我正以这种方式截取我的iPad 3屏幕截图:
UIGraphicsBeginImageContext(self.view.frame.size);
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
int num = arc4random() % 100000000000000;
NSString* path = [documentsDirectory stringByAppendingPathComponent: [NSString stringWithFormat:@"%dtest.png", num]];
NSData* data = UIImagePNGRepresentation(viewImage);
[data writeToFile:path atomically:YES];
问题在于我的质量严重下降。我可以看到像素,但它是一个iPad 3,那怎么可能呢?
答案 0 :(得分:1)
来自doc:
UIGraphicsBeginImageContextWithOptions
Creates a bitmap-based graphics context with the specified options.
void UIGraphicsBeginImageContextWithOptions(
CGSize size,
BOOL opaque,
CGFloat scale
);
然后:
UIGraphicsBeginImageContextWithOptions(self.view.frame.size,NO,2.0);
答案 1 :(得分:1)
- (UIImage*)screenshot
{
// Create a graphics context with the target size
// On iOS 4 and later, use UIGraphicsBeginImageContextWithOptions to take the scale into consideration
// On iOS prior to 4, fall back to use UIGraphicsBeginImageContext
CGSize imageSize = [[UIScreen mainScreen] bounds].size;
if (NULL != UIGraphicsBeginImageContextWithOptions)
UIGraphicsBeginImageContextWithOptions(imageSize, NO, 0);
else
UIGraphicsBeginImageContext(imageSize);
CGContextRef context = UIGraphicsGetCurrentContext();
// Iterate over every window from back to front
for (UIWindow *window in [[UIApplication sharedApplication] windows])
{
if (![window respondsToSelector:@selector(screen)] || [window screen] == [UIScreen mainScreen])
{
// -renderInContext: renders in the coordinate space of the layer,
// so we must first apply the layer's geometry to the graphics context
CGContextSaveGState(context);
// Center the context around the window's anchor point
CGContextTranslateCTM(context, [window center].x, [window center].y);
// Apply the window's transform about the anchor point
CGContextConcatCTM(context, [window transform]);
// Offset by the portion of the bounds left of and above the anchor point
CGContextTranslateCTM(context,
-[window bounds].size.width * [[window layer] anchorPoint].x,
-[window bounds].size.height * [[window layer] anchorPoint].y);
// Render the layer hierarchy to the current context
[[window layer] renderInContext:context];
// Restore the context
CGContextRestoreGState(context);
}
}
// Retrieve the screenshot image
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}
更多信息请参阅此技术报告:Technical Q&A QA1703 Screen Capture in UIKit Applications
答案 2 :(得分:0)
你的尺码错了,请使用:
CGRect screenBounds = [[UIScreen mainScreen] bounds];
CGFloat screenScale = [[UIScreen mainScreen] scale];
CGSize screenSize = CGSizeMake(screenBounds.size.width * screenScale, screenBounds.size.height * screenScale);
UIGraphicsBeginImageContext(screenSize);
//screenshot code..