From 96e7eb1bed378a2b84cafb26068b65291c536d4e Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Mon, 7 Jun 2021 20:16:01 -0400
Subject: [PATCH 1/8] Adds a use-square-pixels option for the Apple II.

---
 Machines/Apple/AppleII/AppleII.cpp |  2 ++
 Machines/Apple/AppleII/AppleII.hpp |  8 +++++++-
 Machines/Apple/AppleII/Video.cpp   | 24 ++++++++++++++++++++++++
 Machines/Apple/AppleII/Video.hpp   |  6 ++++++
 4 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/Machines/Apple/AppleII/AppleII.cpp b/Machines/Apple/AppleII/AppleII.cpp
index 6b6078824..80436626d 100644
--- a/Machines/Apple/AppleII/AppleII.cpp
+++ b/Machines/Apple/AppleII/AppleII.cpp
@@ -787,12 +787,14 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 		std::unique_ptr<Reflection::Struct> get_options() final {
 			auto options = std::make_unique<Options>(Configurable::OptionsType::UserFriendly);
 			options->output = get_video_signal_configurable();
+			options->use_square_pixels = video_.get_use_square_pixels();
 			return options;
 		}
 
 		void set_options(const std::unique_ptr<Reflection::Struct> &str) {
 			const auto options = dynamic_cast<Options *>(str.get());
 			set_video_signal_configurable(options->output);
+			video_.set_use_square_pixels(options->use_square_pixels);
 		}
 
 		// MARK: MediaTarget
diff --git a/Machines/Apple/AppleII/AppleII.hpp b/Machines/Apple/AppleII/AppleII.hpp
index e373da4b8..94aa43289 100644
--- a/Machines/Apple/AppleII/AppleII.hpp
+++ b/Machines/Apple/AppleII/AppleII.hpp
@@ -30,10 +30,16 @@ class Machine {
 		class Options: public Reflection::StructImpl<Options>, public Configurable::DisplayOption<Options> {
 			friend Configurable::DisplayOption<Options>;
 			public:
-				Options(Configurable::OptionsType) : Configurable::DisplayOption<Options>(Configurable::Display::CompositeColour)  {
+				bool use_square_pixels = false;
+
+				Options(Configurable::OptionsType) : Configurable::DisplayOption<Options>(Configurable::Display::CompositeColour) {
 					if(needs_declare()) {
 						declare_display_option();
 						limit_enum(&output, Configurable::Display::CompositeMonochrome, Configurable::Display::CompositeColour, -1);
+
+						if(needs_declare()) {
+							DeclareField(use_square_pixels);
+						}
 					}
 				}
 		};
diff --git a/Machines/Apple/AppleII/Video.cpp b/Machines/Apple/AppleII/Video.cpp
index 7b0df2baa..6a07308b2 100644
--- a/Machines/Apple/AppleII/Video.cpp
+++ b/Machines/Apple/AppleII/Video.cpp
@@ -26,6 +26,30 @@ VideoBase::VideoBase(bool is_iie, std::function<void(Cycles)> &&target) :
 //	crt_.set_immediate_default_phase(0.5f);
 }
 
+void VideoBase::set_use_square_pixels(bool use_square_pixels) {
+	use_square_pixels_ = use_square_pixels;
+
+	if(use_square_pixels) {
+		// From what I can make out, many contemporary Apple II monitors were
+		// calibrated slightly to stretch the Apple II's display slightly wider
+		// than it should be per the NTSC standards, for approximately square
+		// pixels. This reproduces that.
+
+		// 243 lines and 52µs are visible.
+		// i.e. to be square, 1 pixel should be: (1/243 * 52) * (3/4) = 156/972 = 39/243 µs
+		// On an Apple II each pixel is actually 1/7µs.
+		// Therefore the adjusted aspect ratio should be (4/3) * (39/243)/(1/7) = (4/3) * 273/243 = 1092/729 = 343/243 ~= 1.412
+		crt_.set_aspect_ratio(343.0f / 243.0f);
+	} else {
+		// Standard NTSC aspect ratio.
+		crt_.set_aspect_ratio(4.0f / 3.0f);
+	}
+}
+bool VideoBase::get_use_square_pixels() {
+	return use_square_pixels_;
+}
+
+
 void VideoBase::set_scan_target(Outputs::Display::ScanTarget *scan_target) {
 	crt_.set_scan_target(scan_target);
 }
diff --git a/Machines/Apple/AppleII/Video.hpp b/Machines/Apple/AppleII/Video.hpp
index afd332efc..ba414c83e 100644
--- a/Machines/Apple/AppleII/Video.hpp
+++ b/Machines/Apple/AppleII/Video.hpp
@@ -51,8 +51,14 @@ class VideoBase: public VideoSwitches<Cycles> {
 		/// Gets the type of output.
 		Outputs::Display::DisplayType get_display_type() const;
 
+		/// Sets whether the current CRT should be recalibrated away from normative NTSC
+		/// to produce square pixels in 40-column text mode.
+		void set_use_square_pixels(bool);
+		bool get_use_square_pixels();
+
 	protected:
 		Outputs::CRT::CRT crt_;
+		bool use_square_pixels_ = false;
 
 		// State affecting output video stream generation.
 		uint8_t *pixel_pointer_ = nullptr;

From 778b9ef6838e6abb14b6422dc5d4494cb9805713 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Mon, 7 Jun 2021 20:41:02 -0400
Subject: [PATCH 2/8] Ensures set_square_pixels is exposed, works around OpenGL
 aspect ratio bug.

