Fix support for screen fractional scaling with Wayland

The display was wrong when a backing store is in use (which is the case
with Wayland). To fix this in GuiWorkArea::Private::resetScreen(), the
pixelRatio is now stored as a double instead of an int.

Concerning support for QT_SCALE_FACTOR, the existing code was wrong
because this value is already taken into account in devicePixelRatioF
for Qt > 5.6 (no fractional scaling support before that). The
situation is as follows:

                   Qt < 5.6    5.6 <= Qt < 6  Qt 6
devicePixelRatio   int(ratio)  int(ratio)     ratio
devicePixelRatioF  N/A         ratio          ratio

So it is only between Qt 5.6 and Qt 6 that devicePixelRatioF() has to
be used instead of devicePixelRatio().
QGuiApplication::devicePixelRatio() does not have a 'F' version, it
always returns the real thing.

Fixes ticket #13039.
This commit is contained in:
Jean-Marc Lasgouttes 2024-02-25 20:17:31 +01:00
parent 23105b2edd
commit 8f61b0859c
5 changed files with 20 additions and 29 deletions

View File

@ -50,7 +50,6 @@
#include "frontends/Application.h"
#include "support/ConsoleApplication.h"
#include "support/convert.h"
#include "support/lassert.h"
#include "support/debug.h"
#include "support/environment.h"
@ -121,14 +120,6 @@ RunMode run_mode = PREFERRED;
OverwriteFiles force_overwrite = UNSPECIFIED;
// Scale the GUI by this factor. This works whether we have a HiDpi screen
// or not and scales everything, also fonts. Can only be changed by setting
// the QT_SCALE_FACTOR environment variable before launching LyX and only
// works properly with Qt 5.6 or higher.
double qt_scale_factor = 1.0;
namespace {
// Filled with the command line arguments "foo" of "-sysdir foo" or
@ -318,17 +309,6 @@ int LyX::exec(int & argc, char * argv[])
// we need to parse for "-dbg" and "-help"
easyParse(argc, argv);
#if QT_VERSION >= 0x050600
// Check whether Qt will scale all GUI elements and accordingly
// set the scale factor so that to avoid blurred images and text
char const * const scale_factor = getenv("QT_SCALE_FACTOR");
if (scale_factor) {
qt_scale_factor = convert<double>(scale_factor);
if (qt_scale_factor < 1.0)
qt_scale_factor = 1.0;
}
#endif
try {
init_package(os::utf8_argv(0), cl_system_support, cl_user_support);
} catch (ExceptionMessage const & message) {

View File

@ -56,7 +56,6 @@ extern bool verbose;
extern bool ignore_missing_glyphs;
extern RunMode run_mode;
extern OverwriteFiles force_overwrite;
extern double qt_scale_factor;
namespace frontend {
class Application;

View File

@ -1247,7 +1247,7 @@ GuiApplication * theGuiApp()
double GuiApplication::pixelRatio() const
{
return qt_scale_factor * devicePixelRatio();
return devicePixelRatio();
}
@ -2669,7 +2669,7 @@ QPixmap GuiApplication::getScaledPixmap(QString imagedir, QString name) const
qreal dpr = 1.0;
// Consider device/pixel ratio (HiDPI)
if (currentView())
dpr = currentView()->devicePixelRatio();
dpr = currentView()->pixelRatio();
// We render SVG directly for HiDPI scalability
QPixmap pm = getPixmap(imagedir, name, "svgz,png");
FileName fname = imageLibFileSearch(imagedir, name, "svgz,png");

View File

@ -260,7 +260,11 @@ private:
/// Current ratio between physical pixels and device-independent pixels
double pixelRatio() const {
return qt_scale_factor * devicePixelRatio();
#if (QT_VERSION >= QT_VERSION_CHECK(5, 6, 0) && QT_VERSION < QT_VERSION_CHECK(6, 0, 0))
return devicePixelRatioF();
#else
return devicePixelRatio();
#endif
}
qreal fontSize() const {
@ -1844,7 +1848,11 @@ void GuiView::resetCommandExecute()
double GuiView::pixelRatio() const
{
return qt_scale_factor * devicePixelRatio();
#if (QT_VERSION >= QT_VERSION_CHECK(5, 6, 0) && QT_VERSION < QT_VERSION_CHECK(6, 0, 0))
return devicePixelRatioF();
#else
return devicePixelRatio();
#endif
}

View File

@ -179,7 +179,11 @@ GuiWorkArea::GuiWorkArea(Buffer & buffer, GuiView & gv)
double GuiWorkArea::pixelRatio() const
{
return qt_scale_factor * devicePixelRatio();
#if (QT_VERSION >= QT_VERSION_CHECK(5, 6, 0) && QT_VERSION < QT_VERSION_CHECK(6, 0, 0))
return devicePixelRatioF();
#else
return devicePixelRatio();
#endif
}
@ -1264,9 +1268,9 @@ void GuiWorkArea::Private::paintPreeditText(GuiPainter & pain)
void GuiWorkArea::Private::resetScreen()
{
if (use_backingstore_) {
int const pr = p->pixelRatio();
screen_ = QImage(pr * p->viewport()->width(),
pr * p->viewport()->height(),
double const pr = p->pixelRatio();
screen_ = QImage(int(pr * p->viewport()->width()),
int(pr * p->viewport()->height()),
QImage::Format_ARGB32_Premultiplied);
screen_.setDevicePixelRatio(pr);
}