I'm able to capture NSWindows which are visible using code simular to the SonOfGrab Example
But how can I capture a hidden NSWindow? Or what is the way to hide a NSWindow from the user but to still appear in de Windowserver?
Thanks in advance!
It isn't possible to capture the contents of an NSWindow which isn't visible on-screen. When a window is minimized/hidden/whatever, the visual representation is dropped to save memory.
(Not sure on exactly how this is managed, feel free to chime in if you have a deeper knowledge of the window system. I only know this from experience, trying to capture windows with CamTwist and BoinxTV.)
You can do it by:
NSImage *img = [[NSImage alloc] initWithCGImage:[window windowImageShot] size:window.frame.size];
category to NSWindow:
- (CGImageRef)windowImageShot
{
CGWindowID windowID = (CGWindowID)[self windowNumber];
CGWindowImageOption imageOptions = kCGWindowImageBoundsIgnoreFraming | kCGWindowImageNominalResolution;
CGWindowListOption singleWindowListOptions = kCGWindowListOptionIncludingWindow;
CGRect imageBounds = CGRectNull;
CGImageRef windowImage = CGWindowListCreateImage(imageBounds, singleWindowListOptions, windowID, imageOptions);
return windowImage;
}
Related
Does anyone has any idea how can I capture screen using objective c in mac os?
to be more specific, how can I capture the active / focused application screen then create an image into a specified path.
Any help is highly appreciated.
#Daniel,
You don't need to understand and implement the whole "Son of Grab". You just need the code below.
The following function will give you the screenshot
// This just invokes the API as you would if you wanted to grab a screen shot. The equivalent using the UI would be to
// enable all windows, turn off "Fit Image Tightly", and then select all windows in the list.
CGImageRef screenShot = CGWindowListCreateImage(CGRectInfinite, kCGWindowListOptionOnScreenOnly, kCGNullWindowID, kCGWindowImageDefault);
Use the following code to convert it to a NSImage
NSBitmapImageRep *bitmapRep = [[NSBitmapImageRep alloc] initWithCGImage:screenShot];
// Create an NSImage and add the bitmap rep to it...
NSImage *image = [[NSImage alloc] init];
[image addRepresentation:bitmapRep];
[bitmapRep release];
bitmapRep = nil;
Have you checked out Apple's “Son of Grab” for capturing images of windows with the CGWindow api?
You can also check Apple's OpenGLScreenSnapshot
I am developing an app which allows you to select photos and place them into different positions. The workflow is basically:
Tap an area of the screen
UIImagePickerController displays
Select a photo
Photo displays in the tapped area of the screen
I would like it so that if the user goes through this workflow for a second time, the UIImagePickerController when displayed will be showing the same album, and position within that album, that the user was last at.
I've tried saving a reference to the UIImagePickerController, as well as the UIPopoverController, so that they are created only once. However, every time I present the popover containing the UIImagePickerController, it is back at the main photos menu (eg. Camera Roll, Photo Library, My Photo Stream).
Any ideas for how to achieve what I'm after?
You can use ALAssetsLibrary . But this will cost you more effort. First time use – enumerateGroupsWithTypes:usingBlock:failureBlock: to list all album and remember user's choice. And at second time. Just use that album:ALAssetsGroup's – enumerateAssetsUsingBlock: to list all the images and videos. Apple has a few demo you can have a look PhotosByLocation MyImagePicker
keep a UIImagePickerController obj in .h class (for example imagePicker)
alloc the obj once (for example in viewDidLoad)
imagePicker = [[UIImagePickerController alloc] init];
imagePicker.delegate = self;
imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
[self.view addSubview:imagePicker.view];
imagePicker.view.hidden = YES;
imagePicker.view.frame = CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height);
imagePicker.view.bounds = CGRectMake(0,20,self.view.frame.size.width, self.view.frame.size.height);
In didFinishPickingMediaWithInfo
if([[info valueForKey:UIImagePickerControllerMediaType] isEqualToString:#"public.image"]){
imagePicker.view.hidden = YES;
}
When you want to show the imagePickerView just do
imagePicker.view.hidden = NO;
Just to point you to right direction. You can use asset library to show the images as a picker. You can use the apple sample code MyImagePicker. The method [[assetsLibrary] enumerateGroupsWithTypes:ALAssetsGroupAlbum usingBlock:^(ALAssetsGroup *group, BOOL *stop) can be used for photo album. Using the asset library you can check which image was selected last and then use the method,
- (void)enumerateAssetsAtIndexes:(NSIndexSet *)indexSet options:(NSEnumerationOptions)options usingBlock:(ALAssetsGroupEnumerationResultsBlock)enumerationBlock;
You can use this method next time to enumerate which image onwards you want to enumerate. This method can accept an indexSet as [NSIndexSet indexSetWithIndexesInRange:NSMakeRange(index, count)] which should help to indicate the last selected image.
