Optimize for loops

@@ -204,7 +204,7 @@ class PdfString extends PdfDataType {
       encoding.add(unit & UNICODE_BYTE_ZERO_MASK);
     }
 
-    for (var unit in str.codeUnits) {
+    for (final unit in str.codeUnits) {
       if ((unit >= 0 && unit < UNICODE_UTF16_RESERVED_LO) ||
           (unit > UNICODE_UTF16_RESERVED_HI && unit <= UNICODE_PLANE_ONE_MAX)) {
         add(unit);
@@ -225,7 +225,7 @@ class PdfString extends PdfDataType {
   /// Escape special characters
   /// \ddd Character code ddd (octal)
   void _putTextBytes(PdfStream s, List<int> b) {
-    for (var c in b) {
+    for (final c in b) {
       switch (c) {
         case 0x0a: // \n Line feed (LF)
           s.putByte(0x5c);
@@ -274,7 +274,7 @@ class PdfString extends PdfDataType {
     switch (format) {
       case PdfStringFormat.binary:
         s.putByte(0x3c);
-        for (var byte in value) {
+        for (final byte in value) {
           s.putByte(_codeUnitForDigit((byte & 0xF0) >> 4));
           s.putByte(_codeUnitForDigit(byte & 0x0F));
         }

@@ -326,7 +326,7 @@ Iterable<String> _parse(String text) sync* {
   final notArabicWords = <List<int>>[];
 
   var first = true;
-  for (var word in words) {
+  for (final word in words) {
     final newWord = <int>[];
     var isNewWordArabic = false;
 
@@ -375,7 +375,7 @@ Iterable<String> _parse(String text) sync* {
 
     if (isNewWordArabic) {
       isNewWordArabic = false;
-      for (var notArabicNewWord in notArabicWords) {
+      for (final notArabicNewWord in notArabicWords) {
         yield '${String.fromCharCodes(notArabicNewWord)} ';
       }
       notArabicWords.clear();

@@ -57,7 +57,7 @@ class PdfFontMetrics {
     double? firstBearing;
     late double spacing;
 
-    for (var metric in metrics) {
+    for (final metric in metrics) {
       firstBearing ??= metric.leftBearing;
       left ??= metric.left;
       spacing = metric.advanceWidth > 0 ? letterSpacing : 0.0;

@@ -303,15 +303,15 @@ class TtfParser {
 
   /// https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6glyf.html
   void _parseGlyphs() {
-    final baseOffset = tableOffsets[glyf_table];
+    final baseOffset = tableOffsets[glyf_table]!;
     final hmtxOffset = tableOffsets[hmtx_table]!;
     final unitsPerEm = this.unitsPerEm;
     final numOfLongHorMetrics = this.numOfLongHorMetrics;
     final defaultadvanceWidth =
         bytes.getUint16(hmtxOffset + (numOfLongHorMetrics - 1) * 4);
     var glyphIndex = 0;
-    for (var offset in glyphOffsets) {
-      final xMin = bytes.getInt16(baseOffset! + offset + 2); // 2
+    for (final offset in glyphOffsets) {
+      final xMin = bytes.getInt16(baseOffset + offset + 2); // 2
       final yMin = bytes.getInt16(baseOffset + offset + 4); // 4
       final xMax = bytes.getInt16(baseOffset + offset + 6); // 6
       final yMax = bytes.getInt16(baseOffset + offset + 8); // 8

@@ -78,14 +78,14 @@ class TtfWriter {
 
       final glyph =
           ttf.readGlyph(ttf.charToGlyphIndexMap[chars[index]] ?? 0).copy();
-      for (var g in glyph.compounds) {
+      for (final g in glyph.compounds) {
         compounds[g] = -1;
       }
       glyphsInfo.add(glyph);
     }
 
     // Add compound glyphs
-    for (var compound in compounds.keys) {
+    for (final compound in compounds.keys) {
       final index = glyphsInfo.firstWhere(
         (TtfGlyphInfo glyph) => glyph.index == compound,
         orElse: () {
@@ -106,14 +106,14 @@ class TtfWriter {
     glyphsInfo.add(glyph);
 
