Ideal D GUI Toolkit

[Adam Wilson]

On Sun, 19 May 2013 22:25:49 -0700, Tyler Jameson Little  
<beatgammit at gmail.com> wrote:

> I've been looking into trying to fix QtD, but it seems writing a binding  
> to a C++ library is a bit complicated. I've read on the forums that a  
> native D GUI toolkit is the most desirable long-term, so I'd like to  
> start that discussion.
>
> First off, I've heard of the DWT project, which looks promising, but it  
> seems like a direct port of Java's SWT instead of a reimagining using  
> idiomatic D. I understand the allure here (works, little translation for  
> new developers), but since it's not yet in Phobos, I can only assume  
> it's still up for discussion.
>
> Personally, I want these features:
>
> * simple and extensible
>    * minimal components (something like HTMLs feature-set)
>    * custom components (embed OpenGL/direct frame buffer)
> * "native" window decorations by default, but can provide custom  
> decorations
> * markup (like QML) or programmable (like SWT)
>
> Nice-to-haves:
>
> * hardware accelerated (2D OpenGL)
> * GUI designer (much easier with QML-esque markup)
> * part of Phobos
>
> I'm willing to lend a hand, but I'd like to know in what direction the  
> community would like to go. I'd also like to know the likelihood of  
> getting a GUI toolkit into Phobos.
>
> Thoughts?

So I've been around D a while pushing for native D UI toolkit. And here  
are a few trends I've seen in the community.

* There is a deep-seated distrust of any toolkit that does not use the OS  
Native UI widgets. The people in this community prefer native toolkits to  
the point of jihad. Now I am a XAML guy myself, and I saw the light a long  
time ago, but around here, the majority are still command line gurus.
* There is absolutely no chance of inclusion in Phobos, and to-be-honest I  
don't think it really belongs there. GUI toolkits are too use-case  
specific to belong in a standard library. However, if we can make (and I  
think we can) a truly cross-platform UI toolkit, we can make a stronger  
case for using at a standard UI toolkit.
* Nobody believes that we can do it, you'll hear a lot of moaning about  
how much work it is. My reply to that is: And Linux is such a piece of  
cake right? It's only the most widely used kernel on the planet.

Here's the deal. Building a GUI toolkit, particularly a useful one, is a  
massive undertaking. WPF is the single largest library in all of .NET.  
IIRC it weighs in at 40,000 classes. Building a UI toolkit in D will  
require something that D itself does not. A highly dedicated team of  
people with many diverse skills. The project is simply too big for a  
single person.

Part of the problem with UI toolkits is the number of skills you'll need  
for the team. Graphics programmers who can make GPU's sing, API designers  
who can make it easy access, UI designers capable of replicating the looks  
of each OS. Experts for each targeted OS. And I can think of more.

My point here is not to be discouraging, I want a UI toolkit with  
capabilities similar to WPF in D probably more than anybody else here. But  
I want to be realistic about the effort required. The dedication required  
is immense, you'll be writing code for months before you even get anything  
on the screen.

Here is another factor to consider. A UI toolkit must be designed. You  
won't have the luxury of Phobos of design-by-iteration simply because  
you'll be throwing out entire systems. For example a fairly complete  
render path is required before you can show anything on the screen. But  
what happens when your render-path is too OS specific? Oops, you pitch  
months of work and start over from scratch. But now you have to rebuild  
everything you've built on top of it. Do that a few times and you'll give  
up because you can never seem to get anywhere. The smart thing to do is  
sit down with a knowledgeable group of people and design the system, the  
design doesn't have to be perfect or complete, but it does need to provide  
a framework to work within and vision to guide the team.

Lastly, we'll need something that D doesn't have much of, but Linux does.  
Leadership. You can't pull together something this complex without someone  
or someones holding the bigger picture in their heads, otherwise you'll  
end up with a mish-mash of contradictory merged pulled requests.

In my experience in Open-Source, it's never a problem to find people who  
have vision and want to lead a project. The problem is finding people who  
agree with the vision enough to help without wanting to be in charge  
because they really know better. FOSS's major drawback is the ridiculous  
amounts of duplication. I don't see a WPF-style UI toolkit as duplication  
because as near as I can tell there is nothing like WPF in the OSS world,  
but, everybody has their own opinion about HOW it should be done and  
almost nobody is willing to swallow their ego, quit sweating the small  
stuff, and work towards a common goal, even if they don't agree 100%.

A UI toolkit in D would be a fantastic showcase for demonstrating just how  
powerful D is. But make no mistake, it will not be easy getting it done.

-- 
Adam Wilson
IRC: LightBender
Project Coordinator
The Horizon Project
http://www.thehorizonproject.org/