Exchanging with OpenJPEG developers and searching more on the topic, it
seems that YUV is more often refered to as YCbCr. Wikipedia says:
> typically the terms YCbCr and YUV are used interchangeably, leading to
> some confusion. The main difference is that YUV is analog and YCbCr is
> digital
As for eYCC, I am told this is extended YCC. It seems this is refered as
xvYCC (I really can't find much under "eYCC"). So let's rename it too.
Hopefully I made no mistakes!
JPEG 2000 codestream doesn't have a header and guessing the color space
in particular is not foolproof (especially when 3 or 4 components, which
can be many spaces). Therefore the need of a parameter on the API.
Note that JP2 images should always have the color space information. In
interactive mode, I try to be a bit flexible to salvage broken JP2 with
no color space information in the header, but I am not adding a
parameter in file-jp2-load() (on purpose, since we are not going to add
in the API a parameter for a case not supposed to happen with properly
encoded files).
JPEG 2000 codestream (.j2k/.j2c) are only compressed code stream data,
without header. In particular we don't have color information, such as
the color space. So we need to open a dialog asking to set the color
space in interactive mode.
Note: according to OpenJPEG developers, a JP2 image (not codestream)
should always have a color space defined in its header. But just to be
flexible, the same dialog may get raised as well if we try to load a JP2
with no valid color space defined in header and no ICC profile embedded.
Maybe if such a thing happened, it means the image is corrupt, yet we
may as well try and salvage it anyway.
Note 2: I also removed a weird test which was setting some images as
being YUV color space by mistake. This actually fixes bug 794413 as a
side effect.
Even though I haven't seen working samples with this extension,
according to some references, this is a common extension for compressed
JPEG 2000 code stream. Also our old plug-in was listing this extension,
so let's do so now as well.
To this day, the only 2 extensions we used to list in the JasPer-based
plug-in and not in the OpenJPEG one are .jpf and .jpx (JPEG 2000 Part-2)
since OpenJPEG does not have support yet. But actually I think the old
plug-in may have simply been "lying" since JasPer website says the
library is meant to implement JPEG-2000 Part-1 standard.
So I believe we are now on par (and even better on many aspects) with
the former plug-in implementation based on libjasper.
After moving up the profile extraction, I was running
gimp_image_set_color_profile() with a non-existing image id, which was
obviously wrong. Reorder a bit the operations.
Also try to guess the color space from the profile not only with
OPJ_CLRSPC_UNSPECIFIED but also OPJ_CLRSPC_UNKNOWN images. Indeed I
encountered a case of .jp2 image with no color space in the header, but
with an embedded profile. And unlike the .j2c files I encountered
earlier, the color space was now *_UNKNOWN.
See https://github.com/uclouvain/openjpeg/issues/1103
Current OpenJPEG code only supported the base JP2 container. It now
supports also the JPEG 2000 codestream (which is usually contained
inside other formats, like the JP2 container format, but can also
sometimes be on its own).
The current magics and extension strings were also mixing all kind of
formats. This is now cleaned up a bit.
As explained in the previous commit, the color space is not always
properly declared, in particular with J2K files. If a profile is present
in such a case, try to deduct the color space from this information.
It seems that the color space is not necessarily declared for a JPEG2000
image. From tests, it looks like it especially happens with JPEG2000
codestream (.j2c or .j2k). This variant is apparently mostly designed to
be embedded (from what I read), which may explain why the color space is
not always set (I assume the embedding format would have the color space
information). Mostly a guess.
Rather than just assuming all non-gray images are RGB, do a bit more
robust check and reject unknown formats. Indeed even though I see we
took care of YUV, e-YCC and CMYK images above (and normally either
converted them to RGB or already exited with an error), I can see that
the OpenJPEG library could still return OPJ_CLRSPC_UNKNOWN or
OPJ_CLRSPC_UNSPECIFIED. Let's be thorough and not assume we got a SRGB
here.
Also add the alpha-variant tests inside their parent image type
respective test. This should not change anything by any logics, but
let's not leave anything for chance to strike us.
Finally minor coding style fixes:
- Add a space before "if|for" and parenthese.
- Remove some spaces after parentheses.
- Get rid of 2 trailing whitespaces.
- Align function call parameters, declarations, assignments…
Made plug-in support the RGB and grayscale with alpha.
Comment by Jehan: this makes the original branch work finally usable on
some JPEG 2000 images. Support of the format is not complete yet though
but at least the port to OpenJPEG is now in usable test.
...in both the core and libgimp.
Images now know what the default mode for new layers is:
- NORMAL for empty images
- NORMAL for images with any non-legacy layer
- NORMAL_LEGAVY for images with only legacy layers
This changes behavior when layers are created from the UI, but *also*
when created by plug-ins (yes there is a compat issue here):
- Most (all?) single-layer file importers now create NORMAL layers
- Screenshot, Webpage etc also create NORMAL layers
Scripts that create images from scratch (logos etc) should not be
affected because they usually have NORMAL_LEGACY hardcoded.
3rd party plug-ins and scripts will also behave old-style unless they
get ported to gimp_image_get_default_new_layer_mode().
with proper value names. Mark most values as _BROKEN because they use
weird alpha compositing that has to die. Move GimpLayerModeEffects to
libgimpbase, deprecate it, and set it as compat enum for GimpLayerMode.
Add the GimpLayerModeEffects values as compat constants to script-fu
and pygimp.
So the plug-in has the chance to decide whether it wants to trust the
metadata information (e.g. resolution). Also reorder parameters in
gimp_image_metadata_save_finish(). Change all plug-ins accordingly.
Based on original patches from Hartmut Kuhse and modified
by Michael Natterer. Changes include:
- remove libexif dependency and add a hard dependency on gexiv2
- typedef GExiv2Metadata to GimpMetadata to avoid having to
include gexiv2 globally
- add basic GimpMetadata handling functions to libgimpbase
- add image and image file specific metadata functions to libgimp,
including the exif orientation image rotate dialog
- port plug-ins to use the new APIs
- port file-tiff-save's UI to GtkBuilder
- add new plug-in "metadata" to view the image's metadata
- keep metadata around as GimpImage member in the core
- update the image's metadata on image size, resolution and precision
changes
- obsolete the old metadata parasites
- migrate the old parasites to new GimpMetadata object on XCF load
I'm sure some plug-ins need to add their items *not* at the toplevel,
but since making plug-ins really tree-aware is a lot more work than
just fixing insert positions, I went for passing -1 as parent in
almost all cases. And because of laziness...
Improve JPEG2000 error messages by using g_set_error() so we don't
throw many different errors in the users face, and make each error
unique and descriptive instead of using the same message regardless of
the type of error.
