Uploaded image for project: 'Qt'
  1. Qt
  2. QTBUG-71162

Layer-backed backingstore flush copies whole backingstore on each flush

    XMLWordPrintable

    Details

    • Platform/s:
      macOS
    • Commits:
      77a4915bf900aac0c96260018c0a4ccfbdd7c094 (qt/qtbase/5.12)
    • Sprint:
      Bug Fixing Week Q2/2020

      Description

      Painting on a layer-backed window on macOS (which is apparently unavoidable now when building agains the 10.14 SDK?) performs poorly because of QImage::detach copying the image. This is related to QTBUG-63559. The commit message for that issue indicates that it isn't expected to be fixed for layer-backed windows.

      Is there any way to avoid the copy or disable the layer-backed backing store? I tried setting QT_MAC_WANTS_LAYER=0 without success.

        Attachments

        1. detach-in-flush.png
          detach-in-flush.png
          225 kB
        2. layer-backed.png
          layer-backed.png
          199 kB
        3. layer-backed-detach.diff
          1 kB
        4. non-layer-backed.png
          non-layer-backed.png
          245 kB
        5. test.cpp
          0.7 kB

          Issue Links

          No reviews matched the request. Check your Options in the drop-down menu of this sections header.

            Activity

              People

              Assignee:
              vestbo Tor Arne Vestbø
              Reporter:
              jasonhaslam Jason Haslam
              Votes:
              1 Vote for this issue
              Watchers:
              8 Start watching this issue

                Dates

                Created:
                Updated:
                Resolved:

                  Gerrit Reviews

                  There are no open Gerrit changes