If I am getting a CGWindowID (_windowID) as follows...
NSArray *windowList = (__bridge NSArray *)CGWindowListCopyWindowInfo(kCGWindowListOptionOnScreenOnly, kCGNullWindowID);
for (NSDictionary *info in windowList) {
if ([[info objectForKey:(NSString *)kCGWindowOwnerName] isEqualToString:#"window name"] && ![[info objectForKey:(NSString *)kCGWindowName] isEqualToString:#""]) {
_windowID = [[info objectForKey:(NSString *)kCGWindowNumber] unsignedIntValue];
}
}
How do I properly test the window id is still valid and the window has not been closed? Do i just run similar code just checking window id exists?
Thanks in advance
The documentation for the kCGWindowListOptionOnScreenOnly constant says:
List all windows that are currently onscreen. Windows are returned in
order from front to back. When retrieving a list with this option, the
relativeToWindow parameter should be set to kCGNullWindowID.
So the windows would certainly be on screen, since nothing appears to be happening between the call to CGWindowListCopyWindowInfo and your action on it.
Maybe you'd want to test to make sure they are not hidden or minimized?
Related
Note: this question is intentionally very general (e.g. both Objective-C and Swift code examples are requested), as it is intended to document how to capture a window screenshot on macOS as accessibly as possible.
I want to capture a screenshot of a macOS window in Objective-C/Swift code. I know this is possible because of the multitude of ways to take a screenshot on macOS (⇧⌘4, the Grab utility, screencapture on the command line, …), but I’m not sure how to do it in my own code. Ideally, I’d be able to specify a window of a particular application, and then capture it in an NSImage or CGImage that I could then process and display to the user or store in a file.
Screen capture on macOS is possible through Quartz Window Services, a facility of the Core Graphics framework. Our key function here is CGWindowListCreateImage, which “returns a composite image based on a dynamically generated list of windows,” or, in other words, finds windows based on specified criteria and creates an image with the contents of each. Perfect! Its declaration is as follows:
CGImageRef CGWindowListCreateImage(CGRect screenBounds,
CGWindowListOption listOption,
CGWindowID windowID,
CGWindowImageOption imageOption);
So, in order to capture one specific window on the screen, we’ll need its window ID (CGWindowID). To go about retrieving that, we’ll first need a list of all of the windows available on the system. We get that through CGWindowListCopyWindowInfo, which takes CGWindowListOptions and a corresponding CGWindowID that, together, select which windows to include in the resulting list. To get ALL the windows, we specify kCGWindowListOptionAll, and kCGNullWindowID, respectively. Also, if you haven’t figured it out already, this is a C API, so we’ll use a bridging cast to work with the friendlier Objective-C containers rather than the Core Foundation ones.
Objective-C:
NSArray<NSDictionary*> *windowInfoList = (__bridge_transfer id)
CGWindowListCopyWindowInfo(kCGWindowListOptionAll, kCGNullWindowID);
Swift:
let windowInfoList = CGWindowListCopyWindowInfo(.optionAll, kCGNullWindowID)!
as NSArray
From here, we need to filter our windowInfoList down to the specific window that we want. Chances are we want to filter first by application. To do that, we’ll need the process ID of our application of choice. We can use NSRunningApplication to accomplish this:
Objective-C:
NSArray<NSRunningApplication*> *apps =
[NSRunningApplication runningApplicationsWithBundleIdentifier:
/* Bundle ID of the application, e.g.: */ #"com.apple.Safari"];
if (apps.count == 0) {
// Application is not currently running
puts("The application is not running");
return; // Or whatever
}
pid_t appPID = apps[0].processIdentifier;
Swift:
let apps = NSRunningApplication.runningApplications(withBundleIdentifier:
/* Bundle ID of the application, e.g.: */ "com.apple.Safari")
if apps.isEmpty {
// Application is not currently running
print("The application is not running")
return // Or whatever
}
let appPID = apps[0].processIdentifier
With appPID in hand, we can now go ahead and filter down our window info list to only windows with a matching owner PID:
Objective-C:
NSMutableArray<NSDictionary*> *appWindowsInfoList = [NSMutableArray new];
for (NSDictionary *info in windowInfoList) {
if ([info[(__bridge NSString *)kCGWindowOwnerPID] integerValue] == appPID) {
[appWindowsInfoList addObject:info];
}
}
Swift:
var appWindowsInfoList = [NSDictionary]()
for info_ in windowInfoList {
let info = info_ as! NSDictionary
if (info[kCGWindowOwnerPID as NSString] as! NSNumber).intValue == appPID {
appWindowsInfoList.append(info)
}
}
We could have done additional filtering above by testing other keys of the info dictionary—for example, by name (kCGWindowName), or by whether the window is on-screen (kCGWindowIsOnscreen)—but for now, we’ll just take the first window in the list:
Objective-C:
NSDictionary *appWindowInfo = appWindowsInfoList[0];
CGWindowID windowID = [appWindowInfo[(__bridge NSString *)kCGWindowNumber] unsignedIntValue];
Swift:
let appWindowInfo: NSDictionary = appWindowsInfoList[0];
let windowID: CGWindowID = (appWindowInfo[kCGWindowNumber as NSString] as! NSNumber).uint32Value
And we have our window ID! Now, what else did we need for that call again?