To know more about how to use asset library check this.
It should be possible to reach into the resulting UITableView and then find its content offset. You can do this by searching the subviews of the UIImagePickerController's view property for a table view.
for (UIView *view in controller.view) {
if ([view isKindOfClass:[UITableView class]]) {
contentOffset = [(UITableView *)view contentOffset];
}
}
When you represent the view controller, you will want to restore the content offset in a similar fashion.
Note, I haven't actually tested to see the view hierarchy of the UIImagePickerController. Verify its structure by printing its subviews. There is also no guarantee that the structure will stay the same, since you are diving into the private implementation (though it's important to note you are not actually using any private APIs so this is okay).
Use AlAssetsLibrary. It control the image & video capture under the application. there a demo on apple.
https://developer.apple.com/library/ios/#documentation/AssetsLibrary/Reference/ALAssetsLibrary_Class/Reference/Reference.html
look for this or
if you want to make a cutomize album for the image and video here a great example.
https://github.com/Kjuly/ALAssetsLibrary-CustomPhotoAlbum
I am trying to add an overlay image to a photo that is taken. Has anyone seen any examples on how I can do this? I want to have a picture which is a transparent PNG file, and then allow the user to take a picture with the image in it.
Iulius is correct that this is essentially a duplicate question. However, just to rule out one issue-- would you like the user to be able to see the overlay while composing the shot? (i.e. if your app makes different hats appear on people's heads, do you want to show the hat floating in space while they take the photo?). If you want to learn more about that, you'll need to use the cameraOverlayView property of the imagePickerController, which lets you superimpose your own view(s) on the camera. There are questions on this topic already on SO, like this one: How to add a overlay view to the cameraview and save it
Update re: scaling-- LilMoke, I assume when you say that the image is offset you're getting into trouble with the difference with the camera's aspect ratio (4:3) and the screen of the iPhone (3:4). You can define a constant and use it to set the cameraViewTransform property of your UIImagePickerController. Here's a code snippet, partially borrowed, and simplified from the excellent augmented reality tutorial at raywenderlich.com:
#define CAMERA_TRANSFORM 1.24299
// First create an overlay view for your superimposed image
overlay = [[UIView alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
overlay.backgroundColor=[UIColor clearColor];
overlay.opaque = NO;
UIImagePickerController *imagePicker;
imagePicker = [[[UIImagePickerController alloc] init] autorelease];
imagePicker.sourceType = UIImagePickerControllerSourceTypeCamera;
imagePicker.showsCameraControls = YES; // assuming you need these?
imagePicker.toolbarHidden = YES;
imagePicker.navigationBarHidden = YES;
imagePicker.wantsFullScreenLayout = YES;
imagePicker.cameraViewTransform = CGAffineTransformScale(imagePicker.cameraViewTransform,
CAMERA_TRANSFORM, CAMERA_TRANSFORM); // If I understood your problem, this should help
imagePicker.cameraOverlayView = overlay;
If code along these lines doesn't get you on track, then maybe you can post all the relevant code from your troubled project here. Hopefully it's just a matter of setting the cameraViewTransform as I said above.
Okay guys, maybe you can help me out with this one. I'm about ready to pull my hair out.
