ios - 获取屏幕图像并导出为 PDF、JPG、PNG

Question

我想拍摄 iPad 屏幕上的图像并将其导出为 JPG、PNG 或 PDF 文件。

简单来说，用户在屏幕上创建了一些东西，例如他点击“导出到 PNG”，然后创建了一个 PNG 文件。

我该怎么做？

Answer 1

我为 UIView 编写了这个类别，是在一些不记得的来源的帮助下获得的:

@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