---
 Machines/Apple/AppleII/AppleII.hpp               |  5 +----
 Machines/Apple/AppleII/Video.cpp                 | 14 ++++++++++++--
 .../xcschemes/Clock Signal Kiosk.xcscheme        | 16 ++++++++++++----
 3 files changed, 25 insertions(+), 10 deletions(-)

diff --git a/Machines/Apple/AppleII/AppleII.hpp b/Machines/Apple/AppleII/AppleII.hpp
index 94aa43289..97d348578 100644
--- a/Machines/Apple/AppleII/AppleII.hpp
+++ b/Machines/Apple/AppleII/AppleII.hpp
@@ -34,12 +34,9 @@ class Machine {
 
 				Options(Configurable::OptionsType) : Configurable::DisplayOption<Options>(Configurable::Display::CompositeColour) {
 					if(needs_declare()) {
+						DeclareField(use_square_pixels);
 						declare_display_option();
 						limit_enum(&output, Configurable::Display::CompositeMonochrome, Configurable::Display::CompositeColour, -1);
-
-						if(needs_declare()) {
-							DeclareField(use_square_pixels);
-						}
 					}
 				}
 		};
diff --git a/Machines/Apple/AppleII/Video.cpp b/Machines/Apple/AppleII/Video.cpp
index 6a07308b2..ae358c0ab 100644
--- a/Machines/Apple/AppleII/Video.cpp
+++ b/Machines/Apple/AppleII/Video.cpp
@@ -15,9 +15,8 @@ VideoBase::VideoBase(bool is_iie, std::function<void(Cycles)> &&target) :
 	crt_(910, 1, Outputs::Display::Type::NTSC60, Outputs::Display::InputDataType::Luminance1),
 	is_iie_(is_iie) {
 
-	// Show only the centre 75% of the TV frame.
 	crt_.set_display_type(Outputs::Display::DisplayType::CompositeColour);
-	crt_.set_visible_area(Outputs::Display::Rect(0.118f, 0.122f, 0.77f, 0.77f));
+	set_use_square_pixels(use_square_pixels_);
 
 	// TODO: there seems to be some sort of bug whereby switching modes can cause
 	// a signal discontinuity that knocks phase out of whack. So it isn't safe to
@@ -29,6 +28,17 @@ VideoBase::VideoBase(bool is_iie, std::function<void(Cycles)> &&target) :
 void VideoBase::set_use_square_pixels(bool use_square_pixels) {
 	use_square_pixels_ = use_square_pixels;
 
+	// HYPER-UGLY HACK. See correlated hack in the Macintosh.
+#ifdef __APPLE__
+	crt_.set_visible_area(Outputs::Display::Rect(0.128f, 0.122f, 0.75f, 0.77f));
+#else
+	if(use_square_pixels) {
+		crt_.set_visible_area(Outputs::Display::Rect(0.128f, 0.112f, 0.75f, 0.73f));
+	} else {
+		crt_.set_visible_area(Outputs::Display::Rect(0.128f, 0.12f, 0.75f, 0.77f));
+	}
+#endif
+
 	if(use_square_pixels) {
 		// From what I can make out, many contemporary Apple II monitors were
 		// calibrated slightly to stretch the Apple II's display slightly wider
diff --git a/OSBindings/Mac/Clock Signal.xcodeproj/xcshareddata/xcschemes/Clock Signal Kiosk.xcscheme b/OSBindings/Mac/Clock Signal.xcodeproj/xcshareddata/xcschemes/Clock Signal Kiosk.xcscheme
index 131430afb..263537208 100644
--- a/OSBindings/Mac/Clock Signal.xcodeproj/xcshareddata/xcschemes/Clock Signal Kiosk.xcscheme	
+++ b/OSBindings/Mac/Clock Signal.xcodeproj/xcshareddata/xcschemes/Clock Signal Kiosk.xcscheme	
@@ -56,13 +56,17 @@
             argument = "/Users/thomasharte/Downloads/test-dsk-for-rw-and-50-60-hz/TEST-RW-60Hz.DSK"
             isEnabled = "NO">
          </CommandLineArgument>
+         <CommandLineArgument
+            argument = "&quot;/Users/thomasharte/Desktop/Soft/Apple II/WOZs/Prince of Persia side A.woz&quot;"
+            isEnabled = "YES">
+         </CommandLineArgument>
          <CommandLineArgument
             argument = "--rompath=~/ROMs"
             isEnabled = "NO">
          </CommandLineArgument>
          <CommandLineArgument
             argument = "--has-disk-drive"
-            isEnabled = "YES">
+            isEnabled = "NO">
          </CommandLineArgument>
          <CommandLineArgument
             argument = "&quot;/Users/thomasharte/Library/Mobile Documents/com~apple~CloudDocs/Desktop/Soft/Macintosh/MusicWorks 0.42.image&quot;"
@@ -78,7 +82,7 @@
          </CommandLineArgument>
          <CommandLineArgument
             argument = "--volume=0.001"
-            isEnabled = "NO">
+            isEnabled = "YES">
          </CommandLineArgument>
          <CommandLineArgument
             argument = "--new=amstradcpc"
@@ -114,7 +118,7 @@
          </CommandLineArgument>
          <CommandLineArgument
             argument = "--rompath=/Users/thomasharte/Projects/CLK/ROMImages"
-            isEnabled = "NO">
+            isEnabled = "YES">
          </CommandLineArgument>
          <CommandLineArgument
             argument = "--help"
@@ -125,7 +129,11 @@
             isEnabled = "NO">
          </CommandLineArgument>
          <CommandLineArgument
-            argument = "--new=vic20"
+            argument = "--new=appleii"
+            isEnabled = "NO">
+         </CommandLineArgument>
+         <CommandLineArgument
+            argument = "--use-square-pixels"
             isEnabled = "YES">
          </CommandLineArgument>
       </CommandLineArguments>

From 462bbf2e40fefd8d2d8251837b7aa0f9b6bdde7d Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Mon, 7 Jun 2021 21:21:45 -0400
Subject: [PATCH 3/8] Exposes square pixels option on macOS.

