Thread: Making my own GUI tookit. Looking for some advice.

Hi.

Just for fun and exercise I have started to create my own GUI toolkit, much like AWT, Swing, Qt, etc.
Its not my goal to make the next big thing and cash in lots of moneys; I just want to spend some time on more complex projects as a kind of training.

Now this is a fairly complicated project and I have already spent a couple of hours just planning all kinds of classes I could need for this and how all these classes are supposed to work together, and now I want to share some of my thoughts and maybe get some advice from more experienced programmers; maybe a push in the right (or better) direction.

Heres the basic concept:

• Everything in the GUI is a component
• Components are structured in a ComponentTree
• The ComponentTree manages the updating and rendering of all components in the GUI
• Components always have a parent (which is a component) unless they are the root of the ComponentTree
• Components can have any number of children (which are components)
• The componentTree is rendered by an in-order traversal of the tree starting at the root
• The componentTree is updated by a level-order traversal starting at the leafs (going up the tree to the root)
• Each component defines a viewport (rectangular) and its children must be contained completely within the viewport of their parent
• The viewport of a child must be contained completely within the viewport of its parent

Very rough draft of the class hierarchy:
GUI-Toolkit-Classes.jpg

A basic example GUI: (Showing a frame, menubar, panels to the left and bottom, and a pane with a picture in the center. Also: a border layout)
GUI-Example.jpg
This is how the component tree would look like internally: (for the example GUI above)

Frame
{
    Menu Bar
    {
        File MenuButton
        {
            File MenuButton label
        }
        Edit MenuButton
        {
            Edit MenuButton label
        }
        About MenuButton
        {
            About MenuButton label
        }
    }
    Left Panel
    {
    }
    Center Pane
    {
        Picture
    }
    Bottom Panel
    {
    }
}

There are also 2 other important aspects I left out so far:

1. Compositions & Layouts
   
   • A Composition is a component that you can add / remove other components to / from (Composition is an interface)
   • A Composition can have a layout attached. The layout of the composition can change the positioning and size of components which have been added to the composition
2. Floating Components
   
   • An alternative variation of a Component is the FloatingComponent
   • Floating components are NOT components. They can not be the root of a component tree, they are never the parent to a component nor a child of a component
   • Floating components are usually temporary and *float* on top of all other components in the component tree
   • Examples are drop-down menus, tooltips, context menus, etc
   • Floating components are still registered at a component tree and are also updated / rendered by their tree just like regular components

What do you guys think about this? Would this work out this way or should I structure it differently?

Thank you very much and sorry for that big wall of text.

Thank you for the comments.

I dont really see the benefit of using the AWT-Component class. There is a lot of deprecated functionality and things that I might not really need. Furthermore I am using OpenGL for rendering and own input libraries.
The example picture I provided in my original post is actually already showing a working example of the code I have so far. Buttons, Labels, Panels, Layouts, Checkboxes, Pictures, etc; all of them work already.
I am just not sure if I am happy with the way they work right now or if I should try to take an other approach.

Originally Posted by KevinWorkman

Wait, so you're using OpenGL to natively create windows and components? If so, that's actually pretty impressive...

Yes, I am using OpenGL to render everything. For the native calls I am using lwjgl right now, although jogl should work too. Both libraries are only providing a 1:1 binding of OpenGL.
But lwjgl does also give me OpenAL and OpenCL support in just one library, so I prefer that.

Originally Posted by KevinWorkman

Although, AWT isn't really deprecated, it's just older than Swing. Swing is built on top of AWT.

I know that AWT is not really deprecated because Swing is actually still using many of the AWT classes at some points, but the AWTComponent class has so many deprecated methods and/or fields. They are still using the Vector class without generics internally. And there are many other relics of the past.

Originally Posted by KevinWorkman

But now I'm not really sure what your question is?

I just want some people who I can to talk about the concepts I have worked out so far. Its so hard to look into the future and plan ahead; I am just hoping for some experienced users to maybe give me some advice, or simply reconfirm my concepts so far if it isnt that bad after all.