add hidpi option checkbox to UIDialog

src/emucore/FrameBuffer.cxx

@@ -53,6 +53,7 @@ FrameBuffer::FrameBuffer(OSystem& osystem)
     myStatsEnabled(false),
     myLastScanlines(0),
     myGrabMouse(false),
+    myHiDPIAllowed(false),
     myHiDPIEnabled(false),
     myCurrentModeList(nullptr)
 {
@@ -85,9 +86,9 @@ bool FrameBuffer::initialize()
   myDesktopSize = myAbsDesktopSize;
 
   // Check for HiDPI mode (is it activated, and can we use it?)
-  myHiDPIEnabled = myOSystem.settings().getBool("hidpi") &&
-      ((myAbsDesktopSize.w / 2) >= FBMinimum::Width) &&
-      ((myAbsDesktopSize.h / 2) >= FBMinimum::Height);
+  myHiDPIAllowed = ((myAbsDesktopSize.w / 2) >= FBMinimum::Width) &&
+    ((myAbsDesktopSize.h / 2) >= FBMinimum::Height);
+  myHiDPIEnabled = myHiDPIAllowed && myOSystem.settings().getBool("hidpi");
 
   // In HiDPI mode, the desktop resolution is essentially halved
   // Later, the output is scaled and rendered in 2x mode

src/emucore/FrameBuffer.hxx

@@ -259,6 +259,12 @@ class FrameBuffer
     */
     void stateChanged(EventHandlerState state);
 
+    /**
+      Answer whether hidpi mode is allowed.  In this mode, all FBSurfaces
+      are scaled to 2x normal size.
+    */
+    bool hidpiAllowed() const { return myHiDPIAllowed; }
+
     /**
       Answer whether hidpi mode is enabled.  In this mode, all FBSurfaces
       are scaled to 2x normal size.
@@ -562,6 +568,7 @@ class FrameBuffer
     uInt32 myLastScanlines;
 
     bool myGrabMouse;
+    bool myHiDPIAllowed;
     bool myHiDPIEnabled;
 
     // The list of all available video modes for this framebuffer

src/emucore/Settings.cxx

@@ -41,7 +41,6 @@ Settings::Settings()
   setPermanent("center", "false");
   setPermanent("palette", "standard");
   setPermanent("uimessages", "true");
-  setPermanent("hidpi", "false");
 
   // TIA specific options
   setPermanent("tia.zoom", "3");
@@ -122,6 +121,7 @@ Settings::Settings()
                  DebuggerDialog::kMediumFontMinH));
 #endif
   setPermanent("uipalette", "standard");
+  setPermanent("hidpi", "false");
   setPermanent("listdelay", "300");
   setPermanent("mwheel", "4");
   setPermanent("basic_settings", false);
@@ -462,13 +462,16 @@ void Settings::usage() const
     << "  -launcherroms <1|0>          Show only ROMs in the launcher (vs. all files)\n"
     << "  -romviewer    <0|1|2>        Show ROM info viewer at given zoom level in ROM\n"
     << "                                launcher (0 for off)\n"
+    << "  -uipalette    <standard|     Selects GUI theme\n"
+    << "                 classic|light>\n"
+    << "  -hidpi        <0|1>          Enable HiDPI mode\n"
+    << "  -dialogpos    <0..4>         Display all dialogs at given positions\n"
     << "  -listdelay    <delay>        Time to wait between keypresses in list widgets\n"
     << "                                (300-1000)\n"
     << "  -mwheel       <lines>        Number of lines the mouse wheel will scroll in\n"
     << "                                UI\n"
     << "  -basic_settings <0|1>        Display only a basic settings dialog\n"
-    << "  -dialogpos    <0..4>         Display all dialogs at given positions\n"
-    << "  -romdir       <dir>          Directory in which to load ROM files\n"
+    << "  -romdir       <dir>          Directory from which to load ROM files\n"
     << "  -avoxport     <name>         The name of the serial port where an AtariVox is\n"
     << "                                connected\n"
     << "  -holdreset                   Start the emulator with the Game Reset switch\n"

src/gui/UIDialog.cxx

@@ -96,6 +96,11 @@ UIDialog::UIDialog(OSystem& osystem, DialogContainer& parent,
   myPositionPopup = new PopUpWidget(myTab, font, xpos, ypos, pwidth, lineHeight,
     items, "Dialogs position ", lwidth);
   wid.push_back(myPositionPopup);
+  ypos += lineHeight + V_GAP;
+
+  // Enable HiDPI mode
+  myHidpiWidget = new CheckboxWidget(myTab, font, xpos, ypos, "HiDPI mode");
+  wid.push_back(myHidpiWidget);
   ypos += lineHeight + V_GAP * 4;
 
   // Delay between quick-selecting characters in ListWidget
@@ -276,6 +281,17 @@ void UIDialog::loadConfig()
   const string& pal = settings.getString("uipalette");
   myPalettePopup->setSelected(pal, "standard");
 
+  // Enable HiDPI mode
+  if (!instance().frameBuffer().hidpiAllowed())
+  {
+    myHidpiWidget->setState(false);
+    myHidpiWidget->setEnabled(false);
+  }
+  else
+  {
+    myHidpiWidget->setState(settings.getBool("hidpi"));
+  }
+
   // Dialog position
   myPositionPopup->setSelected(settings.getString("dialogpos"), "0");
 
@@ -324,6 +340,9 @@ void UIDialog::saveConfig()
     myPalettePopup->getSelectedTag().toString());
   instance().frameBuffer().setUIPalette();
 
+  // Enable HiDPI mode
+  settings.setValue("hidpi", myHidpiWidget->getState());
+
   // Dialog position
   settings.setValue("dialogpos", myPositionPopup->getSelectedTag().toString());
 
@@ -347,6 +366,7 @@ void UIDialog::setDefaults()
   {
     case 0:  // Misc. options
       myPalettePopup->setSelected("standard");
+      myHidpiWidget->setState(false);
       myPositionPopup->setSelected("0");
       myListDelayPopup->setValue(300);
       myWheelLinesPopup->setValue(4);

src/gui/UIDialog.hxx

@@ -63,6 +63,7 @@ class UIDialog : public Dialog, public CommandSender
 
     // Misc options
     PopUpWidget*      myPalettePopup;
+    CheckboxWidget*   myHidpiWidget;
     PopUpWidget*      myPositionPopup;
     SliderWidget*     myListDelayPopup;
     SliderWidget*     myWheelLinesPopup;