Implement the get_screen_dpi function

This is sadly known to be incorrect on most systems. But it's as incorrect
as it was on Gtk so should work equally well to get roughly the right
sizes for printing - once we implement printing, that is :-)

Also removed a qDebug that snuck in in commit 6fc4d72079dd ("Enable
defautl_filename in settings").

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

2 files changed, 8 insertions, 5 deletions

diff --git a/display.h b/display.h
index 8567bc955..b62ae3ba3 100644
--- a/display.h
+++ b/display.h
@@ -6,15 +6,13 @@ extern "C" {
 #endif
 
 #define SCALE_SCREEN 1.0
-#warning "PORT THE get_screen_dpi to Qt"
-#define SCALE_PRINT 1.0
-//#define SCALE_PRINT (1.0 / get_screen_dpi())
+#define SCALE_PRINT (1.0 / get_screen_dpi())
 
 extern void repaint_dive(void);
 extern void do_print(void);
 
 // Commented out because I don't know how to get the dpi on a paint device yet.
-// extern gdouble get_screen_dpi(void);
+extern double get_screen_dpi(void);
 
 /* Plot info with smoothing, velocity indication
  * and one-, two- and three-minute minimums and maximums */
diff --git a/qt-gui.cpp b/qt-gui.cpp
index 5d858d733..d70e00379 100644
--- a/qt-gui.cpp
+++ b/qt-gui.cpp
@@ -28,6 +28,7 @@
 #include <QTextCodec>
 #include <QTranslator>
 #include <QSettings>
+#include <QDesktopWidget>
 
 class Translator: public QTranslator
 {
@@ -83,7 +84,6 @@ void init_ui(int *argcp, char ***argvp)
 	if (v.isValid()) {
 		QString name = v.toString();
 		prefs.default_filename = strdup(name.toUtf8());
-		qDebug("default filename %s", prefs.default_filename);
 	}
 	settings.endGroup();
 
@@ -200,4 +200,9 @@ QString get_pressure_string(pressure_t pressure, bool showunit)
 	}
 }
 
+double get_screen_dpi()
+{
+	QDesktopWidget *mydesk = application->desktop();
+	return mydesk->physicalDpiX();
+}
 #include "qt-gui.moc"