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#1 Posted : Friday, May 4, 2012 6:57:10 PM(UTC)

kb7  
kb7

Groups: Registered
Posts: 71


Hi,

I want to convert the color image to grayscale image in VC++, Leadtools v17. Is there any demo example or some sample code to do this? Can we use grayscale command to do this? If then how in VC++?


Thanks...
 

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#2 Posted : Saturday, May 5, 2012 11:44:31 PM(UTC)
Maen Hasan

Groups: Registered, Tech Support
Posts: 1,328

Was thanked: 1 time(s) in 1 post(s)

Since you are using VC++, you can use LEADTOOLS C DLL programming interface to convert your images to grayscale. You can do this by using the L_GrayScaleBitmap function. Please check the following code from our C DLL documentation:
+------------------+
L_INT nRet;
BITMAPHANDLE LeadBitmap;   /* Bitmap handle to hold the loaded image. */

/* Load the bitmap, keeping the bits per pixel of the file */
nRet = L_LoadBitmap ("c:\\IMAGE1.CMP", &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL);
if(nRet != SUCCESS)
      return nRet;

/* Change the bitmap to grayscale */
nRet = L_GrayScaleBitmap(&LeadBitmap, 8 );
if(nRet != SUCCESS)
return nRet;

nRet = L_SaveBitmap("c:\\Result.BMP", &LeadBitmap, FILE_BMP, 24, 0, NULL);
if(nRet != SUCCESS)
return nRet;

L_FreeBitmap(&LeadBitmap);
return SUCCESS;
+------------------+

Thanks,
Maen Badwan
LEADTOOLS Technical Support
 
#3 Posted : Wednesday, May 30, 2012 2:17:41 AM(UTC)

kb7  
kb7

Groups: Registered
Posts: 71


Hi,

Can you please provide a sample application for the above code?
One more thing ,is it possible to read the color data from the buffer and then convert that data to grayscale Bmp image?


Thanks...
 
#4 Posted : Wednesday, May 30, 2012 5:26:16 AM(UTC)
Maen Hasan

Groups: Registered, Tech Support
Posts: 1,328

Was thanked: 1 time(s) in 1 post(s)

I am attaching a small C DLL Win32 2008 project that shows how you can convert colored image to grayscale.

About loading the image data from buffer, you can use the L_LoadBitmapMemory() to load the image file from memory. For more information, please see the "L_LoadBitmapMemory" help topic in the LEADTOOLS Raster Imaging C DLL help file.

Thanks,
Maen Badwan
LEADTOOLS Technical Support
File Attachment(s):
Win32GrayScaleBitmap17.zip (111kb) downloaded 35 time(s).
 
#5 Posted : Wednesday, May 30, 2012 7:56:07 PM(UTC)

kb7  
kb7

Groups: Registered
Posts: 71


Thanks a lot for the reply.... it is very helpful.

I tried to implement this code in MFC application on a button click. But it is returning nRet value=-789 when i call the function L_LoadBitmap.

Can you please tell me why is it returning -ve value?

or If I want to create a MFC application same as the above zipped Win32 application, what i have to do or can you provide the same in MFC.

Thanks..
 
#6 Posted : Thursday, May 31, 2012 5:19:27 AM(UTC)
Maen Hasan

Groups: Registered, Tech Support
Posts: 1,328

Was thanked: 1 time(s) in 1 post(s)

If you check our help file and headers, you will find that all LEADTOOLS error codes are negative.

This one in particular means Invalid Structure Size. It usually happens in 2 cases:
1. You did not initialize a structure or it members, especially the uStructSize member.
2. Or you are using a version of LEADTOOLS headers with a different version of our DLLs, which you must NEVER do.

Thanks,
Maen Badwan
LEADTOOLS Technical Support
 
#7 Posted : Friday, June 1, 2012 12:36:09 AM(UTC)

kb7  
kb7

Groups: Registered
Posts: 71


Thanks a lot. [:)]
 
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