, colour hints, font hints, and other which could realistically be desired I think should be included in the spec.

Is DWD secure?

DWD will broadcast window controls, and this obviously means if DWD is done poorly, it could grant access to applications and cause all sorts of trouble.

For a very real example: Dolphin will open a web-browser if you type an HTTP address into it. Odds are a file manager with DWD will offer the location input. Someone hijacking your file managers’ DWD could allow them to open your web browser to a malicious web-page. If DWD is done improperly, scenarios like that become possible. Scary!

Already, my personal DWD specification is addressing issues like this. I won’t get into technical details, but DWD will be locked down by default, and flags will be used to express where, how, and who can access individual widgets; with denial outside non-root window decorations being the default access policy.

So, yes, DWD has security in mind, and will be well locked-down.

DWDs will allow *any* widget in the decoration / Applications will draw the widgets and DWD will just import them.

False. The widgets will be drawn by the consoles, so DWD has it’s own widget vocabulary, independent of the widgets offered by the applications’ toolkit to ensure consoles receive predictable input. We also don’t want to simply include everything + the kitchen sink, as having too many widgets means more complexity, more work for theme designers, and more work for implementations. DWD isn’t meant to be a “put your application in the header” library, it’s meant to compliment the main interface.

That being said, the widgets being drafted cover pretty much all reasonable use-cases and will aim have all the most common widgets, including buttons, buttongroups, breadcrumbs, sliders and other goodies. I don’t know what developers have in mind when they picture the widgets, but the final widget will be well thought out so designers aren’t overburdened creating DWD-ready decorations, and application devs still have the tools they need to build high-quality interfaces.

What will the first KDE release using DWDs look like?

The VDG has been keeping this under-wraps for some time, but we have designed a new, original, beautiful interface which KDE will default to when we switch to DWDs. We believe a lush photographic background will be key to adoption, and bold colours with subtle hints of depth will be the norm in the future.

nononono-dwd
Modern. Beautiful. Original.

Footnotes;

I’m going to be going holding off on DWD-related posts beyond this until I’m more firmly in touch with developers on the topic (which may be far off, we have busy devs!); I’m beginning to rub up against the boundaries which I can reliably talk about without referencing them first. This post was written simply to address C&Qs around the web (which I saw) and thought I’d address; as usual, this post is not guaranteed to be accurate, and when developers start aiming towards an implementation they could go in a complete different direction than what I’ve written here. So, salt people!