On 6/17/20 4:14 pm, Alexey Ivanov wrote:
I've been playing with a build that contains the proposed fix on different devices for a while.>
I see no benefit in fetching several sizes of the icon from Windows API, at this time at least. Rather the opposite: at 150% the rendered icons look pixelated; however, in the build without the fix all the icons look crisp. More details on this below.
I guess it is too early to compare behavior before and after the fix since the
fix has a few bugs.
- It does not fetch several sizes, as it was expected from the code, but load
only one native size
and map it to the different resolutions.
- It reverts part of the JDK-8151385, and as far as I understand the bug
described in
8151385 starts to reproduce.
BTW I think the best possible fix is to load all actually existed icons into
the MRI:
- The user will be able to use any of these icons via
MRI.getResolutionVariants()
- And it solves all problems related to HiDPI.
But the open question is it possible to "load all actually existed icons" or
not.
On 17/06/2020 18:59, Philip Race wrote:
Icon has API that returns size.
I was wondering how problematic this is for returning an Icon backed by an MRI
But this being a Swing API I suspect the reason for it is so Swing can lay out.
So it does not want to know the real icon size in "device" pixels.
That would actually be a problem not a benefit. It wants to know the user
coordinate size for layout.
I think it also means that the size can't change when you drag between display
devices with
different UI scales.
So maybe we can do this properly with an MRI backed Icon and just return
whatever is the base image size.
Also it means that maybe we don't need a new API at all.
I've not understood all of the reasoning behind many of the suggestions (going
back years)
very well but if this can be done without API it would be very helpful in
general.
No problem backporting and apps will get the benefit without re-coding.
I believe it is how it works now. I mean the application requests the logical
size, if Windows Shell API returns the icon of the requested size, the
BufferedImage with icon pixels is returned; if Windows Shell API returns the
icon of different size, the BufferedImage is wrapped into
MultiResolutionIconImage. The latter case handles High DPI environments.
The current Swing API provides access to two sizes: 16×16 and 32×32, small and
large correspondingly.
As I understand the RFE, access to other possible icon sizes is desired. If a
programmer wants to display a larger icon, say 48×48, in their own control,
there's no way to get such an icon without writing code to extract this icon.
Before Java 9, the programmer could access the internal Swing API to retrieve
this icon; with module encapsulation it has become impossible as explained in
JDK-8156183 [1].
Thus, the purpose of the new API is not for High DPI support.
[1] https://bugs.openjdk.java.net/browse/JDK-8156183
As for High DPI support, there's still room for improvement. The icons in
Windows are essentially a multi resolution image but we're not using this fact:
there's always only one icon size stored. Alexander implemented it now: the
icon contains several other sizes in addition to the requested one. But
something does not work as expected.
I have my main monitor and system scaling set to 100%, a regular environment.
I've been using SwingSet2 for my testing.
With Alexander's proposed fix, File Chooser requests two sizes 16 and 32. This
scenario works fine.
If I launch it with uiScale=2.0, the UI is scaled; File Chooser requests two
size 16 and 32, just like before. But the icons in the file list are scaled
versions of 16×16 instead of 32×32 as I would expect. This is clearly seen
because folder icon is flat in 16×16 but it's 3D-like in 32×32. (I cannot
explain why this does not work.)
If I set my laptop screen scaling to 150%, my main monitor and system scaling
remains at 100%, and start SwingSet2 without setting uiScale, then it works as
expected on the main monitor. If I move JFileChooser to my laptop screen, the
UI scales up, but the icons are still scaled up versions of the base 16×16
icon. Windows Explorer starts to display 24×24 icon in this case (folder icon
is 3D-like in 24×24 too).
