How to convert uitextview content to a image in custom size? - objective-c

Question

I create a uitextview and I can add text and images to it with NSAttributedString and NSTextAttachment
self.tvContent = [[UITextView alloc] initWithFrame:CGRectMake(0, 20,
self.view.frame.size.width, self.view.frame.size.height - 64)];
self.tvContent.font = [UIFont fontWithName:#"Arial" size:16.0f];
self.tvContent.backgroundColor = [UIColor whiteColor];
self.tvContent.textContainerInset = UIEdgeInsetsMake(10, 10, 10, 10);
self.tvContent.contentInset = UIEdgeInsetsMake(0, 0, 10, 0);
self.tvContent.layoutManager.allowsNonContiguousLayout=NO;
[self.view addSubview:self.tvContent];
And I convert its content to image with following code
- (UIImage *)imageFromView:(UITextView *)view {
CGRect tmpFrame = self.view.frame;
CGRect aFrame = view.frame;
aFrame.size.height = [view sizeThatFits:[[UIScreen mainScreen] bounds].size].height;
view.frame = aFrame;
UIGraphicsBeginImageContext([view sizeThatFits:[[UIScreen mainScreen] bounds].size]);
CGContextRef resizedContext = UIGraphicsGetCurrentContext();
[view.layer renderInContext:resizedContext];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
view.frame = tmpFrame;
return image;
}
This image's max-width is 375(iPhone 6), if I wrote less content, such as 1234, the image's width is 40, so how can I convert the content to image with custom size, such as the width is 750, and the height is as long as the content height? Any ideas? many thanks.

Answer 1

The UITextView only renders within it's current frame, so you need to either resize the frame to the desired size before rendering, or create a temporary UITextView object to use for rendering purpose.
Here is how rendering with a temporary object can be done:
// Your call to get the image
UIImage *image = [self imageFromTextView:self.tvContent width:750.0]; // Any width you want
// Your text view properties that also can be used for rendering purpose
- (void)setupTextViewProperties:(UITextView *)textView {
textView.font = [UIFont fontWithName:#"Arial" size:16.0f];
textView.backgroundColor = [UIColor whiteColor];
textView.textContainerInset = UIEdgeInsetsMake(10, 10, 10, 10);
textView.contentInset = UIEdgeInsetsMake(0, 0, 10, 0);
textView.layoutManager.allowsNonContiguousLayout=NO;
}
Set up of the temporary UITextView object used for rendering.
- (UIImage *)imageFromTextView:(UITextView *)view width:(CGFloat)desiredWidth {
// Create a new temporary UITextView to use for rendering
CGRect frame = CGRectMake(0.0, 0.0, desiredWidth, 0.0);
UITextView *temporaryTextView = [[UITextView alloc] initWithFrame:frame];
// Setup the temporary text view
// You can have different font, colors etc from the original view
[self setupTextViewProperties:temporaryTextView];
temporaryTextView.attributedText = view.attributedText;
// Calculate the height needed for content with width
CGSize size = CGSizeMake(desiredWidth, 0.0);
size = [temporaryTextView sizeThatFits:size];
// Resize the temporary view
// Note that the calculated size can contain a width smaller that desired with
temporaryTextView.frame = CGRectMake(0.0, 0.0, desiredWidth, size.height);
// Get the image
return [self imageFromView:temporaryTextView];
}
Helper that can render any view as an image.
- (UIImage *)imageFromView:(UIView *)view {
CGSize size = view.bounds.size;
UIGraphicsBeginImageContextWithOptions(size, YES, 0.0);
CGContextRef context = UIGraphicsGetCurrentContext();
[view.layer renderInContext:context];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}