fxruby-users

[Fxruby-users] subclassing FXColor

[meinrad r. <mei...@gm...>]

dear lyle,

id like to subclass FXColor to add some more functionality. like this:

class Color < Fox::FXColor
def initialize r, g, b
end
end

but i don't know how to subclass Bignum (that is what FXRGB returns ...)
how could i do this to integrate with fxruby?

cheers
- mr

Re: [Fxruby-users] subclassing FXColor

[Lyle J. <ly...@kn...>]

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On Jan 30, 2004, at 5:29 PM, meinrad recheis wrote:

> id like to subclass FXColor to add some more functionality. like this:
>
> class Color < Fox::FXColor
> def initialize r, g, b
> end
> end
>
> but i don't know how to subclass Bignum (that is what FXRGB returns 
> ...)
> how could i do this to integrate with fxruby?

Fox::FXColor should really be a Ruby module and not a class; you can't 
create instances of it and use them in any meaningful way. And as you 
already noted, we already have a way to construct color values from the 
red, green and blue (and optionally alpha) components, e.g.

	color = Fox.FXRGB(r, g, b)

or

	color_with_some_alpha = Fox.FXRGBA(r, g, b, a)

It's not clear what advantage a full-blown FXColor class would offer.
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Re: [Fxruby-users] subclassing FXColor

[meinrad r. <mei...@gm...>]

Lyle Johnson wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> 
> 
> On Jan 30, 2004, at 5:29 PM, meinrad recheis wrote:
> 
>> id like to subclass FXColor to add some more functionality. like this:
>>
>> class Color < Fox::FXColor
>> def initialize r, g, b
>> end
>> end
>>
>> but i don't know how to subclass Bignum (that is what FXRGB returns ...)
>> how could i do this to integrate with fxruby?
> 
> 
> Fox::FXColor should really be a Ruby module and not a class; you can't 
> create instances of it and use them in any meaningful way. And as you 
> already noted, we already have a way to construct color values from the 
> red, green and blue (and optionally alpha) components, e.g.
> 
>     color = Fox.FXRGB(r, g, b)
> 
> or
> 
>     color_with_some_alpha = Fox.FXRGBA(r, g, b, a)
> 
> It's not clear what advantage a full-blown FXColor class would offer.
[...]

it is the OO-paradigma that gives many advantages by encapsulating data 
(the color value) and methods that operate on that data (FXRGB, 
FXREDVALUE, etc ...) in an object!

i now see that FXRuby expects bignum where FXColor is stated, so the 
question is how to subclass bignum (and that does not belong to this list).

thanks anyways,
meinrad

[Fxruby-users] Re: a color object

[Lyle J. <ly...@kn...>]

On Jan 30, 2004, at 11:06 PM, meinrad recheis wrote:

> #color object (united fox functions)
> class Color
> 	attr_accessor :r, :g, :b, :a
> 	#construct by red, green, blue and (optionally) alpha value
> 	def initialize r=0, g=0, b=0, a=nil
> 		@r,@g,@b,@a=r,g,b,a
> 	end

<snip>

I have added this as a change request on the list at SourceForge:

	https://sourceforge.net/tracker/index.php? 
func=detail&aid=890161&group_id=20243&atid=370243

I could change things so that methods that currently expect an Integer  
for a FOX color value will accept either an Integer *or* an FXColor  
instance, e.g.

	widget.textColor = Fox.FXRGB(255, 0, 0)

and:

	widget.textColor = Fox::FXColor.new(255, 0, 0)

are equivalent. One concern, however, is how to handle return values  
for methods that currently return colors as Integers. That is, I think  
to preserve back-compatibility those methods would need to continue to  
return color values as integers. Any thoughts?

Lyle

Re: [Fxruby-users] Re: a color object

[Martin H. <ma...@zs...>]

On Wednesday 04 February 2004 04:04, Lyle Johnson wrote:

> .... One concern, however, is how to handle return values
> for methods that currently return colors as Integers. That is, I think
> to preserve back-compatibility those methods would need to continue to
> return color values as integers. Any thoughts?
>

Two that I can think of - one is to provide an alternative method=20
(xxx_as_color) that returns a colour object rather than an integer, or th=
e=20
other is to add to_color to the Integer class which returns an instance o=
f=20
itself as a colour object?

I don't find either very attractive but they would offer both integer and=
=20
colour retrieval.

Another is maybe to allow a class/global setter -=20
Fox.returnColorsAsObject=3D(boolean) and maybe use that to determine what=
 to=20
return from each FXRuby function?=20

Although probably more work from a development point of view, I actually=20
prefer this approach because it does not clutter the rest of the API, nor=
=20
interfere with the Integer class...

Cheers,
Martin