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  1. Qt
  2. QTBUG-55245

QOpenGLWidget::grabFramebuffer is darker than screen: not doing same gamma correction?

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    Details

    • Type: Bug
    • Status: Open
    • Priority: P2: Important
    • Resolution: Unresolved
    • Affects Version/s: 5.6.1
    • Fix Version/s: None
    • Component/s: GUI: OpenGL
    • Labels:
      None
    • Environment:
      Mac OSX 10.11.6, latest xcode, Qt5.6.1 release

      Description

      The QImage produced by QOpenGLWidget::grabFramebuffer is much darker than what appears onscreen (see attached images) – seems like some kind of gamma correction factor is missing? It would be much more useful if the resulting image reflects what is seen onscreen – perhaps as an option?

      Relatedly, when I recently switched from using the QGLWidget to the QOpenGLWidget, it seems that this gamma factor got introduced, as the same underlying opengl rendering code now produces a much brighter image. I have searched extensively for any info about this but can't seem to find anything – perhaps some underlying OpenGL flag somewhere set globally on the entire window that automatically applies a gamma transform?

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            People

            Assignee:
            lagocs Laszlo Agocs
            Reporter:
            rcoreilly Randall O'Reilly
            Votes:
            2 Vote for this issue
            Watchers:
            7 Start watching this issue

              Dates

              Created:
              Updated:

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