InstantPage V2: inline-formula baseline alignment
Snapshot list marker subviews/sublayers before iteration, anchor strike/underline drawing to item frame height, baseline-align inline text, images, and formulas. Also: implementation plan and two spec refreshes (clarify extraDescent nudge removal; refresh stale line numbers).
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isaac
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8dbbf0f715
commit
a53ef1f299
2 changed files with 71 additions and 65 deletions
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@ -522,7 +522,7 @@ final class InstantPageV2TextView: UIView, InstantPageItemView {
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if !line.strikethroughItems.isEmpty {
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for item in line.strikethroughItems {
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let itemFrame = item.frame.offsetBy(dx: lineFrame.minX, dy: 0.0)
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context.fill(CGRect(x: itemFrame.minX, y: itemFrame.minY + floor((lineFrame.size.height / 2.0) + 1.0), width: itemFrame.size.width, height: 1.0))
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context.fill(CGRect(x: itemFrame.minX, y: itemFrame.minY + floor((itemFrame.size.height / 2.0) + 1.0), width: itemFrame.size.width, height: 1.0))
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}
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}
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@ -540,7 +540,7 @@ final class InstantPageV2TextView: UIView, InstantPageItemView {
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context.setFillColor(color.cgColor)
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}
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let itemFrame = item.frame.offsetBy(dx: lineFrame.minX, dy: 0.0)
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context.fill(CGRect(x: itemFrame.minX, y: itemFrame.minY + lineFrame.size.height + 2.0, width: itemFrame.size.width, height: 1.0))
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context.fill(CGRect(x: itemFrame.minX, y: itemFrame.minY + itemFrame.size.height + 2.0, width: itemFrame.size.width, height: 1.0))
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}
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}
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}
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@ -616,14 +616,14 @@ final class InstantPageV2ListMarkerView: UIView, InstantPageItemView {
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}
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private func rebuildContents() {
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for subview in Array(self.subviews) {
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subview.removeFromSuperview()
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}
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if let sublayers = self.layer.sublayers {
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for sublayer in sublayers {
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for sublayer in Array(sublayers) {
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sublayer.removeFromSuperlayer()
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}
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}
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for subview in self.subviews {
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subview.removeFromSuperview()
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}
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let item = self.item
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switch item.kind {
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@ -2412,6 +2412,20 @@ private func v2LocalAttachmentBoundsForRange(_ range: NSRange, imageItems: [Inst
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return result
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}
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private struct PendingV2ImageAttachment {
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let xOffset: CGFloat
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let range: NSRange
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let id: Int64
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let size: CGSize
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}
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private struct PendingV2FormulaAttachment {
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let xOffset: CGFloat
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let range: NSRange
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let attachment: InstantPageMathAttachment
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let baselineOffset: CGFloat
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}
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func layoutTextItem(
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_ string: NSAttributedString,
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boundingWidth: CGFloat,
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@ -2458,6 +2472,8 @@ func layoutTextItem(
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let fontLineHeight = floor(fontAscent + fontDescent)
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let fontLineSpacing = floor(fontLineHeight * lineSpacingFactor)
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let fontDescentBelowBaseline = max(0.0, -fontDescent)
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let baselineToNextTopSlack = max(0.0, fontLineSpacing - 4.0)
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var lastIndex: CFIndex = 0
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var currentLineOrigin = CGPoint()
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@ -2499,7 +2515,6 @@ func layoutTextItem(
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var line = CTTypesetterCreateLineWithOffset(typesetter, CFRangeMake(lastIndex, lineCharacterCount), 100.0)
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var lineWidth = CGFloat(CTLineGetTypographicBounds(line, nil, nil, nil))
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let lineRange = NSMakeRange(lastIndex, lineCharacterCount)
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let substring = string.attributedSubstring(from: lineRange).string
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var stop = false
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if maxNumberOfLines > 0 && lines.count == maxNumberOfLines - 1 && lastIndex + lineCharacterCount < string.length {
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@ -2519,68 +2534,71 @@ func layoutTextItem(
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extraDescent = 0.0
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var lineImageItems: [InstantPageTextImageItem] = []
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var lineFormulaItems: [InstantPageTextFormulaRun] = []
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var lineMaxAttachmentHeight: CGFloat = 0.0
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var pendingImages: [PendingV2ImageAttachment] = []
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var pendingFormulas: [PendingV2FormulaAttachment] = []
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var isRTL = false
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if let glyphRuns = CTLineGetGlyphRuns(line) as? [CTRun], !glyphRuns.isEmpty {
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if let run = glyphRuns.first, CTRunGetStatus(run).contains(CTRunStatus.rightToLeft) {
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isRTL = true
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}
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var appliedLineOffset: CGFloat = 0.0
