https://bugs.kde.org/show_bug.cgi?id=421634
Bug ID: 421634 Summary: Presentation mode misrendering with two monitors and screen scaling Product: okular Version: unspecified Platform: Other OS: Linux Status: REPORTED Severity: normal Priority: NOR Component: general Assignee: okular-devel@kde.org Reporter: oliver.san...@tu-dresden.de Target Milestone: --- Created attachment 128524 --> https://bugs.kde.org/attachment.cgi?id=128524&action=edit Screenshot showing the misrendering I have a setup with a built-in laptop monitor and one external monitor. Both are set to 1920x1080 resolution. They are combined to a single virtual desktop, the external one (set to be the primary display) is stacked on top of the laptop monitor. I use a screen scaling factor of 1.5 for both monitors: ~> echo $QT_SCREEN_SCALE_FACTORS eDP-1=1.5;DP-1=1.5;HDMI-1=1.5;HDMI-2=1.5; Presentation mode on the laptop screen works as expected. On the external screen, however, I see garbage on 2/3 of the screen (see attachment). I started debugging and noticed that the size of m_lastRenderedPixmap in the PresentationWidget::paintEvent method depends on what screen the presentation mode is activated on. That size is set in PresentationWidget::generatePage to 1.5 times the widget size. On the laptop screen, the widget size is reported as being 1280x720 which, multiplied by 1.5, yields the correct 1920x1080. On the external monitor, however, the same code reports a widget size of 1920x1080 right away. Multiply that by 1.5, and m_lastRenderedPixmap ends up with a size of 2880x1620. That seems odd to me. Now at this point I am stuck. Can somebody explain to me why I get two different widget sizes depending on what monitor my widget is on? And which one of the two is correct anyway? In the documentation of QWidget I read: "Do not use [the height function] to find the height of a screen on a multiple screen desktop." But the explanation given there claims that the height method would give me the height of the complete virtual desktop, which is not the case. Can somebody who knows Qt please enlighten me? -- You are receiving this mail because: You are the assignee for the bug.