Getting setproperty! on GtkTextTag for foreground_rgba to work

[guidocalvano]

Hey,

I'm trying to get tags with color to work... But for some reason I can't.

When using setproperty! the code complained that my GdkRGBA class could not be converted to a GType. I could not figure out how the g type system works as I am fairly new to julia. I could also not create a new setproperty! method that specifically targets what I want to do. I suspect it is fairly easy to accomplish what I am trying to do with only a little bit of help from you.

So I have two questions:

1. What is the correct approach to register my GdkRGBA type?
2. If you think it is better to use a custom setproperty! method, how do I pass my GdkRGBA type to ccal to invoke gobject_set

My GdkRGBA type:

type GdkRGBA
  red::Cdouble
  green::Cdouble
  blue::Cdouble
  alpha::Cdouble
  GdkRGBA() = new(0,0,0,0)
  GdkRGBA(red, green, blue, alpha) = new(red, green, blue, alpha);
end
typealias GDKRGBA Union{Mutable{GdkRGBA},GdkRGBA}
zero(::Type{GdkRGBA}) = GdkRGBA()
copy(rgba::GdkRGBA) = rgba
copy(rgba::Mutable{GdkRGBA}) = mutable(rgba[])

My attempt at writing a setproperty! method:

function setproperty!(w::Gtk.GtkTextTag, name::AbstractStringLike, value)
    ccall((:g_object_set_property, libgobject), Void,
        (Ptr{GObject}, Ptr{UInt8}, Ptr{GdkRGBA}), w, GLib.bytestring(name), Ptr(value))
end

Thank you for your great work and the time to have a look at my issue.

ps. I've also gotten a place_cursor! function to work for the GtkTextBuffer. If you want it let, me know and I'll create a pull request.

[guidocalvano]

At the bottom of this page was the solution to what I had to do:
https://github.com/JuliaGraphics/Gtk.jl/blob/master/doc/developer.md#adding-new-gvaluejulia-auto-conversions

I've got two pull requests if you want them:

1. place_cursor now works on a textbuffer
2. I can create text tags with color now.
   (and 3. I've replaced a number of deprecated calls to the bool function, with a call to the Bool function, so Gtk.jl does not break on julia v0.5).

Send me a message and I will send you the code.

[vtjnash]

sgtm if you want to make a PR. I have a RGBA type in displays.jl, but it lacks support for most operations, so if you have found some support methods that would make it more usable, put it in a PR

[guidocalvano]

In order to prevent having two rgba types in the repo, I tried to set the color of a tag using the RGBA type you spoke about but I get errors.
Also; the constructor of the RGBA type in display misses an argument for the alpha value
and apparently get_type doesn’t work for that RGBA value, causing assignment to fail.

Is the RGBA object there used? and if so where? if not, shall I replace it with my RGBA?

I understand the basic principles of writing a binding now, so if you want I can spend half a day adding a few if you like. Just let me know the ones you are eager to have soon.

[vtjnash]

It's used, but not much. it's just provided as a way to describe the image buffer type. You should merge it with your complete definition. Agreed that the constructor is wrong.

[guidocalvano]

Made the pull request. Check the comment there before merging.