     // update compound indices
-    for (var glyph in glyphsInfo) {
+    for (final glyph in glyphsInfo) {
       if (glyph.compounds.isNotEmpty) {
         _updateCompoundGlyph(glyph, compounds);
       }
     }
 
     var glyphsTableLength = 0;
-    for (var glyph in glyphsInfo) {
+    for (final glyph in glyphsInfo) {
       glyphsTableLength =
           _wordAlign(glyphsTableLength + glyph.data.lengthInBytes);
     }
@@ -136,7 +136,7 @@ class TtfWriter {
     {
       final loca = tables[TtfParser.loca_table]!.buffer.asByteData();
       var index = 0;
-      for (var glyph in glyphsInfo) {
+      for (final glyph in glyphsInfo) {
         if (ttf.indexToLocFormat == 0) {
           loca.setUint16(index, offset ~/ 2);
           index += 2;
@@ -195,7 +195,7 @@ class TtfWriter {
       final defaultadvanceWidth =
           ttf.bytes.getUint16(hmtxOffset + (numOfLongHorMetrics - 1) * 4);
       var index = 0;
-      for (var glyph in glyphsInfo) {
+      for (final glyph in glyphsInfo) {
         final advanceWidth = glyph.index < numOfLongHorMetrics
             ? ttf.bytes.getUint16(hmtxOffset + glyph.index * 4)
             : defaultadvanceWidth;

@@ -104,8 +104,8 @@ class PdfCatalog extends PdfObjectDict {
     }
 
     final widgets = <PdfAnnot>[];
-    for (var page in pdfDocument.pdfPageList.pages) {
-      for (var annot in page.annotations) {
+    for (final page in pdfDocument.pdfPageList.pages) {
+      for (final annot in page.annotations) {
         if (annot.annot.subtype == '/Widget') {
           widgets.add(annot);
         }

@@ -55,7 +55,7 @@ class PdfNames extends PdfObjectDict {
 
     final keys = _dests.keys.toList()..sort();
 
-    for (var name in keys) {
+    for (final name in keys) {
       dests.add(PdfSecString.fromString(this, name));
       dests.add(_dests[name]!);
     }

@@ -189,7 +189,7 @@ class PdfOutline extends PdfObjectDict {
     var c = outlines.length; // initially the number of kids
 
     // now call each one for their descendants
-    for (var o in outlines) {
+    for (final o in outlines) {
       c += o.descendants();
     }
 

@@ -163,7 +163,7 @@ class PdfTtfFont extends PdfFont {
     final runes = text.runes;
 
     stream.putByte(0x3c);
-    for (var rune in runes) {
+    for (final rune in runes) {
       var char = unicodeCMap.cmap.indexOf(rune);
       if (char == -1) {
         char = unicodeCMap.cmap.length;

@@ -100,7 +100,7 @@ class PdfXrefTable extends PdfDataType {
   void _writeblock(PdfStream s, int firstid, List<PdfXref> block) {
     s.putString('$firstid ${block.length}\n');
 
-    for (var x in block) {
+    for (final x in block) {
       s.putString(x.ref());
       s.putByte(0x0a);
     }
@@ -125,7 +125,7 @@ class PdfXrefTable extends PdfDataType {
       type: PdfCrossRefEntryType.free,
     ));
 
-    for (var x in offsets) {
+    for (final x in offsets) {
       // check to see if block is in range
       if (x.id != (lastid + 1)) {
         // no, so write this block, and reset
@@ -165,7 +165,7 @@ class PdfXrefTable extends PdfDataType {
     // We need block 0 to exist
     blocks.add(firstid);
 
-    for (var x in offsets) {
+    for (final x in offsets) {
       // check to see if block is in range
       if (x.id != (lastid + 1)) {
         // no, so store this block, and reset
@@ -195,7 +195,7 @@ class PdfXrefTable extends PdfDataType {
     // Write offset zero, all zeros
     ofs += wl;
 
-    for (var x in offsets) {
+    for (final x in offsets) {
       ofs = x.cref(o, ofs, w);
     }
 

@@ -64,7 +64,7 @@ class _BarcodeWidget extends Widget {
 
     final textList = <BarcodeText>[];
 
-    for (var element in barcode!.makeBytes(
+    for (final element in barcode!.makeBytes(
       data,
       width: box!.width,
       height: box!.height,
@@ -93,7 +93,7 @@ class _BarcodeWidget extends Widget {
     if (drawText!) {
       final font = textStyle!.font!.getFont(context);
 
