NSLayoutManager / NSTextContainer忽略比例因子

Question

我試圖使用以下方法測量給定恆定寬度的NSAttributedString的高度：

-(CGFloat)calculateHeightForAttributedString:(NSAttributedString*)attributedNotes {
    CGFloat scrollerWidth = [NSScroller scrollerWidthForControlSize:NSRegularControlSize scrollerStyle:NSScrollerStyleLegacy];
    CGFloat width = self.tableView.frame.size.width - self.cellNotesWidthConstraint - scrollerWidth;
    // http://www.cocoabuilder.com/archive/cocoa/54083-height-of-string-with-fixed-width-and-given-font.html
    NSTextView *tv = [[NSTextView alloc] initWithFrame:NSMakeRect(0, 0, width - 20, 1e7)];
    tv.font = [NSFont userFontOfSize:32];
    [tv.textStorage setAttributedString:attributedNotes];
    [self setScaleFactor:[self convertSliderValueToFontScale:self.fontScaleSlider] forTextView:tv];

    [tv.layoutManager glyphRangeForTextContainer:tv.textContainer];
    [tv.layoutManager ensureLayoutForTextContainer:tv.textContainer];

    return [tv.layoutManager usedRectForTextContainer:tv.textContainer].size.height + 10.0f; // add a little bit of a buffer
}

基本上，寬度是表格視圖的大小減去滾動條，以及用於顯示其他信息的每個單元格的一小部分。 只要文本比例（通過convertSliderValueToFontScale:為1.0，此方法convertSliderValueToFontScale:很好地工作。 如果改變比例因子， usedRectForTextContainer的結果是不正確的 - 好像沒有考慮比例因子。

比例在setScaleFactor:forTextView:設置setScaleFactor:forTextView:在NSTextView上如下（標量是實際比例量）：

[textView scaleUnitSquareToSize:NSMakeSize(scaler, scaler)];

有想法該怎么解決這個嗎？

編輯：我有一個示例項目在這里嘗試： Github 。 奇怪的是，如果比例小於0，事情就會起作用，並且它們隨機似乎在4.XXX范圍內隨機工作......

Answer 1

答案結果是簡單：添加NSTextView作為的子視圖NSClipView具有相同的幀作為NSTextView 。

最終的高度函數如下：

-(CGFloat)calculateHeightForAttributedString:(NSAttributedString*)attributedNotes {
    CGFloat width = self.textView.frame.size.width;
    // http://www.cocoabuilder.com/archive/cocoa/54083-height-of-string-with-fixed-width-and-given-font.html
    NSTextView *tv = [[NSTextView alloc] initWithFrame:NSMakeRect(0, 0, width, 1e7)];
    tv.horizontallyResizable = NO;
    tv.font = [NSFont userFontOfSize:32];
    tv.alignment = NSTextAlignmentLeft;
    [tv.textStorage setAttributedString:attributedNotes];
    [self setScaleFactor:self.slider.floatValue forTextView:tv];

    // In order for usedRectForTextContainer: to be accurate with a scale, you MUST
    // set the NSTextView as a subview of an NSClipView!
    NSClipView *clipView = [[NSClipView alloc] initWithFrame:NSMakeRect(0, 0, width, 1e7)];
    [clipView addSubview:tv];

    [tv.layoutManager glyphRangeForTextContainer:tv.textContainer];
    [tv.layoutManager ensureLayoutForTextContainer:tv.textContainer];
    return [tv.layoutManager usedRectForTextContainer:tv.textContainer].size.height;
}