pulsar/docs/internals-guide.md

A Guide to Atom's Internals

Views

SpacePen Basics

Atom's view system is built around the SpacePen view framework. SpacePen view objects inherit from the jQuery prototype, and wrap DOM nodes

View objects are actually jQuery wrappers around DOM fragments, supporting all the typical jQuery traversal and manipulation methods. In addition, view objects have methods that are view-specific. For example, you could call both general and view-specific on the global rootView instance:

rootView.find('.editor.active') # standard jQuery method
rootView.getActiveEditor()      # view-specific method

If you retrieve a jQuery wrapper for an element associated with a view, use the .view() method to retrieve the element's view object:

# this is a plain jQuery object; you can't call view-specific methods
editorElement = rootView.find('.editor.active')

# get the view object by calling `.view()` to call view-specific methods
editorView = editorElement.view()
editorView.setCursorBufferPosition([1, 2])

Refer to the SpacePen documentation for more details.

RootView

The root of Atom's view hiererchy is a global called rootView, which is a singleton instance of the RootView view class. The root view fills the entire window, and contains every other view. If you open Atom's inspector with alt-meta-i, you can see the internal structure of RootView:

Panes

The RootView contains a #horizontal and a #vertical axis surrounding #panes. Elements in the horizontal axis will tile across the window horizontally, appearing to have a vertical orientation. Items in the vertical axis will tile across the window vertically, appearing to have a horizontal orientation. You would typically attach tool panels to the root view's primary axes. Tool panels are elements which take up some screen real estate that isn't devoted to direct editing. In the example above, the TreeView is present in the #horizontal axis to the left of the #panes, and the CommandPanel is present in the #vertical axis below the #panes.

You can attach a tool panel to an axis using the horizontal or vertical outlets as follows:

# place a view to the left of the panes (or use .append() to place it to the right)
rootView.horizontal.prepend(new MyView)

# place a view below the panes (or use .prepend() to place it above)
rootView.vertical.append(new MyOtherView)

Models