---
 .../Clock Signal.xcodeproj/project.pbxproj    | 10 ++++
 .../Base.lproj/AppleIIOptions.xib             | 36 +++++++++----
 .../Base.lproj/Atari2600Options.xib           | 18 +++----
 .../Mac/Clock Signal/Machine/CSMachine.h      |  2 +
 .../Mac/Clock Signal/Machine/CSMachine.mm     |  4 ++
 .../Clock Signal/Machine/Wrappers/CSAppleII.h | 18 +++++++
 .../Machine/Wrappers/CSAppleII.mm             | 50 +++++++++++++++++++
 7 files changed, 118 insertions(+), 20 deletions(-)
 create mode 100644 OSBindings/Mac/Clock Signal/Machine/Wrappers/CSAppleII.h
 create mode 100644 OSBindings/Mac/Clock Signal/Machine/Wrappers/CSAppleII.mm

diff --git a/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj b/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj
index bda241923..60a7ae8c2 100644
--- a/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj	
+++ b/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj	
@@ -15,6 +15,8 @@
 		4B051C912669C90B00CA44E8 /* ROMCatalogue.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B051C5826670A9300CA44E8 /* ROMCatalogue.cpp */; };
 		4B051C922669C90B00CA44E8 /* ROMCatalogue.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B051C5826670A9300CA44E8 /* ROMCatalogue.cpp */; };
 		4B051C93266D9D6900CA44E8 /* ROMImages in Resources */ = {isa = PBXBuildFile; fileRef = 4BC9DF441D044FCA00F44158 /* ROMImages */; };
+		4B051C95266EF50200CA44E8 /* AppleIIOptionsPanel.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4B051C94266EF50200CA44E8 /* AppleIIOptionsPanel.swift */; };
+		4B051C97266EF5F600CA44E8 /* CSAppleII.mm in Sources */ = {isa = PBXBuildFile; fileRef = 4B051C96266EF5F600CA44E8 /* CSAppleII.mm */; };
 		4B05401E219D1618001BF69C /* ScanTarget.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B05401D219D1618001BF69C /* ScanTarget.cpp */; };
 		4B05401F219D1618001BF69C /* ScanTarget.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B05401D219D1618001BF69C /* ScanTarget.cpp */; };
 		4B055A7A1FAE78A00060FFFF /* SDL2.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 4B055A771FAE78210060FFFF /* SDL2.framework */; };
@@ -1023,6 +1025,9 @@
 		4B04B65622A58CB40006AB58 /* Target.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = Target.hpp; sourceTree = "<group>"; };
 		4B051C5826670A9300CA44E8 /* ROMCatalogue.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = ROMCatalogue.cpp; sourceTree = "<group>"; };
 		4B051C5926670A9300CA44E8 /* ROMCatalogue.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = ROMCatalogue.hpp; sourceTree = "<group>"; };
+		4B051C94266EF50200CA44E8 /* AppleIIOptionsPanel.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = AppleIIOptionsPanel.swift; sourceTree = "<group>"; };
+		4B051C96266EF5F600CA44E8 /* CSAppleII.mm */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.objcpp; path = CSAppleII.mm; sourceTree = "<group>"; };
+		4B051C98266EF60500CA44E8 /* CSAppleII.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = CSAppleII.h; sourceTree = "<group>"; };
 		4B05401D219D1618001BF69C /* ScanTarget.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = ScanTarget.cpp; sourceTree = "<group>"; };
 		4B055A6A1FAE763F0060FFFF /* Clock Signal Kiosk */ = {isa = PBXFileReference; explicitFileType = "compiled.mach-o.executable"; includeInIndex = 0; path = "Clock Signal Kiosk"; sourceTree = BUILT_PRODUCTS_DIR; };
 		4B055A771FAE78210060FFFF /* SDL2.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = SDL2.framework; path = ../../../../Library/Frameworks/SDL2.framework; sourceTree = SOURCE_ROOT; };
@@ -2405,8 +2410,10 @@
 		4B2A53981D117D36003C6002 /* Wrappers */ = {
 			isa = PBXGroup;
 			children = (
+				4B051C98266EF60500CA44E8 /* CSAppleII.h */,
 				4B2A53991D117D36003C6002 /* CSAtari2600.h */,
 				4B14978D1EE4B4D200CE2596 /* CSZX8081.h */,
+				4B051C96266EF5F600CA44E8 /* CSAppleII.mm */,
 				4B2A539A1D117D36003C6002 /* CSAtari2600.mm */,
 				4B14978E1EE4B4D200CE2596 /* CSZX8081.mm */,
 			);
@@ -2777,6 +2784,7 @@
 		4B55CE551C3B7D360093A61B /* Documents */ = {
 			isa = PBXGroup;
 			children = (
+				4B051C94266EF50200CA44E8 /* AppleIIOptionsPanel.swift */,
 				4B8FE21F1DA19D7C0090D3CE /* Atari2600OptionsPanel.swift */,
 				4B55CE5E1C3B7D960093A61B /* MachineDocument.swift */,
 				4B8FE2211DA19FB20090D3CE /* MachinePanel.swift */,
@@ -5402,11 +5410,13 @@
 				4B4518861F75E91A00926311 /* MFMDiskController.cpp in Sources */,
 				4B0ACC2C23775819008902D0 /* IntelligentKeyboard.cpp in Sources */,
 				4B92E26A234AE35100CD6D1B /* MFP68901.cpp in Sources */,
+				4B051C97266EF5F600CA44E8 /* CSAppleII.mm in Sources */,
 				4B0ACC2A23775819008902D0 /* Video.cpp in Sources */,
 				4B54C0BF1F8D8F450050900F /* Keyboard.cpp in Sources */,
 				4B3FE75E1F3CF68B00448EE4 /* CPM.cpp in Sources */,
 				4B2BFDB21DAEF5FF001A68B8 /* Video.cpp in Sources */,
 				4BEDA3BF25B25563000C2DBD /* Decoder.cpp in Sources */,
+				4B051C95266EF50200CA44E8 /* AppleIIOptionsPanel.swift in Sources */,
 				4B4DC82B1D2C27A4003C5BF8 /* SerialBus.cpp in Sources */,
 				4BE8EB6625C750B50040BC40 /* DAT.cpp in Sources */,
 				4BBFFEE61F7B27F1005F3FEB /* TrackSerialiser.cpp in Sources */,
diff --git a/OSBindings/Mac/Clock Signal/Base.lproj/AppleIIOptions.xib b/OSBindings/Mac/Clock Signal/Base.lproj/AppleIIOptions.xib
index 8c80a36f1..5b4ef82a7 100644
--- a/OSBindings/Mac/Clock Signal/Base.lproj/AppleIIOptions.xib	
+++ b/OSBindings/Mac/Clock Signal/Base.lproj/AppleIIOptions.xib	
@@ -1,8 +1,8 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<document type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="3.0" toolsVersion="14460.31" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none" useAutolayout="YES" customObjectInstantitationMethod="direct">
+<document type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="3.0" toolsVersion="18122" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none" useAutolayout="YES" customObjectInstantitationMethod="direct">
     <dependencies>
         <deployment identifier="macosx"/>
