Projects/Usability/HIG/IconDesign

Purpose

Icons are pictorial representations of functions and objects, important not only for aesthetic reasons as part of the visual identity of a program, but also for utilitarian reasons as shorthand for conveying meaning that users perceive almost instantaneously. Well-designed icons improve the visual communication and strongly impact users' overall impression of visual design. Last but not least, icons are space-saving and improve usability by making programs, objects, and actions easier to identify, learn. Icon use should be consistent throughout the interface.

Guidelines

• Design icons with a small number of metaphors [1].
  • Apply metaphors only once (e.g. do not use a brush twice for different options).
  • Rethink conventionally used metaphors (e.g. the clipboard icon of paste).
  • Antiquated metaphors might work well (e.g. a floppy is not necessarily outdated to represent save).
  • Adjust the degree of abstractness according to familiarity of the metaphor.
  • Use arrows only if they can easily be related to spatial features such as Previous/Next in a sequence or Up/Down in a hierarchy. Avoid using arrows metaphorically (such as for Reply/Forward or Undo/Redo).
  • Attempt to use metaphors that are independent of language and culture.
  • Make icons simple.
• If an icon has important details at larger sizes, rather than simply scaling it down, create unique versions of the icon at smaller sizes. Critical details may become unrecognizable when scaled down.
• Avoid using text in icon designs; it may not scale well to smaller sizes.
• Icons of a similar type share a consistent visual language (mimetypes, folders, devices, etc.).
• Follow the guidelines for presenting icons with text
• Test your icon set on strength of association, discriminatory power, conspicuousness, and, if applicable, on accessibility.

Monochrome Icons

• Used for application toolbar and button actions, menus, sidebars and status and notifications. Also may be used for small (16x16) devices and places icons (folders, usb drives, etc.).
• Rely on a distinct shapes instead of fine details to distinguish between them.
• Breeze icons use primarily color #1 and #2 but also use other colors to indicate a different state.

1. Icon Grey - Color used for icons in a normal state and non destructive actions e.g.: back, forward, ok, home.
2. Icon Red - Color used for icons in a normal state and for destructive actions e.g.: close, delete, remove, stop. Also used in addition with color #1.
3. Icon Orange - Color used in addition to color #1. Used to distinguish icons that involve "user input", also used as the color for the "busy" state in IM software.
4. Icon Blue - Color used in addition to color #1. Used to distinguish icons that involve the action "select" or "insert".
5. Icon Yellow - Color used in addition to color #1. Used to distinguish icons that involve a "warning", also used as the color for the "away" state in IM software.
6. Icon Green - Color used in addition to color #1. Used to distinguish icons that involve "connected", "secure" or "successful" actions.

Colorful icons

• Use colorful icons for applications, folders, mimetypes and devices.
• For Breeze icons, use colors from the full Breeze color palette as a starting point.
• Breeze icons use smooth linear gradients (bottom to top/dark to light); they are not flat.
• Application icons should be unique and easily recognizable.
• When creating an system icon theme, respect trademarks by avoiding significant alterations to application icons.

Sizes

Breeze icons come in a variety of sizes depending on their context. The following lists the current sizes in use:

• Breeze/
  • actions/
    • toolbar/ - 22x22
    • toolbar-small/ - 16x16
  • apps/
    • preferences/ - 32x32
    • software/ - 48x48
    • software-medium/ - 22x22
    • software-small/ - 16x16
    • system-power-actions/ - 48x48
    • system-session-actions / - 48x48
  • categories/
    • start-menu/ - 32x32
    • start-menu-small/ - not used in Plasma
  • devices/
    • hardware/ - 48x48
    • sidebars/ - 16x16
  • mimetypes/
    • file-types/ - 64x64
    • file-types-small/ - 16x16
  • status/
    • dialogs/ - 64x64
    • im-status/ - 16x16
    • panel/ - 22x22
  • places/
    • user-folders/ - 64x64
    • user-folders-small/ - 16x16

Implementation

• Use icons available from the system icon theme whenever possible. Avoid using custom icons.
• Follow the Icon theme usage guidelines.
• For standard actions (back forward, open, save, refresh, etc.) use an icon from the platform-provided set. The KDE Platform 4.x uses the Oxygen icon set. The KDE Plasma 5.x desktop and applications use the Breeze icon set.
• If you would like to request help designing icons unique to your application, you can ask for help on the KDE Visual Design Group Forum.

References

[1] http://user-prompt.com/semiotics-in-usability-guidelines-for-the-development-of-icon-metaphors/