Morphic - The Squeak User Interface

by Juan Manuel Vuletich
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Introduction

Morphic is the new User Interface in Squeak. It includes a framework for building interactive graphical objects (morphs), that can be animated, and a set of tools to support the Smalltalk environment. Morphs can be built both interactively (by direct manipulation) or by Smalltalk code.

The original Smalltalk-80 system included the first Graphical User Interface (GUI) ever made. The system and its environment were first described in [1], and later in [2], [3] and [4].

The idea behind its User Interface was that any object in the system should be easily and immediately accessible to the user. The original MVC implementation in Smalltalk made it possible to build general and flexible user interfaces for any object, but it didn't make it easy. MVC means Model-View-Controller. Any object in the system could be a Model. A Model is an object that the user is aware of. Generally a model does not need to know about graphic displays or user interaction. A View and a Controller are usually made to interact with the user. The View shows a visual representation of the Model, that the user can understand. The Controller takes mouse clicks and
keystrokes and changes the View. For example, in a flight simulator, a Model could be a world that includes different objects. It's View would render a perspective of the pilot's sight through the windshield. The Controller would allow to point and click to the visible objects, perhaps to make some query on them. This design allows having multiple different views operating over one single model at the same time.

Later, when the Apple Macintosh popularized some of Smalltalk's visual look, MVC power (and even the idea of Object) was lost. Even Smalltalk environments failed at this. And the original intended book on MVC [5] was never published. The "Inside Smalltalk" volume II [6] filled the gap, but it was late. Commercial Smalltalk environments started to offer only tools for building GUIs, by assembling of standard widgets. Non-Smalltalk programming tools also followed this trend. So software developers started to restrict their imagination to what can be accomplished by selecting controls from a palette, and grouping them on a form.

Morphic was originally developed by John Maloney and Randy Smith as the Self user interface framework. You can read more about this at History. Morphic takes again the idea of any object being visually accessible by the user, but it s much simpler and easier than MVC, and it s more powerful too. Thus, the set of morphs already included in Squeak is probably richer than anything ever done in MVC. (If you don't know MVC, don't worry. Just jump into Morphic. MVC knowledge is decidedly not needed to understand and work with Morphic.)