Module: Idml::Render::Renderers::VerticalEmit

Included in:
TextFrameRenderer
Defined in:
lib/idml/render/renderers/vertical_emit.rb

Overview

Vertical writing path (StoryOrientation="Vertical", CJK): paragraphs flow as upright glyph columns advancing right-to-left; each run starts a fresh column (run-mixing within a column is not modeled). Runs whose columns would cross the frame's left inset overflow to the next frame in the chain. Paragraph spacing, rules, and decorations are not applied in vertical mode.

A class-methods module extended into TextFrameRenderer — it shares the host's constants, font resolution, and layout_frame helper (MECE: this module owns everything vertical; the host owns the horizontal engine).

Instance Method Summary collapse

Instance Method Details

#emit_upright_glyph(canvas, positioned, run, context, size) ⇒ Object 



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# File 'lib/idml/render/renderers/vertical_emit.rb', line 260

def emit_upright_glyph(canvas, positioned, run, context,
                       size)
  text = [positioned.codepoint].pack("U")
  text_kwargs = CharacterStyle.text_kwargs(
    run,
    {
      at: [positioned.x, positioned.y],
      font: font_for_run(run, context),
      size: size,
    },
  )
  canvas.text(text, **text_kwargs)
end

#emit_vertical_ruby(canvas, run, positioned, frame, base_size, context) ⇒ Object

Emits the run's ruby alongside its vertical glyphs: stacked top-to-bottom beside the column — right side by default, left for Below* RubyPosition values (the horizontal above/below convention mirrored under rotation).



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# File 'lib/idml/render/renderers/vertical_emit.rb', line 285

def emit_vertical_ruby(canvas, run, positioned, frame,
                       base_size, context)
  ruby_text = run.ruby_string
  return if ruby_text.nil? || ruby_text.empty?

  ruby_size = run.ruby_font_size ||
    (base_size * TextFrameRenderer::RUBY_SIZE_FACTOR)
  x = ruby_vertical_x(positioned.first, run, base_size)
  y = frame.y + frame.height - (frame.inset_top || 0)
  ruby_text.each_codepoint do |codepoint|
    text_kwargs = CharacterStyle.text_kwargs(
      run,
      {
        at: [x, y - ruby_size],
        font: font_for_run(run, context),
        size: ruby_size,
      },
    )
    canvas.text([codepoint].pack("U"), **text_kwargs)
    y -= ruby_size
  end
end

#emit_vertical_run(canvas, positioned, grouped, run, context, size) ⇒ Object

Emits a vertical run's glyphs: rotated/normal vertical handling for stacked columns, plain upright emission for tate-chu-yoko groups.



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# File 'lib/idml/render/renderers/vertical_emit.rb', line 202

def emit_vertical_run(canvas, positioned, grouped, run,
                      context, size)
  if grouped
    positioned.each do |glyph|
      emit_upright_glyph(canvas, glyph, run, context, size)
    end
  else
    emit_vertical_stack(canvas, positioned, run, context, size)
  end
end

#emit_vertical_stack(canvas, positioned, run, context, size) ⇒ Object

Vertical-stack emission: CJK glyphs stand upright per glyph; consecutive non-CJK glyphs rotate as ONE group (the whole Latin word sideways, as InDesign does). The group's string renders as a single text op inside one rotated graphics state — the font's advances land each glyph exactly where per-glyph rotation placed it. A group never spans columns (x reset) and shares the run's styling, so one text op is lossless.



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# File 'lib/idml/render/renderers/vertical_emit.rb', line 221

def emit_vertical_stack(canvas, positioned, run, context,
                        size)
  segment = []
  positioned.each do |glyph|
    if TextEngine::CjkLayout.cjk?(glyph.codepoint)
      flush_vertical_segment(canvas, segment, run, context, size)
      emit_upright_glyph(canvas, glyph, run, context, size)
    else
      if !segment.empty? && segment.last.x != glyph.x
        flush_vertical_segment(canvas, segment, run, context, size)
      end
      segment << glyph
    end
  end
  flush_vertical_segment(canvas, segment, run, context, size)
end

#flush_vertical_segment(canvas, segment, run, context, size) ⇒ Object 



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# File 'lib/idml/render/renderers/vertical_emit.rb', line 238

def flush_vertical_segment(canvas, segment, run, context,
                           size)
  return if segment.empty?

