Cocos2d-x 更改文字换行风格 ( cocos2dx change line )

Cocos2dx change line

在 cocos2dx change line 的实现中，我们可以简单的使用dimensions属性控制换行。使用它只需将对应的参数值传入构造函数，或者调用 setDimensions 函数即可。

它的换行策略是：当一个单词超出限制长度时，将它移动到下一行。有时这种策略并不合适。例如，在某些语言中，单词都比较长。如果采用这种策略，会出现每一行中只有一个单词。因此需要更改换行策略。当超出限制长度时，使用-作为一个分隔单词的标志。

换行策略调用

通过查看Cocos2d-x中换行的实现方式，我发现换行策略是区分平台编程出来的代码。也就是说，为了更改换行策略，我需要分别编写 IOS 和 Java 两部分代码。因为我的目标平台是 Android 平台，因此我只对Java文件进行了更改。IOS 平台的换行策略调用的是系统函数，有兴趣研究的读者可以跟踪源码更改。入口函数为:

bool CCTexture2D::initWithString(const char *text,ccFontDeFinition *textDeFinition)
{
    ......
 
    CCImage* pImage = new CCImage();
    do
    {
        CC_BREAK_IF(NULL == pImage);
        
        bRet = pImage->initWithStringShadowstroke(text,(int)textDeFinition->m_dimensions.width,(int)textDeFinition->m_dimensions.height,eAlign,textDeFinition->m_fontName.c_str(),textDeFinition->m_fontSize,textDeFinition->m_fontFillColor.r / 255,textDeFinition->m_fontFillColor.g / 255,textDeFinition->m_fontFillColor.b / 255,shadowEnabled,shadowDX,shadowDY,shadowOpacity,shadowBlur,strokeEnabled,strokeColorR,strokeColorG,strokeColorB,strokeSize);
        
        
        CC_BREAK_IF(!bRet);
        bRet = initWithImage(pImage);
        
    } while (0);
    
    ......
}

更改Java实现

Android 平台对应的 Java 文件位于 $(2DX-Root)/cocos2dx/platform/android/java/src/org/cocos2dx/lib 文件夹中，文件名是 Cocos2dxBitmap.java

首先，我增加了 divideStringWithMaxWidthByFlag 函数，将它作为另一个换行策略的实现函数。

// add by fansy for "—" style words
    private static LinkedList<String> divideStringWithMaxWidthByFlag(
           final String pString,final int pMaxWidth,final Paint pPaint) {
        final int charLength = pString.length();
        int start = 0;
        int tempWidth = 0;
        LinkedList<String> strList = new LinkedList<String>();
        
        if( !isChinese(pString) )
        {
            /* Break a String into String[] by the width & should wrap the word. */
            for (int i = 1; i < charLength-1; ++i) {
                tempWidth = (int) FloatMath.ceil(pPaint.measureText(pString,start,i+1));
                if (tempWidth >= pMaxWidth) {
                    if(pString.charat(i) == ' ') //end with " "
                    {
                        //change line at i
                        strList.add(pString.substring(start,i));
                        i = i + 1; // skip space
                    }
                    else if(i>1 && pString.charat(i-2) == ' ') //only one "-" left after change line
                    {
                        //change line at i-2
                        strList.add(pString.substring(start,i-2));
                        i = i -2; // skip space
                    }
                    else if(i>0 && pString.charat(i-1) == ' ') //only one "-" left after change line
                    {
                        //change line at i-1
                        strList.add(pString.substring(start,i-1));
                        i = i -1; // skip space
                    }
                    else if(i>0) //replace "-" at i-2
                    {
                        //split at i-1 add "-" at tail change line at i-1
                        strList.add(pString.substring(start,i-1)+"-");
                        i--;
                    }
                    
                    /* Remove spaces at the beginning of a new line. */
                    while (pString.charat(i) == ' ') {
                        ++i;
                    }
                    
                    start = i;
                }
            }
            
            /* Add the last chars. */
            if (start < charLength) {
                strList.add(pString.substring(start));
            }
        }
        else
        {
            strList = divideStringWithMaxWidth(pString,pMaxWidth,pPaint);
        }
        return strList;
    }
    
    // 根据Unicode编码完美的判断中文汉字和符号
    private static boolean isChinese(char c) {
        Character.UnicodeBlock ub = Character.UnicodeBlock.of(c);
        if (ub == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS
            || ub == Character.UnicodeBlock.CJK_COMPATIBILITY_IDEOGRAPHS
            || ub == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS_EXTENSION_A
            || ub == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS_EXTENSION_B
            || ub == Character.UnicodeBlock.CJK_SYMBOLS_AND_PUNCTUATION
            || ub == Character.UnicodeBlock.HALFWIDTH_AND_FULLWIDTH_FORMS
            || ub == Character.UnicodeBlock.GENERAL_PUNCTUATION) {
            return true;
        }
        return false;
    }
    
    // 完整的判断中文汉字和符号
    public static boolean isChinese(String strName) {
        char[] ch = strName.tochararray();
        for (int i = 0; i < ch.length; i++) {
            char c = ch[i];
            if (isChinese(c)) {
                return true;
            }
        }
        return false;
    }
    
 //end add by fansy

增加函数之后，修改在 splitString 中的调用：

private static String[] splitString(final String pString,final int pMaxHeight,final Paint pPaint) {
        final String[] lines = pString.split("\\n");
        String[] ret = null;
        final FontMetricsInt fm = pPaint.getFontMetricsInt();
        final int heightPerLine = (int) Math.ceil(fm.bottom - fm.top);
        final int maxLines = pMaxHeight / heightPerLine;
 
        if (pMaxWidth != 0) {
            final LinkedList<String> strList = new LinkedList<String>();
            for (final String line : lines) {
                /*
                 * The width of line is exceed maxWidth,should divide it into
                 * two or more lines.
                 */
                final int linewidth = (int) FloatMath.ceil(pPaint
                        .measureText(line));
                if (linewidth > pMaxWidth) {
                    strList.addAll(Cocos2dxBitmap.divideStringWithMaxWidthByFlag(
                            line,pPaint));
                } else {
                    strList.add(line);
        ......
}

更换调用函数后，编译打包，运行程序即可看到不同的换行效果。

本篇博客出自 阿修罗道 ，转载请注明出处，禁止用于商业用途： http://blog.csdn.net/fansongy/article/details/39992241