NSTextView 在使用不同的 NSParagraphStyles 更改属性时更新速度太慢

Question

我希望 NSTextView 对象通过更改 NSParagraphStyle 间距来响应 Tab 键命中。它确实非常慢！事实上，如果我做这个更改太快（按 Tab 键太快），我最终会出现故障，有时甚至会导致崩溃。这是视频：https://drive.google.com/open?id=0B4aMQXnlIOvCUXNjWTVXVkR3NHc. And another one: https://drive.google.com/open?id=0B4aMQXnlIOvCUDJjSEN0bFdqQXc

来自我的 NSTextStorage 子类的代码片段：

override func attributesAtIndex(index: Int, effectiveRange range: NSRangePointer) -> [String : AnyObject] {
    return storage.attributesAtIndex(index, effectiveRange: range)
}


override func replaceCharactersInRange(range: NSRange, withString str: String) {
    let delta = str.characters.count - range.length
    beginEditing()
    storage.replaceCharactersInRange(range, withString:str)
    edited([.EditedCharacters, .EditedAttributes], range: range, changeInLength: delta)
    endEditing()
}


override func setAttributes(attrs: [String : AnyObject]!, range: NSRange) {
    beginEditing()
    storage.setAttributes(attrs, range: range)
    edited(.EditedAttributes, range: range, changeInLength: 0)
    endEditing()
}

来自我的 NSTextView 子类的代码片段：

override func shouldChangeTextInRange(affectedCharRange: NSRange, replacementString: String?) -> Bool {
    super.shouldChangeTextInRange(affectedCharRange, replacementString: replacementString)
    guard replacementString != nil else { return true }

    if replacementString == "\t" {
        defer {
            let selectedRangesValues = self.selectedRanges
            var selectedRanges = [NSRange]()
            for value in selectedRangesValues {
                selectedRanges.append(value.rangeValue)
            }
            textController.switchToAltAttributesInRange(selectedRanges)
        }
        return false
    }
    return true
}

我的 TextController 中创建并应用替代属性的代码片段：

func switchToAltAttributesInRange(ranges : [NSRange]) {
    // get paragraph indexes from the ranges
    var indexes = [Int]()
    for range in ranges {
        for idx in textStorage.paragraphsInRange(range) {
            indexes.append(idx)
        }
    }

    // change attributes for all the paragraphs in those ranges
    for index in indexes {
        let paragraphRange = textStorage.paragraphRangeAtIndex(index)
        let element = elementAtIndex(index)
        let altElementType = altElementTypeForElementType(element.type)

        // change the attributes
        let newAttributes = paragraphAttributesForElement(type: altElementType.rawValue)
        self.textStorage.beginUpdates()
        self.textStorage.setAttributes(newAttributes, range: paragraphRange)
        self.textStorage.endUpdates()
    }
}

func paragraphAttributesForElement(type typeString: String) -> [String : AnyObject] {
    let elementPreset = elementPresetForType(elementType)

    // set font
    let font = NSFont (name: elementPreset.font, size: CGFloat(elementPreset.fontSize))!

    // set attributes
    let elementAttributes = [NSFontAttributeName: font,
                  NSParagraphStyleAttributeName : paragraphStyleForElementPreset(elementPreset, font: font),
                  NSForegroundColorAttributeName: NSColor.colorFromHexValue(elementPreset.color),
                  NSUnderlineStyleAttributeName : elementPreset.underlineStyle,
              ElementAttribute.AllCaps.rawValue : elementPreset.allCaps]

    return elementAttributes
}

func paragraphStyleForElementPreset(elementPreset : TextElementPreset, font : NSFont) -> NSParagraphStyle {
    let sceneParagraphStyle = NSMutableParagraphStyle()

    let spacing = elementPreset.spacing
    let spacingBefore = elementPreset.spacingBefore
    let headIndent = elementPreset.headIndent
    let tailIndent = elementPreset.tailIndent

    let cFont = CTFontCreateWithName(font.fontName, font.pointSize, nil)
    let fontHeight = CTFontGetDescent(cFont) + CTFontGetAscent(cFont) + CTFontGetLeading(cFont)

    sceneParagraphStyle.paragraphSpacingBefore = CGFloat(spacingBefore)
    sceneParagraphStyle.paragraphSpacing = fontHeight * CGFloat(spacing)
    sceneParagraphStyle.headIndent = ScreenMetrics.pointsFromInches(CGFloat(headIndent))
    sceneParagraphStyle.tailIndent = ScreenMetrics.pointsFromInches(CGFloat(tailIndent))
    sceneParagraphStyle.firstLineHeadIndent = sceneParagraphStyle.headIndent
    sceneParagraphStyle.lineBreakMode = .ByWordWrapping
    return sceneParagraphStyle
}

当我按 Tab 键时，Time Profiler 工具显示一个高峰。它说每次我按 Tab 键时，NSTextStorage attributesAtIndex 最多需要 40 毫秒。

我检查过：如果我删除 NSParagraphStyle 更改，一切都会变得正常。所以问题是：我应该如何更新段落样式？

Answer 1

嗯...在 Apple 文档或 Google 中都没有找到这样的解决方案...只是进行了实验，结果是我在 textView.display() 调用后添加 self.textStorage.setAttributes，一切正常！

更新：setNeedsDisplay(invalidRect) 做得更好，因为您可能只重绘文本视图可见矩形的脏部分

NSTextView 在使用不同的 NSParagraphStyles 更改属性时更新速度太慢

NSTextView is too slow to update while changing the attributes with different NSParagraphStyles

macos

nstextview

ios

swift

nsparagraphstyle