NewLC - Set Exif GPS latitude information. - Comments

Re: Set Exif GPS latitude information.

Alex25 — Tue, 29 Jan 2008 16:10:42 +0100

Hi Shashi
I know it's a pretty old thread. However, have you found a solution to write EXIF GPS information?
I have exactly the same problem. I'm not able to build the required ETagRational buffer. Any hints?

Thanks
Alex

Re: Set Exif GPS latitude information.

shashishaw — Tue, 05 Dec 2006 11:45:59 +0100

I tried using the method suggested. However, it still gives the same -6 error. I believe there has to be some special syntax for setting the value within the Exif header. From whatever i have read about exif tags, i believe there are 3 bytes used to hold the latitude information within the GPS IFD.
The problem is how do i convert the information available in TReal64 to fit into those 3 bytes. Also, i 'm not sure if we can directly store the TReal value or we have to convert the value into degrees, minutes and seconds before storing them.

Anyways i appreciate your help.
Thanks,
Shashi.

Re: Set Exif GPS latitude information.

alh — Tue, 05 Dec 2006 10:29:16 +0100

Oh, I see...
misunderstood the problem slightly

I have never used the SetTagL so I don't really know what it expects...

It might be a TPckgBuf or TPckgC with the value in it though.

you can create one like this:

Code:

TPckgBuf<TReal64> numbuf(aMyValue);
TPckgC<TReal64> numbuf2(aMyValue);

The first line will mean one extra copying of the data since TPckgBuf has its own buffer, since TPckgC is just a pointer to existing data.

It will store the number in the buffer as raw binary data.

Re: Set Exif GPS latitude information.

shashishaw — Tue, 05 Dec 2006 10:14:08 +0100

Hi Alh,
Thanks for the reply. However using either Format or AppendFormat does not help.
I tried to set, say a latitude value of 10.1234 using

buf.Format(_L8("%f"),10.1234);

This when passed to the SetTagL function, it still leaves with the reason code -6. (KErrArgument).

Re: Set Exif GPS latitude information.

alh — Mon, 04 Dec 2006 13:54:58 +0100

You can try use the Format() function.

you find the format string syntax here:
Symbian OS Guide
C++ API guide
Base
Using User Library (E32)
Buffers and Strings
Using Descriptors
How to Use Descriptors
Format string syntax

%f seems to be useful for your needs.

Code:

Format(_L("%f"),myvalue);

There is an AppendFormat too.

Set Exif GPS latitude information.

shashishaw — Mon, 04 Dec 2006 11:22:06 +0100