CGImageRef CGWindowListCreateImage(CGRect screenBounds,
CGWindowListOption listOption,
CGWindowID windowID,
CGWindowImageOption imageOption);
First, we need a screenBounds to capture. According to the documentation, we can specify CGRectNull for this parameter to enclose all specified windows as tightly as possible. Works for me.
Second, we have to specify how we want to select our windows with listOption. We actually used one of these earlier, in our call to CGWindowListCopyWindowInfo, but there we wanted all the windows on the system; here, we only want one, so we’ll specify kCGWindowListOptionIncludingWindow, which, contrary to its documentation page, is meaningful on its own for CGWindowListCreateImage in that it specifies the window we pass, and only the window we pass.
Third, we pass our windowID as the window we want captured.
Fourth and finally, we can specify CGWindowImageOptions with the imageOption parameter. These affect the appearance of the resulting image; you can combine them through bitwise OR. The full list is here, but common ones include either kCGWindowImageDefault, which captures the window's contents along with its frame and shadow, or kCGWindowImageBoundsIgnoreFraming, which captures only the content, and kCGWindowImageBestResolution, which captures the window's content at the best resolution available, regardless of actual size (and, depending on the window, may be considerably large), or kCGWindowImageNominalResolution, which captures the window at its current size on the screen. Here, I’ve gone with kCGWindowImageBoundsIgnoreFraming and kCGWindowImageNominalResolution to capture only the content at the same size as on the screen.
Aaand, drumroll please:
Objective-C:
CGImageRef windowImage =
CGWindowListCreateImage(CGRectNull, kCGWindowListOptionIncludingWindow,
windowID, kCGWindowImageBoundsIgnoreFraming|
kCGWindowImageNominalResolution);
// NOTE: windowImage may be NULL if the capture failed
Swift:
let windowImage: CGImage? =
CGWindowListCreateImage(.null, .optionIncludingWindow, windowID,
[.boundsIgnoreFraming, .nominalResolution])
Here's the Objective C code without all the exposition, and no need to know your bundle ID ahead of time:
int processID = [[NSProcessInfo processInfo] processIdentifier];
NSArray<NSDictionary*>* windowInfoList = (__bridge_transfer id) CGWindowListCopyWindowInfo(kCGWindowListOptionOnScreenOnly, kCGNullWindowID);
int windowID = -1;
for (NSDictionary* info in windowInfoList) {
int thisProcess = [info[(__bridge NSString *)kCGWindowOwnerPID] integerValue];
if (thisProcess == processID) {
windowID = [info[(__bridge NSString *)kCGWindowNumber] integerValue];
break;
}
}
CGImageRef screenCG = nil;
if (windowID != -1)
screenCG = CGWindowListCreateImage(CGRectNull, kCGWindowListOptionIncludingWindow, windowID, kCGWindowImageBoundsIgnoreFraming);
I am trying to launch the built-in calculator.app on my Mac(which means it is external to my application) within my application and force the calculator to stay frontmost permanently on screen.