-      for (var text in textList) {
+      for (final text in textList) {
         final metrics = font!.stringMetrics(text.text);
 
         final top = box!.top -
@@ -136,7 +136,7 @@ class _BarcodeWidget extends Widget {
     super.debugPaint(context);
 
     if (drawText!) {
-      for (var element in barcode!.makeBytes(
+      for (final element in barcode!.makeBytes(
         data,
         width: box!.width,
         height: box!.height,

@@ -105,13 +105,13 @@ class CartesianGrid extends ChartGrid {
     final datasets = Chart.of(context).datasets;
 
     clip(context, box!.size);
-    for (var dataSet in datasets) {
+    for (final dataSet in datasets) {
       dataSet.paintBackground(context);
     }
     context.canvas.restoreContext();
     paintBackground(context);
     clip(context, box!.size);
-    for (var dataSet in datasets) {
+    for (final dataSet in datasets) {
       dataSet.paint(context);
     }
     context.canvas.restoreContext();

@@ -69,13 +69,13 @@ class RadialGrid extends ChartGrid {
     final datasets = Chart.of(context).datasets;
 
     clip(context, box!.size);
-    for (var dataSet in datasets) {
+    for (final dataSet in datasets) {
       dataSet.paintBackground(context);
     }
     context.canvas.restoreContext();
     paintBackground(context);
     clip(context, box!.size);
-    for (var dataSet in datasets) {
+    for (final dataSet in datasets) {
       dataSet.paint(context);
     }
     context.canvas.restoreContext();

@@ -88,19 +88,19 @@ class PieGrid extends ChartGrid {
         Matrix4.translationValues(box!.width / 2, box!.height / 2, 0),
       );
 
-    for (var dataSet in datasets) {
+    for (final dataSet in datasets) {
       if (dataSet is PieDataSet) {
         dataSet.paintBackground(context);
       }
     }
 
-    for (var dataSet in datasets) {
+    for (final dataSet in datasets) {
       if (dataSet is PieDataSet) {
         dataSet.paint(context);
       }
     }
 
-    for (var dataSet in datasets) {
+    for (final dataSet in datasets) {
       if (dataSet is PieDataSet) {
         dataSet.paintLegend(context);
       }

@@ -121,7 +121,7 @@ class Document {
 
   Future<Uint8List> save() async {
     if (!_paint) {
-      for (var page in _pages) {
+      for (final page in _pages) {
         page.postProcess(this);
       }
       _paint = true;

@@ -118,7 +118,7 @@ class Flex extends MultiChildWidget with SpanningWidget {
       var inflexibleSpace = 0.0;
       var maxFlexFractionSoFar = 0.0;
 
-      for (var child in children) {
+      for (final child in children) {
         final flex = child is Flexible ? child.flex : 0;
         totalFlex += flex;
         if (flex > 0) {
@@ -140,7 +140,7 @@ class Flex extends MultiChildWidget with SpanningWidget {
       var totalFlex = 0;
       var inflexibleSpace = 0.0;
       var maxCrossSize = 0.0;
-      for (var child in children) {
+      for (final child in children) {
         final flex = child is Flexible ? child.flex : 0;
         totalFlex += flex;
         double? mainSize;
@@ -167,7 +167,7 @@ class Flex extends MultiChildWidget with SpanningWidget {
           math.max(0.0, (availableMainSpace! - inflexibleSpace) / totalFlex);
 
       // Size remaining (flexible) items, find the maximum cross size.
-      for (var child in children) {
+      for (final child in children) {
         final flex = child is Flexible ? child.flex : 0;
         if (flex > 0) {
           maxCrossSize =
@@ -241,7 +241,7 @@ class Flex extends MultiChildWidget with SpanningWidget {
     var allocatedSize = 0.0; // Sum of the sizes of the non-flexible children.
     var index = _context.firstChild;
 
-    for (var child in children.sublist(_context.firstChild)) {
+    for (final child in children.sublist(_context.firstChild)) {
       final flex = child is Flexible ? child.flex : 0;
       final fit = child is Flexible ? child.fit : FlexFit.loose;
       if (flex > 0) {
@@ -305,7 +305,7 @@ class Flex extends MultiChildWidget with SpanningWidget {
       final spacePerFlex =
           canFlex && totalFlex > 0 ? (freeSpace / totalFlex) : double.nan;
 
-      for (var child in children) {
+      for (final child in children) {
         final flex = child is Flexible ? child.flex : 0;
         final fit = child is Flexible ? child.fit : FlexFit.loose;
         if (flex > 0) {

