kSBCanvas is a SBCanvas, which is a subclass of UIImageView. It has a few UIImageView subviews. It all renders great to the iPhone screen.
I need composite the kSBCanvas and its subviews to an imageview that I want to write to disk.
I do the following:
UIGraphicsBeginImageContext(kSBCanvas.bounds.size);
[kSBCanvas drawRect: [kSBCanvas bounds]];
UIImage *theImage=UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
then get a PNG representation and write it to disk.
The kSBCanvas renders, but not the subview images. I checked, and kBCanvas has subviews. Do I have to call drawRect on the subviews explicitly? Easy enough, but it does not seem right.
Try this instead:
UIGraphicsBeginImageContext(kSBCanvas.bounds.size);
{
[kSBCanvas.layer renderInContext: UIGraphicsGetCurrentContext()];
UIImage *theImage = UIGraphicsGetImageFromCurrentImageContext();
}
UIGraphicsEndImageContext();
Rendering the layer should also render all the subviews.
Related
I have uiview and i want to convert that view to image which is working quite well but when i pressed the home button of iphone and run the app again the image become zoom in .Here is my code to converting view to image.
- (UIImage *)captureView {
CGRect rect = [myview bounds];
UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
[myview.layer renderInContext:context];
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return img;
}
checkImage.image = [self captureView];
here this code is not wrong but you used some other object instead of whole view . i don't know but try to use that view bounds in which that whole Image display.. See my answer same like your this answer from this bellow link..
how to capture uiview top uiview
Also try with self.view instead of myView in your code.
add this code instead of your checkImage.image = [self captureView]; line..
UIImageView *imgTempHeader = [[UIImageView alloc]initWithImage:[self captureView]];
imgTempHeader.frame = self.view.frame;
[self.view addSubview:imgTempHeader];
[self.view bringSubviewToFront:imgTempHeader];
You should be creating the context in a way which uses the scale of the device:
UIGraphicsBeginImageContextWithOptions(rect.size, NO, 0);
Then when you display the image in the image view ensure that the content mode is set to prevent scaling.
My experience is with setting up imageViews in IB. I assume checkImage is an instance of UIImageView?
If you were displaying an image in a UIImageView and had only set the view mode to center in interface builder it would appear zoomed in if the image was large.
Have a look at this way to process your image first:
UIImage *newImage = [[UIImage alloc] initWithCGImage:myCGImageRef scale:myZoomSCale orientation:UIImageOrientationDown];
Of course you will need to give it a CGImageRef for your image. Over to you or somebody else for that.
I hope that title makes some sense.
I have UIView (created in IB) where I add stuff (images). Then, I have a UILabel with some text. Now, I want to make a UIImage out of that, which I do like this:
UIView *comp = [[UIView alloc] initWithFrame:self.previewView.frame];
[comp addSubview:self.previewView];
[comp addSubview:self.lblCaption];
UIGraphicsBeginImageContextWithOptions(comp.bounds.size, NO, 1.0);
[comp.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
self.previewView and self.lblCaption are both created in IB. previewView is just a screen-filling view.
The code-block is executed in an IBAction after a button-tap.
Which works wonderful, I get the image as expected and can process it further.
But after that, the contents of «self.previewView» are gone? When I do an NSLog, everything seems to be there, but it's not visible on screen anymore.
Does anyone have an idea what's going on here?
[Edit]
As the answer below states, the view was added to self.view before, so it was removed when I added it to the comp. The solution is pretty easy, actually, I changed the code to the following: (created a function that returns a UIImage. That's a bit cleaner than doing it in code....
-(UIImage *)imageFromView:(UIView *)theView andLabel:(UILabel *)theLabel{
UIGraphicsBeginImageContextWithOptions(comp.bounds.size, NO, 1.0);
[theView.layer renderInContext:UIGraphicsGetCurrentContext()];
[theLabel.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return viewImage;
}
I am just guessing assuming possible situations...
Assuming you were showing self.previewView on some other view, say self.view.
