[2 次拉伸图片]

stretch.m

/// 通过 2 次拉伸图片达到效果，聊天气泡，尖尖在气泡中间
- (UIImage *)returnImageStretchLeftAndRightWith:(CGSize)size {
    
    UIImage *originalImage = UIImageMake(@"course_module_tab_bg");
    CGSize imageSize = originalImage.size;
    CGSize bgSize = size;
    
    UIEdgeInsets leftInsets = UIEdgeInsetsMake(0, imageSize.height/2, 0, imageSize.width/2 + 5);
    UIImage *tempImage = [originalImage resizableImageWithCapInsets:leftInsets resizingMode:UIImageResizingModeStretch];
    
    CGFloat tempWidth = (bgSize.width)/2 + imageSize.width/2;
    UIGraphicsBeginImageContextWithOptions(CGSizeMake(tempWidth, imageSize.height), NO, [UIScreen mainScreen].scale);
    [tempImage drawInRect:CGRectMake(0, 0, tempWidth, bgSize.height)];
    UIImage *firstStrechImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    
    UIEdgeInsets rightInsets = UIEdgeInsetsMake(0, (bgSize.width)/2 + 5, 0, imageSize.height/2);
    UIImage *rightStretchedImage = [firstStrechImage resizableImageWithCapInsets:rightInsets resizingMode:UIImageResizingModeStretch];
    return rightStretchedImage;
}