Information regarding Interlaced PNG images

Hi all,

I need some information regarding interlaced PNG images.

 

For non-interlaced png images, the decoded output is available in row wise. I captured that data into a file from rowbuf (in libpng), and i was able to display the raw data using a software tool.(irfan view)

 

while coming to interlaced images, the decoded output image is available in 7 passes.

how to display these ;7 passes data. In each pass only some pixel data availabe.

how to combine these 7 passes data to get the display image.

 

is it like, add each pixel data correspondingly in all the 7 passes?

 

can anybody help me, how to display the decoded  interlaced png image using a software tool.

 

Thanks & Regds

Mallikarjun