Turn on torch/flash on iPhone - ios

I know that the only way to turn on the flash and keep it on on iPhone 4 is by turning the video camera on. I'm not too sure of the code though. Here is what I am trying:
-(IBAction)turnTorchOn {
AVCaptureSession *captureSession = [[AVCaptureSession alloc] init];
AVCaptureDevice *videoCaptureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
NSError *error = nil;
AVCaptureDeviceInput *videoInput = [AVCaptureDeviceInput deviceInputWithDevice:videoCaptureDevice error:&error];
if (videoInput) {
[captureSession addInput:videoInput];
AVCaptureVideoDataOutput* videoOutput = [[AVCaptureVideoDataOutput alloc] init];
[videoOutput setSampleBufferDelegate:self queue:dispatch_get_current_queue()];
[captureSession addOutput:videoOutput];
[captureSession startRunning];
videoCaptureDevice.torchMode = AVCaptureTorchModeOn;
}
}
Does anybody know if this would work or am I missing anything? (I don't have an iPhone 4 yet to test on -just trying out some of the new API's).
Thanks

Here's a shorter version you can now use to turn the light on or off:
AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
if ([device hasTorch]) {
[device lockForConfiguration:nil];
[device setTorchMode:AVCaptureTorchModeOn]; // use AVCaptureTorchModeOff to turn off
[device unlockForConfiguration];
}
UPDATE: (March 2015)
With iOS 6.0 and later, you can control the brightness or level of the torch using the following method:
- (void)setTorchToLevel:(float)torchLevel
{
AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
if ([device hasTorch]) {
[device lockForConfiguration:nil];
if (torchLevel <= 0.0) {
[device setTorchMode:AVCaptureTorchModeOff];
}
else {
if (torchLevel >= 1.0)
torchLevel = AVCaptureMaxAvailableTorchLevel;
BOOL success = [device setTorchModeOnWithLevel:torchLevel error:nil];
}
[device unlockForConfiguration];
}
}
You may also want to monitor the return value (success) from setTorchModeOnWithLevel:. You may get a failure if you try to set the level too high and the torch is overheating. In that case setting the level to AVCaptureMaxAvailableTorchLevel will set the level to the highest level that is allowed given the temperature of the torch.

iWasRobbed's answer is great, except there is an AVCaptureSession running in the background all the time. On my iPhone 4s it takes about 12% CPU power according to Instrument so my app took about 1% battery in a minute. In other words if the device is prepared for AV capture it's not cheap.
Using the code below my app requires 0.187% a minute so the battery life is more than 5x longer.
This code works just fine on any device (tested on both 3GS (no flash) and 4s). Tested on 4.3 in simulator as well.
#import <AVFoundation/AVFoundation.h>
- (void) turnTorchOn:(BOOL)on {
Class captureDeviceClass = NSClassFromString(#"AVCaptureDevice");
if (captureDeviceClass != nil) {
AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
if ([device hasTorch] && [device hasFlash]){
[device lockForConfiguration:nil];
if (on) {
[device setTorchMode:AVCaptureTorchModeOn];
[device setFlashMode:AVCaptureFlashModeOn];
torchIsOn = YES;
} else {
[device setTorchMode:AVCaptureTorchModeOff];
[device setFlashMode:AVCaptureFlashModeOff];
torchIsOn = NO;
}
[device unlockForConfiguration];
}
}
}

See a better answer below: https://stackoverflow.com/a/10054088/308315
Old answer:
First, in your AppDelegate .h file:
#import <AVFoundation/AVFoundation.h>
#interface AppDelegate : NSObject <UIApplicationDelegate> {
AVCaptureSession *torchSession;
}
#property (nonatomic, retain) AVCaptureSession * torchSession;
#end
Then in your AppDelegate .m file:
#implementation AppDelegate
#synthesize torchSession;
- (void)dealloc {
[torchSession release];
[super dealloc];
}
- (id) init {
if ((self = [super init])) {
// initialize flashlight
// test if this class even exists to ensure flashlight is turned on ONLY for iOS 4 and above
Class captureDeviceClass = NSClassFromString(#"AVCaptureDevice");
if (captureDeviceClass != nil) {
AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
if ([device hasTorch] && [device hasFlash]){
if (device.torchMode == AVCaptureTorchModeOff) {
NSLog(#"Setting up flashlight for later use...");
AVCaptureDeviceInput *flashInput = [AVCaptureDeviceInput deviceInputWithDevice:device error: nil];
AVCaptureVideoDataOutput *output = [[AVCaptureVideoDataOutput alloc] init];
AVCaptureSession *session = [[AVCaptureSession alloc] init];
[session beginConfiguration];
[device lockForConfiguration:nil];
[session addInput:flashInput];
[session addOutput:output];
[device unlockForConfiguration];
[output release];
[session commitConfiguration];
[session startRunning];
[self setTorchSession:session];
[session release];
}
}
}
}
return self;
}
Then anytime you want to turn it on, just do something like this:
// test if this class even exists to ensure flashlight is turned on ONLY for iOS 4 and above
Class captureDeviceClass = NSClassFromString(#"AVCaptureDevice");
if (captureDeviceClass != nil) {
AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
[device lockForConfiguration:nil];
[device setTorchMode:AVCaptureTorchModeOn];
[device setFlashMode:AVCaptureFlashModeOn];
[device unlockForConfiguration];
}
And similar for turning it off:
// test if this class even exists to ensure flashlight is turned on ONLY for iOS 4 and above
Class captureDeviceClass = NSClassFromString(#"AVCaptureDevice");
if (captureDeviceClass != nil) {
AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
[device lockForConfiguration:nil];
[device setTorchMode:AVCaptureTorchModeOff];
[device setFlashMode:AVCaptureFlashModeOff];
[device unlockForConfiguration];
}