@@ -162,7 +162,7 @@ class GridView extends MultiChildWidget with SpanningWidget {
     var c = 0;
     _context.lastChild = _context.firstChild;
 
-    for (var child in children.sublist(
+    for (final child in children.sublist(
         _context.firstChild,
         math.min(children.length,
             _context.firstChild + crossAxisCount * _mainAxisCount!))) {

@@ -368,7 +368,7 @@ class MultiPage extends Page {
     final pageWidthMargin = _mustRotate ? _margin.vertical : _margin.horizontal;
     final availableWidth = pageWidth - pageWidthMargin;
 
-    for (var page in _pages) {
+    for (final page in _pages) {
       var offsetStart = pageHeight -
           (_mustRotate ? pageHeightMargin - _margin.bottom : _margin.top);
       var offsetEnd =
@@ -386,7 +386,7 @@ class MultiPage extends Page {
       var totalFlex = 0;
       var allocatedSize = 0.0;
       Widget? lastFlexChild;
-      for (var widget in page.widgets) {
+      for (final widget in page.widgets) {
         final child = widget.child;
         final flex = child is Flexible ? child.flex : 0;
         if (flex > 0) {
@@ -467,7 +467,7 @@ class MultiPage extends Page {
         }
       }
 
-      for (var widget in page.widgets) {
+      for (final widget in page.widgets) {
         final child = widget.child;
 
         final flex = child is Flexible ? child.flex : 0;
@@ -505,7 +505,7 @@ class MultiPage extends Page {
       }
 
       var pos = offsetStart - leadingSpace;
-      for (var widget in page.widgets) {
+      for (final widget in page.widgets) {
         pos -= widget.child.box!.height;
         late double x;
         switch (crossAxisAlignment) {

@@ -135,7 +135,7 @@ class Partitions extends Widget with SpanningWidget {
 
     // Calculate fixed width columns
     var index = 0;
-    for (var child in children) {
+    for (final child in children) {
       if (child.flex > 0) {
         assert(() {
           if (!canFlex) {
@@ -160,7 +160,7 @@ class Partitions extends Widget with SpanningWidget {
       final spacePerFlex = freeSpace / totalFlex;
 
       index = 0;
-      for (var child in children) {
+      for (final child in children) {
         if (child.flex > 0) {
           final childExtent = spacePerFlex * child.flex;
           allocatedSize += childExtent;
@@ -173,7 +173,7 @@ class Partitions extends Widget with SpanningWidget {
     // Layout the columns and compute the total height
     var totalHeight = 0.0;
     index = 0;
-    for (var child in children) {
+    for (final child in children) {
       if (widths[index]! > 0) {
         final innerConstraints = BoxConstraints(
             minWidth: widths[index]!,
@@ -190,7 +190,7 @@ class Partitions extends Widget with SpanningWidget {
     // Update Y positions
     index = 0;
     allocatedSize = 0.0;
-    for (var child in children) {
+    for (final child in children) {
       if (widths[index]! > 0) {
         final offsetY = totalHeight - child.box!.height;
         child.box = PdfRect.fromPoints(
@@ -213,7 +213,7 @@ class Partitions extends Widget with SpanningWidget {
     context.canvas
       ..saveContext()
       ..setTransform(mat);
-    for (var child in children) {
+    for (final child in children) {
       child.paint(context);
     }
     context.canvas.restoreContext();

@@ -147,7 +147,7 @@ class Stack extends MultiChildWidget {
         break;
     }
 
-    for (var child in children) {
+    for (final child in children) {
       if (child is! Positioned) {
         hasNonPositionedChildren = true;
 
@@ -168,7 +168,7 @@ class Stack extends MultiChildWidget {
       box = PdfRect.fromPoints(PdfPoint.zero, constraints.biggest);
     }
 
-    for (var child in children) {
+    for (final child in children) {
       if (child is! Positioned) {
         child.box = PdfRect.fromPoints(
             alignment.inscribe(child.box!.size, box!).offset, child.box!.size);
@@ -232,7 +232,7 @@ class Stack extends MultiChildWidget {
         ..drawRect(0, 0, box!.width, box!.height)
         ..clipPath();
     }
-    for (var child in children) {
+    for (final child in children) {
       child.paint(context);
     }
     context.canvas.restoreContext();

