Wireless Application Protocol Bitmap Format (shortened to Wireless Bitmap and with file extension .wbmp) is a monochrome

Monochrome

Monochrome describes paintings, drawings, design, or photographs in one color or shades of one color. A monochromatic object or image has colors in shades of limited colors or hues. Images using only shades of grey are called grayscale or black-and-white...

 graphics file format optimized for mobile computing

Mobile computing

Mobile computing is a form of human–computer interaction by which a computer is expected to be transported during normal usage. Mobile computing has three aspects: mobile communication, mobile hardware, and mobile software...

 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.

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 Byte The byte is a unit of digital information in computing and telecommunications that most commonly consists of eight bits. Historically, a byte was the number of bits used to encode a single character of text in a computer and for this reason it is the basic addressable element in many computer...	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

The 3x3 bitmap:
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)


External links

• WAP WAE Specification
• Open Mobile Alliance
• WBMP support plugin for Mozilla Firefox
  Mozilla Firefox
  Mozilla Firefox is a free and open source web browser descended from the Mozilla Application Suite and managed by Mozilla Corporation. , Firefox is the second most widely used browser, with approximately 25% of worldwide usage share of web browsers...