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for run in glyphRuns {
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let cfRunRange = CTRunGetStringRange(run)
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let runRange = NSMakeRange(cfRunRange.location == kCFNotFound ? NSNotFound : cfRunRange.location, cfRunRange.length)
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string.enumerateAttributes(in: runRange, options: []) { attributes, range, _ in
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if let id = attributes[NSAttributedString.Key.init(rawValue: InstantPageMediaIdAttribute)] as? Int64, let dimensions = attributes[NSAttributedString.Key.init(rawValue: InstantPageMediaDimensionsAttribute)] as? PixelDimensions {
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var imageFrame = CGRect(origin: CGPoint(), size: dimensions.cgSize.fitted(CGSize(width: boundingWidth, height: boundingWidth)))
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let imageSize = dimensions.cgSize.fitted(CGSize(width: boundingWidth, height: boundingWidth))
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let xOffset = CTLineGetOffsetForStringIndex(line, CTRunGetStringRange(run).location, nil)
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let yOffset = fontLineHeight.isZero ? 0.0 : floorToScreenPixels((fontLineHeight - imageFrame.size.height) / 2.0)
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imageFrame.origin = imageFrame.origin.offsetBy(dx: workingLineOrigin.x + xOffset, dy: workingLineOrigin.y + yOffset)
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let minSpacing = fontLineSpacing - 4.0
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let delta = workingLineOrigin.y - minSpacing - imageFrame.minY - appliedLineOffset
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if !fontAscent.isZero && delta > 0.0 {
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workingLineOrigin.y += delta
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appliedLineOffset += delta
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imageFrame.origin = imageFrame.origin.offsetBy(dx: 0.0, dy: delta)
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}
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if !fontLineHeight.isZero {
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extraDescent = max(extraDescent, imageFrame.maxY - (workingLineOrigin.y + fontLineHeight + minSpacing))
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}
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lineMaxAttachmentHeight = max(lineMaxAttachmentHeight, imageFrame.height)
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lineImageItems.append(InstantPageTextImageItem(frame: imageFrame, range: range, id: EngineMedia.Id(namespace: Namespaces.Media.CloudFile, id: id)))
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pendingImages.append(PendingV2ImageAttachment(xOffset: xOffset, range: range, id: id, size: imageSize))
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} else if let attachment = attributes[NSAttributedString.Key(rawValue: InstantPageFormulaAttribute)] as? InstantPageMathAttachment {
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let xOffset = CTLineGetOffsetForStringIndex(line, range.location, nil)
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let baselineOffset = (attributes[NSAttributedString.Key.baselineOffset] as? CGFloat) ?? 0.0
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var formulaFrame = CGRect(
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origin: CGPoint(
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x: workingLineOrigin.x + xOffset,
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y: workingLineOrigin.y + fontLineHeight + baselineOffset - attachment.rendered.ascent
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),
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size: attachment.rendered.size
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)
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let minSpacing = fontLineSpacing - 4.0
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let delta = workingLineOrigin.y - minSpacing - formulaFrame.minY - appliedLineOffset
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if !fontAscent.isZero && delta > 0.0 {
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workingLineOrigin.y += delta
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appliedLineOffset += delta
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formulaFrame.origin = formulaFrame.origin.offsetBy(dx: 0.0, dy: delta)
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}
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if !fontLineHeight.isZero {
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extraDescent = max(extraDescent, formulaFrame.maxY - (workingLineOrigin.y + fontLineHeight + minSpacing))
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}
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lineMaxAttachmentHeight = max(lineMaxAttachmentHeight, formulaFrame.height)
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lineFormulaItems.append(InstantPageTextFormulaRun(frame: formulaFrame, range: range, attachment: attachment))
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pendingFormulas.append(PendingV2FormulaAttachment(xOffset: xOffset, range: range, attachment: attachment, baselineOffset: baselineOffset))
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}
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}
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}
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}
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if substring.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty && (!lineImageItems.isEmpty || !lineFormulaItems.isEmpty) {
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extraDescent += max(6.0, fontLineSpacing / 2.0)
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var lineAscent: CGFloat = fontLineHeight
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var lineDescent: CGFloat = fontDescentBelowBaseline
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for image in pendingImages {
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if image.size.height > lineAscent {
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lineAscent = image.size.height
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}
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}
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for formula in pendingFormulas {
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let formulaAscent = formula.attachment.rendered.size.height - formula.attachment.rendered.descent
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if formulaAscent > lineAscent {
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lineAscent = formulaAscent
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}
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if formula.attachment.rendered.descent > lineDescent {
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lineDescent = formula.attachment.rendered.descent
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}
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}
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let baselineY = workingLineOrigin.y + lineAscent
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for image in pendingImages {
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let imageFrame = CGRect(
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x: workingLineOrigin.x + image.xOffset,
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y: baselineY - image.size.height,
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width: image.size.width,
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height: image.size.height