-        <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="14460.31"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="18122"/>
         <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
     </dependencies>
     <objects>
@@ -13,17 +13,27 @@
         </customObject>
         <customObject id="-1" userLabel="First Responder" customClass="FirstResponder"/>
         <customObject id="-3" userLabel="Application" customClass="NSObject"/>
-        <window title="Options" allowsToolTipsWhenApplicationIsInactive="NO" autorecalculatesKeyViewLoop="NO" hidesOnDeactivate="YES" releasedWhenClosed="NO" visibleAtLaunch="NO" frameAutosaveName="" animationBehavior="default" id="ZW7-Bw-4RP" customClass="MachinePanel" customModule="Clock_Signal" customModuleProvider="target">
+        <window title="Options" allowsToolTipsWhenApplicationIsInactive="NO" autorecalculatesKeyViewLoop="NO" hidesOnDeactivate="YES" releasedWhenClosed="NO" visibleAtLaunch="NO" frameAutosaveName="" animationBehavior="default" id="ZW7-Bw-4RP" customClass="AppleIIOptionsPanel" customModule="Clock_Signal" customModuleProvider="target">
             <windowStyleMask key="styleMask" titled="YES" closable="YES" utility="YES" nonactivatingPanel="YES" HUD="YES"/>
             <windowPositionMask key="initialPositionMask" leftStrut="YES" rightStrut="YES" topStrut="YES" bottomStrut="YES"/>
-            <rect key="contentRect" x="80" y="150" width="200" height="61"/>
-            <rect key="screenRect" x="0.0" y="0.0" width="1440" height="900"/>
-            <view key="contentView" id="tpZ-0B-QQu">
-                <rect key="frame" x="0.0" y="0.0" width="200" height="61"/>
+            <rect key="contentRect" x="80" y="150" width="200" height="159"/>
+            <rect key="screenRect" x="0.0" y="0.0" width="2560" height="1440"/>
+            <view key="contentView" misplaced="YES" id="tpZ-0B-QQu">
+                <rect key="frame" x="0.0" y="0.0" width="200" height="159"/>
                 <autoresizingMask key="autoresizingMask"/>
                 <subviews>
+                    <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="kDb-7g-cVx">
+                        <rect key="frame" x="18" y="47" width="162" height="18"/>
+                        <buttonCell key="cell" type="check" title="Use Square Pixels" bezelStyle="regularSquare" imagePosition="left" state="on" inset="2" id="h9q-Wb-em8">
+                            <behavior key="behavior" changeContents="YES" doesNotDimImage="YES" lightByContents="YES"/>
+                            <font key="font" metaFont="system"/>
+                        </buttonCell>
+                        <connections>
+                            <action selector="optionDidChange:" target="ZW7-Bw-4RP" id="pNS-aK-0no"/>
+                        </connections>
+                    </button>
                     <popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="ex3-VM-58z">
-                        <rect key="frame" x="18" y="17" width="165" height="25"/>
+                        <rect key="frame" x="17" y="16" width="167" height="25"/>
                         <popUpButtonCell key="cell" type="push" title="Colour" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" state="on" borderStyle="borderAndBezel" tag="1" imageScaling="proportionallyDown" inset="2" selectedItem="gOu-dv-tre" id="u3N-Je-c2L">
                             <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
                             <font key="font" metaFont="menu"/>
@@ -40,16 +50,20 @@
                     </popUpButton>
                 </subviews>
                 <constraints>
-                    <constraint firstAttribute="bottom" secondItem="ex3-VM-58z" secondAttribute="bottom" constant="20" id="4ZS-q5-TJL"/>
+                    <constraint firstAttribute="bottom" secondItem="ex3-VM-58z" secondAttribute="bottom" constant="20" symbolic="YES" id="4ZS-q5-TJL"/>
                     <constraint firstItem="ex3-VM-58z" firstAttribute="leading" secondItem="tpZ-0B-QQu" secondAttribute="leading" constant="20" id="8Pj-Ns-TrJ"/>
+                    <constraint firstAttribute="trailing" secondItem="kDb-7g-cVx" secondAttribute="trailing" constant="20" symbolic="YES" id="KHa-of-eY7"/>
+                    <constraint firstItem="kDb-7g-cVx" firstAttribute="leading" secondItem="tpZ-0B-QQu" secondAttribute="leading" constant="20" symbolic="YES" id="OcZ-Xa-394"/>
                     <constraint firstAttribute="trailing" secondItem="ex3-VM-58z" secondAttribute="trailing" constant="20" id="QWA-lY-ugz"/>
-                    <constraint firstItem="ex3-VM-58z" firstAttribute="top" secondItem="tpZ-0B-QQu" secondAttribute="top" constant="20" id="szw-WO-3tS"/>
+                    <constraint firstItem="ex3-VM-58z" firstAttribute="top" secondItem="kDb-7g-cVx" secondAttribute="bottom" constant="8" id="jDW-N8-c4V"/>
+                    <constraint firstItem="kDb-7g-cVx" firstAttribute="top" secondItem="tpZ-0B-QQu" secondAttribute="top" constant="20" symbolic="YES" id="wdj-PF-zxO"/>
                 </constraints>
             </view>
             <connections>
                 <outlet property="displayTypeButton" destination="ex3-VM-58z" id="lmZ-aN-lcj"/>
+                <outlet property="squarePixelButton" destination="kDb-7g-cVx" id="zbx-o8-7yC"/>
             </connections>
-            <point key="canvasLocation" x="-161" y="38.5"/>
+            <point key="canvasLocation" x="-161" y="104.5"/>
         </window>
     </objects>
 </document>
diff --git a/OSBindings/Mac/Clock Signal/Base.lproj/Atari2600Options.xib b/OSBindings/Mac/Clock Signal/Base.lproj/Atari2600Options.xib
index 2e6e00fb0..41c6e7572 100644
--- a/OSBindings/Mac/Clock Signal/Base.lproj/Atari2600Options.xib	
+++ b/OSBindings/Mac/Clock Signal/Base.lproj/Atari2600Options.xib	
@@ -1,8 +1,8 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<document type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="3.0" toolsVersion="14113" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none" useAutolayout="YES" customObjectInstantitationMethod="direct">
