Attempt to fix leading

Needed to handle chosen opts for a line separately to those merged into
defaults.

lib/mudbrick/text_block.ex

@@ -105,7 +105,7 @@ defmodule Mudbrick.TextBlock do
     %{tb | lines: lines}
   end
 
-  defp write_lines(tb, text, opts) do
+  defp write_lines(tb, text, chosen_opts) do
     line_texts = String.split(text, "\n")
 
     text_block_opts = [
@@ -115,36 +115,43 @@ defmodule Mudbrick.TextBlock do
       leading: tb.leading
     ]
 
-    opts =
+    merged_opts =
       Keyword.merge(
         text_block_opts,
-        opts,
+        chosen_opts,
         &prefer_lhs_over_nil/3
       )
 
     Map.update!(tb, :lines, fn
       [] ->
-        add_texts([], line_texts, opts, text_block_opts)
+        add_texts([], line_texts, merged_opts, text_block_opts)
 
       existing_lines ->
         case line_texts do
           # \n at beginning of new line
           ["" | new_line_texts] ->
             existing_lines
-            |> add_texts(new_line_texts, opts, text_block_opts)
+            |> add_texts(new_line_texts, merged_opts, text_block_opts)
 
           # didn't start with \n, so first part belongs to previous line
           [first_new_line_text | new_line_texts] ->
             existing_lines
-            |> update_previous_line(first_new_line_text, opts)
-            |> add_texts(new_line_texts, opts, text_block_opts)
+            # Update previous line with chosen opts, to allow logic around
+            # choices.
+            |> update_previous_line(first_new_line_text, merged_opts, chosen_opts)
+            |> add_texts(new_line_texts, merged_opts, text_block_opts)
         end
     end)
   end
 
-  defp update_previous_line([previous_line | existing_lines], first_new_line_text, opts) do
+  defp update_previous_line(
+         [previous_line | existing_lines],
+         first_new_line_text,
+         merged_opts,
+         opts
+       ) do
     [
-      Line.append(previous_line, first_new_line_text, opts)
+      Line.append(previous_line, first_new_line_text, merged_opts, opts)
       | existing_lines
     ]
   end
@@ -160,6 +167,11 @@ defmodule Mudbrick.TextBlock do
     end
   end
 
-  defp prefer_lhs_over_nil(_key, lhs, nil), do: lhs
-  defp prefer_lhs_over_nil(_key, _lhs, rhs), do: rhs
+  defp prefer_lhs_over_nil(_key, lhs, nil) do
+    lhs
+  end
+
+  defp prefer_lhs_over_nil(_key, _lhs, rhs) do
+    rhs
+  end
 end

lib/mudbrick/text_block/line.ex

@@ -41,12 +41,11 @@ defmodule Mudbrick.TextBlock.Line do
     struct(__MODULE__, Keyword.put(opts, :parts, [Part.new(text, opts)]))
   end
 
-  def append(line, text, opts) do
-    line = Map.update!(line, :parts, &[Part.new(text, opts) | &1])
-    new_leading = Keyword.fetch!(opts, :leading)
+  def append(line, text, merged_opts, chosen_opts) do
+    line = Map.update!(line, :parts, &[Part.new(text, merged_opts) | &1])
 
-    if new_leading > line.leading do
-      Map.put(line, :leading, new_leading)
+    if chosen_opts[:leading] do
+      Map.put(line, :leading, chosen_opts[:leading])
     else
       line
     end

lib/mudbrick/text_block/output.ex

@@ -146,7 +146,7 @@ defmodule Mudbrick.TextBlock.Output do
           position: position = {x, y}
         } = tb
       ) do
-    tl = %TL{leading: leading(tb)}
+    tl = %TL{leading: tb.leading}
     tf = %Tf{font: font, size: font_size}
 
     %__MODULE__{position: position, font: font, font_size: font_size}
@@ -175,7 +175,7 @@ defmodule Mudbrick.TextBlock.Output do
     |> RightAlign.reduce_lines(tb.lines, fn output, line, line_number ->
       right_offset(output, tb, line, line_number)
     end)
-    |> add(%TL{leading: leading(tb)})
+    |> add(%TL{leading: tb.leading})
     |> add(tf)
     |> deduplicate(tf)
     |> Map.update!(:operations, &Enum.reverse/1)
@@ -227,7 +227,7 @@ defmodule Mudbrick.TextBlock.Output do
 
     add(output, %Td{
       tx: x - Line.width(line),
-      ty: y - leading(tb) * n
+      ty: y - tb.leading * n
     })
   end
 
@@ -263,8 +263,4 @@ defmodule Mudbrick.TextBlock.Output do
   defp remove(output, operation) do
     Map.update!(output, :operations, &List.delete(&1, operation))
   end
-
-  defp leading(tb) do
-    tb.leading || tb.font_size * 1.2
-  end
 end

test/mudbrick/text_block_test.exs

@@ -164,6 +164,54 @@ defmodule Mudbrick.TextBlockTest do
   end
 
   describe "leading" do
+    test "is set correctly for lines composed with writes" do
+      output(fn %{fonts: fonts} ->
+        heading_leading = 70
+        overlap_leading = 20
+        # 120% of default 80 font size
+        expected_final_leading = 96.0
+
+        text_block =
+          TextBlock.new(
+            align: :left,
+            font: fonts.regular,
+            font_size: 80,
+            position: {0, 500}
+          )
+          |> TextBlock.write("Warning!\n", font_size: 140, leading: heading_leading)
+          |> TextBlock.write("Leading ", leading: overlap_leading)
+          |> TextBlock.write("changes")
+          |> TextBlock.write("\nthis overlaps")
+
+        assert [
+                 ^expected_final_leading,
+                 ^overlap_leading,
+                 ^heading_leading
+               ] =
+                 Enum.map(text_block.lines, & &1.leading)
+
+        text_block
+      end)
+    end
+
+    test "is set correctly for linebreaks inside writes" do
+      output(fn %{fonts: fonts} ->
+        text_block =
+          TextBlock.new(
+            align: :left,
+            font: fonts.regular,
+            font_size: 80,
+            position: {0, 500}
+          )
+          |> TextBlock.write("Warning!\n", font_size: 140, leading: 20)
+          |> TextBlock.write("Steps under\nconstruction", leading: 70)
+
+        assert [70, 70, 20] = Enum.map(text_block.lines, & &1.leading)
+
+        text_block
+      end)
+    end
+
     test "can be set per line" do
       block =
         TextBlock.new(font_size: 10)