Fixes vector-im/element-ios/issues/6441 - Incorrect timeline item text height calculation (#6679)

Riot/Modules/MatrixKit/Models/Room/MXKRoomBubbleCellData.m

@@ -518,46 +518,39 @@
 
 - (CGSize)textContentSize:(NSAttributedString*)attributedText removeVerticalInset:(BOOL)removeVerticalInset
 {
-    static UITextView* measurementTextView = nil;
-    static UITextView* measurementTextViewWithoutInset = nil;
-    
-    if (attributedText.length)
-    {
-        if (!measurementTextView)
-        {
-            measurementTextView = [[UITextView alloc] init];
-            
-            measurementTextViewWithoutInset = [[UITextView alloc] init];
-            // Remove the container inset: this operation impacts only the vertical margin.
-            // Note: consider textContainer.lineFragmentPadding to remove horizontal margin
-            measurementTextViewWithoutInset.textContainerInset = UIEdgeInsetsZero;
-        }
-        
-        // Select the right text view for measurement
-        UITextView *selectedTextView = (removeVerticalInset ? measurementTextViewWithoutInset : measurementTextView);
-        
-        selectedTextView.frame = CGRectMake(0, 0, _maxTextViewWidth, 0);
-        selectedTextView.attributedText = attributedText;
-            
-        CGSize size = [selectedTextView sizeThatFits:selectedTextView.frame.size];
-
-        // Manage the case where a string attribute has a single paragraph with a left indent
-        // In this case, [UITextView sizeThatFits] ignores the indent and return the width
-        // of the text only.
-        // So, add this indent afterwards
-        NSRange textRange = NSMakeRange(0, attributedText.length);
-        NSRange longestEffectiveRange;
-        NSParagraphStyle *paragraphStyle = [attributedText attribute:NSParagraphStyleAttributeName atIndex:0 longestEffectiveRange:&longestEffectiveRange inRange:textRange];
-
-        if (NSEqualRanges(textRange, longestEffectiveRange))
-        {
-            size.width = size.width + paragraphStyle.headIndent;
-        }
-
-        return size;
+    if (attributedText.length == 0) {
+        return CGSizeZero;
     }
     
-    return CGSizeZero;
+    // Grab the default textContainer insets and lineFragmentPadding from a dummy text view.
+    // This has no business being here but the refactoring effort would be too great (sceriu 05.09.2022)
+    static UITextView* measurementTextView = nil;
+    if (!measurementTextView)
+    {
+        measurementTextView = [[UITextView alloc] init];
+    }
+    
+    CGFloat verticalInset = measurementTextView.textContainerInset.top + measurementTextView.textContainerInset.bottom;
+    CGFloat horizontalInset = measurementTextView.textContainer.lineFragmentPadding * 2;
+    
+    CGSize size = [attributedText boundingRectWithSize:CGSizeMake(_maxTextViewWidth - horizontalInset, CGFLOAT_MAX)
+                                               options:NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading
+                                               context:nil].size;
+    
+    //In iOS 7 and later, this method returns fractional sizes (in the size component of the returned rectangle);
+    // to use a returned size to size views, you must use raise its value to the nearest higher integer using the
+    // [ceil](https://developer.apple.com/documentation/kernel/1557272-ceil?changes=latest_major) function.
+    size.width = ceil(size.width);
+    size.height = ceil(size.height);
+
+    // The result is expected to contain the textView textContainer's paddings. Add them back if necessary
+    if (removeVerticalInset == NO) {
+        size.height += verticalInset;
+    }
+    
+    size.width += horizontalInset;
+    
+    return size;
 }
 
 #pragma mark - Properties

changelog.d/6441.bugfix

@@ -0,0 +1 @@
+Fixed incorrect iOS 16 timeline item text height calculations leading to empty gaps.