计算适合矩形的最大字体大小？ [英] Calculate max font size that fits in a rect?

问题描述

我试图找到一个给定的字符串适合给定rect的最大字体大小。算法的目标是尽可能多地填充尽可能大的字体。我的方法 - 这是从我在网上找到的一个修改 - 是一个公平的工作，但它通常不填充整个rect。我希望看到一些关于如何改进这种算法的协作，以便每个人都可以从中受益：

I'm attempting to find the maximum font size that will fit in a given rect for a given string. The goal of the algorithm is to fill as much of the rect as possible with as large of a font as possible. My approach -- which is modified from one I found online -- does a fair job, but it often doesn't fill the entire rect. I'd love to see some collaboration on how to improve this algorithm so that everyone might benefit from it:

-(float) maxFontSizeThatFitsForString:(NSString*)_string 
                               inRect:(CGRect)rect 
                             withFont:(NSString *)fontName 
                             onDevice:(int)device 
{   

    // this is the maximum size font that will fit on the device
    float _fontSize = maxFontSize;
    float widthTweak;

    // how much to change the font each iteration. smaller
    // numbers will come closer to an exact match at the 
    // expense of increasing the number of iterations.
    float fontDelta = 2.0;

    // sometimes sizeWithFont will break up a word 
    // if the tweak is not applied. also note that 
    // this should probably take into account the
    // font being used -- some fonts work better
    // than others using sizeWithFont.
    if(device == IPAD)
        widthTweak = 0.2;
    else
        widthTweak = 0.2;

    CGSize tallerSize = 
           CGSizeMake(rect.size.width-(rect.size.width*widthTweak), 100000);
    CGSize stringSize = 
           [_string sizeWithFont:[UIFont fontWithName:fontName size:_fontSize]
               constrainedToSize:tallerSize];

    while (stringSize.height >= rect.size.height)
    {       
        _fontSize -= fontDelta;
        stringSize = [_string sizeWithFont:[UIFont fontWithName:fontName 
                                          size:_fontSize] 
                             constrainedToSize:tallerSize];
    }

    return _fontSize;
}

推荐答案

使用以下方法计算

您可以将字体更改为所需的字体。
此外，如果需要，您可以添加默认字体高度;

You can change the font to the one which you require. Also, If required you can add a default font height;

方法是自解释的。

-(UIFont*) getFontTofitInRect:(CGRect) rect forText:(NSString*) text {
       CGFloat baseFont=0;
        UIFont *myFont=[UIFont systemFontOfSize:baseFont];
        CGSize fSize=[text sizeWithFont:myFont];
        CGFloat step=0.1f;

        BOOL stop=NO;
        CGFloat previousH;
        while (!stop) {
            myFont=[UIFont systemFontOfSize:baseFont+step ];
            fSize=[text sizeWithFont:myFont constrainedToSize:rect.size lineBreakMode:UILineBreakModeWordWrap];

            if(fSize.height+myFont.lineHeight>rect.size.height){           
                myFont=[UIFont systemFontOfSize:previousH];
                fSize=CGSizeMake(fSize.width, previousH);
                stop=YES;
            }else {
                 previousH=baseFont+step;
            }

            step++;
    }
    return myFont;

 }

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