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)
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lineImageItems.append(InstantPageTextImageItem(frame: imageFrame, range: image.range, id: EngineMedia.Id(namespace: Namespaces.Media.CloudFile, id: image.id)))
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}
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for formula in pendingFormulas {
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let attachment = formula.attachment
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let formulaAscent = attachment.rendered.size.height - attachment.rendered.descent
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let formulaFrame = CGRect(
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x: workingLineOrigin.x + formula.xOffset,
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y: baselineY - formulaAscent + formula.baselineOffset,
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width: attachment.rendered.size.width,
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height: attachment.rendered.size.height
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)
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lineFormulaItems.append(InstantPageTextFormulaRun(frame: formulaFrame, range: formula.range, attachment: attachment))
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}
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extraDescent = max(0.0, lineDescent - baselineToNextTopSlack)
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if !minimizeWidth && !hadIndexOffset && lineCharacterCount > 1 && lineWidth > currentMaxWidth + 5.0 {
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if let imageItem = lineImageItems.last {
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@ -2603,14 +2621,14 @@ func layoutTextItem(
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let lowerX = floor(CTLineGetOffsetForStringIndex(line, range.location, nil))
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let upperX = ceil(CTLineGetOffsetForStringIndex(line, range.location + range.length, nil))
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let x = lowerX < upperX ? lowerX : upperX
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strikethroughItems.append(InstantPageTextStrikethroughItem(frame: CGRect(x: workingLineOrigin.x + x, y: workingLineOrigin.y, width: abs(upperX - lowerX), height: fontLineHeight)))
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strikethroughItems.append(InstantPageTextStrikethroughItem(frame: CGRect(x: workingLineOrigin.x + x, y: workingLineOrigin.y + (lineAscent - fontLineHeight), width: abs(upperX - lowerX), height: fontLineHeight)))
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}
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if let _ = attributes[NSAttributedString.Key.underlineStyle] {
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let lowerX = floor(CTLineGetOffsetForStringIndex(line, range.location, nil))
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let upperX = ceil(CTLineGetOffsetForStringIndex(line, range.location + range.length, nil))
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let x = lowerX < upperX ? lowerX : upperX
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underlineItems.append(InstantPageTextUnderlineItem(
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frame: CGRect(x: workingLineOrigin.x + x, y: workingLineOrigin.y, width: abs(upperX - lowerX), height: fontLineHeight),
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frame: CGRect(x: workingLineOrigin.x + x, y: workingLineOrigin.y + (lineAscent - fontLineHeight), width: abs(upperX - lowerX), height: fontLineHeight),
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range: range,
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color: attributes[NSAttributedString.Key.underlineColor] as? UIColor
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))
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@ -2626,7 +2644,7 @@ func layoutTextItem(
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let lowerX = floor(CTLineGetOffsetForStringIndex(line, range.location, nil))
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let upperX = ceil(CTLineGetOffsetForStringIndex(line, range.location + range.length, nil))
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let x = lowerX < upperX ? lowerX : upperX
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markedItems.append(InstantPageTextMarkedItem(frame: CGRect(x: workingLineOrigin.x + x, y: workingLineOrigin.y + delta, width: abs(upperX - lowerX), height: lineHeight), color: color, range: range))
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markedItems.append(InstantPageTextMarkedItem(frame: CGRect(x: workingLineOrigin.x + x, y: workingLineOrigin.y + (lineAscent - fontLineHeight) + delta, width: abs(upperX - lowerX), height: lineHeight), color: color, range: range))
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}
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if let item = attributes[NSAttributedString.Key.init(rawValue: InstantPageAnchorAttribute)] as? Dictionary<String, Any>, let name = item["name"] as? String, let empty = item["empty"] as? Bool {
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anchorItems.append(InstantPageTextAnchorItem(name: name, anchorText: item["text"] as? NSAttributedString, empty: empty))
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@ -2641,19 +2659,7 @@ func layoutTextItem(
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workingLineOrigin.y += fontLineSpacing
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}
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let height = !fontLineHeight.isZero ? max(fontLineHeight, lineMaxAttachmentHeight) : lineMaxAttachmentHeight
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if !lineFormulaItems.isEmpty {
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let baselineAdjustment = height - fontLineHeight
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if !baselineAdjustment.isZero {
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lineFormulaItems = lineFormulaItems.map { item in
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InstantPageTextFormulaRun(
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frame: item.frame.offsetBy(dx: 0.0, dy: baselineAdjustment),
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range: item.range,
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attachment: item.attachment
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)
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}
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}
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}
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let height = lineAscent
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if !markedItems.isEmpty {
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markedItems = markedItems.map { item in
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if let attachmentBounds = v2LocalAttachmentBoundsForRange(item.range, imageItems: lineImageItems, formulaItems: lineFormulaItems) {
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@ -2676,7 +2682,7 @@ func layoutTextItem(
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}
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workingLineOrigin.x = 0.0
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workingLineOrigin.y += fontLineHeight + fontLineSpacing + extraDescent
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workingLineOrigin.y += lineAscent + fontLineSpacing + extraDescent
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currentLineOrigin = workingLineOrigin
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lastIndex += lineCharacterCount
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