Display Preferred Display Name.

Makefile

@@ -24,7 +24,7 @@ ARCH_FLAGS=-arch i386 -arch x86_64
 build: screenresolution
 
 screenresolution: main.c cg_utils.o version.h 
-		$(CC) $(CPPFLAGS) $(CFLAGS) $(ARCH_FLAGS) -framework Foundation -framework ApplicationServices $< *.o -o $@
+		$(CC) $(CPPFLAGS) $(CFLAGS) $(ARCH_FLAGS) -framework Foundation -framework ApplicationServices -framework IOKit $< *.o -o $@
 
 %.o: %.c
 	$(CC) $(CPPFLAGS) $(CFLAGS) $(ARCH_FLAGS) $< -c -o $@

cg_utils.c

@@ -170,3 +170,59 @@ CFComparisonResult _compareCFDisplayModes (CGDisplayModeRef *mode1Ptr, CGDisplay
     else 
         return (width1 < width2) ? kCFCompareLessThan : kCFCompareGreaterThan;
 }
+
+char* convertCFStringToCString(CFStringRef toConvert)
+{   
+    char* toReturn = "";
+
+    if (NULL != toConvert) 
+    {
+        CFIndex length = CFStringGetLength(toConvert);
+        CFIndex maxSize = CFStringGetMaximumSizeForEncoding(length, kCFStringEncodingUTF8);
+        char *buffer = (char *)malloc(maxSize);
+
+        if (CFStringGetCString(toConvert, buffer, maxSize, kCFStringEncodingUTF8)) 
+        {
+            toReturn = buffer;
+        }
+    }
+
+    return toReturn;
+}
+
+char* getPreferredDisplayName(CGDirectDisplayID displayID)
+{
+    char* name = "Unknown";
+
+    //TODO: 'CGDisplayIOServicePort' is deprecated (but still available) in OS X 10.9
+    // I believe something else will come out by the time it is fully deprecated...or
+    // Apple will document a way of getting this additional display info while using
+    // CoreGraphics.
+    io_service_t displayServicePort = CGDisplayIOServicePort(displayID);
+
+    if (displayServicePort)
+    {   
+        CFDictionaryRef displayInfoDict = IODisplayCreateInfoDictionary(displayServicePort, kIODisplayOnlyPreferredName); 
+
+        if(displayInfoDict)
+        {
+            // this array will be populated with the localized names for the display (i.e. names of the
+            // display in different languages)
+            CFDictionaryRef namesForDisplay = CFDictionaryGetValue(displayInfoDict, CFSTR(kDisplayProductName));        
+            CFStringRef value;
+
+            if (namesForDisplay)
+            {
+                // TODO: get this working with system's default locale...the rest of the program is in English
+                // for now, so it's not an utterly obtuse decision to stick with English.
+                name = convertCFStringToCString(CFDictionaryGetValue(namesForDisplay, CFSTR("en_US")));       
+            }     
+
+            CFRelease(displayInfoDict);
+        }
+
+        IOObjectRelease(displayServicePort);
+    }
+
+    return strdup(name);
+}

cg_utils.h

@@ -22,6 +22,12 @@
 #define __CG_UTILS__H
 
 #include <ApplicationServices/ApplicationServices.h>
+#include <IOKit/graphics/IOGraphicsLib.h>
+
+/*
+#include <CoreVideo/CVBase.h>
+#include <CoreVideo/CVDisplayLink.h>
+*/
 
 // http://stackoverflow.com/questions/3060121/core-foundation-equivalent-for-nslog/3062319#3062319
 #ifndef __OBJC__
@@ -43,5 +49,6 @@ unsigned int configureDisplay(CGDirectDisplayID display,
 unsigned int parseStringConfig(const char *string, struct config *out);
 size_t bitDepth(CGDisplayModeRef mode);
 CFComparisonResult _compareCFDisplayModes (CGDisplayModeRef *mode1Ptr, CGDisplayModeRef *mode2Ptr, void *context);
+char* getPreferredDisplayName(CGDirectDisplayID displayID);
 
 #endif

main.c

@@ -135,6 +135,8 @@ unsigned int listAvailableModes(CGDirectDisplayID display, int displayNum) {
     int numModes = 0;
     int i;
 
+    char* displayName = getPreferredDisplayName(display);
+
     CFArrayRef allModes = CGDisplayCopyAllDisplayModes(display, NULL);
     if (allModes == NULL) {
         returncode = 0;
@@ -159,7 +161,7 @@ unsigned int listAvailableModes(CGDirectDisplayID display, int displayNum) {
 #ifndef LIST_DEBUG
     if(displayNum != 0)
         printf("\n\n");
-    printf("Available Modes on Display %d\n", displayNum);
+    printf("Available Modes on Display %d (%s)\n", displayNum, displayName);
 #endif
 
     CGDisplayModeRef mode;