Fall back to defaults if user preference is set to incorrect type

Author: emreyolcu

DiscreteScroll.xcodeproj/project.pbxproj

@@ -249,13 +249,14 @@
 			buildSettings = {
 				CODE_SIGN_STYLE = Automatic;
 				COMBINE_HIDPI_IMAGES = YES;
+				CURRENT_PROJECT_VERSION = 2;
 				INFOPLIST_FILE = DiscreteScroll/Info.plist;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/../Frameworks",
 				);
 				MACOSX_DEPLOYMENT_TARGET = 10.9;
-				MARKETING_VERSION = 1.0.0;
+				MARKETING_VERSION = 1.0.1;
 				PRODUCT_BUNDLE_IDENTIFIER = com.emreyolcu.DiscreteScroll;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 			};
@@ -266,13 +267,14 @@
 			buildSettings = {
 				CODE_SIGN_STYLE = Automatic;
 				COMBINE_HIDPI_IMAGES = YES;
+				CURRENT_PROJECT_VERSION = 2;
 				INFOPLIST_FILE = DiscreteScroll/Info.plist;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/../Frameworks",
 				);
 				MACOSX_DEPLOYMENT_TARGET = 10.9;
-				MARKETING_VERSION = 1.0.0;
+				MARKETING_VERSION = 1.0.1;
 				PRODUCT_BUNDLE_IDENTIFIER = com.emreyolcu.DiscreteScroll;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 			};

DiscreteScroll/Info.plist

@@ -17,7 +17,7 @@
 	<key>CFBundleShortVersionString</key>
 	<string>$(MARKETING_VERSION)</string>
 	<key>CFBundleVersion</key>
-	<string>1</string>
+	<string>$(CURRENT_PROJECT_VERSION)</string>
 	<key>LSApplicationCategoryType</key>
 	<string>public.app-category.utilities</string>
 	<key>LSMinimumSystemVersion</key>

DiscreteScroll/main.c

@@ -1,13 +1,14 @@
 #include <ApplicationServices/ApplicationServices.h>
 
+#define DEFAULT_LINES 3
 #define SIGN(x) (((x) > 0) - ((x) < 0))
 
 static int LINES;
 
 CGEventRef callback(CGEventTapProxy proxy, CGEventType type, CGEventRef event, void *userInfo)
 {
-    if (!CGEventGetIntegerValueField(event, kCGScrollWheelEventIsContinuous)) {
-        int64_t delta = CGEventGetIntegerValueField(event, kCGScrollWheelEventPointDeltaAxis1);
+    if (CGEventGetIntegerValueField(event, kCGScrollWheelEventIsContinuous) == 0) {
+        int delta = (int)CGEventGetIntegerValueField(event, kCGScrollWheelEventPointDeltaAxis1);
         CGEventSetIntegerValueField(event, kCGScrollWheelEventDeltaAxis1, SIGN(delta) * LINES);
     }
 
@@ -32,24 +33,24 @@ int main(void)
         (const void **)&kAXTrustedCheckOptionPrompt, (const void **)&kCFBooleanTrue, 1,
         &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks
     );
-    Boolean trusted = AXIsProcessTrustedWithOptions(options);
+    bool trusted = AXIsProcessTrustedWithOptions(options);
     CFRelease(options);
     if (!trusted)
         displayNoticeAndExit(
             CFSTR("Restart DiscreteScroll after granting it access to accessibility features.")
         );
 
-    CFStringRef key = CFSTR("lines");
     CFNumberRef value = (CFNumberRef)CFPreferencesCopyAppValue(
-        key, kCFPreferencesCurrentApplication
+        CFSTR("lines"), kCFPreferencesCurrentApplication
     );
-    Boolean got = false;
+    bool got = false;
     if (value) {
-        got = CFNumberGetValue(value, kCFNumberIntType, &LINES);
+        if (CFGetTypeID(value) == CFNumberGetTypeID())
+            got = CFNumberGetValue(value, kCFNumberIntType, &LINES);
         CFRelease(value);
     }
     if (!got)
-        LINES = 3;
+        LINES = DEFAULT_LINES;
 
     CFMachPortRef tap = CGEventTapCreate(
         kCGSessionEventTap, kCGHeadInsertEventTap, kCGEventTapOptionDefault,

README.md

@@ -14,7 +14,7 @@ As of May 2024, this application works on macOS versions 10.9–14.0.
 
 ### Installation
 
-You may download the binary [here](https://github.com/emreyolcu/discrete-scroll/releases/download/v1.0.0/DiscreteScroll.zip).
+You may download the binary [here](https://github.com/emreyolcu/discrete-scroll/releases/download/v1.0.1/DiscreteScroll.zip).
 
 It needs to be run each time you boot.
 If you want this to be automatic, do the following:
@@ -40,7 +40,10 @@ This number may even be negative, which inverts scrolling direction.
 defaults write com.emreyolcu.DiscreteScroll lines -int LINES
 ```
 
-You should restart the application for this setting to take effect.
+If you set the key `lines` to some value other than an integer,
+the default value of 3 is used as a fallback.
+
+You should restart the application for the setting to take effect.
 
 ### Potential problems