Optimizing WordWrap Algorithm

Posted by Milo on Stack Overflow See other posts from Stack Overflow or by Milo
Published on 2011-03-16T23:11:23Z Indexed on 2011/03/17 0:10 UTC
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I have a word-wrap algorithm that basically generates lines of text that fit the width of the text. Unfortunately, it gets slow when I add too much text.

I was wondering if I oversaw any major optimizations that could be made. Also, if anyone has a design that would still allow strings of lines or string pointers of lines that is better I'd be open to rewriting the algorithm.

Thanks

void AguiTextBox::makeLinesFromWordWrap()
{
    textRows.clear();
    textRows.push_back("");
    std::string curStr;
    std::string curWord;

    int curWordWidth = 0;
    int curLetterWidth = 0;
    int curLineWidth = 0;

    bool isVscroll = isVScrollNeeded();
    int voffset = 0;
    if(isVscroll)
    {
        voffset = pChildVScroll->getWidth();
    }
    int AdjWidthMinusVoffset = getAdjustedWidth() - voffset;
    int len = getTextLength();
    int bytesSkipped = 0;
    int letterLength = 0;
    size_t ind = 0;

    for(int i = 0; i < len; ++i)
    {

        //get the unicode character
        letterLength = _unicodeFunctions.bringToNextUnichar(ind,getText());
        curStr = getText().substr(bytesSkipped,letterLength);


        bytesSkipped += letterLength;

        curLetterWidth = getFont().getTextWidth(curStr);

        //push a new line
        if(curStr[0] == '\n')
        {
            textRows.back() += curWord;
            curWord = "";
            curLetterWidth = 0;
            curWordWidth = 0;
            curLineWidth = 0;
            textRows.push_back("");
            continue;
        }



            //ensure word is not longer than the width
            if(curWordWidth + curLetterWidth >= AdjWidthMinusVoffset && 
                curWord.length() >= 1)
            {
                textRows.back() += curWord;

                textRows.push_back("");
                curWord = "";
                curWordWidth = 0;
                curLineWidth = 0;
            }

            //add letter to word
            curWord += curStr;
            curWordWidth += curLetterWidth;


        //if we need a Vscroll bar start over
        if(!isVscroll && isVScrollNeeded())
        {
            isVscroll = true;
            voffset = pChildVScroll->getWidth();
            AdjWidthMinusVoffset = getAdjustedWidth() - voffset;
            i = -1;
            curWord = "";
            curStr = "";
            textRows.clear();
            textRows.push_back("");
            ind = 0;

            curWordWidth = 0;
            curLetterWidth = 0;
            curLineWidth = 0;

            bytesSkipped = 0;
            continue;
        }

        if(curLineWidth + curWordWidth >= 
            AdjWidthMinusVoffset && textRows.back().length() >= 1)
        {
            textRows.push_back("");
            curLineWidth = 0;
        }

        if(curStr[0] == ' ' || curStr[0] == '-')
        {
            textRows.back() += curWord;
            curLineWidth += curWordWidth;
            curWord = "";
            curWordWidth = 0;
        }
    }

    if(curWord != "")
    {
        textRows.back() += curWord;
    }

    updateWidestLine();
}

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