iOS 截图、截长图、图片拼接

图片拼接

/* Image 拼接
 * masterImage  主图片
 * headImage   头图片
 * footImage   尾图片
 */
+ (UIImage *)addHeadImage:(UIImage *)headImage footImage:(UIImage *)footImage toMasterImage:(UIImage *)masterImage {
    
    CGSize size;
    size.width = masterImage.size.width;
    
    CGFloat headHeight = !headImage? 0:size.width/headImage.size.width*headImage.size.height;
    CGFloat footHeight = !footImage? 0:size.width/footImage.size.width*footImage.size.height;
    
//    CGFloat headHeight = !headImage? 0:headImage.size.height/2.0;
//    CGFloat footHeight = !footImage? 0:footImage.size.height/2.0;
    
    size.height = masterImage.size.height + headHeight + footHeight;
    
    UIGraphicsBeginImageContextWithOptions(size, YES, 0.0);
    
    if (headImage)
        [headImage drawInRect:CGRectMake(0, 0, masterImage.size.width, headHeight)];
    
    
    [masterImage drawInRect:CGRectMake(0, headHeight, masterImage.size.width, masterImage.size.height)];
    
    if (footImage)
        [footImage drawInRect:CGRectMake(0, masterImage.size.height + headHeight, masterImage.size.width, footHeight)];
    
    UIImage *resultImage = UIGraphicsGetImageFromCurrentImageContext();
    
    UIGraphicsEndImageContext();
    return resultImage;
}

截图

/**
 获取一个view的截图,注意,只能截取能看的见的部分
 
 @param view view
 @param size 截图大小
 @return image
 */
+ (UIImage *)makeImageWithView:(UIView *)view withSize:(CGSize)size
{
    // 下面方法，第一个参数表示区域大小。第二个参数表示是否是非透明的。如果需要显示半透明效果，需要传NO，否则传YES。第三个参数就是屏幕密度了，关键就是第三个参数 [UIScreen mainScreen].scale。
    UIGraphicsBeginImageContextWithOptions(size, NO, 0.0);
    [view.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}

UIScroolView、UITableView截取长图

截取长图部分我采用的逻辑是，首先获取contentSize，将ScroolView或TableView的高度设置为contentSize大小，设置[[self.tableView layer] renderInContext:UIGraphicsGetCurrentContext()];然后截取图片，注意：在重设ScroolView或TableView的高度后，延迟执行了截图方法，因为立马截图超出视图部分的截图无法截出

/**
 点击分享label
 */
- (void)clickShareLabel
{
    //重新设置控件的大小,以能显示所有内容
    [self.tableView mas_remakeConstraints:^(MASConstraintMaker *make) {
        make.left.right.offset(0);
        make.top.equalTo(self.customNavBar.mas_bottom);
        make.height.offset(self.tableView.contentSize.height);
    }];
    //延迟截屏
    [self performSelector:@selector(beginCapture) withObject:nil afterDelay:0.1];
}

#pragma mark 生成image
- (UIImage *)captureImage
{
    //设置截屏大小
    UIGraphicsBeginImageContextWithOptions(self.tableView.contentSize, NO, 0.0);
    [[self.tableView layer] renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}

/**
 开始截图
 */
- (void)beginCapture
{
    //tableview的截图
    UIImage *image = [self captureImage];
    CoinDetailShareViewController *vc = [[CoinDetailShareViewController alloc] init];
    vc.image = image;
    vc.coinName = self.coinName;
    [self presentViewController:vc animated:YES completion:^{
        //将控件大小设置回去
        [self.tableView mas_remakeConstraints:^(MASConstraintMaker *make) {
            make.left.right.offset(0);
            make.bottom.equalTo(self.collectLabel.mas_top);
            make.top.equalTo(self.customNavBar.mas_bottom);
        }];
    }];
}