[wikireader] Images on the WR not so imposible :P [was [wikireader]Error on parsing the spanish wikipedia]

David Reyes Samblas Martinez david at tuxbrain.com
Tue Nov 3 14:10:05 CET 2009

David Reyes Samblas Martinez
Open ultraportable & embedded solutions
Openmoko, Openpandora,  Arduino
Hey, watch out!!! There's a linux in your pocket!!!

2009/11/3 David Garabana Barro <david at garabana.com>:
> On Tuesday 03 November 2009 12:15:11 David Reyes Samblas Martinez wrote:
>> Regarding compression, I believe lzma is already builded in the
>> wikireader application and it compress the images  a 50%. enough for
>> start I guess. but I have to recongnize than the image on png looks
>> really good do maybe it worth the meaning to implemente it on the
>> device if it's not much resource hungr
> Both png and pbm are 1 bit images without lossy compression.
> You can obtain exactly the same final image quality on both formats, but png
> will have smaller disk size.
As I said lzma compresed pbm files are about the same size like a png
file so if same results can be achieved, I vote for stay on what's
already implemented
And seems this way isi commpressed a litte bit more
I see the sample png file is 4263 bytes and the same pmb+lzma is about 2937
(sucotronic please can you email me with the name of  "treshold tool"
in spanish and post the values you  chose if any?)
> Final result only depends on RGB->1 bit indexed conversion method used.

> AFAIK png decompression is not resource hungry. Compression *IS*.
well compresion is done on host so no problem on this side, in fact WR
is decompresing huge amount of text in lzma quite fast so a tiny file
of 2-4Kb will be no problem
> PS For minimal png archive size, you *MUST* convert image to 1 bit indexed
> palette before saving it.
> If you use "greyscale", RBG or more than 1 bit palette, png will waste space
> saving palette or RBG/greyscale info.
totally agree :)
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