Wireless Application Protocol Bitmap Format
From Wikipedia, the free encyclopedia
| Wireless Bitmap | |
|---|---|
| File name extension | .wbmp |
| Internet media type | image/vnd.wap.wbmp |
| Developed by | WAP Forum |
| Type of format | Image file formats |
Wireless Application Protocol Bitmap Format (shortened to Wireless Bitmap and with file extension .wbmp) is a monochrome graphics file format optimized for mobile computing devices.
WBMP images are monochrome (black & white) so that the image size is kept to a minimum. A black pixel is denoted by 0 and a white pixel is denoted by 1.
For colored images, WAP supports the Portable Network Graphics format. [1]
Contents |
[edit] Format of Wireless Bitmap Files
| Field name | Field type | Size (in bytes) | Purpose |
|---|---|---|---|
| Type | uintvar | variable | Type of the image, and is 0 for monochrome bitmaps. |
| Fixed header | byte | 1 | Reserved. Always 0. |
| Width | uintvar | variable | Width of the image in pixels. |
| Height | uintvar | variable | Height of the image in pixels. |
| Data | byte array | variable | Data bytes arranged in rows – one bit per pixel. A black pixel is denoted by 0 and a white pixel is denoted by 1. Where the row length is not divisible by 8, the row is 0-padded to the byte boundary. |
[edit] Example of a Wireless bitmap
The bitmap where b = black and w = white
Row1 - bwb
Row2 - wbw
Row3 - bwb
becomes
Octet 1: 00000000 (WBMP type)
Octet 2: 00000000 (Fixed header)
Octet 3: 00000011 (Width) = 3
Octet 4: 00000011 (Height) = 3
Octet 5-7: 3 bits for data then Padding (8-3=5)
Octet 5: 010 00000 (Row 1)
Octet 6: 101 00000 (Row 2)
Octet 7: 010 00000 (Row 3)
[edit] References
[edit] External links
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