Add back deleted file

lib/common/ui/dimens.dart

@@ -0,0 +1,51 @@
+import '../common.dart';
+
+const double borderRadius = 8;
+const double activeIconSize = 8;
+const double iconSize = 24;
+const double badgeSize = 36;
+const double messageBarHeight = 59;
+const double scrollBarRadius = 50;
+
+bool isLTR(BuildContext context) =>
+    !forceRTL && Directionality.of(context) == TextDirection.ltr;
+
+Widget mirrorLTR({required BuildContext context, required Widget child}) =>
+    Transform(
+      alignment: Alignment.center,
+      transform: Matrix4.rotationY(isLTR(context) ? 0 : pi),
+      child: child,
+    );
+
+bool shouldScroll({
+  required BuildContext context,
+  required int numElements,
+  required double elHeight,
+}) {
+  var height = MediaQuery.of(context).size.height;
+  var padding = MediaQuery.of(context).padding;
+  var safeHeight = height - padding.top - padding.bottom;
+  var topBarHeight = elHeight;
+
+  // TODO: needs to be tested
+  return safeHeight - topBarHeight < numElements * elHeight;
+}
+
+double calculateStickerHeight(BuildContext context, int messageCount) {
+  final conversationInnerHeight = MediaQuery.of(context).size.height -
+      100.0 -
+      100.0; // rough approximation for inner height - top bar height - message bar height
+  final messageHeight =
+      60.0; // rough approximation of how much space a message takes up, including paddings
+  final minStickerHeight = 353.0;
+  return max(
+    minStickerHeight,
+    conversationInnerHeight - ((messageCount - 1) * messageHeight),
+  );
+}
+
+double appBarHeight = 56.0;
+
+double defaultWarningBarHeight = 30.0;
+
+BorderRadius defaultBorderRadius = BorderRadius.circular(6.0);