the lockforConfiguration is set in your code, where you declare your AVCaptureDevice is a property.
[videoCaptureDevice lockForConfiguration:nil];

From iOS 6.0 and above, toggling torch flash on/off,
- (void) toggleFlash {
AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
if ([device hasTorch] && [device hasFlash]){
[device lockForConfiguration:nil];
[device setFlashMode:(device.flashActive) ? AVCaptureFlashModeOff : AVCaptureFlashModeOn];
[device setTorchMode:(device.torchActive) ? AVCaptureTorchModeOff : AVCaptureTorchModeOn];
[device unlockForConfiguration];
}
}
P.S. This approach is only suggestible if you don't have on/off function. Remember there's one more option Auto. i.e. AVCaptureFlashModeAuto and AVCaptureTorchModeAuto. To support auto mode as well, you've keep track of current mode and based on that change mode of flash & torch.

Swift 2.0 version:
func setTorchLevel(torchLevel: Float)
{
self.captureSession?.beginConfiguration()
defer {
self.captureSession?.commitConfiguration()
}
if let device = backCamera?.device where device.hasTorch && device.torchAvailable {
do {
try device.lockForConfiguration()
defer {
device.unlockForConfiguration()
}
if torchLevel <= 0.0 {
device.torchMode = .Off
}
else if torchLevel >= 1.0 {
try device.setTorchModeOnWithLevel(min(torchLevel, AVCaptureMaxAvailableTorchLevel))
}
}
catch let error {
print("Failed to set up torch level with error \(error)")
return
}
}
}

//import fremework in .h file
#import <AVFoundation/AVFoundation.h>
{
AVCaptureSession *torchSession;
}
#property(nonatomic,retain)AVCaptureSession *torchSession;
-(IBAction)onoff:(id)sender;
//implement in .m file
#synthesize torchSession;
-(IBAction)onoff:(id)sender
{
AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
if ([device hasTorch] && [device hasFlash])
{
if (device.torchMode == AVCaptureTorchModeOff)
{
[button setTitle:#"OFF" forState:UIControlStateNormal];
AVCaptureDeviceInput *flashInput = [AVCaptureDeviceInput deviceInputWithDevice:device error: nil];
AVCaptureVideoDataOutput *output = [[AVCaptureVideoDataOutput alloc] init];
AVCaptureSession *session = [[AVCaptureSession alloc] init];
[session beginConfiguration];
[device lockForConfiguration:nil];
[device setTorchMode:AVCaptureTorchModeOn];
[device setFlashMode:AVCaptureFlashModeOn];
[session addInput:flashInput];
[session addOutput:output];
[device unlockForConfiguration];
[output release];
[session commitConfiguration];
[session startRunning];
[self setTorchSession:session];
[session release];
}
else
{
[button setTitle:#"ON" forState:UIControlStateNormal];
[torchSession stopRunning];
}
}
}
- (void)dealloc
{
[torchSession release];
[super dealloc];
}

This work's very well.. hope it help's someone !
-(IBAction)flashlight:(id)sender {
AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
if ([device hasTorch] && [device hasFlash]){
if (device.torchMode == AVCaptureTorchModeOff) {
[sender setTitle:#"Torch Off" forState:UIControlStateNormal];
AVCaptureDeviceInput *flashInput = [AVCaptureDeviceInput deviceInputWithDevice:device error: nil];
AVCaptureVideoDataOutput *output = [[AVCaptureVideoDataOutput alloc] init];
AVCaptureSession *cam = [[AVCaptureSession alloc] init];
[cam beginConfiguration];
[device lockForConfiguration:nil];
[device setTorchMode:AVCaptureTorchModeOn];
[device setFlashMode:AVCaptureFlashModeOn];
[cam addInput:flashInput];
[cam addOutput:output];
[device unlockForConfiguration];
[cam commitConfiguration];
[cam startRunning];
[self setTorchSession:cam];
}
else {
[sender setTitle:#"Torch On" forState:UIControlStateNormal];
[_torchSession stopRunning];
}
}
}

Related

How to check the auto focus is still going on in IOS?