Here is my process. Firstly, I launch the calculator and place it frontmost temporarily.
if ([[NSWorkspace sharedWorkspace] respondsToSelector:#selector(launchApplicationAtURL:options:configuration:error:)])
[[NSWorkspace sharedWorkspace] launchApplicationAtURL:[NSURL fileURLWithPath:#"/Applications/Calculator.app/Contents/MacOS/Calculator" isDirectory:NO]
options:NSWorkspaceLaunchDefault
configuration:nil
error:NULL];
After that, I recognize the Calculator by it's owner name and try to pin Calculator.app frontmost. I was stuck here. What I would like to do is either these two ways:
1.Set an attribute to place it always frontmost. (Can't find suitable
attribute, only found attributes to resize or position)
2.Get the NSWindow of Calculator and set the level to frontmost. (Seems to be non-viable: How to convert a Carbon AXUIElementRef to Cocoa NSWindow)
But seems that both of them are not available.
CFArrayRef windowList = CGWindowListCopyWindowInfo(kCGWindowListOptionOnScreenOnly | kCGWindowListExcludeDesktopElements, kCGNullWindowID);
NSArray *arr = CFBridgingRelease(windowList);
for (NSMutableDictionary *entry in arr){
NSString *ownerName = [entry objectForKey:(id)kCGWindowOwnerName];
if([ownerName isEqualToString:#"Calculator"]){
pid_t pid = [[entry objectForKey:(id)kCGWindowOwnerPID] intValue];
AXUIElementRef appRef = AXUIElementCreateApplication(pid);
CFArrayRef windowList;
AXUIElementCopyAttributeValue(appRef, kAXWindowsAttribute, (CFTypeRef *)&windowList);
AXUIElementRef windowRef = (AXUIElementRef) CFArrayGetValueAtIndex( windowList, 0);
CFTypeRef role;
AXUIElementCopyAttributeValue(windowRef, kAXRoleAttribute, (CFTypeRef *)&role);
/*Would like to get the window of the application or assign some attribute to set Calculator frontmost*/
}
Are there any ways to achieve the two aspects I've mentioned above? Or are there any suggestions for setting an external application always being frontmost?
For example, a user puts my application on his/her desktop. Then he/she copied (instead of moving) it to the /Application folder.
If the one at ~/Desktop has been launched, how can I prevent duplicated launching of the one at ~/Application? Any simple way?
Or if the user launches the one in /Application, I can detect the pre-launched app, and then switch to that immediately?
How about getting a list of all running applications and quitting immediately if your app detects there's another instance already running?
You can get a list of all active apps via NSWorkspace and runningApplications:
NSWorkspace * ws = [NSWorkspace sharedWorkspace];
NSArray *allRunningApps = [ws runningApplications];
It'll return an array of NSRunningApplication instances so all you'd have to do is check the list for e.g. your app's ID via the bundleIdentifier method.
cacau's answer had given me inspiration to achieve my goal. Here are my codes (ARC):
- (BOOL)checkAppDuplicateAndBringToFrontWithBundle:(NSBundle *)bundle
{
NSRunningApplication *app;
NSArray *appArray;
NSUInteger tmp;
pid_t selfPid;
BOOL ret = NO;
selfPid = [[NSRunningApplication currentApplication] processIdentifier];
appArray = [NSRunningApplication runningApplicationsWithBundleIdentifier:[bundle bundleIdentifier]];
for (tmp = 0; tmp < [appArray count]; tmp++)
{
app = [appArray objectAtIndex:tmp];
if ([app processIdentifier] == selfPid)
{
/* do nothing */
}
else
{
[[NSWorkspace sharedWorkspace] launchApplication:[[app bundleURL] path]];
ret = YES;
}
}
return ret;
}
It checks app duplicate by bundle identifier. As bundle duplicated, it brings all other applications to front and returns YES. As receiving YES, application can terminate itself.
However, as cacau has given me significant help, I gave him the reputation point of this question. Thank you!
Would it not be simplest to actually just create a file inside NSTempDirectory, check for it and if it is there, you quit, or perhaps offer a way to delete the file ?
This would work for both running in and out of sandbox.
I'm trying to learn to code for the Mac. I've been a Java guy for a while, so I hope the problem I'm running into is a simple misunderstanding of Cocoa.