  text = segment.map { |g| [g.codepoint].pack("U") }.join
  first = segment.first
  canvas.save_graphics_state do
    # 90° clockwise: exact matrix (rotate would emit
    # cos/sin float noise like 6.1e-17).
    canvas.concat(0, -1, 1, 0, first.x, first.y)
    text_kwargs = CharacterStyle.text_kwargs(
      run,
      {
        at: [0, 0],
        font: font_for_run(run, context),
        size: size,
      },
    )
    canvas.text(text, **text_kwargs)
  end
end

#keep_all_deferred?(paragraph, needed, room) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/idml/render/renderers/vertical_emit.rb', line 90

def keep_all_deferred?(paragraph, needed, room)
  paragraph.keep_all_lines_together && needed > room
end

#keep_flagged?(paragraph) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/idml/render/renderers/vertical_emit.rb', line 83

def keep_flagged?(paragraph)
  paragraph.keep_all_lines_together ||
    !paragraph.keep_with_next.nil? ||
    paragraph.keep_first_lines ||
    paragraph.keep_last_lines
end

#resume_vertical_paragraph(state) ⇒ Object

Folds a chain-resumed paragraph (runs_remaining) back to the head of the paragraph list so the vertical path sees a uniform sequence. The consumed column offset persists in the state so the next frame continues right where this frame's columns ended.



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# File 'lib/idml/render/renderers/vertical_emit.rb', line 144

def resume_vertical_paragraph(state)
  return unless state.current_paragraph

  state.current_paragraph.runs = state.runs_remaining
  state.paragraphs.unshift(state.current_paragraph)
  state.current_paragraph = nil
  state.runs_remaining = []
end

#ruby_vertical_x(positioned, run, base_size) ⇒ Object 



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# File 'lib/idml/render/renderers/vertical_emit.rb', line 308

def ruby_vertical_x(positioned, run, base_size)
  offset = base_size * 0.9
  if run.ruby_position.to_s.include?("Below")
    positioned.x - offset
  else
    positioned.x + offset
  end
end

#tatechuyoko_group(run, glyphs, layout_frame, leading, size, start_column) ⇒ Object

A tate-chu-yoko group for runs that declare it (and whose glyphs fit horizontally in a column slot); nil otherwise.



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# File 'lib/idml/render/renderers/vertical_emit.rb', line 189

def tatechuyoko_group(run, glyphs, layout_frame, leading,
                      size, start_column)
  return nil unless run.tatechuyoko

  TextEngine::VerticalTextLayout.tatechuyoko_group(
    glyphs: glyphs, frame: layout_frame, leading: leading,
    size: size, start_column: start_column
  )
end

#vertical_available_columns(layout_frame, leading, left_limit, next_column) ⇒ Object 



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# File 'lib/idml/render/renderers/vertical_emit.rb', line 132

def vertical_available_columns(layout_frame, leading, left_limit,
                               next_column)
  right = layout_frame.x + layout_frame.width -
    (layout_frame.inset_right || 0)
  (((right - left_limit) / leading).floor - next_column).to_i
end

#vertical_fits?(layout_frame, leading, columns, left_limit) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/idml/render/renderers/vertical_emit.rb', line 274

def vertical_fits?(layout_frame, leading, columns, left_limit)
  right = layout_frame.x + layout_frame.width -
    (layout_frame.inset_right || 0)
  (right - (columns * leading)) >= left_limit
end

#vertical_keep_deferred?(paragraph, next_paragraph, layout_frame, _font, left_limit, next_column, pending, entry_offset) ⇒ Boolean

Keep options in vertical mode (TODO 153, column-count approximation — one column per run under-estimates runs that span several columns, so deferral errs toward placing): KeepAllLinesTogether defers the paragraph wholly to the next frame; KeepWithNext also defers when the follower (or its forced break) would strand. Never defers the frame's first paragraph — the progress guarantee, shared with KeepPolicy.

Returns:

  • (Boolean) 


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# File 'lib/idml/render/renderers/vertical_emit.rb', line 66

def vertical_keep_deferred?(paragraph, next_paragraph,
                            layout_frame, _font, left_limit,
                            next_column, pending, entry_offset)
  placed = pending.positive? || entry_offset.positive?
  return false unless placed
  return false unless keep_flagged?(paragraph)

  needed = [paragraph.runs.length, 1].max
  room = vertical_room(layout_frame, paragraph, left_limit,
                       next_column)
  return true if keep_all_deferred?(paragraph, needed, room)
  return true if window_deferred?(paragraph, needed, room)

  with_next_deferred?(paragraph, next_paragraph, layout_frame,
                      left_limit, next_column, needed)
end

#vertical_paragraph(canvas, paragraph, context, layout_frame, font, left_limit, start_column) ⇒ Object

Renders one paragraph's runs as vertical columns starting at start_column. Returns [runs that did not fit (empty when all placed), the next unused column index].



