NSString sizeWithFont：返回不一致的结果？已知的错误？

发布于 2024-09-03 06:54:22 字数 1009 浏览 3 评论 0原文

我正在尝试创建一个简单的自定义 UIView，其中包含用单一字体绘制的字符串，但第一个字符稍大。

我认为这可以通过两个相邻放置的 UILabel:s 轻松实现。

我使用 NSString sizeWithFont 来测量我的字符串，以便能够正确地布局它。

但我注意到返回的矩形中的字体基线根据我设置的字体大小而变化 +/- 1 像素。这是我的代码：

NSString* ctxt = [text substringToIndex:1];
NSString* ttxt = [text substringFromIndex:1];

CGSize sz = [ctxt sizeWithFont: cfont ];
clbl = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, sz.width, sz.height)];
clbl.text = ctxt;
clbl.font = cfont;
clbl.backgroundColor = [UIColor clearColor];
[contentView addSubview:clbl];

CGSize sz2 = [ttxt sizeWithFont: tfont];
tlbl = [[UILabel alloc] initWithFrame:CGRectMake(sz.width, (sz.height - sz2.height), sz2.width, sz2.height)];
tlbl.text = ttxt;
tlbl.font = tfont;
tlbl.backgroundColor = [UIColor clearColor];
[contentView addSubview:tlbl];

如果我使用 12.0 和 14.0 作为大小，它工作正常。但如果我改用 13.0 和 15.0，那么第一个字符就高了 1 个像素。

这是一个已知问题吗？

有什么建议如何解决这个问题吗？

使用 CSS 和 HTML 页面创建 UIWebView 似乎有点矫枉过正。以及处理动态字符串的更多工作。这是我应该做的吗？

原文

I'm trying to create a simple custom UIView wich contain a string drawn with a single font, but where the first character is slightly larger.

I thought this would be easily implemented with two UILabel:s placed next to eachother.

I use NSString sizeWithFont to measure my string to be able to lay it out correctly.

But I noticed that the font baseline in the returned rectangle varies with +/- 1 pixel depending on the font size I set.
Here is my code:

NSString* ctxt = [text substringToIndex:1];
NSString* ttxt = [text substringFromIndex:1];

CGSize sz = [ctxt sizeWithFont: cfont ];
clbl = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, sz.width, sz.height)];
clbl.text = ctxt;
clbl.font = cfont;
clbl.backgroundColor = [UIColor clearColor];
[contentView addSubview:clbl];

CGSize sz2 = [ttxt sizeWithFont: tfont];
tlbl = [[UILabel alloc] initWithFrame:CGRectMake(sz.width, (sz.height - sz2.height), sz2.width, sz2.height)];
tlbl.text = ttxt;
tlbl.font = tfont;
tlbl.backgroundColor = [UIColor clearColor];
[contentView addSubview:tlbl];

If I use 12.0 and 14.0 as sizes, it works fine.
But if I instead use 13.0 and 15.0, then the first character is 1 pixel too high.

Is this a known problem?

Any suggestions how to work around it?

Creating a UIWebView with a CSS and HTML page seems way overkill for this. and more work to handle dynamic strings. Is that what I'm expected to do?

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