fix float precision bug in text box rendering

prawnpdf · Mar 2, 2023 · b319393 · b319393
1 parent 7d4f6b8
commit b319393
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Showing 3 changed files with 6 additions and 2 deletions.
diff --git a/lib/prawn/text/formatted/line_wrap.rb b/lib/prawn/text/formatted/line_wrap.rb
@@ -101,7 +101,7 @@ def add_fragment_to_line(fragment)
  @document.width_of(segment, kerning: @kerning)
  end
 
- if @accumulated_width + segment_width <= @width
+ if @accumulated_width + segment_width <= @width + FLOAT_PRECISION_DELTA
  @accumulated_width += segment_width
  shy = soft_hyphen(segment.encoding)
  if segment[-1] == shy

diff --git a/lib/prawn/text/formatted/wrap.rb b/lib/prawn/text/formatted/wrap.rb
@@ -131,7 +131,7 @@ def enough_height_for_this_line?
  @descender + @line_height + @leading
  end
  require_relatived_total_height = @baseline_y.abs + diff
- if require_relatived_total_height > @height + 0.0001
+ if require_relatived_total_height > @height + FLOAT_PRECISION_DELTA
  # no room for the full height of this line
  @arranger.repack_unretrieved
  false

diff --git a/lib/prawn/utilities.rb b/lib/prawn/utilities.rb
@@ -7,6 +7,10 @@
 # This is free software. Please see the LICENSE and COPYING files for details.
 
 module Prawn
+ # Useful for comparing floats for equality to avoid precision errors.
+ # Based on pdf-core output precision: https://github.com/prawnpdf/pdf-core/blob/1021ffc94b9d8d37854ef5199d3cbaf220bb5ab2/lib/pdf/core/pdf_object.rb#L16
+ FLOAT_PRECISION_DELTA = 1e-6
+
  # Throughout the Prawn codebase, repeated calculations which can benefit from
  # caching are made.
  # In some cases, caching and reusing results can not only save CPU cycles but