Re: PNG Loves EXIF

Thanks, Cosmin. I just did a new release. Try it now.

I did observe one thing with the libpng implementation: Initially, I used
the test image used for the EXIF unit-tests from libpng in my own
unit-tests, but I ended-up not being able to. An EXIF IFD block ends in a
uint32, which is a pointer to another IFD. This is usually only non-zero
for IFD0, where it points to IFD1. Either way, this is required. It is
missing from the IFD in the test PNG. I'm guessing that the libpng
implementation has a bug where it doesn't actually read/write this integer,
or is, at least, not checking for this in the unit-tests.



Dustin

On Sat, Jun 16, 2018 at 1:56 AM, Cosmin Truta <[email protected]> wrote:

> On Thu, 14 Jun 2018 at 05:13, Dustin Oprea wrote:
> > I just created an reader/writer EXIF library for Go (go-exif) and a
> command-line wrapper (go-exif-knife). Both the library and command-line
> tool support thumbnails, GPS, JSON-formatting, writing tags, etc.. . It's
> licensed as MIT.
>
> Thanks a lot, Dustin, both for your work and for your enthustiastic
> support. I welcome your contribution.
>
> On the PNG application side, outside of libpng, we have eXIf support
> in exiftool (cheers, Phil), and in the proof-of-concept
> implementations that some of us here wrote last year while debating
> the eXIf spec. But we still have a very long way to go and catch up
> with the EXIF support present in other formats, which why I find your
> contribution so valuable.
>
> If I'm not mistaken, this is the first Go implementation brought on
> png-mng-implement. We are overwhelmingly C-centric. Even mentioning
> C++ was a rarity, or Java, an extreme rarity. Bringing a Go
> implementation here feels modern and fresh.
>
> If you allow me a bug report:
> GOPATH is required, and it shouldn't be. go-exif-knife works fine on
> my machine, with the Go development environment set up, but it panics
> when I switch that environment off.
>
> Sincerely,
> Cosmin
>
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