Bforartists: Compositor - Pick better preview toggle icon in nodes' headers

[iyadahmed]

Most compositor nodes have an icon shaped button that toggles node preview,
currently it uses "material" icon, it doesn't really match its function,

it is defined here:
source/blender/editors/space_node/node_draw.c

Code:

related: #2046

[ReinerBforartists]

Thanks for creating the task. Now let's have a look what icon could fit best here ...

[ReinerBforartists]

We have already a TOGGLE_NODE_PREVIEW icon. It's a bit ugly. But should do the trick :)

[iyadahmed]

Great, there's also another idea, but needs a bit time, make a "show preview" toggle button on top of where preview would show, that way it is more clear

or at least we could emboss the preview toggle icon, as it wasn't clear at first that it can be clicked, also for node group node header icon

[ReinerBforartists]

Yes, this needs fine tuning.