[Lazarus] GUI development for web UI

michael.vancanneyt at wisa.be michael.vancanneyt at wisa.be
Wed Nov 24 11:42:12 CET 2010

On Wed, 24 Nov 2010, Michael Schnell wrote:

> On 11/24/2010 08:32 AM, ik wrote:
>> Hello List,
>> Well I know about the framework fur Javascript library in Lazarus, but I'm 
>> thinking in the past year or so, what will it take to design a gui 
>> application using Lazarus, and make it work like a web app that act the 
>> same as the desktop version, without any specific components for it.
> A decent way to do this would be creating an appropriate "Widget Type" 
> Interface (See "How to tell lazarus the location of a used package" in this 
> forum).
> I did some research on that some months ago. I found that this supposedly 
> best would be done using "ExtJS".

This, I agree with. In my experience, ExtJS is the best available toolkit
for the browser.

> "ExtPascal" is a way to try ExtJS with Lazarus and shows how to generate 
> "dual-mode" controls that can be used in the IDE at design time and in a 
> client-server way at runtime.

Extpascal has some serious design flaws, and by the looks of it they will
not be solved anytime soon.

I tried making moderatly complicated production applications with it. 
It cannot be done without redesigning ExtPascal from the ground up.

> To make up for a decent Widget Type, "Comet" technology would be needed to be 
> used for allowing for having server generated events introduce visual changes 
> at the client site.

Comet is a rickety technology. Not robust at all, and creates more problems
than it solves. You can use polling, but that's just plain HTTP, not even
worth of putting a name on it.

> Of course TTimer and an Inter Thread event Queue would be needed to be 
> implemented within the new Widget Type (for Linux use similar as in the FPGUI 
> Widget Type or as in MSEGUI).

Hehe, I was waiting for you to bring this one up. Never fails :-)


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