Wireless Application Protocol Bitmap Format

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Wireless Bitmap
Filename 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]

Format of Wireless Bitmap Files[edit]

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.

Example of a Wireless bitmap[edit]

The 3x3 bitmap:

TwoTone.svg

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)

Notes[edit]

External links[edit]