I also tested it with system scaling set to 150% and 200%. This scenario works
fine without the fix: the displayed icons are crisp. As I mentioned above, some
of the icons look pixelated in 150% setting with the proposed fix. In 200%
scaling, File Chooser UI got weird: file list had a mix of 64×64 and 32×32
icons displayed for files; text on the left side panel was clipped.
http://cr.openjdk.java.net/~aivanov/8182043/webrev.01-JFileChooser-200.png
This is what happens, to the best of my understanding. To get the icon pixels,
a DC is used; this DC is created with GetDC(NULL). Swing requests 16×16 icon,
but the API actually returns 24×24 and 32×32 icons, the scaling being 150% and
200% correspondingly. This is why sometimes BufferedImage is wrapped in
MultiResolutionIconImage, see JDK-8151385 [2].
And at 200% scaling, the rendering code gets confused: the
MultiResolutionIconImage returned for the base size of 16 now contains 32×32
image, and 64×64 image for the base size of 32. Since the initial size is 16,
when scaling is set to 200%, the 32px-sized image should be used for rendering
but there's larger image actually.
This problem also exists at 150%, the images for 16 and 32 come from native as
24 and 48.
I didn't test the High DPI scenario where another monitor with 100% scaling
exists in the system. I expect that icon sizes do not adjust correctly, I mean
that a larger icon will be down-scaled just like a smaller icon is up-scaled in
the case where main display is at 100%.
[2] https://bugs.openjdk.java.net/browse/JDK-8151385
To address JDK-8182043, this RFE, I would suggest extending the current API to
allow for arbitrary size. The requested size is in Swing logical pixels, it's
passed to native code. An application developer would choose the size,
JFileChooser will continue to use 16 and 32 as the icon size like it does now.
The result will contain either BufferedImage or MultiResolutionIconImage to
accommodate High DPI environments.
I would suggest submitting a separate bug to address High DPI environment
issues and to fetch a more suitable icon size from Windows. The icons displayed
in JOptionPane are also affected.
Regards,
Alexey
If this is not possible can someone summarise why it is absolutely impossible.
Going back the submitter needed to dig out the hi-res icon because we didn't do
it for them but
that doesn't mean it is what he wants to do, it is what he had to do. He'll
have to re-code
regardless because of using internal APIs.
So if we re-phrase the problem as "automatically pick the best image at
*display* time
without requiring applications to re-code", what would this look like and what
is lost ?
Would it look like no API change, and the only thing that is lost is what does
not actually
exist (API for the application to dig in to internals) ?
-phil.
On 6/15/20, 9:40 PM, Sergey Bylokhov wrote:
Hi, Alexander.
Some generic questions about the general approach:
- Did you experiment using LookupIconIdFromDirectoryEx? This method was
referred in the previous email.
- Did you check how the performance will be affected if we always load a few
icons, all icons, or if we try to load them on
the fly when the user request some size from the MRI?
- As far as I understand to access the list of icons the user will need to use
instanceof MRI, can we improve it somehow?
Probably add example to the javadoc, and to the test?
- What about returning the array of icons, will that solution be
simpler/faster then using MRI or not?
- Did you try to merge implementation of
getSystemIcon(File)/getSystemIcon(File, size)?
- I think we need to improve the spec for the new method:
* "width and height of the icon in pixels to be scaled" - what does it mean "to
be scaled", is
the returned icon will always have this size in pixels?
* "Whenever possible the icon returned will be a multi-resolution icon image
with maximum quality icon provided by the system and the size stored
reflecting the size requested by the user. That will allow nice scaling
with differen magnification factors." Does our implementation follow this
spec?
On 6/9/20 2:24 pm, Alexander Zuev wrote:
while generally agree i'm not sure that we need to populate ALL of the
resolutions for every sing> icon we request. So my idea that you can see in the
new webrev is to create the true MRI which will
hold all standatd resolutions within the range of half of requested icon size
and double of it. That would
cover magnification factors from 50% to 200%. I tested it and the icons in the
standard JFioleChooser looks
pretty good on display with different magnification factors.
- Looks like in the fix we always use the "size" passed by the user when we
call getShell32Icon() so we
always fetch the same icons from the native?
- The change in the makeIcon reverts back the fix for JDK-8151385, can you
please confirm that those fix
still works as expected?
- The new parameter "size" in the makeIcon(long hIcon, int size) is unused.
--
Best regards, Sergey.