Recently I decided to upgrade my app and make it look better, and with that I wanted to move it into full support for iPad platforms as well. For a while everything worked great. Just press copy MainWindow.xib for iPad, add the views that I used on the iPhone configurations, and everything should be great, but that didn't work too well. Take a look:
Here is the iPhone screenshot:
Here is the iPad screenshot:
Where's the tab bar? I don't understand! I added the initial view when I was first putting it together, but when I linked all of the IBOutlets to the proper pieces, the tab bar no longer shows up.
Screenshot of IB:
Tab Bar properties:
Tint: A bluish color
Image Tint: A goldish color
Mode: Scale to fill
Tag: 0
User Interaction Enabled: (Checked)
Multiple Touch: (Unchecked)
Alpha: 1
Opaque: (Checked)
Hidden (Unchecked)
Clears Graphic Context: (Checked)
Clip Subviews: (Unchecked)
Autoresize Subviews: (Checked)
Stretching: (x,y,w,h):(0,0,1,1)
The viewController.h file is a delegate for UITabBar, UITextField, and UITextView
ViewDidLoad (bar is the IBOutlet for the tab bar):
- (void)viewDidLoad
{
[super viewDidLoad];
[self playMovieIntro];
NSURL *url = [NSURL URLWithString:#"http://www.faithlifefellowship.us/Audio/Sermons/NewSermonBanner.png"];
NSData *data = [NSData dataWithContentsOfURL:url];
UIImage *image = [UIImage imageWithData:data];
if(!image == NULL)
{
NewSermonBanner.image = image;
}
series = [[Series alloc] init];
SeriesName = #"";
NSRange range = [[[UIDevice currentDevice] name] rangeOfString:#"iPad"];
int i = 0;
if(range.location != NSNotFound)
i = 1;
bar.selectedItem = hometab;
//set delegates
[bar setDelegate:self];
[personalName setDelegate:self];
[personalEmail setDelegate:self];
[content setDelegate:self];
[prContent setDelegate:self];
[prName setDelegate:self];
[prEmail setDelegate:self];
}
I'm stumped. If you have any ideas or need any more information, let me know.
Thanks!
I'm going to give you a few things I'm getting in order to fix this. It will be tons easier if you could upload the source code for me/us to download and be able to pinpoint the problem.
Sometimes (I can't remember exactly when) I've had my navigation bar not show up because it was missing a connection.
Make sure you are not hiding the tab bar anywhere in code, though it doesn't seem to be the case since it shows up on iPhone.
Otherwise I'm gonna take a guess and say it's something in the NIB. Here are some things you can try:
Check all your connections to outlets
Make sure your objects in the NIB are of the correct class
Verify that the tab bar's "hidden" property is not check in Interface Builder
Compare and verify all the structure of the NIB file between iPhone and iPad
These are just some ideas :) again if you can post the code it would be fantastic.
Let us know how it goes,
Felipe
I had this problem with a app that support both iPhone and iPad. Make sure 'is initial view controller' is checked for the UITabBarController when you examine the view controller using the object inspector. When you do this, xcode will display a 'inbound' arrow on the left side of the view controller if you're using storyboards.
I'm trying to use the select and copy feature of the IKImageView. If all you want to do is have an app with an image, select a portion and copy it to the clipboard, it's easy. You set the copy menu pick to the first responder's copy:(id) method and magically everything works.
However, if you want something more complicated, like you want to copy as part of some other operation, I can't seem to find the method to do this.
IKImageView doesn't seem to have a copy method, it doesn't seem to have a method that will even tell you the selected rectangle!
I have gone through Hillegass' book, so I understand how the clipboard works, just not how to get the portion of the image out of the view...
Now, I'm starting to think that I made a mistake in basing my project on IKImageView, but it's what Preview is built on (or so I've read), so I figured it had to be stable... and anyway, now it's too late, I'm too deep in this to start over...
So, other than not using IKImageView, any suggestions on how to copy the select region to the clipboard manually?
EDIT actually, I have found the copy(id) method, but when I call it, I get
<Error>: CGBitmapContextCreate: unsupported parameter combination: 8 integer bits/component; 16 bits/pixel; 1-component color space; kCGImageAlphaPremultipliedLast; 2624 bytes/row.
