Issue #59: Use optionally logical pixels when zooming

Pdf4QtLib/sources/pdfdrawspacecontroller.cpp

@@ -29,6 +29,8 @@
 #include <QTimer>
 #include <QPainter>
 #include <QFontMetrics>
+#include <QScreen>
+#include <QGuiApplication>
 
 namespace pdf
 {
@@ -535,10 +537,23 @@ void PDFDrawWidgetProxy::update()
     Q_ASSERT(m_verticalScrollbar);
 
     QWidget* widget = m_widget->getDrawWidget()->getWidget();
+    QScreen* primaryScreen = QGuiApplication::primaryScreen();
 
     // First, we must calculate pixel per mm ratio to obtain DPMM (device pixel per mm),
     // we also assume, that zoom is correctly set.
-    m_pixelPerMM = static_cast<PDFReal>(widget->width()) / static_cast<PDFReal>(widget->widthMM());
+    QSizeF physicalSize = primaryScreen->physicalSize();
+    QSizeF pixelSize = primaryScreen->size();
+
+    m_pixelPerMM = pixelSize.width() / physicalSize.width();
+
+    // Are we using logical pixels instead of physical ones?
+    if (m_features.testFlag(PDFRenderer::LogicalSizeZooming))
+    {
+        qreal ldpi = primaryScreen->logicalDotsPerInch();
+        qreal pdpi = primaryScreen->physicalDotsPerInch();
+        qreal ratioLogicalToPhysical = ldpi / pdpi;
+        m_pixelPerMM *= ratioLogicalToPhysical;
+    }
 
     Q_ASSERT(m_zoom > 0.0);
     Q_ASSERT(m_pixelPerMM > 0.0);

Pdf4QtLib/sources/pdfrenderer.h

@@ -88,6 +88,7 @@ public:
         InvertColors            = 0x0100,   ///< Invert colors
         DenyExtraGraphics       = 0x0200,   ///< Do not display additional graphics, for example from tools
         DisplayAnnotations      = 0x0400,   ///< Display annotations
+        LogicalSizeZooming      = 0x0800,   ///< Use logical pixel resolution instead of physical one when zooming
     };
 
     Q_DECLARE_FLAGS(Features, Feature)

Pdf4QtViewer/pdfviewersettingsdialog.cpp

@@ -329,6 +329,7 @@ void PDFViewerSettingsDialog::loadData()
     ui->maximumUndoStepsEdit->setValue(m_settings.m_maximumUndoSteps);
     ui->maximumRedoStepsEdit->setValue(m_settings.m_maximumRedoSteps);
     ui->developerModeCheckBox->setChecked(m_settings.m_allowDeveloperMode);
+    ui->logicalPixelZoomCheckBox->setChecked(m_settings.m_features.testFlag(pdf::PDFRenderer::LogicalSizeZooming));
 
     // CMS
     ui->cmsTypeComboBox->setCurrentIndex(ui->cmsTypeComboBox->findData(int(m_cmsSettings.system)));
@@ -602,6 +603,10 @@ void PDFViewerSettingsDialog::saveData()
     {
         m_settings.m_maximumRedoSteps = ui->maximumRedoStepsEdit->value();
     }
+    else if (sender == ui->logicalPixelZoomCheckBox)
+    {
+        m_settings.m_features.setFlag(pdf::PDFRenderer::LogicalSizeZooming, ui->logicalPixelZoomCheckBox->isChecked());
+    }
     else if (sender == ui->signatureVerificationEnableCheckBox)
     {
         m_settings.m_signatureVerificationEnabled = ui->signatureVerificationEnableCheckBox->isChecked();

Pdf4QtViewer/pdfviewersettingsdialog.ui

@@ -35,7 +35,7 @@
      <item>
       <widget class="QStackedWidget" name="stackedWidget">
        <property name="currentIndex">
-        <number>10</number>
+        <number>7</number>
        </property>
        <widget class="QWidget" name="enginePage">
         <layout class="QVBoxLayout" name="enginePageLayout">
@@ -901,6 +901,30 @@
                 </property>
                </widget>
               </item>
+              <item row="1" column="0">
+               <widget class="QLabel" name="magnifierSizeLabel">
+                <property name="text">
+                 <string>Magnifier size</string>
+                </property>
+               </widget>
+              </item>
+              <item row="0" column="1">
+               <widget class="QSpinBox" name="maximumRecentFileCountEdit"/>
+              </item>
+              <item row="3" column="1">
+               <widget class="QSpinBox" name="maximumUndoStepsEdit">
+                <property name="maximum">
+                 <number>20</number>
+                </property>
+               </widget>
+              </item>
+              <item row="3" column="0">
+               <widget class="QLabel" name="maximumUndoStepsLabel">
+                <property name="text">
+                 <string>Maximum undo steps</string>
+                </property>
+               </widget>
+              </item>
               <item row="4" column="1">
                <widget class="QSpinBox" name="maximumRedoStepsEdit">
                 <property name="maximum">
@@ -908,6 +932,16 @@
                 </property>
                </widget>
               </item>
+              <item row="2" column="1">
+               <widget class="QDoubleSpinBox" name="magnifierZoomEdit">
+                <property name="minimum">
+                 <double>1.000000000000000</double>
+                </property>
+                <property name="maximum">
+                 <double>10.000000000000000</double>
+                </property>
+               </widget>
+              </item>
               <item row="4" column="0">
                <widget class="QLabel" name="maximumRedoStepsLabel">
                 <property name="text">
@@ -915,17 +949,17 @@
                 </property>
                </widget>
               </item>
-              <item row="1" column="0">
+              <item row="6" column="1">
-               <widget class="QLabel" name="magnifierSizeLabel">
+               <widget class="QCheckBox" name="developerModeCheckBox">
                 <property name="text">
-                 <string>Magnifier size</string>
+                 <string>Enable</string>
                 </property>
                </widget>
               </item>
-              <item row="3" column="1">
+              <item row="6" column="0">
-               <widget class="QSpinBox" name="maximumUndoStepsEdit">
+               <widget class="QLabel" name="developerModeLabel">
-                <property name="maximum">
+                <property name="text">
-                 <number>20</number>
+                 <string>Developer mode</string>
                 </property>
                </widget>
               </item>
@@ -949,37 +983,17 @@
                 </property>
                </widget>
               </item>
-              <item row="0" column="1">
-               <widget class="QSpinBox" name="maximumRecentFileCountEdit"/>
-              </item>
-              <item row="3" column="0">
-               <widget class="QLabel" name="maximumUndoStepsLabel">
-                <property name="text">
-                 <string>Maximum undo steps</string>
-                </property>
-               </widget>
-              </item>
-              <item row="2" column="1">
-               <widget class="QDoubleSpinBox" name="magnifierZoomEdit">
-                <property name="minimum">
-                 <double>1.000000000000000</double>
-                </property>
-                <property name="maximum">
-                 <double>10.000000000000000</double>
-                </property>
-               </widget>
-              </item>
               <item row="5" column="1">
-               <widget class="QCheckBox" name="developerModeCheckBox">
+               <widget class="QCheckBox" name="logicalPixelZoomCheckBox">
                 <property name="text">
                  <string>Enable</string>
                 </property>
                </widget>
               </item>
               <item row="5" column="0">
-               <widget class="QLabel" name="developerModeLabel">
+               <widget class="QLabel" name="logicalPixelZoomLabel">
                 <property name="text">
-                 <string>Developer mode</string>
+                 <string>Use logical pixels when zooming</string>
                 </property>
                </widget>
               </item>