This thread is very long and despite trying I am sure I have not
absorbed every discussion point to date.
I think a concise summary of the current opinions from Semyon would help as
I don't yet see a concensus emerging and if we are adding a new public
API we need to be sure that
1) It is supportable ?
- The question around whether Windows sometimes gives us a scaled
image even when we think it
is giving us a full resolution image is one that needs to be considered
2) returning something backed by a multi-res image seems like it should
be explored for feasibility.
I am not sure why a developer would need multiple images to be
manually managed and selected
in this case when elsewhere we can select an appropriate one
automatically. PERHAPS we can
even retro-fit the implementation of the existing API to support this ?
3) It does what the developer actually needs ?
Although he is just one person, has anyone gone to ask the person
who submitted
this request what he would LIKE to see .. as distinct from what he
has been doing as
a workaround to date. By this I mean maybe he has had to manually
select a large icon and use it
where he needs it .. perhaps he is doing this only because we aren't
doing it automatically ?
So I am not even really looking at the code here .. although I have ..
we need to get the high level
issues sorted out first.
So Semyon: AI: provide that summary .. and along with it answer as much
of 1 - 3 as you can and
also go find the submitter and ask him for input.
-phil.
On 10/24/2017 09:10 AM, Alexey Ivanov wrote:
Hi Sergey,
On 24/10/2017 00:22, Sergey Bylokhov wrote:
On 17/10/2017 09:42, Alexey Ivanov wrote:
This is my understanding, before those fix the maximum size was 32x32.
It is my understanding too. Thus limiting the size of icon to 128
pixels seemed reasonable.
At this moment the buffer for icon pixels is allocated on the stack,
therefore the size cannot be dynamic. If memory for icon pixels is
allocated dynamically, the limitation can be removed.
It makes sense to address this limitation under a separate issue, do
you agree?
I agree that this can be moved to a separate bug. But my complaints
were not related to it.
- The new flags are not strictly specified. It is unclear what are
small and large icons. For example the old "getSystemIcon" specified
that it returns "an icon as it would be displayed by a native file
chooser". How the new flags are related to this? I see that the SMALL
flag is the same as the old method, and the large cion is just a
HiDPI version of default icon.
- SMALL/LARGE flags depends from the native main screen scale,
probably it is possible to remove this dependency? Otherwise in the
two screen configuration it will produce different images depending
from the main screen.
Per my understanding, SMALL and LARGE flags correspond to the previous
private API behaviour where you could get two icon sizes: 16×16 and
32×32. These flags will return the same logical-sized icons, subject
to HiDPI scaling performed by native system.
So these constants provide backward compatibility to
sun.awt.shell.ShellFolder.getShellFolder(file).getIcon(getLargeIcon):
either SMALL or LARGE.
- In case of multi-monitor config in the discussion above there was
a suggestion that the user can create MRI on top of the new API. I am
not sure how it will work because we already return MRI for most of
the files.
I am still thinking that we should investigate the possibility to
return MRI directly w/o ImageIcon/Icon wrappers. This MRI could load
data lazily depends from the destination scale. The user ill able to
get any resolution variants via getResolutionVariant(double,double)
and also can get the list of the icons attached to some file via
getResolutionVariants();
My suggestion was to create MRI internally inside the new API. [1]
This seems like the best option. On the other hand, we need to
overcome native system scaling, otherwise the rendering could be broken.
Testing performed by you [2] and me [3] shows that native system
scales the returned hIcon, and, if there are several displays in the
system with different scaling factors, the underlying icon size could
be wrong.
It seems there's no easy-to-use API for icons, Microsoft admits [4]
working with icons is one of the areas where Win32 API does not
provide a DPI context. It is still possible to use low-level resource
APIs to enumerate all the provided sizes in RT_GROUP_ICON resource.
Regards,
Alexey
[1]
http://mail.openjdk.java.net/pipermail/awt-dev/2017-September/013147.html
[2]
http://mail.openjdk.java.net/pipermail/awt-dev/2017-October/013179.html
[3]
http://mail.openjdk.java.net/pipermail/awt-dev/2017-October/013181.html
[4]
https://msdn.microsoft.com/library/windows/desktop/mt843498(v=vs.85).aspx#Common_Pitfalls__Win32__
