11

可能重复：
UITextView ：获取带有换行信息的文本

我一直在寻找 NSString 库和众多库中的一个函数，该函数可以采用这样的长字符串：

Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis egestas. Vestibulum tortor quam, feugiat vitae, ultricies eget, tempor sit amet, ante. Donec eu libero sit amet quam egestas semper. Aenean ultricies mi vitae est. Mauris placerat eleifend leo. Quisque sit amet est et sapien ullamcorper pharetra. Vestibulum erat wisi, condimentum sed, commodo vitae, ornare sit amet, wisi. Aenean fermentum, elit eget tincidunt condimentum, eros ipsum rutrum orci, sagittis tempus lacus enim ac dui.

并与指示宽度的 CGSize 或浮点数以及正在使用的字体一起返回给我一个带有 \n 中断和换行的字符串。

结果（大致）：

Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac\n
egestas. Vestibulum tortor quam, feugiat vitae, ultricies eget, tempor sit amet.\n
 Donec eu libero sit amet quam egestas semper. Aenean ultricies mi vitae est. \n
placerat eleifend leo. Quisque sit amet est et sapien ullamcorper pharetra.\n
 Vestibulum erat wisi, condimentum sed, commodo vitae, ornare sit amet, wisi.\n
 Aenean fermentum, elit eget tincidunt condimentum, eros ipsum rutrum orci,\n
 sagittis tempus lacus enim ac dui.

我已经知道 UITextViews 等这样做，但这没有帮助，因为我需要在原始 OpenGL 环境中呈现文本，所以我没有使用常规 UI 元素。

我知道这要么作为框架存在，要么作为某个公共类存在。我只是找不到任何统一的方法来处理这个问题。

我想它接近 [NSString sizeWithFont:forWidth:lineBreakMode:]，但我不需要大小，我需要字符串本身。

4

2 回答 2

9

确实没有必要重新发明这个轮子，因为它正是文本引擎每次包装文本时为您所做的。什么是文本引擎？它是核心文本。如果您下拉到 Core Text 级别并让 CTFramesetter 为您布置文本，您可以通过询问生成的 CTLines 来了解它在哪里放置换行符。

该文档将帮助您入门：

http://developer.apple.com/library/ios/#documentation/StringsTextFonts/Conceptual/CoreText_Programming/Operations/Operations.html

网上有很多很好的教程。

简单的例子：

NSString* s = @"Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do "
@"eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut "
@"enim ad minim veniam, quis nostrud exercitation ullamco laboris "
@"nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor "
@"in reprehenderit in voluptate velit esse cillum dolore eu fugiat "
@"nulla pariatur. Excepteur sint occaecat cupidatat non proident, "
@"sunt in culpa qui officia deserunt mollit.";
NSAttributedString* text = [[NSAttributedString alloc] initWithString:s];

CTFramesetterRef fs =
CTFramesetterCreateWithAttributedString((__bridge CFAttributedStringRef)text);
CGMutablePathRef path = CGPathCreateMutable();
CGPathAddRect(path, NULL, CGRectMake(0,0,200,100000));
CTFrameRef f = CTFramesetterCreateFrame(fs, CFRangeMake(0, 0), path, NULL);
CTFrameDraw(f, NULL);

NSArray* lines = (__bridge NSArray*)CTFrameGetLines(f);
for (id aLine in lines) {
    CTLineRef theLine = (__bridge CTLineRef)aLine;
    CFRange range = CTLineGetStringRange(theLine);
    NSLog(@"%ld %ld", range.location, range.length);
}
CGPathRelease(path);
CFRelease(f);
CFRelease(fs);

正如您将看到的，输出显示了每行换行文本的范围。这不是你追求的那种东西吗？

于 2012-11-27T16:10:40.570 回答
1

似乎没有工厂方法可以做到这一点，所以已经开始构建一个类函数来处理这个问题，基于这个密切相关的堆栈中引入的解决方案：

+ (NSString*)wrappedString:(NSString*)string withFont:(UIFont*)font andWidth:(float)width {
    NSMutableString *resultString = [[NSMutableString alloc] initWithString:@""];

    CGSize textSize = [string sizeWithFont:font];
    float textWidth = textSize.width;
    if (textWidth < width) {
        return string;
    }
    float wordLength;
    float lineLength;
    NSUInteger length = [string length];
    unichar buffer[length];
    [string getCharacters:buffer range:NSMakeRange(0, length)];

    NSString *singleLine = @"";
    NSString *word = @"";
    NSString *longWord = @"";

    for (NSUInteger i = 0; i < length; i++) {

        unichar character = buffer[i];
        if (character != '\n') {
            word = [NSString stringWithFormat:@"%@%c", word, character];
        }

        if (character == '\n') {
            float wordLength = [word sizeWithFont:font].width;
            float lineLength = [singleLine sizeWithFont:font].width;
            if ((lineLength + wordLength) > width) {
                [resultString appendString:singleLine];
                [resultString appendString:@"\n"];
                singleLine = @"";
                singleLine = [singleLine stringByAppendingFormat:@"%@\n",word];
                word = @"";
            } else {
                singleLine = [singleLine stringByAppendingString: word];
                word = @"";
                [resultString appendString:singleLine];
                [resultString appendString:@"\n"];
                singleLine = @"";
            }
        }

        else if (character == ' ') {
            float wordLength = [word sizeWithFont:font].width;
            float lineLength = [singleLine sizeWithFont:font].width;

            if ((lineLength + wordLength) > width) {
                if (wordLength > textWidth) {
                    [resultString appendString:singleLine];
                    [resultString appendString:@"\n"];
                    singleLine = @"";
                    int j = 0;
                    for (; j < [word length]; j++) {
                        unichar longChar = [word characterAtIndex:j];
                        longWord = [NSString stringWithFormat:@"%@%c", longWord, longChar];
                        float longwordLength = [longWord sizeWithFont:font].width;
                        float longlineLength = [singleLine sizeWithFont:font].width;
                        if ((longlineLength + longwordLength) >= width) {
                            singleLine = [singleLine stringByAppendingString:longWord];
                            word = @"";
                            longWord = @"";
                            break;
                        }
                    }

                }
                [resultString appendString:singleLine];
                [resultString appendString:@"\n"];
                singleLine = @"";
            }
            singleLine = [singleLine stringByAppendingString: word];
            word = @"";
        }
    }

    wordLength = [word sizeWithFont:font].width;
    lineLength = [singleLine sizeWithFont:font].width;

    if (wordLength > 0) {
        if ((lineLength + wordLength) > width) {
            [resultString appendString:singleLine];
            [resultString appendString:@"\n"];
            singleLine = @"";
        }
        singleLine = [singleLine stringByAppendingString:word];
    }


    if (lineLength > 0) {
        [resultString appendString:singleLine];
        [resultString appendString:@"\n"];
    }
    return resultString;
}
于 2012-11-27T14:12:33.683 回答