+<document type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="3.0" toolsVersion="18122" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none" useAutolayout="YES" customObjectInstantitationMethod="direct">
     <dependencies>
         <deployment identifier="macosx"/>
-        <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="14113"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="18122"/>
         <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
     </dependencies>
     <objects>
@@ -13,17 +13,17 @@
         </customObject>
         <customObject id="-1" userLabel="First Responder" customClass="FirstResponder"/>
         <customObject id="-3" userLabel="Application" customClass="NSObject"/>
-        <window title="Options" allowsToolTipsWhenApplicationIsInactive="NO" autorecalculatesKeyViewLoop="NO" hidesOnDeactivate="YES" oneShot="NO" releasedWhenClosed="NO" showsToolbarButton="NO" visibleAtLaunch="NO" frameAutosaveName="" animationBehavior="default" id="gsl-7V-TTU" customClass="Atari2600OptionsPanel" customModule="Clock_Signal" customModuleProvider="target">
+        <window title="Options" allowsToolTipsWhenApplicationIsInactive="NO" autorecalculatesKeyViewLoop="NO" hidesOnDeactivate="YES" releasedWhenClosed="NO" visibleAtLaunch="NO" frameAutosaveName="" animationBehavior="default" id="gsl-7V-TTU" customClass="Atari2600OptionsPanel" customModule="Clock_Signal" customModuleProvider="target">
             <windowStyleMask key="styleMask" titled="YES" closable="YES" utility="YES" nonactivatingPanel="YES" HUD="YES"/>
             <windowPositionMask key="initialPositionMask" leftStrut="YES" rightStrut="YES" topStrut="YES" bottomStrut="YES"/>
             <rect key="contentRect" x="80" y="150" width="200" height="121"/>
-            <rect key="screenRect" x="0.0" y="0.0" width="1440" height="900"/>
+            <rect key="screenRect" x="0.0" y="0.0" width="2560" height="1440"/>
             <view key="contentView" id="aQh-Pm-DEo">
                 <rect key="frame" x="0.0" y="0.0" width="200" height="121"/>
                 <autoresizingMask key="autoresizingMask"/>
                 <subviews>
                     <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="rQO-uD-fwn">
-                        <rect key="frame" x="14" y="73" width="86" height="32"/>
+                        <rect key="frame" x="13" y="74" width="88" height="32"/>
                         <buttonCell key="cell" type="push" title="Reset" bezelStyle="rounded" alignment="center" borderStyle="border" imageScaling="proportionallyDown" inset="2" id="l3H-0m-aK0">
                             <behavior key="behavior" pushIn="YES" lightByBackground="YES" lightByGray="YES"/>
                             <font key="font" metaFont="system"/>
@@ -33,7 +33,7 @@
                         </connections>
                     </button>
                     <button translatesAutoresizingMaskIntoConstraints="NO" id="3qw-C1-NYW">
-                        <rect key="frame" x="18" y="58" width="164" height="18"/>
+                        <rect key="frame" x="18" y="58" width="162" height="18"/>
                         <buttonCell key="cell" type="check" title="Black and White" bezelStyle="regularSquare" imagePosition="left" inset="2" id="UP7-mf-IKo">
                             <behavior key="behavior" changeContents="YES" doesNotDimImage="YES" lightByContents="YES"/>
                             <font key="font" metaFont="system"/>
@@ -43,7 +43,7 @@
                         </connections>
                     </button>
                     <button translatesAutoresizingMaskIntoConstraints="NO" id="Xbc-cw-Sc2">
-                        <rect key="frame" x="18" y="38" width="164" height="18"/>
+                        <rect key="frame" x="18" y="36" width="162" height="18"/>
                         <buttonCell key="cell" type="check" title="Left Player Difficulty" bezelStyle="regularSquare" imagePosition="left" inset="2" id="wlJ-8s-PEh">
                             <behavior key="behavior" changeContents="YES" doesNotDimImage="YES" lightByContents="YES"/>
                             <font key="font" metaFont="system"/>
@@ -53,7 +53,7 @@
                         </connections>
                     </button>
                     <button translatesAutoresizingMaskIntoConstraints="NO" id="kPV-Tm-TTc">
-                        <rect key="frame" x="18" y="18" width="164" height="18"/>
+                        <rect key="frame" x="18" y="14" width="162" height="18"/>
                         <buttonCell key="cell" type="check" title="Right Player Difficulty" bezelStyle="regularSquare" imagePosition="left" inset="2" id="F05-cA-66S">
                             <behavior key="behavior" changeContents="YES" doesNotDimImage="YES" lightByContents="YES"/>
                             <font key="font" metaFont="system"/>
@@ -63,7 +63,7 @@
                         </connections>
                     </button>
                     <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="nt7-8K-xY9">
-                        <rect key="frame" x="100" y="73" width="86" height="32"/>
+                        <rect key="frame" x="99" y="74" width="88" height="32"/>
                         <buttonCell key="cell" type="push" title="Select" bezelStyle="rounded" alignment="center" borderStyle="border" imageScaling="proportionallyDown" inset="2" id="8Na-Z1-EXS">
                             <behavior key="behavior" pushIn="YES" lightByBackground="YES" lightByGray="YES"/>
                             <font key="font" metaFont="system"/>
diff --git a/OSBindings/Mac/Clock Signal/Machine/CSMachine.h b/OSBindings/Mac/Clock Signal/Machine/CSMachine.h
index 7654899ed..258073934 100644
--- a/OSBindings/Mac/Clock Signal/Machine/CSMachine.h	
+++ b/OSBindings/Mac/Clock Signal/Machine/CSMachine.h	
@@ -36,6 +36,7 @@ typedef NS_ENUM(NSInteger, CSMachineKeyboardInputMode) {
 // Deliberately low; to ensure CSMachine has been declared as an @class already.
 #import "CSAtari2600.h"
 #import "CSZX8081.h"
+#import "CSAppleII.h"
 
