如何正确确定属性字符串的宽度

Question

我想要做的：使用 NSLayoutManager 布局文本并将其 NSTextContainer 设置为字符串数组中最宽字符串（字形）的宽度。

我的问题是：确定总“字形宽度”的方法似乎不正确，因为当我渲染文本时它会换行。

我使用 Monaco 12 点字体的 32 个字符的字符串做了一个实验，长度报告为 224.0，但只有当长度设置为 234.0 时，文本才会停止换行。

此代码演示了我上面所说的内容，并在计算的字形宽度右侧显示一条垂直线。

- (void)drawRect:(NSRect)rect {
    NSRect bounds = [self bounds];

    [[NSColor whiteColor] drawSwatchInRect: bounds];
    [[NSColor blackColor] setStroke];
    [[NSBezierPath bezierPathWithRect: bounds] stroke];

    NSMutableParagraphStyle *thisParagraphStyle = [[NSMutableParagraphStyle defaultParagraphStyle] mutableCopy];
    [thisParagraphStyle setLineBreakMode: NSLineBreakByCharWrapping];
    [thisParagraphStyle setAlignment: NSLeftTextAlignment];

    NSFont *fontUsed = [NSFont fontWithName: @"Monaco" size: 12];

    NSDictionary *glyphAttributes = [NSDictionary dictionaryWithObjectsAndKeys:
                                     fontUsed, NSFontAttributeName,
                                     thisParagraphStyle, NSParagraphStyleAttributeName,
                                     [NSColor blackColor], NSForegroundColorAttributeName,
                                     NULL];

    NSTextStorage *textStorage = [[NSTextStorage alloc] initWithString:@"00112233445566778899001122334455\n00112233445566778899001122334455\n00112233445566778899001122334455\n00112233445566778899001122334455\n"];

    [textStorage setAttributes: glyphAttributes range:  NSMakeRange(0, [textStorage length])];

    NSLayoutManager *layoutManager = [[NSLayoutManager alloc] init];

    NSSize textContainerSize;
    textContainerSize.width = [@"00112233445566778899001122334455" sizeWithAttributes: glyphAttributes].width;
    textContainerSize.height = bounds.size.height;

    NSTextContainer *textContainer = [[NSTextContainer alloc] initWithContainerSize: textContainerSize];
    [layoutManager addTextContainer:textContainer];

    [textContainer release];
    [textStorage addLayoutManager:layoutManager];
    [layoutManager release];
    NSRange glyphRange = [layoutManager glyphRangeForTextContainer: textContainer];

    [layoutManager drawGlyphsForGlyphRange: glyphRange atPoint: NSMakePoint(0.0 , 0.0)];
    [textStorage release];
    [thisParagraphStyle release];

    // Indicate right text boundary from computed width
    NSBezierPath *rightTextBoundary = [NSBezierPath bezierPath];
    [rightTextBoundary moveToPoint: NSMakePoint(textContainerSize.width, 0.0)];
    [rightTextBoundary lineToPoint: NSMakePoint(textContainerSize.width, bounds.size.height-1)];
    [rightTextBoundary stroke];

    NSLog(@"View width: %f", bounds.size.width);
    NSLog(@"Calculated width1: %f", textContainerSize.width);
    NSLog(@"Calculated width2: %f\n\n", [@"00112233445566778899001122334455" boundingRectWithSize: NSMakeSize(FLT_MAX, FLT_MAX)
                                                                         options: NSStringDrawingUsesDeviceMetrics
                                                                      attributes: glyphAttributes].size.width);
}

- (BOOL) isFlipped {
    return YES;
}

Answer 1

您是否考虑过文本容器的 -lineFragmentPadding？

Answer 2

您是否看过 NSString 和 NSAttributedString NS(Attributed)String+Geometrics？

如果这不完全是您正在寻找的内容，您也许可以看到他们为计算大小所做的一些事情。