Compute sum of List element dims on-axis and max of cross-axis

gfx/list.lua

@@ -77,20 +77,28 @@ function List:draw()
   return dirty
 end
 
-function List:getHeight()
-  local h = 0
-  for _,v in ipairs(self.children) do
-    h = h + v:getHeight()
+local function maxOrSum(shouldSum, values, getValue)
+  if shouldSum then
+    local sum = 0
+    for _,v in ipairs(values) do
+      sum = sum + getValue(v)
+    end
+    return sum
+  else
+    local max = 0
+    for _,v in ipairs(values) do
+      max = math.max(max, getValue(v))
+    end
+    return max
   end
-  return h
+end
+
+function List:getHeight()
+  return maxOrSum(self:isVertical(), self.elements, function(e) return e:getHeight() end)
 end
 
 function List:getWidth()
-  local w = 0
-  for _,v in ipairs(self.children) do
-    w = w + v:getWidth()
-  end
-  return w
+  return maxOrSum(self:isHorizontal(), self.elements, function(e) return e:getWidth() end)
 end
 
 function List:findById(id)