Optimized Textview size calculations (#207)

* Updated recalculation of grid cell bounds

* Moved size calculation of AutogrowingTextView to background

Author: rajdeep

Diff for: Proton/Sources/Swift/Attachment/Attachment.swift

@@ -329,6 +329,14 @@ open class Attachment: NSTextAttachment, BoundsObserving {
     public override func attachmentBounds(for textContainer: NSTextContainer?, proposedLineFragment lineFrag: CGRect, glyphPosition position: CGPoint, characterIndex charIndex: Int) -> CGRect {
         self.indexInContainer = charIndex
 
+        // When calculating size of EditorView, this may be called on the background thread. Since size of attachment depends on contained view,
+        // we need to put the bounds calculation back on main.
+        guard Thread.isMainThread else {
+            return DispatchQueue.main.sync {
+                attachmentBounds(for: textContainer, proposedLineFragment: lineFrag, glyphPosition: position, characterIndex: charIndex)
+            }
+        }
+
         guard let textContainer = textContainer,
               textContainer.size.height > 0,
               textContainer.size.width > 0

Diff for: Proton/Sources/Swift/Base/AutogrowingTextView.swift

@@ -65,8 +65,10 @@ class AutogrowingTextView: UITextView {
     private func recalculateHeight() {
         let bounds = self.bounds.integral
         let fittingSize = self.calculatedSize(attributedText: attributedText, frame: frame.size, textContainerInset: textContainerInset)
+
         self.isScrollEnabled = (fittingSize.height > bounds.height) || (self.maxHeight > 0 && self.maxHeight < fittingSize.height)
-        heightAnchorConstraint.constant = min(fittingSize.height, contentSize.height)
+        self.heightAnchorConstraint.constant = min(fittingSize.height, self.contentSize.height)
+
     }
 
     override open func sizeThatFits(_ size: CGSize) -> CGSize {
@@ -90,11 +92,13 @@ class AutogrowingTextView: UITextView {
     }
 
     private func calculatedSize(attributedText: NSAttributedString, frame: CGSize, textContainerInset: UIEdgeInsets) -> CGSize {
-        // Adjust for horizontal paddings in textview to exclude from overall available width for attachment
-        let horizontalAdjustments = (textContainer.lineFragmentPadding * 2) + (textContainerInset.left + textContainerInset.right)
-        let boundingRect = attributedText.boundingRect(with: CGSize(width: frame.width - horizontalAdjustments, height: .greatestFiniteMagnitude), options: [.usesLineFragmentOrigin], context: nil).integral
+        DispatchQueue.global(qos: .userInteractive).sync { [lineFragmentPadding = textContainer.lineFragmentPadding ]  in
+            // Adjust for horizontal paddings in textview to exclude from overall available width for attachment
+            let horizontalAdjustments = (lineFragmentPadding * 2) + (textContainerInset.left + textContainerInset.right)
+            let boundingRect = attributedText.boundingRect(with: CGSize(width: frame.width - horizontalAdjustments, height: .greatestFiniteMagnitude), options: [.usesLineFragmentOrigin], context: nil).integral
 
-        let insets = UIEdgeInsets(top: -textContainerInset.top, left: -textContainerInset.left, bottom: -textContainerInset.bottom, right: -textContainerInset.right)
-        return boundingRect.inset(by: insets).size
+            let insets = UIEdgeInsets(top: -textContainerInset.top, left: -textContainerInset.left, bottom: -textContainerInset.bottom, right: -textContainerInset.right)
+            return boundingRect.inset(by: insets).size
+        }
     }
 }

Diff for: Proton/Sources/Swift/Grid/View/GridContentView.swift

@@ -283,38 +283,43 @@ class GridContentView: UIScrollView {
         recalculateCellBounds()
     }
 
-    private func recalculateCellBounds() {
+    private func recalculateCellBounds(initiatingCell: GridCell? = nil) {
         frozenRowsConstraints.forEach { $0.isActive = false }
         frozenColumnsConstraints.forEach { $0.isActive = false }
         removeConstraints(frozenRowsConstraints + frozenColumnsConstraints)
 
-        for c in grid.cells.reversed() {
+        var cells = grid.cells
+        if let initiatingCell {
+            cells = [initiatingCell]
+        }
+
+        for cell in cells {
             // TODO: Optimize to recalculate frames for affected cells only i.e. row>=current
 
             // Set the frame of the cell before adding to superview
             // This is required to avoid breaking layout constraints
             // as default size is 0
-            let frame = grid.frameForCell(c, basedOn: bounds.size)
-            c.frame = frame
-            c.contentView.frame = frame
-            c.widthAnchorConstraint.constant = frame.width
-            c.heightAnchorConstraint.constant = frame.height
+            let frame = grid.frameForCell(cell, basedOn: bounds.size)
+            cell.frame = frame
+            cell.contentView.frame = frame
+            cell.widthAnchorConstraint.constant = frame.width
+            cell.heightAnchorConstraint.constant = frame.height
 
             // Add to grid if this is a newly inserted cell after initial setup.
             // A new cell may exist as a result of inserting a new row/column
             // or splitting an existing merged cell
-            if c.contentView.superview == nil {
-                addSubview(c.contentView)
-                c.topAnchorConstraint = c.contentView.topAnchor.constraint(equalTo: topAnchor, constant: frame.minY)
-                c.leadingAnchorConstraint = c.contentView.leadingAnchor.constraint(equalTo: leadingAnchor, constant: frame.minX)
+            if cell.contentView.superview == nil {
+                addSubview(cell.contentView)
+                cell.topAnchorConstraint = cell.contentView.topAnchor.constraint(equalTo: topAnchor, constant: frame.minY)
+                cell.leadingAnchorConstraint = cell.contentView.leadingAnchor.constraint(equalTo: leadingAnchor, constant: frame.minX)
             } else {
-                c.topAnchorConstraint?.constant = frame.minY
-                c.leadingAnchorConstraint?.constant = frame.minX
+                cell.topAnchorConstraint?.constant = frame.minY
+                cell.leadingAnchorConstraint?.constant = frame.minX
             }
 
-            freezeColumnCellIfRequired(c)
-            freezeRowCellIfRequired(c)
-            gridContentViewDelegate?.gridContentView(self, didLayoutCell: c)
+            freezeColumnCellIfRequired(cell)
+            freezeRowCellIfRequired(cell)
+            gridContentViewDelegate?.gridContentView(self, didLayoutCell: cell)
         }
 
         boundsObserver?.didChangeBounds(CGRect(origin: bounds.origin, size: frame.size), oldBounds: bounds)
@@ -404,7 +409,7 @@ extension GridContentView: GridCellDelegate {
             grid.rowHeights[row].currentHeight = grid.maxContentHeightCellForRow(at: row)?.contentSize.height ?? 0
         }
 
-        recalculateCellBounds()
+        recalculateCellBounds(initiatingCell: cell)
         gridContentViewDelegate?.gridContentView(self, didChangeBounds: cell.frame, in: cell)
     }