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Posted to batik-users@xmlgraphics.apache.org by Nishant <ni...@yahoo.com> on 2003/03/11 12:30:40 UTC
how to extract palette information
hi all,
I need to read a .png file and read the palette value as an
integer.
I dont have any idea what is a palette.
could anyone provide help, about how to extract the same.
Thanks for any help.
Regards,
Nishant
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Re: how to extract palette information
Posted by Loïc Minier <lo...@via.ecp.fr>.
Nishant <ni...@yahoo.com> - Tue, Mar 11, 2003:
> I was wondering if JAI can help me?
dunnno :(
> Is there anything like palette defined for an entire png
> image type? because the palette sounds like for a pixel for
> me!
?
> one person told me that he extracts the palette information
> for gif using this code... will this work also for png
> format.
Ouch, this is brute binary file reading, I strongly suggest you use a
lib that does the job for you!
Look at libpng's api and examples at
<http://www.libpng.org/pub/png/libpng-manual.html>.
Regards,
--
Loïc Minier <lo...@via.ecp.fr>
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Re: how to extract palette information
Posted by Nishant <ni...@yahoo.com>.
thanks a lot for the help lool.
I was wondering if JAI can help me?
Is there anything like palette defined for an entire png
image type? because the palette sounds like for a pixel for
me!
one person told me that he extracts the palette information
for gif using this code... will this work also for png
format.
------ source
// 幅 の読込
byte len1 = dis.readByte();
byte len2 = dis.readByte();
//
リトルエンディアン
width = (len2 & 0xff) * 256 + len1 & 0xff;
// 高さ の読込
byte hei1 = dis.readByte();
byte hei2 = dis.readByte();
//
リトルエンディアン
height = (hei2 & 0xff) * 256 + hei1 & 0xff;
// Packet Fields の読込
byte packetFields = dis.readByte();
// Global Color Table Flag の読込
globalColorTableFlag = ((packetFields & 128) == 128);
// Color Resolution の読込
int colorResolution = (packetFields & (16 + 32 + 64))
>> 4;
// Size of Global Color Table の読込
sizeOfGlobalColorTable = (packetFields & (1 + 2 + 4));
// palette の設定
palette = (1 << (sizeOfGlobalColorTable + 1));
-------------------------------------
Thanks and Regards,
nishant
--- Loïc Minier <lo...@via.ecp.fr> wrote: > Nishant
<ni...@yahoo.com> - Tue, Mar 11, 2003:
>
> > I need to read a .png file and read the palette value
> as an
> > integer.
> > I dont have any idea what is a palette.
>
> I don't know if you're attached to Java, but libpng
> might help you
> more than batik will in this case. There are functions
> to retrieve the
> palette. The palette is an array of color description,
> for example
> color #0 is blue 0,0,250 etc.
>
>
> --
> Loïc Minier <lo...@via.ecp.fr>
>
>
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> To unsubscribe, e-mail:
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> For additional commands, e-mail:
> batik-users-help@xml.apache.org
>
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Re: how to extract palette information
Posted by Loïc Minier <lo...@via.ecp.fr>.
Nishant <ni...@yahoo.com> - Tue, Mar 11, 2003:
> I need to read a .png file and read the palette value as an
> integer.
> I dont have any idea what is a palette.
I don't know if you're attached to Java, but libpng might help you
more than batik will in this case. There are functions to retrieve the
palette. The palette is an array of color description, for example
color #0 is blue 0,0,250 etc.
--
Loïc Minier <lo...@via.ecp.fr>
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