[jdk8u-dev] RFR: 8189687: Swing: Invalid position of candidate pop-up of InputMethod in Hi-DPI on Windows

[Paul Hohensee]

On Tue, 20 Aug 2024 11:34:03 GMT, Kazuhisa Takakuri <ktakakuri at openjdk.org> wrote:

> This is a backport of JDK-8189687: Swing: Invalid position of candidate pop-up of InputMethod in Hi-DPI on Windows.
> JDK-8189687 contains two fixes to AwtComponent:: OpenCandidateWindow
> 
> 1. Fix to make OpenCandidateWindow reference the correct Window
> Fix OpenCandidateWindow to reference the proxy window that has focus when getting "HWND."
> 
> 
> --- a/src/java.desktop/windows/native/libawt/windows/awt_Component.cpp
> +++ b/src/java.desktop/windows/native/libawt/windows/awt_Component.cpp
> @@ -3880,19 +3880,21 @@ void AwtComponent::OpenCandidateWindow(int x, int y)
>  {
>      UINT bits = 1;
>      POINT p = {0, 0}; // upper left corner of the client area
> -    HWND hWnd = GetHWnd();
> +    HWND hWnd = ImmGetHWnd();
>      if (!::IsWindowVisible(hWnd)) {
>          return;
>      }
> 
> 
> 
> 2. Scaling fixes to enhance JDK-8073320
> OpenJDK9 has supported HiDPI Graphics since JEP 263 (JDK-8055212). This fix is one of its enhancements: when OpenCandidateWindow opens an IME conversion candidate, it corrects the coordinates for the device.
> 
> 
> --- a/src/java.desktop/windows/native/libawt/windows/awt_Component.cpp
> +++ b/src/java.desktop/windows/native/libawt/windows/awt_Component.cpp
> @@ -3880,19 +3880,21 @@ void AwtComponent::OpenCandidateWindow(int x, int y)
>      HWND hTop = GetTopLevelParentForWindow(hWnd);
>      ::ClientToScreen(hTop, &p);
> +    int sx = ScaleUpX(x) - p.x;
> +    int sy = ScaleUpY(y) - p.y;
>      if (!m_bitsCandType) {
> -        SetCandidateWindow(m_bitsCandType, x - p.x, y - p.y);
> +        SetCandidateWindow(m_bitsCandType, sx, sy);
>          return;
>      }
>      for (int iCandType=0; iCandType<32; iCandType++, bits<<=1) {
>          if ( m_bitsCandType & bits )
> -            SetCandidateWindow(iCandType, x - p.x, y - p.y);
> +            SetCandidateWindow(iCandType, sx, sy);
>      }
>  }
> 
> 
> In the attached test that reproduces the issue problem, the Panel containing the TextField is a child component, so it refers to the wrong window to get the position coordinate of the candidate window.
> Therefore, the candidate window will appear in the correct position with the "1" fix.
> Note that OpenJDK8 does not implement JEP 263, so the "2" fix is not included in this pull request.

Marked as reviewed by phh (Reviewer).

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PR Review: https://git.openjdk.org/jdk8u-dev/pull/564#pullrequestreview-2251544345