 @interface CSMachine : NSObject
 
@@ -103,5 +104,6 @@ typedef NS_ENUM(NSInteger, CSMachineKeyboardInputMode) {
 // Special-case accessors; undefined behaviour if accessed for a machine not of the corresponding type.
 @property (nonatomic, readonly, nullable) CSAtari2600 *atari2600;
 @property (nonatomic, readonly, nullable) CSZX8081 *zx8081;
+@property (nonatomic, readonly, nullable) CSAppleII *appleII;
 
 @end
diff --git a/OSBindings/Mac/Clock Signal/Machine/CSMachine.mm b/OSBindings/Mac/Clock Signal/Machine/CSMachine.mm
index 3b641ddae..d24bc889e 100644
--- a/OSBindings/Mac/Clock Signal/Machine/CSMachine.mm	
+++ b/OSBindings/Mac/Clock Signal/Machine/CSMachine.mm	
@@ -577,6 +577,10 @@ struct ActivityObserver: public Activity::Observer {
 	return [[CSZX8081 alloc] initWithZX8081:_machine->raw_pointer() owner:self];
 }
 
+- (CSAppleII *)appleII {
+	return [[CSAppleII alloc] initWithAppleII:_machine->raw_pointer() owner:self];
+}
+
 #pragma mark - Input device queries
 
 - (BOOL)hasJoystick {
diff --git a/OSBindings/Mac/Clock Signal/Machine/Wrappers/CSAppleII.h b/OSBindings/Mac/Clock Signal/Machine/Wrappers/CSAppleII.h
new file mode 100644
index 000000000..ba5f4f3f9
--- /dev/null
+++ b/OSBindings/Mac/Clock Signal/Machine/Wrappers/CSAppleII.h	
@@ -0,0 +1,18 @@
+//
+//  CSAppleII.h
+//  Clock Signal
+//
+//  Created by Thomas Harte on 07/06/2021.
+//  Copyright © 2021 Thomas Harte. All rights reserved.
+//
+
+@class CSAppleII;
+#import "CSMachine.h"
+
+@interface CSAppleII : NSObject
+
+- (instancetype)initWithAppleII:(void *)appleII owner:(CSMachine *)machine;
+
+@property (nonatomic, assign) BOOL useSquarePixels;
+
+@end
diff --git a/OSBindings/Mac/Clock Signal/Machine/Wrappers/CSAppleII.mm b/OSBindings/Mac/Clock Signal/Machine/Wrappers/CSAppleII.mm
new file mode 100644
index 000000000..0c9fc35bd
--- /dev/null
+++ b/OSBindings/Mac/Clock Signal/Machine/Wrappers/CSAppleII.mm	
@@ -0,0 +1,50 @@
+//
+//  CSAppleII.m
+//  Clock Signal
+//
+//  Created by Thomas Harte on 07/06/2021.
+//  Copyright © 2021 Thomas Harte. All rights reserved.
+//
+
+#import "CSAppleII.h"
+
+#include "AppleII.hpp"
+
+@implementation CSAppleII {
+	Apple::II::Machine *_appleII;
+	__weak CSMachine *_machine;
+}
+
+- (instancetype)initWithAppleII:(void *)appleII owner:(CSMachine *)machine {
+	self = [super init];
+	if(self) {
+		_appleII = (Apple::II::Machine *)appleII;
+		_machine = machine;
+	}
+	return self;
+}
+
+#pragma mark - Options
+
+- (void)setUseSquarePixels:(BOOL)useSquarePixels {
+	Configurable::Device *const configurable = dynamic_cast<Configurable::Device *>(_appleII);
+
+	@synchronized(_machine) {
+		auto options = configurable->get_options();
+		auto appleii_configurable = dynamic_cast<Apple::II::Machine::Options *>(options.get());
+		appleii_configurable->use_square_pixels = useSquarePixels;
+		configurable->set_options(options);
+	}
+}
+
+- (BOOL)useSquarePixels {
+	Configurable::Device *const configurable = dynamic_cast<Configurable::Device *>(_appleII);
+
+	@synchronized(_machine) {
+		auto options = configurable->get_options();
+		auto appleii_configurable = dynamic_cast<Apple::II::Machine::Options *>(options.get());
+		return appleii_configurable->use_square_pixels ? YES : NO;
+	}
+}
+
+@end

