Re: [boost] thoughts on a GUI component library

From: John Torjo (john.lists_at_[hidden])
Date: 2004-12-15 03:12:21

> The first thing that comes to mind when reading "data that is associated 
> with the component" is data binding. I think it is a mistake to build 

What do you mean by this? Could you give an example?

> The majority of the current proposals (mine included) have taken the 
> approach of providing native interoperability with the OS-specific data 
> structures. This is very difficult to maintain properly and support 
> generic code because of the different names of the data elements, types 
> used (long or float) and whether an area is (position + size) or 
> (top-left + bottom-right). Also, most OSs have (0,0) being the top-left 
> corner, but MacOS has (0,0) being bottom-left.
> 
> With this in mind, I have taken a drastic approach: do not provide 
> native interoperability for size, position and area. I have designed 
> them as:
> 
>   struct position{ float x; float y; };
>   struct size{ float dx; float dy; };
>   struct area
>   {
>      float top; float left;
>      float width; float height;
>   };
> 
> This means that the interface must convert these to the native 
> representations and vise versa.
> 

I would say that this is the correct approach.

As a side-node, I'm moderately against having float coordinates. Why 
would you think int is not enough?

Best,
John

-- 
John Torjo,    Contributing editor, C/C++ Users Journal
-- "Win32 GUI Generics" -- generics & GUI do mix, after all
-- http://www.torjo.com/win32gui/
-- http://www.torjo.com/cb/ - Click, Build, Run!