15
User Display Interface
15 User Display Interface
The J2ME standard allows specific Canvas, Hardware Mapping and External Event Interaction functionality.
Canvas Functionality
The J2ME standard specifies that the Canvas class is available to the J2ME application.
The J2ME Canvas functionality controls the rendering of objects on the entire display. In addition, the J2ME Canvas requirements a minimum display size and functional soft key area for use by the application.
•There is a minimum of 96 x 54 pixels screen size to be available to the J2ME application.
•The lower 10 pixels are reserved for two soft keys and the menu icon. These 10 pixels are not counted in the 54 pixels reserved for the J2ME Canvas display.
•The soft keys and menu icon, located in the 10 pixel reserved area, are rendered in 11 high font.
•The soft keys and menu icon follow noted below:
oMIDlet UI design can be designated in the J2ME Style Guide or Developer Guide but implementation is still decided by the developer.
The application supports the Portable Network Graphic (PNG) Image Format.
•Implementations are required to support images stored in the PNG format. All of the 'critical' chunks specified by PNG must be supported, with the following considerations:
oThe IHDR chunk. MIDP devices must handle the following values in the IHDR chunk:
All positive values of width and height are supported; however, a very large image may not be readable because of memory constraints.
65