@@ -108,7 +108,7 @@ class TableBorder extends Border {
     if (verticalInside.style.paint) {
       verticalInside.style.setStyle(context);
       var offset = box.x;
-      for (var width in widths!.sublist(0, widths.length - 1)) {
+      for (final width in widths!.sublist(0, widths.length - 1)) {
         offset += width!;
         context.canvas.moveTo(offset, box.y);
         context.canvas.lineTo(offset, box.top);
@@ -123,7 +123,7 @@ class TableBorder extends Border {
     if (horizontalInside.style.paint) {
       horizontalInside.style.setStyle(context);
       var offset = box.top;
-      for (var height in heights!.sublist(0, heights.length - 1)) {
+      for (final height in heights!.sublist(0, heights.length - 1)) {
         offset -= height;
         context.canvas.moveTo(box.x, offset);
         context.canvas.lineTo(box.right, offset);
@@ -437,9 +437,9 @@ class Table extends Widget with SpanningWidget {
     _heights.clear();
     var index = 0;
 
-    for (var row in children) {
+    for (final row in children) {
       var n = 0;
-      for (var child in row.children) {
+      for (final child in row.children) {
         final columnWidth = columnWidths != null && columnWidths![n] != null
             ? columnWidths![n]!
             : defaultColumnWidth;
@@ -495,7 +495,7 @@ class Table extends Widget with SpanningWidget {
     // Compute final widths
     var totalHeight = 0.0;
     index = 0;
-    for (var row in children) {
+    for (final row in children) {
       if (index++ < _context.firstLine && !row.repeat) {
         continue;
       }
@@ -504,7 +504,7 @@ class Table extends Widget with SpanningWidget {
       var x = 0.0;
 
       var lineHeight = 0.0;
-      for (var child in row.children) {
+      for (final child in row.children) {
         final childConstraints = BoxConstraints.tightFor(width: _widths[n]);
         child.layout(context, childConstraints);
         assert(child.box != null);
@@ -521,7 +521,7 @@ class Table extends Widget with SpanningWidget {
         // Compute the layout again to give the full height to all cells
         n = 0;
         x = 0;
-        for (var child in row.children) {
+        for (final child in row.children) {
           final childConstraints =
               BoxConstraints.tightFor(width: _widths[n], height: lineHeight);
           child.layout(context, childConstraints);
@@ -545,14 +545,14 @@ class Table extends Widget with SpanningWidget {
     // Compute final y position
     index = 0;
     var heightIndex = 0;
-    for (var row in children) {
+    for (final row in children) {
       if (index++ < _context.firstLine && !row.repeat) {
         continue;
       }
 
       final align = row.verticalAlignment ?? defaultVerticalAlignment;
 
-      for (var child in row.children) {
+      for (final child in row.children) {
         double? childY;
 
         switch (align) {
@@ -602,7 +602,7 @@ class Table extends Widget with SpanningWidget {
       ..setTransform(mat);
 
     var index = 0;
-    for (var row in children) {
+    for (final row in children) {
       if (index++ < _context.firstLine && !row.repeat) {
         continue;
       }
@@ -610,7 +610,7 @@ class Table extends Widget with SpanningWidget {
       if (row.decoration != null) {
         var y = double.infinity;
         var h = 0.0;
-        for (var child in row.children) {
+        for (final child in row.children) {
           y = math.min(y, child.box!.y);
           h = math.max(h, child.box!.height);
         }
@@ -621,7 +621,7 @@ class Table extends Widget with SpanningWidget {
         );
       }
 
-      for (var child in row.children) {
+      for (final child in row.children) {
         context.canvas
           ..saveContext()
           ..drawRect(
@@ -636,7 +636,7 @@ class Table extends Widget with SpanningWidget {
     }
 
     index = 0;
-    for (var row in children) {
+    for (final row in children) {
       if (index++ < _context.firstLine && !row.repeat) {
         continue;
       }
@@ -644,7 +644,7 @@ class Table extends Widget with SpanningWidget {
       if (row.decoration != null) {
         var y = double.infinity;
         var h = 0.0;
-        for (var child in row.children) {
+        for (final child in row.children) {
           y = math.min(y, child.box!.y);
           h = math.max(h, child.box!.height);
         }