From 70851f3b2dff6a161e2027aa01139ebe38b8329f Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Mon, 7 Jun 2021 21:43:26 -0400
Subject: [PATCH 4/8] Resolve misplacement.

---
 OSBindings/Mac/Clock Signal/Base.lproj/AppleIIOptions.xib | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/OSBindings/Mac/Clock Signal/Base.lproj/AppleIIOptions.xib b/OSBindings/Mac/Clock Signal/Base.lproj/AppleIIOptions.xib
index 5b4ef82a7..25cbc0a49 100644
--- a/OSBindings/Mac/Clock Signal/Base.lproj/AppleIIOptions.xib	
+++ b/OSBindings/Mac/Clock Signal/Base.lproj/AppleIIOptions.xib	
@@ -18,8 +18,8 @@
             <windowPositionMask key="initialPositionMask" leftStrut="YES" rightStrut="YES" topStrut="YES" bottomStrut="YES"/>
             <rect key="contentRect" x="80" y="150" width="200" height="159"/>
             <rect key="screenRect" x="0.0" y="0.0" width="2560" height="1440"/>
-            <view key="contentView" misplaced="YES" id="tpZ-0B-QQu">
-                <rect key="frame" x="0.0" y="0.0" width="200" height="159"/>
+            <view key="contentView" id="tpZ-0B-QQu">
+                <rect key="frame" x="0.0" y="0.0" width="200" height="84"/>
                 <autoresizingMask key="autoresizingMask"/>
                 <subviews>
                     <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="kDb-7g-cVx">

From de3b37799c5f3439a7f83caedb732096d31113ce Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Tue, 8 Jun 2021 17:37:28 -0400
Subject: [PATCH 5/8] Switches to a `static_cast`. No need for reflection here.

---
 .../Mac/Clock Signal/Machine/Wrappers/CSAppleII.mm       | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/OSBindings/Mac/Clock Signal/Machine/Wrappers/CSAppleII.mm b/OSBindings/Mac/Clock Signal/Machine/Wrappers/CSAppleII.mm
index 0c9fc35bd..23dc1268c 100644
--- a/OSBindings/Mac/Clock Signal/Machine/Wrappers/CSAppleII.mm	
+++ b/OSBindings/Mac/Clock Signal/Machine/Wrappers/CSAppleII.mm	
@@ -28,10 +28,17 @@
 
 - (void)setUseSquarePixels:(BOOL)useSquarePixels {
 	Configurable::Device *const configurable = dynamic_cast<Configurable::Device *>(_appleII);
+#ifndef NDEBUG
+	assert(configurable);
+#endif
 
 	@synchronized(_machine) {
 		auto options = configurable->get_options();
-		auto appleii_configurable = dynamic_cast<Apple::II::Machine::Options *>(options.get());
+#ifndef NDEBUG
+		assert(dynamic_cast<Apple::II::Machine::Options *>(options.get()));
+#endif
+
+		auto appleii_configurable = static_cast<Apple::II::Machine::Options *>(options.get());
 		appleii_configurable->use_square_pixels = useSquarePixels;
 		configurable->set_options(options);
 	}

From 85fab2abc4010f004c553efa2d7d1a3f9f0e2e6b Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Tue, 8 Jun 2021 17:37:46 -0400
Subject: [PATCH 6/8] Takes a swing at adding a square pixels toggle for Qt.

