Wireless Application Protocol Bitmap Format (shortened to Wireless Bitmap and with file extension .wbmp) is a raster image file format optimized for early mobile computing devices.

WBMP images are monochrome black and white binary images in which a black pixel is denoted by 0 and a white pixel is denoted by 1. The simple pixel encoding and the small size of the file header mean that the file size is kept to a minimum, enabling fast transmission on slow networks.

File format

{|class="wikitable" style="margin: 1em auto 1em auto"

|-

!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. The pixel order within a byte is MLP (most left pixel) = MSB (most significant bit). Where the row length is not divisible by 8, the row is 0-padded to the byte boundary.

|}

References

  • WAP WAE Specification
  • Open Mobile Alliance