需要截取wkwebview的内容成图片，保存或者分享出去；
建分类，写截图方法；本文的截图方法适用wkwebview截长图，但是如果网页有导航，可能会存在问题，即多个导航拼接的情况。这种可能考虑另一种方案了。
#import <WebKit/WebKit.h>
#import <UIKit/UIKit.h>
@interface WKWebView (CYScreenshotWebView)
- (NSArray *)prepareSnapShotOffsets;
- (void)captureWebSnapshotWithScale:(CGFloat)scale andCompletion:(void (^)(UIImage *capturedImage)) completion;
@end
#import "WKWebView+CYScreenshotWebView.h"
@implementation WKWebView (CYScreenshotWebView)
//根据当前网页的内容大小（即网页的scrollView的contentSize）来创建一个图形上下文，保存每次渲染的网页内容
- (void)captureWebSnapshotWithScale:(CGFloat)scale andCompletion:(void (^)(UIImage *capturedImage))completion{
//为达到无感知截图，添加遮照，截图完成后去掉
UIView *coverView = [self snapshotViewAfterScreenUpdates:YES];
coverView.frame = CGRectMake(self.frame.origin.x, self.frame.origin.y, coverView.frame.size.width, coverView.frame.size.height);
[self.superview addSubview:coverView];
//首先根据网页内容大小（contentSize）与显示大小（bounds.size）的关系，计算网页需要截取多少次图，以及每次截图的页面的偏移量contentOffset
NSArray *offsets = [self prepareSnapShotOffsets];
CGPoint bckUp = self.scrollView.contentOffset;//保存网页当前偏移量。便于截图
UIGraphicsBeginImageContextWithOptions(self.scrollView.contentSize, YES, scale);
//根据步骤2中所获取的偏移点的坐标，将当前显示的内容渲染到图形上下文中，然后继续滚动和渲染直到将所有网页内容渲染完成，结束上下文
__weak __typeof(self) weakSelf = self;
[self captureAtPage:0 point:offsets drawCallback:^{
UIImage *captureImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
if (completion) {
completion(captureImage);
}
__strong __typeof(weakSelf) strongSelf = weakSelf;
[strongSelf.scrollView setContentOffset:bckUp animated:false];//恢复截图前
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.01*NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
[coverView removeFromSuperview];//去掉遮罩
});
}];
}
- (NSArray *)prepareSnapShotOffsets{
NSMutableArray *offsets = [NSMutableArray arrayWithCapacity:0];
int pageX = ceilf(self.scrollView.contentSize.width / self.scrollView.bounds.size.width);
int pageY = ceilf(self.scrollView.contentSize.height / self.scrollView.bounds.size.height);
for (int i = 0; i< pageX *pageY; i++) {
int x = i / pageY;
int y = i % pageY;
CGFloat orginX = x * self.scrollView.bounds.size.width;
CGFloat orginY = y *self.scrollView.bounds.size.height;
NSValue *value = [NSValue valueWithCGPoint:CGPointMake(orginX, orginY)];
[offsets addObject:value];
}
return offsets;
}
-(void)captureAtPage:(int)page point:(NSArray *)offsets drawCallback:(void(^)(void))callback {
NSValue *valuePoint = offsets[page];
CGPoint point = [valuePoint CGPointValue];
[self.scrollView setContentOffset:point animated:NO];
__weak __typeof(self)weakSelf = self;
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.35 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
__strong __typeof(weakSelf)strongSelf = weakSelf;
CGRect rect = CGRectMake(point.x, point.y, strongSelf.scrollView.bounds.size.width, strongSelf.scrollView.bounds.size.height);
BOOL finish = [strongSelf.scrollView drawViewHierarchyInRect:rect afterScreenUpdates:YES];
if (finish) {
if (page < offsets.count - 1) {
[strongSelf captureAtPage:page + 1 point:offsets drawCallback:callback];
} else {
callback();
}
}
});
}
//保存图片到内存
- (void)saveShareImageInTmp{
NSData *data = UIImagePNGRepresentation(_currentImg);
//截图存入文件夹
_imgFilePath = [self tempFilePath:@"shareImg.png"];
[data writeToFile:_imgFilePath atomically:YES];
}
//保存图片到相册
- (void)saveImgToLibrary{
[[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
PHAssetChangeRequest *req = [PHAssetChangeRequest creationRequestForAssetFromImage:self.currentImg];
} completionHandler:^(BOOL success, NSError * _Nullable error) {
dispatch_async(dispatch_get_main_queue(), ^{
self.saveImgBtn.enabled = YES;
[self.view CY_showHudText:@"保存完成" duration:2.0];
});
}];
}
#pragma mark - 分享方法
//分享链接
- (void)shareClick:(UIButton *)sender{
_docVC = [[UIDocumentInteractionController alloc] init];
_docVC.URL = [NSURL URLWithString:_shareUrl];
[_docVC presentOptionsMenuFromRect:self.view.frame inView:self.view animated:YES];
}
//1、截网页整张图并分享
- (void)setupQRCodeImageWithCatoryWebViewAndShare{
__weak __typeof(self) weakSelf = self;
[self.cotentWebView captureWebSnapshotWithScale: [UIScreen
mainScreen].nativeScale andCompletion:^(UIImage * _Nonnull
capturedImage) {
weakSelf.currentImg = capturedImage;
//保存到临时文件下
[weakSelf saveShareImageInTmp];
weakSelf.docVC = [[UIDocumentInteractionController alloc] init];
weakSelf.docVC.URL = [NSURL fileURLWithPath:weakSelf.imgFilePath];
[weakSelf.docVC presentOptionsMenuFromRect:weakSelf.view.frame inView:weakSelf.view animated:YES];
weakSelf.inviteBtn.enabled = YES;
}];
}
//2.截网页整张图并保存相册
- (void)setupQRCodeImageWithCatoryWebViewAndSave{
__weak __typeof(self) weakSelf = self;
[self.cotentWebView captureWebSnapshotWithScale:[UIScreen mainScreen].nativeScale andCompletion:^(UIImage * _Nonnull capturedImage) {
weakSelf.currentImg = capturedImage;
[self saveImgToLibrary];
}];
}
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