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  1. Qt
  2. QTBUG-80834

QPainter::drawLines does not always give the same output as multiple calls to QPainter::drawLine

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    Details

    • Type: Bug
    • Status: Closed
    • Priority: Not Evaluated
    • Resolution: Done
    • Affects Version/s: 5.12.3
    • Fix Version/s: 5.14.1, 5.15.0 Alpha
    • Component/s: GUI: Painting
    • Labels:
      None
    • Platform/s:
      Windows
    • Commits:
      05d52685028a46e340d610093c7e7c98479ac18b (qt/qtbase/5.14)

      Description

      In Qt 5.12.3 on Windows, given a number of lines to draw, a QPainter instance seems to give different output between a single call to drawLines and iterative calls to drawLine. In the case of drawLines, some of the lines were not visibly rendered at all.

      See attached file for a minimal reproduction - the vast number of lines is a set of data known to produce the issue, and removing lines made the issue more difficult to observe. The output of iterative calls to drawLine is displayed in green, while that of a single call to drawLines is displayed in red.

        Attachments

        1. repro.cpp
          28 kB
          David Cagnacci
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          Activity

            People

            Assignee:
            vgt Eirik Aavitsland
            Reporter:
            david_fmod David Cagnacci
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              Dates

              Created:
              Updated:
              Resolved:

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