RFR: JDK-8255439: System Tray icons get corrupted when windows scaling changes [v9]

[Alexey Ivanov]

On Mon, 16 May 2022 17:04:20 GMT, Harshitha Onkar <duke at openjdk.java.net> wrote:

>> In Windows, when desktop scaling is changed the tray icons was distorted/blurred a bit each time scaling changes.
>> 
>> With the proposed fix, the tray icon scales according to on-the-fly DPI scale settings. A test case has been added which adds a MRI icon to system tray, to observe the icon scaling when DPI is changed. Since the scale cannot be programmatically changed (for dynamic on-the-fly scale changes), I have used a manual test case to test this scenario.
>> 
>> When DPI changes usually two messages are sent by windows -
>> 
>> - [WM_DPICHANGED](https://docs.microsoft.com/en-us/windows/win32/hidpi/wm-dpichanged)
>> - [WMPOSCHANGING](https://docs.microsoft.com/en-us/windows/win32/winmsg/wm-windowposchanging)
>> 
>> I'm triggering an update on tray icons on receiving WMPOSCHANGING msg through the Tray icon's Window Procedure. Triggering an update on WM_DPICHANGED was still causing the icons to be distorted, hence WMPOSCHANGING is being used as the message to trigger the update.
>
> Harshitha Onkar has updated the pull request incrementally with one additional commit since the last revision:
> 
>   added ExceptionClear, fixed CI debug build issue

I clean-built it and tested it, it works correctly on both Windows 10 and 11.

src/java.desktop/windows/native/libawt/windows/awt_TrayIcon.cpp line 73:

> 71: jfieldID AwtTrayIcon::idID;
> 72: jfieldID AwtTrayIcon::actionCommandID;
> 73: jmethodID AwtTrayIcon::updateImageDpiID;

I'd rather drop 'Dpi' from the name because the name of the Java method is `updateImage`.

If you prefer, the C++ class method could also be changed to `UpdateImage`, dropping 'DPI'.

-------------

Marked as reviewed by aivanov (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/8441