When you added self.previewView to comp, it may have been removed from self.view. (Considering that UIView.superview is only single instance, I am thinking this is very likely).
If this is the case, re-adding self.previewView to self.view after obtaining image would solve the problem.
I would like to truncate one end of a UIImageView by changing the size of the frame dynamically. Of course, if it autoresizes it won't look 'truncated', but will look shrunk. The former is the effect I would like, the latter not.
So far I've set up the UIImageView in IB and then hooked it up programmatically using IBOutlet. I then placed this in ViewDidLoad, but still get the autoresizing:
[self.stringImageView setAutoresizingMask:UIViewAutoresizingNone];
self.stringImageView.frame = CGRectMake(9.0f, 508.0f, 500.0f, 26.0f);
Any ideas how I can clip my UIImageView instead of having it resize?
EDIT 1
It should also be noted that in IB I have deselected Clip Subviews and Autoresize Subviews.
Use : stringImageView.contentMode = UIViewContentModeCenter; so the image you add to the UIImageView always keeps the same size and the same position in your view.
You need to clip the UIImage object first according to imageview's frame and then set it as image for image view. See also Cropping an UIImage
#implementation UIImage (Resize)
// Returns a copy of this image that is cropped to the given bounds.
// The bounds will be adjusted using CGRectIntegral.
// This method ignores the image's imageOrientation setting.
- (UIImage *)croppedImage:(CGRect)bounds {
CGImageRef imageRef = CGImageCreateWithImageInRect([self CGImage], bounds);
UIImage *croppedImage = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
return croppedImage;
}
In Interface Builder set Mode in the View Tab to "Top" or whatever it should be.
Another more efficient way to go if you only wish to make part of the image visible,
or for example animate its appearance,
is to set the content mode of the UIImageView to UIViewContentModeCenter (or any other alignment) and include it in a UIScrollView.
You will only need to change the frame of the scroll view and your image will be visually cropped without you having to create the cropped image (which would be a very high price if it is for animation purpose).
I have UIView that contain a pin image and a label, as we know UIView is rectangle so if I convert UIView to UIImage,UIImage is also rectangle, I want make UIImage like the a pin image because if user click a background, UIImage's event will be called too.. I want to convert UIView to UIImage without it's background, how can it be?
I use this method to change UIView to UIImage
-(UIImage *) ChangeViewToImage : (UIView *) view{
UIGraphicsBeginImageContext(view.bounds.size);
[view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return img;
}
Hmm.. example like this, I have a rectangle as a UIView and a triangle as a shape in UIView. and then I want to make this UIView become a UIImage, but I just want the triangle without background, so the image just a triangle.. how can I do It?
A UIImage is always rectangular. What you can play with is the opacity in your views. If you make everything except your pin image transparent, it will seem as if you just have an image of the pin.
Use:
view.backgroundColor = [UIColor clearColor];
to make your view's background transparent.
In iPhone application I want to generate a image of UIScrollView whose content size is near about 600*41000. If I use current graphic image context to capture the scroll view layer, then it only captures the visible part of the scroll view not the whole layer of that scroll view.
I am using the below code:
{
UIGraphicsBeginImageContext(CGSizeMake(600, 4100));
[scrollView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIImageView *img = [[UIImageView alloc]initWithFrame:CGRectMake(00, 100, 710, 4100)];
img.image = viewImage;
[anotherScrollView addSubview:img];
}
Try to generate image not from UIScrollView but from its content view. When you add some views to UIScrollView with something like addSubview: they become scroll's content ones. Of course, UIScrollView can have more than one content view (just as any UIView can have more than one subview) and this case it will be more difficult to render its layer. But in case of only one subview (content view) you can use something like (contentView here is just some view, added to UIScrollView before):
[contentView.layer renderInContext:UIGraphicsGetCurrentContext()];
or:
[[[[scrollView subviews] lastObject] layer] renderInContext:UIGraphicsGetCurrentContext()];
When you want to use more than one view, it will be easier (I think) to add one more "root" view and add others as that view's subviews: so you can also use the code above.