以下是我的看法。我也从GLFW 3.1的代码中开始,文件名为cocoa_monitor.m。
但是我必须以不同于Hiroshi所说的方式进行修改,因此在这里列出:
- (NSString*) screenNameForDisplay: (NSNumber*) screen_id
{
CGDirectDisplayID displayID = [screen_id unsignedIntValue];
io_service_t serv = [self IOServicePortFromCGDisplayID: displayID];
if (serv == 0)
return @"unknown";
CFDictionaryRef info = IODisplayCreateInfoDictionary(serv, kIODisplayOnlyPreferredName);
IOObjectRelease(serv);
CFStringRef display_name;
CFDictionaryRef names = CFDictionaryGetValue(info, CFSTR(kDisplayProductName));
if ( !names ||
!CFDictionaryGetValueIfPresent(names, CFSTR("en_US"), (const void**) & display_name) )
{
CFRelease( info );
return @"unknown";
}
NSString * displayname = [NSString stringWithString: (__bridge NSString *) display_name];
CFRelease(info);
return displayname;
}
- (io_service_t) IOServicePortFromCGDisplayID: (CGDirectDisplayID) displayID
{
io_iterator_t iter;
io_service_t serv, servicePort = 0;
CFMutableDictionaryRef matching = IOServiceMatching("IODisplayConnect");
kern_return_t err = IOServiceGetMatchingServices( kIOMasterPortDefault, matching, & iter );
if ( err )
return 0;
while ( (serv = IOIteratorNext(iter)) != 0 )
{
CFDictionaryRef displayInfo;
CFNumberRef vendorIDRef;
CFNumberRef productIDRef;
CFNumberRef serialNumberRef;
displayInfo = IODisplayCreateInfoDictionary( serv, kIODisplayOnlyPreferredName );
Boolean success;
success = CFDictionaryGetValueIfPresent( displayInfo, CFSTR(kDisplayVendorID), (const void**) & vendorIDRef );
success &= CFDictionaryGetValueIfPresent( displayInfo, CFSTR(kDisplayProductID), (const void**) & productIDRef );
if ( !success )
{
CFRelease(displayInfo);
continue;
}
SInt32 vendorID;
CFNumberGetValue( vendorIDRef, kCFNumberSInt32Type, &vendorID );
SInt32 productID;
CFNumberGetValue( productIDRef, kCFNumberSInt32Type, &productID );
SInt32 serialNumber = 0;
if ( CFDictionaryGetValueIfPresent(displayInfo, CFSTR(kDisplaySerialNumber), (const void**) & serialNumberRef) )
{
CFNumberGetValue( serialNumberRef, kCFNumberSInt32Type, &serialNumber );
}
if( CGDisplayVendorNumber(displayID) != vendorID ||
CGDisplayModelNumber(displayID) != productID ||
CGDisplaySerialNumber(displayID) != serialNumber )
{
CFRelease(displayInfo);
continue;
}
servicePort = serv;
CFRelease(displayInfo);
break;
}
IOObjectRelease(iter);
return servicePort;
}
对我而言,在macOS 10.11(El Capitan)下编写的屏幕保护程序中,这个方法运行正常。我使用了我的MacBookPro自带的显示器和通过Thunderbolt连接的苹果外置显示器进行了测试。