如何突出显示图像中的文字？

Question

如何在图像中突出显示“手机”文字？

更新

我想在网页上搜索文字，如果找到，则应按照我在附加图片中显示的方式突出显示文字。

Answer 1

<强>输出

此Regular Expressions tutorial详细介绍了如何使用UITextview上的正则表达式搜索所需文字以及如何突出显示该文字。

要使用的基本代码：

- (void)viewDidLoad
{
  [super viewDidLoad];
  [self searchData];
}

1）以下代码从数据中搜索所需的模式，即TextView：

 - (void) searchData
{


    NSError *error = NULL;
    NSString *pattern = @"Hello";  // pattern to search thee data either regular expression or word.
    NSString *string = self.textView.text;
    NSRange range = NSMakeRange(0, string.length);
    NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:pattern options:NSRegularExpressionCaseInsensitive error:&error];
    NSArray *matches = [regex matchesInString:string options:NSMatchingProgress ran     ge:range];
   [self highlightMatches:matches];
}

2）这里我们通过使用CALayer和标签突出显示从正则表达式匹配结果中获得的匹配：

 - (void)highlightMatches:(NSArray *)matches
 {


      __block NSMutableAttributedString *mutableAttributedString = self.textView.attributedText.mutableCopy;
     [matches enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop)
    {

     if ([obj isKindOfClass:[NSTextCheckingResult class]])
     {
         NSTextCheckingResult *match = (NSTextCheckingResult *)obj;
         CGRect rect = [self frameOfTextRange:match.range inTextView:self.textView];

         /** Shadow */

         CALayer *shadowLayer = [CALayer new];
         shadowLayer.frame = CGRectMake(rect.origin.x, rect.origin.y-4, rect.size.width, rect.size.height);
         shadowLayer.cornerRadius = 5;

         shadowLayer.backgroundColor = [UIColor yellowColor].CGColor;
         shadowLayer.shadowColor = [UIColor blackColor].CGColor;
         shadowLayer.shadowOpacity = 0.6;
         shadowLayer.shadowOffset = CGSizeMake(1,1);
         shadowLayer.shadowRadius = 3;

         /** Label */
         UILabel *lbl = [[UILabel alloc] initWithFrame:CGRectMake(rect.origin.x, rect.origin.y-4, rect.size.width, rect.size.height)];
         lbl.font = [UIFont fontWithName:@"Helvetica" size:12];
         lbl.textColor = [UIColor blackColor];
         [lbl setText:[[mutableAttributedString attributedSubstringFromRange:match.range] string]];
         lbl.backgroundColor = [UIColor clearColor];
         lbl.textAlignment = NSTextAlignmentCenter;
         lbl.layer.cornerRadius = 10;

         /** Add Label and layer*/

         [self.view.layer addSublayer:shadowLayer];
         [self.view addSubview:lbl];  
      }
  }];

  }

用于获取textView中匹配文本框架的函数：

- (CGRect)frameOfTextRange:(NSRange)range inTextView:(UITextView *)textView
 {
    UITextPosition *beginning = textView.beginningOfDocument; //Error=: request for member 'beginningOfDocument' in something not a structure or union

    UITextPosition *start = [textView positionFromPosition:beginning offset:range.location];
    UITextPosition *end = [textView positionFromPosition:start offset:range.length];
    UITextRange *textRange = [textView textRangeFromPosition:start toPosition:end];
    CGRect rect = [textView firstRectForRange:textRange];  //Error: Invalid Intializer

    return [textView convertRect:rect fromView:textView.textInputView]; // Error: request for member 'textInputView' in something not a structure or union

 }

Answer 2

使用NSMutableAttributedString这可能对你有用。

NSString *myString = @"Hello";
NSMutableAttributedString *aString = [[NSMutableAttributedString alloc] initWithString:myString];
NSRange theRange = NSMakeRange(0,[aString length]);

  

//这里我们为文本设置前景色和背景色   突出它。

[aString addAttribute:NSFontAttributeName value:[UIFont fontWithName:@"MyriadPro-Bold" size:17.5f] range:theRange];
[aString addAttribute:NSForegroundColorAttributeName value:[UIColor purpleColor] range:theRange];
[aString addAttribute:NSBackgroundColorAttributeName value:[UIColor yellowColor] range:theRange];

  

//您可以根据您的文本部分更改范围   想突出显示。

Answer 3

为此你必须使用core Text＆amp;要突出显示，您必须使用drawRect方法绘制文本，即将背景颜色更改为黄色＆amp;增加文字的字体大小

tutorial on coreText

Answer 4

There is a github repository "HighlightedWebView"实现与您所希望的几乎相同的效果。

  

Drop-in WebView子类，增加了Safari风格的页内搜索结果突出显示。