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# File 'lib/idml/render/renderers/vertical_emit.rb', line 156

def vertical_paragraph(canvas, paragraph, context,
                       layout_frame, font, left_limit,
                       start_column)
  next_column = start_column
  paragraph.runs.each_with_index do |run, index|
    size = run.point_size || TextFrameRenderer::DEFAULT_SIZE
    leading = TextEngine::VerticalLayout.leading_for(
      paragraph.auto_leading, size
    )
    glyphs = TextEngine::Shaper.shape(text: run.text, font: font,
                                      size: size)
    grouped = tatechuyoko_group(run, glyphs, layout_frame,
                                leading, size, next_column)
    positioned, next_column = grouped ||
      TextEngine::VerticalTextLayout.layout(
        glyphs: glyphs, frame: layout_frame, leading: leading,
        size: size, start_column: next_column
      )
    unless vertical_fits?(layout_frame, leading, next_column,
                          left_limit)
      return [paragraph.runs[index..], start_column]
    end

    emit_vertical_run(canvas, positioned, grouped, run, context,
                      size)
    emit_vertical_ruby(canvas, run, positioned, layout_frame,
                       size, context)
  end
  [[], next_column]
end

#vertical_render(canvas, state, context, box, font) ⇒ Object 



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# File 'lib/idml/render/renderers/vertical_emit.rb', line 23

def vertical_render(canvas, state, context, box, font)
  layout_frame = layout_frame(context.item, box)
  left_limit = layout_frame.x + (layout_frame.inset_left || 0)
  resume_vertical_paragraph(state)
  entry_offset = state.column_offset || 0
  next_column = entry_offset
  pending = 0

  state.paragraphs.each_with_index do |paragraph, index|
    if vertical_keep_deferred?(paragraph, state.paragraphs[index + 1],
                               layout_frame, font, left_limit,
                               next_column, pending, entry_offset)
      state.current_paragraph = nil
      state.runs_remaining = []
      state.column_offset = 0
      break
    end

    remaining_runs, next_column = vertical_paragraph(
      canvas, paragraph, context, layout_frame, font,
      left_limit, next_column
    )
    if remaining_runs.empty?
      pending += 1
    else
      state.current_paragraph = paragraph
      state.runs_remaining = remaining_runs
      state.column_offset = next_column
      break
    end
  end

  state.paragraphs = state.paragraphs[pending..]
end

#vertical_room(layout_frame, paragraph, left_limit, next_column) ⇒ Object 



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# File 'lib/idml/render/renderers/vertical_emit.rb', line 121

def vertical_room(layout_frame, paragraph, left_limit,
                  next_column)
  leading = TextEngine::VerticalLayout.leading_for(
    paragraph.auto_leading,
    paragraph.runs.first&.point_size ||
      TextFrameRenderer::DEFAULT_SIZE,
  )
  vertical_available_columns(layout_frame, leading, left_limit,
                             next_column)
end

#vertical_story?(story) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/idml/render/renderers/vertical_emit.rb', line 19

def vertical_story?(story)
  story.inner&.story_preference&.story_orientation == "Vertical"
end

#window_deferred?(paragraph, needed, room) ⇒ Boolean

Keep windows on the same column-count approximation: defer a splitting paragraph when fewer than KeepFirstLines columns fit, or when the stranded tail would hold fewer than KeepLastLines columns.

Returns:

  • (Boolean) 


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# File 'lib/idml/render/renderers/vertical_emit.rb', line 98

def window_deferred?(paragraph, needed, room)
  return false unless needed > room

  if paragraph.keep_first_lines &&
      room < paragraph.keep_first_lines
    return true
  end

  paragraph.keep_last_lines &&
    (needed - room) < paragraph.keep_last_lines
end

#with_next_deferred?(paragraph, next_paragraph, layout_frame, left_limit, next_column, needed) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/idml/render/renderers/vertical_emit.rb', line 110

def with_next_deferred?(paragraph, next_paragraph, layout_frame,
                        left_limit, next_column, needed)
  return false if paragraph.keep_with_next.nil?

  follower_needed = [next_paragraph&.runs&.length || 1, 1].max
  follower_break = KeepPolicy.paragraph_break?(next_paragraph)
  room = vertical_room(layout_frame, paragraph, left_limit,
                       next_column)
  follower_break || needed + follower_needed > room
end