Re: [Gegl-developer] Support for loading meta-operations from .json now in master

["Joao S. O. Bueno" <gwidion mpc com br>]

Yay!  :-)

On 20 January 2015 at 15:08, Jon Nordby <jononor gmail com> wrote:
> Hi,
>
> a long standing enhancement[1] in GEGL has been to allow loading
> meta-operations from a serializable file instead of requiring them to be
> coded in C.
> At 31c3 I started working on this, and yesterday it reached a generally
> working state. Today I merged the code to master[2].
>
> Each .json file of right format that is found in the module path for GEGL
> will create a new GeglOperationMeta subclass. It will be register it with
> the specified operation name, and exported properties/pads.
> When the operation is instantiated, it builds up the subgraph of GeglNodes
> specified and connects. Property changes on the meta-operation are forwarded
> onto the real node inside.
>
> An example of the .json format can be seen here:
> https://git.gnome.org/browse/gegl/tree/operations/json/grey2.json
> This is a format also used by other dataflow/flow-based-programming
> tools[3].
>
> This for instance allows one to use the node-based editor Flowhub+imgflo to
> build a new image filter, save it as .json and then use it in GIMP[4]
> (screenshot). One can of course also hand-write the json files, or implement
> other editors for these.
> It might make sense to also implement serialization of a graph/sub-graph to
> this format directly in GEGL itself.
>
> Note: This adds json-glib 1.0 as a dependency of GEGL, so make sure you have
> it installed (including development headers).
>
> References
> 1. https://bugzilla.gnome.org/show_bug.cgi?id=465743
> 2.
> https://git.gnome.org/browse/gegl/commit/?id=564f45bad76eb0f888e628ea70345912dd68cbbb
> 3. http://noflojs.org/documentation/json
> 4. https://twitter.com/jononor/status/557570481206099969
>
> --
> Jon Nordby - www.jonnor.com
>
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