Launcher icon basics
Launcher icons represent the main applications within the phone. These include pre-installed applications such as Calendar, Camera, and Contacts, as well as third party applications, for example those downloaded from Nokia Store.
PNG format
Series 40 devices from Nokia require PNG (Portable Network Graphics) icon files. PNG is a bitmap image format that employs lossless data compression and can include transparencies.
PNG images can be created in bitmap-based software such as Adobe Photoshop and Adobe Fireworks, or vector-based programs such as Adobe Illustrator CS5, with an optimised PNG saving option. The guidelines in this library also explain how to use Inkscape to create a launcher icon.
Anti-aliasing
The transition from vector to pixel format can involve unwanted transition effects. Vector lines and vector shape edges which travel across the pixels (instead of following the grid between pixels) will be anti-aliased and may turn out blurry.
Series 40 full touch phones have a high quality standard for their graphics and icons. Every icon needs to be as sharp and optimized as possible. In order to output a crisp icon, please prevent unnecessary anti-aliasing on even edges. Preserve the anti-aliasing effect on roundings and curves.
In Adobe Illustrator you can switch on/off a pixel preview (View > Pixel Preview) to check for the current state of the pixels and to amend your icon shape if necessary. The Inkscape templates show a pixel grid and you can snap objects or nodes/dots to the grid so that the final exported PNG will be optimised.
Figure 1. Optimised shape
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Figure 2. Shape not optimised
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Global understanding
To ensure success, icons need to be easy for a global audience to understand. They should enable users to quickly recognise your product, and help them to decide if they want to learn more about it.
Simplicity
Simplicity is a key issue, because icons will need to communicate the essence of your app within a small space. Focus on the most distinguishable feature of your product and forget the rest. Key icon imagery and metaphors should also be easy to distinguish. Ensure that there is sufficient contrast between the subject and the background colour.
Use of colour
The colour of the icon background can be customised to match your brand colours, or it can follow the Nokia colour-coding spectrum. The Nokia colour spectrum assigns colour groups based on the core functionality of the application (for example: media, tools, utilities).
Icon canvas
A launcher icon consists of the following elements and composition:
- A mandatory 50 x 50 pixel surround shape with highlight.
- A white glyph, shape, or logo, centered within a 30 x 30 focal zone.
- These elements are centrally aligned within a 56 x 56 pixel boundary box. The boundary box must be included with the final icon as a transparent outline.
