1. Change INSUFFICIENT_MEMORY to TOO_LARGE
GTK crashes on insufficient memory, we don't emit GErrors.
2. Split UNSUPPORTED into UNSUPPORTED_CONTENT and UNSUPPORTED_FORMAT
So we know if you need to find an RPM with a loader or curse and
the weird file.
3. Translate error messages, they are meant for end users.
When loading, convert all >8-bit data to
GDK_MEMORY_R16G16B16A16_PREMULTIPLIED.
When saving, save all 8-bit formats as 8-bit RGBA,
and save all >8-bt formats as 16-bit RGBA.
Use our own loader to (de)serialiaze textures
to and from png and tiff.
We still fall back to gdk-pixbuf for handling all
the other image formats, and for pixbufs.
This is a companion to gdk_texture_save_to_png, using
the tiff format, which will let us avoid lossy conversion
of HDR data, since we can store floating point data.
Add support for the tiff format, which is flexible
enough to handle all our memory texture formats
without loss.
As a consequence, we are now linking against libtiff.
Using libpng instead of the lowest-common-denominator
gdk-pixbuf loader. This will allow us to load >8bit data,
and apply gamma and color correction in the future.
For now, this still just provides RGBA8 data.
As a consequence, we are now linking against libpng.
GLES only allows downloading float if the texture matches specific
criteria and I'm too lazy to determine them, so always fall back.
And the custom stride fallback code isn't necessary, because falling
back does exactly that step already.
This happens in the real world when using the inspector to look at a
node recording of a GStreamer video while the video is still playing.
GStreamer will use the GL context in a different thread while we are
busy trying to download it.
A test is included.
1. The download via gdk_cairo_draw_from_gl() was broken sometimes
2. We get easy conversion on fallback by chaining up and using
download_texture().
3. One more place where Cairo is no longer necessary.
1. It avoids Cairo, and in particular conversion to Cairo.
2. Keeping a texture allows easy chaining in the vfuncs.
3. Using a texture means releasing will work for HDR formats
too, once we add them.
A private vfunc that downloads a texture as a GdkMemoryTexture in
whatever format the texture deems best.
There are multiple reasons for this:
* GLES cannot download the Cairo format. But it can download some
format and then just delegate to the GdkMemoryTexture implementation.
* All the other download vfuncs (including the ones still coming) can
be implemented via download_texture() and delegation, making the
interface easier.
* We want to implement image loading and saving support. By using
download_texture(), we can save in the actual format of the texture.
* A potential GdkCompressedTexture could be implemented by just
providing this one vfunc as a compress() step.
