A pixel is a pixel, regardless of DPI. However things matter when you use point sizes (which assumes 72 points per inch) there are also Screen.devicePixelRatio ( http://doc.qt.io/qt-5/qml-qtquick-window-screen.html#devicePixelRatio-attached-prop ) to contend with. I haven't had to worry about this for some time, so my intel may be out of date. It was a mess around 5.6...
I'm assuming the 72 has something to do with the point size, and being able to calculate scaling relative to 72. > Sent: Wednesday, October 17, 2018 at 11:59 AM > From: "Tomasz Olszak" <olszak.tom...@gmail.com> > To: development@qt-project.org > Subject: [Development] Why on Linux using FreeType engine fonts are rendered > in 72 dpi instead of Screen DPI? > > Hi, > > I would like just to ensure that I missed something and there is > documentation somewhere informing that Linux fonts are rendered > *always* in 72 dpi > (https://www.freetype.org/freetype2/docs/reference/ft2-base_interface.html#FT_Set_Char_Size) > (which makes font.pixelSize inaccurate for regular screens). > > I found: https://bugreports.qt.io/browse/QTBUG-8890 which fixes the > problem but it was rejected. I see the default 72 dpi is also used in > current Qt 5.11 FT engine > (https://code.woboq.org/qt5/qtbase/src/platformsupport/fontdatabases/freetype/qfontengine_ft.cpp.html#297). > > Does it surprise any of Qt developers or is it only me? Am I right > thinking that when we do following: > Rectangle { > height: 100 > Text {font.pixelSize: 100} > } > then the relation between height of text and height of rectangle will > differ depending on screen dpi (don't have a way to test it > currently)? > > Moreover I'm pretty sure that's the cause I very often use > Text.fontSizeMode: Text.Fit because setting pixelSize to height of > desired text size never worked correctly :) > > tl;dr: Is it a bug? > _______________________________________________ > Development mailing list > Development@qt-project.org > http://lists.qt-project.org/mailman/listinfo/development > _______________________________________________ Development mailing list Development@qt-project.org http://lists.qt-project.org/mailman/listinfo/development