getting RGB (unsigned char *) from JPEG (binary).

Could somebody guide me how to convert JPEG to RGB?

Any suggestion.
neel3333Asked:
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

x
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

neel3333Author Commented:
I found some code.
 jpeg_decompress_struct cInfo;
     FILE *filePtr;
               
     unsigned char     *imageData;
     unsigned int     imageWidth;
     unsigned int     imageHeight;
     unsigned char     bitDepth;

     filePtr = fopen(path, "rb");
               
     jpeg_error_mgr jerr;
     cInfo.err = jpeg_std_error(&jerr);
     jpeg_create_decompress(&cInfo);
     jpeg_stdio_src(&cInfo, filePtr);

     jpeg_read_header(&cInfo, TRUE);
     jpeg_start_decompress(&cInfo);
     bitDepth = cInfo.num_components;
     imageWidth = cInfo.image_width;
     imageHeight = cInfo.image_height;

     imageData = ((unsigned char*)malloc(sizeof(unsigned char)*imageWidth*imageHeight*bitDepth));

     jpeg_finish_decompress(&cInfo);

     jpeg_destroy_decompress(&cInfo);
     free(imageData);
     fclose(filePtr);

but it seem that it does not get pass jpeg_finish_decompress(&cInfo) when I compile the code. Someone plz help me get the imageData from jpeg image.

thank you.
0
DanRollinsCommented:
I don't know aanything about those jpeg_Xxxxx calls you are making.  But...

If you are programming for Windows, there is an API that loads a JPG file and produces a bitmap image in memory.   That lets you get the image data in RGB format quit easily.  See these references for the first step.  When you are able to successfully load a JPG file, then post back and I'll show you how to obtain RGB values from the image data.

    C++ Q&A: Displaying a JPG in your MFC Application -- MSDN Magazine, October 2001
    http://msdn.microsoft.com/msdnmag/issues/01/10/c/default.aspx
    http://msdn.microsoft.com/msdnmag/issues/01/10/c

    OleLoadPicture API call
    http://msdn.microsoft.com/library/en-us/com/htm/ofn_ol2z_0k4l.asp

    SAMPLE: How to Load and Display Graphics Files with LOADPIC.EXE
    http://support.microsoft.com/support/kb/articles/Q218/9/72.ASP

-- Dan
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
monkesdbCommented:
0
Acronis True Image 2019 just released!

Create a reliable backup. Make sure you always have dependable copies of your data so you can restore your entire system or individual files.

jonninCommented:
The standard jpg library (from the jpeg group page) has code to decompress into a targa. An uncompressed targa (one of the options) is a rgb file with headers, I hacked this code to return the rgb array in short order.

0
neel3333Author Commented:
I did that at first, but the
    put_scanline_someplace(buffer[0], row_stride);
has undeclared identifier.
My idea of the whole thing is get the unsigned char* of the image, b/c my SetDIBitsToDevice() function only accept unsigned char *.
Plz help ASAP.

Thank you
0
DanRollinsCommented:
neel3333,
You are clearly using Windows.  Are you set on using the standard jpg library, or have you tried using the OleLoadPicture API?  

If you are in a hurry, I can help, but not if you will be using some third-party library code.

-- Dan
0
neel3333Author Commented:
I'm using standard jpg library
0
neel3333Author Commented:
Hi Dan. Sorry we did not able to reply your post in time.
We modified the loadpic code to recieve jpeg file, but we a problem with displaying the images. I didn't have the code on the machine, but I'll put it up later. Basicly, I deleted most of the option with loadpic  and inserted socket to recieve the gif file and then loading it.

Right now I'm have problem of view sequence of files (streaming).
0
migoEXCommented:
No comment has been added lately, so it's time to clean up this TA.
I will leave a recommendation in the Cleanup topic area that this question is:

Accept DanRollins's comment as answer.

Please leave any comments here within the next four days.

PLEASE DO NOT ACCEPT THIS COMMENT AS AN ANSWER!

migoEX
EE Cleanup Volunteer
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Web Graphics Software

From novice to tech pro — start learning today.