Pixlr is a layered raster graphics format associated with the Web based Pixlr application.
Pixlr was founded in 2008. It was acquired by Autodesk in 2011, then by 123RF in 2017.
pixlr.com limited documentation
Pixlr document format
The pixlr format is a compressed binary format, why we choose this and not a xml/jpg ish format is due to many reasons.
It all comes down to quality, speed and file size.
The pxd file is compressed with zlib to reduce the file size.
The uncompressed data are then ordered into two main sections. The Header and the Layer section.
The header includes, pxd version, color-mode, width, height and number of layers.
Reverse engineered information (after inflating the file): 2 bytes - version = 3 2 bytes - colorMode = 0 4 bytes - width 4 bytes - height 2 bytes - numLayers 4 bytes - The total size of the layers in bytes for every layer 4 bytes - total layer size in bytes 2 bytes - namelen n bytes - name 1 byte - layer type: 0=bitmap, 1=text (text layer also contains bitmap) 4 bytes - layer x-pos 4 bytes - layer y-pos 4 bytes - layer width 4 bytes - layer height 1 byte - opacity (0..100) 1 byte - visible 2 bytes - blendmode 4 bytes - size in bytes of layer bitmap data n bytes - layer bitmap data in ARGB format (not premultiplied) 4 bytes - size in bytes of layer mask data (0 if no mask) 1 byte - number of layer style effects for every effect 4 bytes - size in bytes of effect data 1 byte - type of effect n bytes - effect data (TODO) end every effect 2 bytes - unknown if text layer text + font data (TODO) end if end every layer (TODO: Merged image data may be at the end ?)