Added color and font styles.
This commit is contained in:
Michael Griebling
250
Sources/SwiftMathRender/MathRender/MTMathUILabel.swift
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250
Sources/SwiftMathRender/MathRender/MTMathUILabel.swift
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//
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// MTMathUILabel.swift
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// MathRenderSwift
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//
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// Created by Mike Griebling on 2023-01-01.
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//
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import Foundation
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import CoreText
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/**
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Different display styles supported by the `MTMathUILabel`.
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The only significant difference between the two modes is how fractions
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and limits on large operators are displayed.
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*/
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public enum MTMathUILabelMode {
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/// Display mode. Equivalent to $$ in TeX
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case display
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/// Text mode. Equivalent to $ in TeX.
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case text
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}
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/**
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@typedef MTTextAlignment
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@brief Horizontal text alignment for `MTMathUILabel`.
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*/
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public enum MTTextAlignment : UInt {
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/// Align left.
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case left
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/// Align center.
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case center
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/// Align right.
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case right
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}
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/** The main view for rendering math.
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`MTMathLabel` accepts either a string in LaTeX or an `MTMathList` to display. Use
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`MTMathList` directly only if you are building it programmatically (e.g. using an
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editor), otherwise using LaTeX is the preferable method.
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The math display is centered vertically in the label. The default horizontal alignment is
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is left. This can be changed by setting `textAlignment`. The math is default displayed in
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*Display* mode. This can be changed using `labelMode`.
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When created it uses `[MTFontManager defaultFont]` as its font. This can be changed using
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the `font` parameter.
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*/
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class MTMathUILabel : MTView {
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/** The `MTMathList` to render. Setting this will remove any
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`latex` that has already been set. If `latex` has been set, this will
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return the parsed `MTMathList` if the `latex` parses successfully. Use this
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setting if the `MTMathList` has been programmatically constructed, otherwise it
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is preferred to use `latex`.
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*/
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var mathList:MTMathList? {
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didSet {
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self.error = nil
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self.latex = MTMathListBuilder.mathListToString(mathList)
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self.invalidateIntrinsicContentSize()
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self.setNeedsLayout()
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}
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}
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/** The latex string to be displayed. Setting this will remove any `mathList` that
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has been set. If latex has not been set, this will return the latex output for the
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`mathList` that is set.
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@see error */
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var latex = "" {
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didSet {
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self.error = nil
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var error: NSError? = nil
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self.mathList = MTMathListBuilder.build(fromString: latex, error: &error)
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if error != nil {
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self.mathList = nil
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self.error = error
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self.errorLabel?.text = error?.localizedDescription
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self.errorLabel?.frame = self.bounds
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self.errorLabel?.isHidden = !self.displayErrorInline
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} else {
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self.errorLabel?.isHidden = true
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}
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self.invalidateIntrinsicContentSize()
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self.setNeedsLayout()
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}
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}
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/** This contains any error that occurred when parsing the latex. */
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var error:NSError?
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/** If true, if there is an error it displays the error message inline. Default true. */
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var displayErrorInline = true
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/** The MTFont to use for rendering. */
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var font = MTFontManager.fontManager.defaultFont {
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didSet {
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self.invalidateIntrinsicContentSize()
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self.setNeedsLayout()
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}
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}
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/** Convenience method to just set the size of the font without changing the fontface. */
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var fontSize = MTFontManager.fontManager.kDefaultFontSize {
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didSet {
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self.font = font?.copy(withSize: fontSize)
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}
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}
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/** This sets the text color of the rendered math formula. The default color is black. */
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var textColor:MTColor? = MTColor.black {
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didSet {
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self.displayList?.textColor = textColor
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self.setNeedsDisplay()
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}
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}
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/** The minimum distance from the margin of the view to the rendered math. This value is
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`UIEdgeInsetsZero` by default. This is useful if you need some padding between the math and
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the border/background color. sizeThatFits: will have its returned size increased by these insets.
