Fix bottom origins underflowing buffer

lib/remedy/align.rb

@@ -38,6 +38,8 @@ def hv_center content, buffer
       buffer[voffset,hoffset] = content
     end
 
+    # Middle offset.
+    #
     # Given the actual space something takes up,
     #   determine what the offset to get it centered in the available space.
     #
@@ -50,6 +52,20 @@ def mido actual, available
       offset = ((available - actual) / 2.0).floor
     end
 
+    # Bottom offset.
+    #
+    # Given the actual space something takes up,
+    #   determine what the offset to get it at the far edge in the available space.
+    #
+    # @param actual [Numeric] the space already taken
+    # @param available [Numeric] the available space
+    # @return [Integer] the offset from the end of the availabe space to place the actual content at the end
+    def boto actual, available
+      return available unless actual < available
+
+      offset = available - actual
+    end
+
     # Given the actual space something takes up,
     #   determine what the offset to get it centered in the available space,
     #   including the trailing space remaining.

lib/remedy/frame.rb

@@ -274,28 +274,32 @@ def arrange_arbitrary content_to_arrange
 
       result = depth_sort(content_to_arrange).each do |frame|
         # FIXME: what happens when the buffer size is zero? the buffer will grow, right?
-        frame.available_size = arrange_buffer.size
+        frame.available_size = buffer_size
         content = frame.compile_contents
         fsize = frame.computed_size || frame.content_size
 
         case frame.vorigin
         when :top
           voffset = 0
         when :center
-          voffset = Align.mido fsize.height, arrange_buffer.size.height
+          voffset = Align.mido fsize.height, buffer_size.height
         when :bottom
-          voffset = arrange_buffer.size.height - fsize.height
+          voffset = Align.boto fsize.height, buffer_size.height
         else
           raise "Unknown vorigin:#{frame.vorigin}"
         end
 
+        # this line works around an edge case where only :top vorigins would
+        #   be rendered when available_size was zero and the frame size was :none
+        voffset = 0 if frame.vorigin != :top && buffer_size.height == 0 && voffset < 0
+
         case frame.horigin
         when :left
           hoffset = 0
         when :center
-          hoffset = Align.mido fsize.width, arrange_buffer.size.width
+          hoffset = Align.mido fsize.width, buffer_size.width
         when :right
-          hoffset = arrange_buffer.size.width - fsize.width
+          voffset = Align.boto fsize.height, buffer_size.height
         else
           raise "Unknown horigin:#{frame.horigin}"
         end
@@ -306,6 +310,7 @@ def arrange_arbitrary content_to_arrange
         offset = Tuple voffset, hoffset
 
         arrange_buffer[offset] = content
+        buffer_size = arrange_buffer.size
       end
 
       arrange_buffer.to_a

spec/frame_spec.rb

@@ -509,11 +509,8 @@
         f.arrangement = :arbitrary
         f.reset!
 
-
         f1.size = Tuple 3, 3
         f1.fill = "."
-        f1.valign = :center
-        f1.halign = :center
 
         f1.horigin = :center
         f1.vorigin = :bottom
@@ -526,7 +523,7 @@
         expect(actual).to eq expected
       end
 
-      context "available size is zero" do
+      context "available_size.zero? = true" do
         before do
           f.available_size = sizeclass.zero
         end
@@ -536,6 +533,21 @@
           actual = f.to_s
           expect(actual).to eq expected
         end
+
+        context "size = :none" do
+          before do
+            f.size = :none
+            f1.depth = 2
+            f2.size = Tuple 2,1
+            f << f2
+          end
+
+          it "puts the frame at the bottom of the actual space" do
+            expected = "b  \n...\n.a.\n..."
+            actual = f.to_s
+            expect(actual).to eq expected
+          end
+        end
       end
     end
   end