Which obviously doesn't happen when I do a normal copy through the first-responder... I understand the error message, but I'm not sure where it's getting those parameters from...
Is there any way to trace through this and see how this is happening? A debugger won't help for obvious reasons, as well as the fact that I'm doing this in Mozilla, so a debugger isn't an option anyway...
EDIT 2 It occurs to me that the copy:(id) method I found may be copying the VIEW rather than copying a chunk of the image to the clipboard, which is what I need.
The reason I thought it was the clipboard copy is that in another project, where I'm copying from an IKImageView to the clipboard straight from the edit menu, it just sends a copy:(id) to the firstResponder, but I'm not actually sure what the firstresponder does with it...
EDIT 3 It appears that the CGBitmapContextCreate error is coming from [imageView image] which, oddly enough, IS a documented method.
It's possible that this is happening because I'm putting the image in there with a setImage:(id) method, passing it an NSImage*... Is there some other, more clever way of getting an NSImage into an IKImageView?
The -copy: method in IKImageView does what every other -copy: method does: it copies the current selection to the clipboard. It is, however, implemented as a private method in IKImageView for some reason.
You can just call it directly:
[imageView copy:nil];
This will copy whatever is currently selected to the clipboard.
I don't think there's a way to directly access the image content of the current selection in IKImageView using public methods, this is a good candidate for a bug report/feature request.
You can, however, use the private method -selectionRect to get a CGRect of the current selection and use that to extract the selected portion of the image:
//stop the compiler from complaining when we call a private method
#interface IKImageView (CompilerSTFU)
- (CGRect)selectionRect
#end
#implementation YourController
//imageView is an IBOutlet connected to your IKImageView
- (NSImage*)selectedImage
{
//get the current selection
CGRect selection = [imageView selectionRect];
//get the portion of the image that the selection defines
CGImageRef selectedImage = CGImageCreateWithImageInRect([imageView image],(CGRect)selection);
//convert it to an NSBitmapImageRep
NSBitmapImageRep* bitmap = [[[NSBitmapImageRep alloc] initWithCGImage:selectedImage] autorelease];
CGImageRelease(selectedImage);
//create an image from the bitmap data
NSImage* image = [[[NSImage alloc] initWithData:[bitmap TIFFRepresentation]] autorelease];
//in 10.6 you can skip converting to an NSBitmapImageRep by doing this:
//NSImage* image = [[NSImage alloc] initWithCGImage:selectedImage size:NSZeroSize];
return image;
}
#end
Ok, so the copy: nil fails, and the [imageView image] fails, but it turns out that I have another copy of the NSImage from when I added it into the view in the first place, so I could that. Also, CGImageCreateWithImageInRect expects a CGImageRef not an NSImage*, so I had to do some conversions.
In addition, for some reason the selection rectangle is flipped, either it's bottom origined, and the image is top, or the other way around, so I had to flip it.
And for some reason, the compiler suddenly started complaining that NSRect isn't the same type as CGRect (Which implies that it suddenly went from 32 to 64 bit or something... not sure why...)
Anyway, here is my copy of selectedImage:
- (NSImage*)selectedImage
{
//get the current selection
CGRect selection = flipCGRect(imageView, [imageView selectionRect]);
//get the portion of the image that the selection defines
struct CGImage * full = [[doc currentImage] CGImageForProposedRect: NULL context: NULL hints: NULL];
CGImageRef selectedImage = CGImageCreateWithImageInRect( full, selection);
//convert it to an NSBitmapImageRep
NSBitmapImageRep* bitmap = [[[NSBitmapImageRep alloc] initWithCGImage:selectedImage] autorelease];
CGImageRelease(selectedImage);
// //create an image from the bitmap data
NSImage* image = [[[NSImage alloc] initWithData:[bitmap TIFFRepresentation]] autorelease];
// //in 10.6 you can skip converting to an NSBitmapImageRep by doing this:
//NSImage* image = [[NSImage alloc] initWithCGImage:selectedImage size:NSZeroSize];
return image;
}
I wrote flipCGRect, and [doc currentImage] returns an NSImage*...