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1.1 Design Principles and Concerns ¶

This section conveys the principles and concerns used by Anju to inform its design decisions.

Editorially, all design decisions for Anju are ultimately the opinion of Charles Y. Choi.

General Principles ¶

• Menus should be organized.
  • A coherent information architecture should be conveyed.
  • Balance between concision and discoverability should be made in a menu’s offerings.
• Nesting of sub-menus should be carefully considered, ideally not exceeding a depth of two.
• Mouse workflows that require keyboard input should be minimized.
• If the opportunity to provide a direct manipulation experience is available, it should be taken.
• Unconventional mouse interactions should be avoided.

Concerns ¶

Anju takes the position that different types of menus have different concerns or objectives. This is most apparent in contrasting the design of a main menu section (e.g. File, Edit, Options, …) to that of a context menu.

For Anju:

• The highest concern of a main menu section is discoverability.
• The highest concern of a context menu is concision.

A common implementation practice in Emacs is to reuse menu keymaps for both the main menu and context menus. This violates the above concerns, which Anju seeks to address.

The next sub-sections further detail the design concerns with respect to an area where mouse interaction occurs.

Context Menu ¶

A context menu (as its name implies) should constrain itself to commands relevant to context. The parameters of this context are usually (although not exclusively) defined by a subset of:

• Point (cursor) position
• Text selection
• Mouse cursor position
• Major mode
• Read-only state (on or off)

Anju takes the opinion that context menus should not support general command discovery. The context menu offering should be concise. Users seeking command discovery should instead look at the main menu.

Direct Manipulation ¶

Support for direct action based on mouse cursor position is a common user interaction technique. Anju applies this to Emacs window management, where window creation, deletion, and swapping are supported from both the context menu and the mode line.

No Middle Button Bindings ¶

Anju eschews Emacs’ default middle mouse button bindings as they presume usage of a 90’s style 3-button mouse. This style of mouse design has long been superseded with a middle scroll-wheel+button control. This widespread hardware change has resulted in the majority of mouse-supporting applications to emphasize scrolling actions with the middle control and clicking actions to the left and right buttons. Anju follows suit, primarily binding the right mouse button click (down) event to raising a context menu. In addition, Anju reconfigures commands that were previously bound to the middle button to ones accessible via a context menu.

The only exception Anju makes in this matter is to keep the Emacs default binding of mouse-2 to mouse-yank-primary.