I've got the following code:
-(IBAction)beginEventMonitor:(id)sender {
_eventMonitor = [NSEvent addGlobalMonitorForEventsMatchingMask:(NSLeftMouseUpMask)
handler:^(NSEvent *incomingEvent) {
//NSWindow *targetWindowForEvent = [incomingEvent window];
NSLog(#"Got a mouse click event at %#", NSStringFromPoint([incomingEvent locationInWindow]));
}];
}
-(IBAction)stopEventMonitor:(id)sender {
if (_eventMonitor) {
[NSEvent removeMonitor:_eventMonitor];
_eventMonitor = nil;
}
}
This is a simple hook to tell me when a mouse click happens at a global level. The handler is working, but the contents of the incomingEvent don't seem to be set to anything. The only useful information that I can find is the location of the mouse at the time of the click, and the windowId of the window that was clicked in.
Shouldn't I be able to get more information? Am I not setting up the monitor correctly? I'd really like to be able to know which window was clicked in, but I can't even find a way to turn the mouse location or windowId into something useful.
You can retrieve more information about the window using the CGWindow APIs (new in Leopard), for example:
CGWindowID windowID = (CGWindowID)[incomingEvent windowNumber];
CFArrayRef a = CFArrayCreate(NULL, (void *)&windowID, 1, NULL);
NSArray *windowInfos = (NSArray *)CGWindowListCreateDescriptionFromArray(a);
CFRelease(a);
if ([windowInfos count] > 0) {
NSDictionary *windowInfo = [windowInfos objectAtIndex:0];
NSLog(#"Name: %#", [windowInfo objectForKey:(NSString *)kCGWindowName]);
NSLog(#"Owner: %#", [windowInfo objectForKey:(NSString *)kCGWindowOwnerName]);
//etc.
}
[windowInfos release];
There's lots of information there (look in CGWindow.h or refer to the docs for available keys). There are also functions to create screenshots of just one window (which even works if it's partially covered by another window), cool stuff!
Is there a way (some API) to get the list of installed apps on an iPhone device.
While searching for similar questions, I found some thing related to url registration, but I think there must be some API to do this, as I don't want to do any thing with the app, I just want the list.
No, apps are sandboxed and Apple-accepted APIs do not include anything that would let you do that.
You can, however, test whether a certain app is installed:
if the app is known to handle URLs of a certain type
by using [[UIApplication sharedApplication] canOpenURL:[NSURL URLWithString:#"thisapp://foo"]
You can get a list of apps and URL schemes from here.
For jailbroken devices you can use next snipped of code:
-(void)appInstalledList
{
static NSString* const path = #"/private/var/mobile/Library/Caches/com.apple.mobile.installation.plist";
NSDictionary *cacheDict = nil;
BOOL isDir = NO;
if ([[NSFileManager defaultManager] fileExistsAtPath: path isDirectory: &isDir] && !isDir)
{
cacheDict = [NSDictionary dictionaryWithContentsOfFile: path];
NSDictionary *system = [cacheDict objectForKey: #"System"]; // First check all system (jailbroken) apps
for (NSString *key in system)
{
NSLog(#"%#",key);
}
NSDictionary *user = [cacheDict objectForKey: #"User"]; // Then all the user (App Store /var/mobile/Applications) apps
for (NSString *key in user)
{
NSLog(#"%#",key);
}
return;
}
NSLog(#"can not find installed app plist");
}
for non jailbroken device, we can use third party framework which is called "ihaspp", also its free and apple accepted. Also they given good documentation how to integrate and how to use. May be this would be helpful to you. Good luck!!
https://github.com/danielamitay/iHasApp
You could do this by using the following:
Class LSApplicationWorkspace_class = objc_getClass("LSApplicationWorkspace");
SEL selector = NSSelectorFromString(#"defaultWorkspace");
NSObject* workspace = [LSApplicationWorkspace_class performSelector:selector];
SEL selectorALL = NSSelectorFromString(#"allApplications");
NSMutableArray *Allapps = [workspace performSelector:selectorALL];
NSLog(#"apps: %#", Allapps);
And then by accessing each element and splitting it you can get your app name, and even the Bundle Identifier, too.
Well, not sure if this was available back when the last answer was given or not (Prior to iOS 6)
Also this one is time intensive, yet simple:
Go into settings > Gen. >usage. The first category under usage at least right now is Storage.
It will show a partial list of apps. At the bottom of this partial list is a button that says "show all apps".
Tap that and you'll have to go through screen by screen, and take screenshots (Quick lock button and home button takes a screenshot).
I'm doing this now and I have hundreds of apps on my iPhone. So it's going to take me a while. But at least at the end of the process I'll have Images of all my apps.