---
 OSBindings/Qt/mainwindow.cpp | 37 +++++++++++++++++++++++++++++++++++-
 OSBindings/Qt/mainwindow.h   |  3 +++
 2 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/OSBindings/Qt/mainwindow.cpp b/OSBindings/Qt/mainwindow.cpp
index 88762db58..b2a1c8e40 100644
--- a/OSBindings/Qt/mainwindow.cpp
+++ b/OSBindings/Qt/mainwindow.cpp
@@ -403,7 +403,7 @@ void MainWindow::launchMachine() {
 		break;
 
 		case Analyser::Machine::AppleII:
-			addDisplayMenu(settingsPrefix, "Colour", "Monochrome", "", "");
+			addAppleIIMenu();
 		break;
 
 		case Analyser::Machine::Atari2600:
@@ -671,6 +671,41 @@ void MainWindow::toggleAtari2600Switch(Atari2600Switch toggleSwitch) {
 	});
 }
 
+void MainWindow::addAppleIIMenu() {
+	// Add the standard display settings.
+	addDisplayMenu(settingsPrefix, "Colour", "Monochrome", "", "");
+
+	// Add an additional tick box, for square pixels.
+	QAction *const squarePixelsAction = new QAction(tr("Square Pixels"));
+	squarePixelsAction->setCheckable(true);
+	connect(squarePixelsAction, &QAction::triggered, this, [=] {
+		std::lock_guard lock_guard(machineMutex);
+
+		// Apply the new setting to the machine.
+		setAppleIISquarePixels(squarePixelsAction->isChecked());
+
+		// Also store it.
+		Settings settings;
+		settings.setValue("appleII.squarePixels", squarePixelsAction->isChecked());
+	});
+	displayMenu->addAction(squarePixelsAction);
+
+	// Establish initial selection.
+	Settings settings;
+	const bool useSquarePixels = settings.value("appleII.squarePixels").toBool();
+	squarePixelsAction->setIsChecked(useSquarePixels);
+	setAppleIISquarePixels(useSquarePixels);
+}
+
+void MainWindow::setAppleIISquarePixels(bool squarePixels) {
+	const auto configurable = dynamic_cast<Configurable::Device *>(machine->raw_pointer());
+	auto options = configurable->get_options();
+	auto appleii_configurable = static_cast<Apple::II::Machine::Options *>(options.get());
+
+	appleii_configurable->use_square_pixels = squarePixelsAction->isChecked();
+	configurable->set_options(options);
+}
+
 void MainWindow::speaker_did_complete_samples(Outputs::Speaker::Speaker *, const std::vector<int16_t> &buffer) {
 	audioBuffer.write(buffer);
 }
diff --git a/OSBindings/Qt/mainwindow.h b/OSBindings/Qt/mainwindow.h
index b83f92633..2fe4230ed 100644
--- a/OSBindings/Qt/mainwindow.h
+++ b/OSBindings/Qt/mainwindow.h
@@ -137,6 +137,9 @@ class MainWindow : public QMainWindow, public Outputs::Speaker::Speaker::Delegat
 		void addAtari2600Menu();
 		void toggleAtari2600Switch(Atari2600Switch toggleSwitch);
 
+		void addAppleIIMenu();
+		void setAppleIISquarePixels(bool);
+
 		void setWindowTitle();
 		bool mouseIsCaptured = false;
 

From 0982141442f3f7ef48b741847a117761d4da11be Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Tue, 8 Jun 2021 17:52:39 -0400
Subject: [PATCH 7/8] Corrects many minor errors.

---
 OSBindings/Qt/mainwindow.cpp | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/OSBindings/Qt/mainwindow.cpp b/OSBindings/Qt/mainwindow.cpp
index b2a1c8e40..5a3f791bc 100644
--- a/OSBindings/Qt/mainwindow.cpp
+++ b/OSBindings/Qt/mainwindow.cpp
@@ -673,7 +673,7 @@ void MainWindow::toggleAtari2600Switch(Atari2600Switch toggleSwitch) {
 
 void MainWindow::addAppleIIMenu() {
 	// Add the standard display settings.
-	addDisplayMenu(settingsPrefix, "Colour", "Monochrome", "", "");
+	addDisplayMenu("appleII", "Colour", "Monochrome", "", "");
 
 	// Add an additional tick box, for square pixels.
 	QAction *const squarePixelsAction = new QAction(tr("Square Pixels"));
@@ -693,16 +693,16 @@ void MainWindow::addAppleIIMenu() {
 	// Establish initial selection.
 	Settings settings;
 	const bool useSquarePixels = settings.value("appleII.squarePixels").toBool();
-	squarePixelsAction->setIsChecked(useSquarePixels);
+	squarePixelsAction->setChecked(useSquarePixels);
 	setAppleIISquarePixels(useSquarePixels);
 }
 
 void MainWindow::setAppleIISquarePixels(bool squarePixels) {
-	const auto configurable = dynamic_cast<Configurable::Device *>(machine->raw_pointer());
+	Configurable::Device *const configurable = machine->configurable_device();
 	auto options = configurable->get_options();
-	auto appleii_configurable = static_cast<Apple::II::Machine::Options *>(options.get());
+	auto appleii_options = static_cast<Apple::II::Machine::Options *>(options.get());
 
-	appleii_configurable->use_square_pixels = squarePixelsAction->isChecked();
+	appleii_options->use_square_pixels = squarePixels;
 	configurable->set_options(options);
 }
 

From ae2993625c60052229d6df8304f493bf42bea094 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Tue, 8 Jun 2021 17:54:30 -0400
Subject: [PATCH 8/8] Add missing header.

---
 OSBindings/Qt/mainwindow.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/OSBindings/Qt/mainwindow.h b/OSBindings/Qt/mainwindow.h
index 2fe4230ed..ab02f14e9 100644
--- a/OSBindings/Qt/mainwindow.h
+++ b/OSBindings/Qt/mainwindow.h
@@ -20,8 +20,9 @@
 #include "../../Activity/Observer.hpp"
 
 // There are machine-specific controls for the following:
-#include "../../Machines/Sinclair/ZX8081/ZX8081.hpp"
+#include "../../Machines/Apple/AppleII/AppleII.hpp"
 #include "../../Machines/Atari/2600/Atari2600.hpp"
+#include "../../Machines/Sinclair/ZX8081/ZX8081.hpp"
 
 QT_BEGIN_NAMESPACE
 namespace Ui { class MainWindow; }