@@ -458,16 +458,16 @@ class TextSpan extends InlineSpan {
     AnnotationBuilder? annotation,
   ) {
     final _style = parentStyle?.merge(style);
-    final _a = this.annotation ?? annotation;
+    final _annotation = this.annotation ?? annotation;
 
     if (text != null) {
-      if (!visitor(this, _style, _a)) {
+      if (!visitor(this, _style, _annotation)) {
         return false;
       }
     }
     if (children != null) {
-      for (var child in children!) {
-        if (!child.visitChildren(visitor, _style, _a)) {
+      for (final child in children!) {
+        if (!child.visitChildren(visitor, _style, _annotation)) {
           return false;
         }
       }
@@ -534,7 +534,7 @@ class _Line {
         }
         delta = (totalWidth - wordsWidth) / (spans.length - 1);
         var x = 0.0;
-        for (var span in spans) {
+        for (final span in spans) {
           span.offset = span.offset.translate(x, -baseline);
           x += delta;
         }
@@ -542,7 +542,7 @@ class _Line {
     }
 
     if (textDirection == TextDirection.rtl) {
-      for (var span in spans) {
+      for (final span in spans) {
         span.offset = PdfPoint(
           totalWidth - (span.offset.x + span.width) - delta,
           span.offset.y - baseline,
@@ -552,7 +552,7 @@ class _Line {
       return;
     }
 
-    for (var span in spans) {
+    for (final span in spans) {
       span.offset = span.offset.translate(delta, -baseline);
     }
 
@@ -978,7 +978,7 @@ class RichText extends Widget with SpanningWidget {
         ..clipPath();
     }
 
-    for (var decoration in _decorations) {
+    for (final decoration in _decorations) {
       assert(() {
         if (Document.debug && RichText.debug) {
           decoration.debugPaint(context, textScaleFactor, box!, _spans);
@@ -994,7 +994,7 @@ class RichText extends Widget with SpanningWidget {
       );
     }
 
-    for (var span in _spans.sublist(_context.spanStart, _context.spanEnd)) {
+    for (final span in _spans.sublist(_context.spanStart, _context.spanEnd)) {
       assert(() {
         if (Document.debug && RichText.debug) {
           span.debugPaint(context, textScaleFactor, box);
@@ -1018,7 +1018,7 @@ class RichText extends Widget with SpanningWidget {
       );
     }
 
-    for (var decoration in _decorations) {
+    for (final decoration in _decorations) {
       decoration.foregroundPaint(
         context,
         textScaleFactor,

@@ -35,7 +35,7 @@ class TextDecoration {
   /// Creates a decoration that paints the union of all the given decorations.
   factory TextDecoration.combine(List<TextDecoration> decorations) {
     var mask = 0;
-    for (var decoration in decorations) {
+    for (final decoration in decorations) {
       mask |= decoration._mask;
     }
     return TextDecoration._(mask);

@@ -192,7 +192,7 @@ class Wrap extends MultiChildWidget with SpanningWidget {
     var runCrossAxisExtent = 0.0;
     var childCount = 0;
 
-    for (var child in children.sublist(_context.firstChild)) {
+    for (final child in children.sublist(_context.firstChild)) {
       child.layout(context, childConstraints, parentUsesSize: true);
 
       final childMainAxisExtent = _getMainAxisExtent(child)!;
@@ -339,7 +339,7 @@ class Wrap extends MultiChildWidget with SpanningWidget {
       }
 
       var currentWidget = _context.lastChild;
-      for (var child in children.sublist(currentWidget)) {
+      for (final child in children.sublist(currentWidget)) {
         final runIndex = childRunMetrics[child];
         if (runIndex != i) {
           break;

@@ -460,7 +460,7 @@ void main() {
       ),
     );
 
-    for (var item in cases) {
+    for (final item in cases) {
       expect(
         arabic.convert(item.original).codeUnits,
         equals(item.reshaped),

@@ -107,7 +107,7 @@ void main() {
     final fontData = ttfFont.readAsBytesSync();
     final font = PdfTtfFont(pdf.document, fontData.buffer.asByteData());
 
-    for (var letter in
+    for (final letter in
         //font.font.charToGlyphIndexMap.keys
         'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz&%!?0123456789'
             .codeUnits) {

@@ -54,8 +54,8 @@ void main() {
     final image = generateBitmap(100, 200);
 
     final widgets = <Widget>[];
-    for (var shape in BoxShape.values) {
-      for (var fit in BoxFit.values) {
+    for (final shape in BoxShape.values) {
+      for (final fit in BoxFit.values) {
         widgets.add(
           Container(
             alignment: Alignment.center,

