如何使用NSString drawInRect来居中文本？

Question

我怎样才能画出一个NSString居中的NSRect？

我开始时:(来自我的自定义视图的drawRect方法的摘录)

NSString* theString = ...
[theString drawInRect:theRect withAttributes:0];
[theString release];

现在我假设我需要设置一些属性.我已经浏览了Apple的Cocoa文档,但它有点压倒性,无法找到任何有关如何向属性添加段落样式的内容.

另外,我只能找到水平对齐,垂直对齐怎么样？

Answer 1

您必须自己进行垂直对齐((视图高度+字符串高度)/ 2).您可以使用水平对齐:

NSMutableParagraphStyle *style = [[NSParagraphStyle defaultParagraphStyle] mutableCopy];
style.alignment = NSTextAlignmentCenter;
NSDictionary *attr = [NSDictionary dictionaryWithObject:style forKey:NSParagraphStyleAttributeName];
[myString drawInRect:someRect withAttributes:attr];

Answer 2

这适用于我的水平对齐

[textX drawInRect:theRect 
         withFont:font 
    lineBreakMode:UILineBreakModeClip 
        alignment:UITextAlignmentCenter];

Answer 3

马丁斯的答案非常接近,但它有一些小错误.试试这个:

NSMutableParagraphStyle* style = [[NSMutableParagraphStyle alloc] init];
[style setAlignment:NSCenterTextAlignment];
NSDictionary *attr = 
  [NSDictionary dictionaryWithObject:style 
                              forKey:NSParagraphStyleAttributeName];
[myString drawInRect:someRect withAttributes:attr];
[style release];

您将不得不创建一个新的NSMutableParagraphStyle(而不是像Martin建议的那样使用默认的段落样式)因为[NSMutableParagraphStyle defaultParagraphStyle]返回a NSParagraphStyle,它没有setAlignment方法.此外,你不需要字符串 - @"NSParagraphStyleAttributeName"只是NSParagraphStyleAttributeName.

Answer 4

这对我有用:

    CGRect viewRect = CGRectMake(x, y, w, h);
    UIFont* font = [UIFont systemFontOfSize:15];
    CGSize size = [nsText sizeWithFont:font
                     constrainedToSize:viewRect.size
                         lineBreakMode:(UILineBreakModeWordWrap)];  
    float x_pos = (viewRect.size.width - size.width) / 2; 
    float y_pos = (viewRect.size.height - size.height) /2; 
    [someText drawAtPoint:CGPointMake(viewRect.origin.x + x_pos, viewRect.origin.y + y_pos) withFont:font];

Answer 5

[NSMutableParagraphStyle defaultParagraphStyle] 不会工作使用：

[NSMutableParagraphStyle new]

此外，似乎水平对齐仅适用于drawInRect，而不适用drawAtPoint（问我我怎么知道 :-)