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*/
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var contentInsets = MTEdgeInsetsZero {
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didSet {
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self.invalidateIntrinsicContentSize()
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self.setNeedsLayout()
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}
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}
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/** The Label mode for the label. The default mode is Display */
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var labelMode = MTMathUILabelMode.display {
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didSet {
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self.invalidateIntrinsicContentSize()
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self.setNeedsLayout()
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}
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}
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/** Horizontal alignment for the text. The default is align left. */
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var textAlignment = MTTextAlignment.left {
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didSet {
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self.invalidateIntrinsicContentSize()
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self.setNeedsLayout()
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}
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}
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/** The internal display of the MTMathUILabel. This is for advanced use only. */
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var displayList: MTMathListDisplay? = nil
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var currentStyle:MTLineStyle {
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switch labelMode {
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case .display: return .display
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case .text: return .text
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}
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}
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var errorLabel: MTLabel?
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override init(frame: CGRect) {
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super.init(frame: frame)
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self.initCommon()
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}
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required init?(coder: NSCoder) {
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super.init(coder: coder)
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self.initCommon()
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}
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func initCommon() {
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#if os(macOS)
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self.layer?.isGeometryFlipped = true
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errorLabel?.layer?.isGeometryFlipped = true
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#else
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self.layer.isGeometryFlipped = true
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errorLabel?.layer.isGeometryFlipped = true
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#endif
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self.backgroundColor = MTColor.clear
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errorLabel = MTLabel()
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errorLabel?.isHidden = true
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errorLabel?.textColor = MTColor.red
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self.addSubview(errorLabel!)
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}
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override func draw(_ dirtyRect: MTRect) {
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super.draw(dirtyRect)
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if self.mathList == nil { return }
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// drawing code
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let context = MTGraphicsGetCurrentContext()!
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context.saveGState()
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displayList!.draw(context)
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context.restoreGState()
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}
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func _layoutSubviews() {
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if mathList != nil {
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displayList = MTTypesetter.createLineForMathList(mathList, font: font, style: currentStyle)
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displayList?.textColor = textColor
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var textX = CGFloat(0)
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switch self.textAlignment {
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case .left:
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textX = self.contentInsets.left
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case .center:
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textX = (bounds.size.width - contentInsets.left - contentInsets.right - displayList!.width) / 2 +
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contentInsets.left
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case .right:
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textX = bounds.size.width - displayList!.width - contentInsets.right
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}
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let availableHeight = bounds.size.height - contentInsets.bottom - contentInsets.top
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// center things vertically
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var height = displayList!.ascent + displayList!.descent
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if height < fontSize/2 {
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height = fontSize/2 // set height to half the font size
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}
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let textY = (availableHeight - height) / 2 + displayList!.descent + contentInsets.bottom
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displayList?.position = CGPointMake(textX, textY)
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} else {
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displayList = nil
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}
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errorLabel?.frame = self.bounds
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self.setNeedsDisplay()
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}
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func _sizeThatFits(_ size:CGSize) -> CGSize {
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var size = size
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var displayList:MTMathListDisplay? = nil
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if mathList != nil {
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displayList = MTTypesetter.createLineForMathList(mathList, font: font, style: currentStyle)
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}
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size.width = displayList!.width + contentInsets.left + contentInsets.right
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size.height = displayList!.ascent + displayList!.descent + contentInsets.top + contentInsets.bottom
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return size
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}
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override var intrinsicContentSize: CGSize { _sizeThatFits(CGSizeZero) }
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#if os(macOS)
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override var isFlipped: Bool { false }
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func setNeedsDisplay() { self.needsDisplay = true }
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func setNeedsLayout() { self.needsLayout = true }
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override func layout() {
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self._layoutSubviews()
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super.layout()
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}
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#else
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override func layoutSubviews() { self._layoutSubviews() }
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override func sizeThatFits(_ size: CGSize) -> CGSize { self._sizeThatFits(size) }
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#endif
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}
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