@@ -30,7 +30,7 @@ List<TableRow> buildTable(
   final rows = <TableRow>[];
   {
     final tableRow = <Widget>[];
-    for (var cell in <String>['Hue', 'Color', 'RGBA']) {
+    for (final cell in <String>['Hue', 'Color', 'RGBA']) {
       tableRow.add(Container(
           alignment: Alignment.center,
           margin: const EdgeInsets.all(5),

@@ -32,7 +32,7 @@ Iterable<TextDecoration> permute(
     List<TextDecoration> prefix, List<TextDecoration> remaining) sync* {
   yield TextDecoration.combine(prefix);
   if (remaining.isNotEmpty) {
-    for (var decoration in remaining) {
+    for (final decoration in remaining) {
       final next = List<TextDecoration>.from(remaining);
       next.remove(decoration);
       yield* permute(prefix + <TextDecoration>[decoration], next);
@@ -99,7 +99,7 @@ void main() {
     final para = LoremText().paragraph(40);
 
     final widgets = <Widget>[];
-    for (var align in TextAlign.values) {
+    for (final align in TextAlign.values) {
       widgets.add(
         Text(
           '$align:\n' + para,
@@ -191,8 +191,8 @@ void main() {
       ),
     );
 
-    for (var decorationStyle in TextDecorationStyle.values) {
-      for (var decoration in decorationSet) {
+    for (final decorationStyle in TextDecorationStyle.values) {
+      for (final decoration in decorationSet) {
         widgets.add(
           Text(
             decoration.toString().replaceAll('.', ' '),
@@ -217,7 +217,7 @@ void main() {
     final para = LoremText(random: rnd).paragraph(40);
 
     final spans = <TextSpan>[];
-    for (var word in para.split(' ')) {
+    for (final word in para.split(' ')) {
       spans.add(
         TextSpan(
           text: word,

@@ -31,9 +31,9 @@ void main() {
 
   test('Wrap Widget Horizontal 1', () {
     final wraps = <Widget>[];
-    for (var direction in VerticalDirection.values) {
+    for (final direction in VerticalDirection.values) {
       wraps.add(Text('$direction'));
-      for (var alignment in WrapAlignment.values) {
+      for (final alignment in WrapAlignment.values) {
         wraps.add(Text('$alignment'));
         wraps.add(
           Wrap(
@@ -63,9 +63,9 @@ void main() {
 
   test('Wrap Widget Vertical 1', () {
     final wraps = <Widget>[];
-    for (var direction in VerticalDirection.values) {
+    for (final direction in VerticalDirection.values) {
       wraps.add(Transform.rotateBox(child: Text('$direction'), angle: 1.57));
-      for (var alignment in WrapAlignment.values) {
+      for (final alignment in WrapAlignment.values) {
         wraps.add(Transform.rotateBox(child: Text('$alignment'), angle: 1.57));
         wraps.add(
           Wrap(
@@ -95,7 +95,7 @@ void main() {
 
   test('Wrap Widget Horizontal 2', () {
     final wraps = <Widget>[];
-    for (var alignment in WrapCrossAlignment.values) {
+    for (final alignment in WrapCrossAlignment.values) {
       final rnd = math.Random(42);
       wraps.add(Text('$alignment'));
       wraps.add(
@@ -129,7 +129,7 @@ void main() {
 
   test('Wrap Widget Vertical 2', () {
     final wraps = <Widget>[];
-    for (var alignment in WrapCrossAlignment.values) {
+    for (final alignment in WrapCrossAlignment.values) {
       final rnd = math.Random(42);
       wraps.add(Transform.rotateBox(child: Text('$alignment'), angle: 1.57));
       wraps.add(
@@ -163,7 +163,7 @@ void main() {
 
   test('Wrap Widget Horizontal 3', () {
     final wraps = <Widget>[];
-    for (var alignment in WrapAlignment.values) {
+    for (final alignment in WrapAlignment.values) {
       final rnd = math.Random(42);
       wraps.add(Text('$alignment'));
       wraps.add(
@@ -199,7 +199,7 @@ void main() {
 
   test('Wrap Widget Vertical 3', () {
     final wraps = <Widget>[];
-    for (var alignment in WrapAlignment.values) {
+    for (final alignment in WrapAlignment.values) {
       final rnd = math.Random(42);
       wraps.add(Transform.rotateBox(child: Text('$alignment'), angle: 1.57));
       wraps.add(