Module: Idml::Render::WrapContour

Defined in:
lib/idml/render/wrap_contour.rb

Overview

Shape-mode text wrap: builds a PDF-space polygon from a page item's PathGeometry (Bézier segments flattened at a fixed resolution) and measures the horizontal overlap of a text line's band with the polygon, expanded by the wrap offsets. Band coverage uses even-odd ray casting at the band's midline, so compound paths with holes wrap correctly.

Defined Under Namespace

Classes: Shape

Constant Summary collapse

FLATTEN_STEPS = 
8

Class Method Summary collapse

Class Method Details

.bounding_box(shape) ⇒ Object

The shape's bounding box: [left, bottom, right, top] in PDF coordinates, flattened across subpaths.



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# File 'lib/idml/render/wrap_contour.rb', line 33

def self.bounding_box(shape)
  points = shape.polygons.flatten(1)
  xs = points.map(&:first)
  ys = points.map(&:last)
  [xs.min, ys.min, xs.max, ys.max]
end

.overlap_width(shape, line_y, line_height, frame_x, frame_right) ⇒ Object

Total horizontal overlap of the text line's band with the shape, expanded by the offsets and clipped to the frame. The caller (TextWrapResolver) owns inverse flipping.



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# File 'lib/idml/render/wrap_contour.rb', line 135

def self.overlap_width(shape, line_y, line_height, frame_x,
                       frame_right)
  mid_y = line_y + (line_height / 2.0)
  width = shape.polygons.sum do |polygon|
    polygon_overlap(polygon, mid_y, shape.offset)
  end
  clip_width(width, frame_x, frame_right)
end

.shape(item, pref, page_height) ⇒ Object

Builds the wrap shape for an item's PathGeometry and wrap preference. Returns nil when the item has no geometry.



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

def self.shape(item, pref, page_height)
  polygons = polygons_for(item, page_height)
  return nil if polygons.empty?

  Shape.new(polygons: polygons, offset: wrap_offset(pref),
            inverse: pref.inverse, side: pref.text_wrap_side)
end