Question

I would like to take the image that is on my iPad’s screen and export it as a JPG, PNG or PDF file.

In simpler terms, the user created something on the screen, he clicks ‘export to PNG’ for example, and then a PNG file is created.

How do I go about doing that?

Answer 1

I wrote this category for UIView, taken with some help from unremembered sources:

@interface UIView (Rendering)

+ (UIImage *)renderImageFromLayer:(CALayer *)layer withRect:(CGRect)frame;
- (UIImage *)renderImageWithRect:(CGRect)frame;

@end

@implementation UIView (Rendering)

+ (UIImage *)renderImageFromLayer:(CALayer *)layer withRect:(CGRect)frame
{
    // Create a new context of the desired size to render the image
    UIGraphicsBeginImageContextWithOptions(frame.size, YES, 1.0);
    CGContextRef context = UIGraphicsGetCurrentContext();

    // Translate it, to the desired position
    CGContextTranslateCTM(context, -frame.origin.x, -frame.origin.y);

    // Render the view as image
    [layer renderInContext:context];

    // Fetch the image
    UIImage *renderedImage = UIGraphicsGetImageFromCurrentImageContext();

    // Cleanup
    UIGraphicsEndImageContext();

    return renderedImage;
}

- (UIImage *)renderImageWithRect:(CGRect)frame
{
    return [UIView renderImageFromLayer:self.layer withRect:frame];
}

@end