I created camera app now what i want to do is need to check is the focus going on continuously or stopped.
This is what i tried :
NSError *error=nil;
//Capture Session
AVCaptureSession *session = [[AVCaptureSession alloc]init];
session.sessionPreset = AVCaptureSessionPresetPhoto;
//Add device
AVCaptureDevice *device =
[AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
// SETUP FOCUS MODE
if ([device lockForConfiguration:nil]) {
[device setFocusMode:AVCaptureFocusModeAutoFocus];
[device unlockForConfiguration];
}
else{
NSLog(#"error while configuring focusMode");
}
NSLog(#"%#" ,NSStringFromCGPoint(device.focusPointOfInterest));
if ([device isFocusModeSupported:AVCaptureFocusModeContinuousAutoFocus] && [device lockForConfiguration:&error]){
[device setFocusMode:AVCaptureFocusModeContinuousAutoFocus];
if ([device isFocusPointOfInterestSupported])
[device setFocusPointOfInterest:CGPointMake(0.5f,0.5f)];
[device unlockForConfiguration];
}
else{
NSLog(#"problem ");
}
//Input
AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:nil];
if (!input)
{
NSLog(#"No Input");
}
[session addInput:input];
//Preview Layer
AVCaptureVideoPreviewLayer *previewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];
UIView *myView = viewForCamera;
previewLayer.frame = myView.bounds;
previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
[viewForCamera.layer addSublayer:previewLayer];
//Start capture session
[session startRunning];
I searched is there any delegate method but i didn't get ,Please help me to solve this problem .
I got the solution.I tried with sample.I googled and went through lot of answers.
We must set the point of interest before calling setFocusMode
In your coding you have not called the point of interest
if ([device isFocusPointOfInterestSupported])
{
[device setFocusPointOfInterest:CGPointMake(0.5f,0.5f)];
[device setFocusMode:AVCaptureFocusModeAutoFocus];
//OR
[device setFocusMode:AVCaptureFocusModeContinuousAutoFocus];
[device unlockForConfiguration];
}
AutoFocus is not working
Then finding whether the Auto focus is going or not
Auto Focus Observer

Disable auto focus during video recording using AVCam

I am using video recording from AVCam. Auto focus works fine before video recording is started. But it keeps on focusing after the video has started recording which is an annoying behavior. I have disabled video stabilization in AVCaptureConnection but still no use
AVCaptureConnection *connection = [movieFileOutput connectionWithMediaType:AVMediaTypeVideo];
if ([connection isVideoStabilizationSupported]) {
if (SYSTEM_VERSION_LESS_THAN(#"8.0")) {
// For iOS 7
[connection setEnablesVideoStabilizationWhenAvailable:NO];
} else {
connection.preferredVideoStabilizationMode = AVCaptureVideoStabilizationModeOff;
}
}
Please guide me how can I disable auto focus during video recording?
I have called following method from viewDidLoad to achieve required functionality
- (void)disableAutoFocus {
AVCaptureDevice *device = [[self videoDeviceInput] device];
[device lockForConfiguration:nil];
NSArray *devices = [AVCaptureDevice devices];
NSError *error;
for (AVCaptureDevice *device in devices) {
if (([device hasMediaType:AVMediaTypeVideo]) &&
([device position] == AVCaptureDevicePositionBack) ) {
[device lockForConfiguration:&error];
if ([device isFocusModeSupported:AVCaptureFocusModeLocked]) {
device.focusMode = AVCaptureFocusModeLocked;
NSLog(#"Focus locked");
}
[device unlockForConfiguration];
}
}
}

Toggle on/off flash with AVCam

I'm using Apple's AVCam source code to create a custom camera, I'm trying to toggle flash on/off but its not working. Here is my code, not sure what's wrong. I'm new to AVCam.
- (void) toggleFlash:(id)sender {
dispatch_async([self sessionQueue], ^{
AVCaptureDevice *currentVideoDevice = [[self videoDeviceInput] device];
AVCaptureDevicePosition currentPosition = [currentVideoDevice position];
if(currentPosition == AVCaptureDevicePositionUnspecified || currentPosition == AVCaptureDevicePositionBack) {
if([currentVideoDevice hasFlash]) {
[currentVideoDevice lockForConfiguration:nil];
[currentVideoDevice setFlashMode:AVCaptureFlashModeOn];
[currentVideoDevice unlockForConfiguration];
}
}
});
}
Its go through each line in code, and not logs any errors from this but still no luck.
- (void) toggleFlash {
AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
if ([device hasTorch] && [device hasFlash]){
[device lockForConfiguration:nil];
[device setTorchMode:!device.torchActive];
[device setFlashMode:!device.torchActive];
[device unlockForConfiguration];
}
}
P.S. In my case, torch/flash is off initially.

