Small jpg manipulation library?

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I have a simple request:

I need a small proggie that will let me rotate a 640x480 jpeg image 180
degrees, and add a short piece of text (about 2 lines, maybe 25 chars
each) to the image itself.

My embedded sytem only has about 500K of flash left, so I really need
something that fits in that space.

I can create the image as raw RGB, do the manipulations, and then save it
as a jpeg if that would help.

I would appreciate any pointers....

Thanks,

--Yan

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Re: Small jpg manipulation library?

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How much RAM you got?  You need to store two fully decompressed images
at least.

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Re: Small jpg manipulation library?

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The images should only take up ~1MB uncompressed; I have 32 MB total and
15-16MB free:

root@apollo:/bin# free
              total         used         free       shared      buffers
  Mem:        30556        15368        15188            0         1520

So RAM shouldn't be an issue.  I figured out I can do the jpeg rotation
with jpegtran; now I just need to find something I can use to add a
watermark....

--Yan

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Re: Small jpg manipulation library?

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Is the text static?  We have a program to overlay one image on another,
If you first create the text overlay image elsewhere.  You can just
screen capture from a word processor.  Is your target x86, arm or what?

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Re: Small jpg manipulation library?

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No, the text is dynamic.  It is generated on the fly from GPS data and a
database lookup.

I am trying to avoid using a lot of resources with font-rendering stuff; I
really just want a stamp much like the date and time stamp you can put on
digital photographs taken with a regular camera.

--Yan

Re: Small jpg manipulation library?

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OK, if you provide the character images (one jpg per character), we can
give you a tool to overlay it on an image.  We have a program:

jpg -i old.jpg -c blue -m mask.jpg -o new.jpg

Will work on:
new_program -x 100 -y 100 -i old.jpg-o mask.jpg -t text

What is your target cpu?


Re: Small jpg manipulation library?

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mips.  This is for an app running on OpenWrt - a Linksys WRTSL54GL
wireless router, with a webcam and a GPS attached.

--Yan

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Re: Small jpg manipulation library?

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OK, we can deal with mips later.  We also want to have text overlays.
We need character bit maps for letters and symbols,  We already have
numbers.  They should be like:

"*        * ",
"* *    * * ",
"*  *  *  * ",
"*  *  *  * ",
"*   **   * ",
"*        * ",
"*        * ",
"*        * ",
"*        * ",
"*        * "

This is just a on-time program to generate the intermediate structure,
so don't worry about efficience.

If you can help, I'll set you up with an account on our server.  Do you
want to do it?

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Re: Small jpg manipulation library?

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Why reinvent the wheel? http://www.kevinboone.com/README_txt2jpg.html

It's java, but with this being a one-off, it doesn't really matter.

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I can help some.  Remove the obvious from my email address to contact me
directly.  I'm going out of town today, and when I return I may have to go
on yet another business trip (overseas, yet) so my time for the next 3-4
weeks is severly limited, though.

--Yan

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Java (jpeg Jre) is heavy.  It's much easier to strip down jpeg lib.
We have about 150K binary so far.  The following is an example
(for our dance teacher) for jpg resolution reductions.  We want to
overlay both texts and images on it as well.

http://rumba.fine-arts.ws

-rw-r--r--  1 root  wheel     133 Jun 19 19:00 Makefile
-rw-r--r--  1 root  wheel   38603 Jun 19 19:02 a1.jpg
-rw-r--r--  1 root wheel     24366 Jun 19 19:02 a2.jpg
-rw-r--r--  1 root  wheel   14051 Jun 19 19:05 b1.jpg
-rw-r--r--  1 root  wheel   14510 Jun 19 19:05 b2.jpg
-rw-r--r--  1 root  wheel    5353 Jun 19 19:05 c1.jpg
-rw-r--r--  1 root  wheel    5491 Jun 19 19:05 c2.jpg
-rw-r--r--  1 root  wheel      38 Jun 19 19:00 data
-rw-r--r--  1 root  wheel     604 Jun 19 19:06 index.html
-rwxr-xr-x  1 root  wheel  124878 Jun 19 18:55 jpg
-rwxr-xr-x  1 root  wheel    2635 Jun 19 19:29 main.php
-bash-2.05b# more Makefile
all:
        ./jpg -i a1.jpg -o b1.jpg -r 2
        ./jpg -i a2.jpg -o b2.jpg -r 2
        ./jpg -i b1.jpg -o c1.jpg -r 2
        ./jpg -i b2.jpg -o c2.jpg -r 2


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