<AWT Dev> RFR: 8182043 Access to Windows Large Icons

Alexander Zuev alexander.zuev at oracle.com
Tue Mar 31 00:02:27 UTC 2020

He Sergey,

   please look for answers inline.

On 30-Mar-20 21:35, Sergey Bylokhov wrote:
> Hi, Alexander.
> A few initial question before I have look to the webrev:
>  - Why we need a new class for only one method, why we cannot enhance 
> the FileSystemView
>    where the similar method is implemented already getSystemIcon(File)?
As you know this is not the first attempt to fix this issue and when i 
asked about "Why do we need
a separate class for one new method" the answer was "There is a reason, 
we tried different approaches
and this one is what we ended up with". Exact reason buried somewhere in 
the previous reviews.
Personally for me i would prefer adding the new method to some existing 
public class.
Here's the link to the latest bit of the discussion that i found and 
there was exactly the same question
raised by Alexey Ivanov, there are some reasons for creating a separate 
For some reason the discussion looks incomplete as if some part of it 
outside of the alias so i can't say what was the outcome - aside of the 
fact that last proposed
implementation still had a separate class.
>  - Can we try to re-implement the places where the old method 
> ShellFolder.getIcon(boolean)
>    was used, and change it to use the new public API, just to confirm 
> that our new code is a
>    a good replacement of the old/private api. I guess we could get rid 
> the boolean version.
It is outside of the initial scope of the request but yes - i can do it. 
Should i do it within this fix or
should i create a new bug and do it there?
>  - The current spec for SystemIcon.getSystemIcon() specify that the 
> icon will store the
>    "maximum quality icon" what does it meant?
It means that the maximum size of the icon allowed by the system will be 
used. Right now on
Windows (and this issue is Windows specific) the maximum icon size 
allowed is 256x256 pixels.
That is the size we will request and store in the MultiResolutionImageIcon.
>  - Another question is about multi-screen environment, if the 
> JFileChooser will be shown
>    on the non-HiDPI screen and then moved to the HiDPI screen which 
> icons we will request
>    from the native and which actual icons(resolution) will we draw on 
> each screen?(both types
>    of icons large/small are interesting).
Right now Swing is handling scaling and with my limited testing 
capability (i don't have access to
the different multi-monitor configurations for obvious reasons) i don't 
see any problem. Both
small and large sized icons got scaled together with the scaling factor 
change, obviously
quality of icons with size 32 and up is much better since they all are 
downscale of the 256x256
icon and both 16x16 and 24x24 icons are pretty pixelated with scaling 
factor 200% and up,
but that was a trade off for allowing of the custom small icons to be 
used where available.


> On 3/30/20 4:19 am, Alexander Zuev wrote:
>> Hello,
>>    please review my fix for the issue 8182043: Access to Windows 
>> Large Icons
>>    Bug: https://bugs.openjdk.java.net/browse/JDK-8182043
>>    Webrev: http://cr.openjdk.java.net/~kizune/8182043/webrev 
>> <http://cr.openjdk.java.net/~kizune/8182043/webrev/>
>>    Main idea is to provide a new API call to retrieve image of the 
>> specified size
>> and to make Windows implementation that for all the resolutions 
>> higher than 24 pixels
>> returns the multi resolution image icon with image inside being the 
>> highest quality icon
>> available and the size set to the size requested by the user. This 
>> way we will have good
>> scaling across the different resolution while maintaining relative 
>> sizes in the UI intact.
>> The exception made for images size of 24 and less since sometimes 
>> application has
>> different image for the small icons in its resource section which is 
>> optimized to
>> make sure that on low resolution screen this icon is not displayed as 
>> just scaled down
>> blurry little square.
>> /Alex

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