iOS6 flashlight does not work

I'm trying to make hello-world-type app to learn how to turn on/off flashlight.
So there is only two buttons in this app: On and Off.
Here is action for "ON" button:
AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
[device lockForConfiguration:nil];
[device setTorchMode:AVCaptureTorchModeOn];
[device unlockForConfiguration];
It works fine on iOS7, but does not work on iOS6. What am I doing wrong?
UPD: [device setFlashMode:AVCaptureFlashModeOn] does not work either
It seems you are missing some steps :
- (void)toggleFlashlight
{
AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
if (device.torchMode == AVCaptureTorchModeOff)
{
// Create an AV session
AVCaptureSession *session = [[AVCaptureSession alloc] init];
// Create device input and add to current session
AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error: nil];
[session addInput:input];
// Create video output and add to current session
AVCaptureVideoDataOutput *output = [[AVCaptureVideoDataOutput alloc] init];
[session addOutput:output];
// Start session configuration
[session beginConfiguration];
[device lockForConfiguration:nil];
// Set torch to on
[device setTorchMode:AVCaptureTorchModeOn];
[device unlockForConfiguration];
[session commitConfiguration];
// Start the session
[session startRunning];
// Keep the session around
[self setAVSession:session];
[output release];
}
else
{
[AVSession stopRunning];
[AVSession release], AVSession = nil;
}
}
Hope it will help you ;)
PS : Not my code - http://iosdevelopertips.com/camera/flashlight-application-using-the-iphone-led.html
The problem was in broken flashlight on my phone: even camera app did not take photo with flashlight. I should check such hardware problems first.

IOS Toggle AVFoundation Camera

In my App I'm capturing images using AVFoundation
I made a button to switch between front and back cameras but it won't work.
Here's the code I used :
if (captureDevice.position == AVCaptureDevicePositionFront) {
for ( AVCaptureDevice *device in [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo] ) {
if ( device.position == AVCaptureDevicePositionBack) {
NSError * error;
AVCaptureDeviceInput * newDeviceInput = [[AVCaptureDeviceInput alloc]initWithDevice:device error:&error];
[captureSesion beginConfiguration];
for (AVCaptureDeviceInput *oldInput in [captureSesion inputs]) {
[captureSesion removeInput:oldInput];
}
if ([captureSesion canAddInput:newDeviceInput]) {
[captureSesion addInput:newDeviceInput];
}
[captureSesion commitConfiguration];
break;
}
}
}
THX.
If your captureSession's sessionPreset is not compatible with the camera you're switching to it will fail the canAddInput test. I always reset to AVCaptureSessionPresetHigh before toggling cameras then try to switch it to whatever preset I have preferred. Here's the code I use:
- (void)toggleCamera {
AVCaptureDevicePosition newPosition = self.currentCameraPossition == AVCaptureDevicePositionBack ? AVCaptureDevicePositionFront : AVCaptureDevicePositionBack;
AVCaptureDevice *device = [self videoDeviceWithPosition:newPosition];
AVCaptureDeviceInput *deviceInput = [[AVCaptureDeviceInput alloc] initWithDevice:device error:nil];
[_captureSession beginConfiguration];
[_captureSession removeInput:self.deviceInput];
[_captureSession setSessionPreset:AVCaptureSessionPresetHigh]; //Always reset preset before testing canAddInput because preset will cause it to return NO
if ([_captureSession canAddInput:deviceInput]) {
[_captureSession addInput:deviceInput];
self.deviceInput = deviceInput;
self.currentCameraPossition = newPosition;
} else {
[_captureSession addInput:self.deviceInput];
}
if ([device supportsAVCaptureSessionPreset:self.sessionPreset]) {
[_captureSession setSessionPreset:self.sessionPreset];
}
if ([device lockForConfiguration:nil]) {
[device setSubjectAreaChangeMonitoringEnabled:YES];
[device unlockForConfiguration];
}
[_captureSession commitConfiguration];
}
I have seen issues with toggle code not working if it is not run on the main thread. Can you try wrapping your code with the following block:
dispatch_async(dispatch_get_main_queue(), ^{
// Your camera toggle code goes here
});

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