Class: Ea::Svg::EaEmitter::BoundsCalculator

Inherits:
Object
  • Object
show all
Defined in:
lib/ea/svg/ea_emitter/bounds_calculator.rb

Overview

Computes the (min_x, min_y, width, height) tuple for a Diagram's canvas. Encapsulates the union rules so Canvas stays a small value-object with just coordinate translation and formatting concerns.

Sources contributing to the bounds:

- ElementBounds:    logical x-extent, logical+image y-extent
- ConnectorBounds:  waypoint positions
- MarkerExtent:     MARKER_EXTENT padding around end points
- PackageTabExtent: extra space above Package elements for
                  the tab polygon (which sits above the
                  element's logical top).

Each source is a method returning an Array<[x, y]> points. Composing new sources = adding a method, no modification of existing ones (OCP).

Constant Summary collapse

MARKER_EXTENT = 
15
PACKAGE_TAB_HEIGHT = 
20
INSET_LEFT =

EA's canvas includes non-uniform frame insets around the element content. Reverse-engineered from reference SVG byte-diff: maintenance diagram has element 169x80 at logical (0,0), ref canvas is 254x177 with element at (35, 40). So:

canvas_width  = element_width + INSET_LEFT + INSET_RIGHT
canvas_height = element_height + INSET_TOP + INSET_BOTTOM

The top inset accommodates the frame tab + label space above the element.

35
INSET_RIGHT = 
50
INSET_TOP = 
40
INSET_BOTTOM = 
57

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(diagram, model_index: nil) ⇒ BoundsCalculator

Returns a new instance of BoundsCalculator.



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# File 'lib/ea/svg/ea_emitter/bounds_calculator.rb', line 41

def initialize(diagram, model_index: nil)
  @diagram = diagram
  @model_index = model_index
end

Instance Attribute Details

#diagram ⇒ Object (readonly)

Returns the value of attribute diagram.



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# File 'lib/ea/svg/ea_emitter/bounds_calculator.rb', line 39

def diagram
  @diagram
end

#model_index ⇒ Object (readonly)

Returns the value of attribute model_index.



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# File 'lib/ea/svg/ea_emitter/bounds_calculator.rb', line 39

def model_index
  @model_index
end

Instance Method Details

#compute ⇒ Object 



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# File 'lib/ea/svg/ea_emitter/bounds_calculator.rb', line 46

def compute
  points = []
  points.concat(element_points)
  points.concat(connector_points)
  points.concat(marker_points)
  points.concat(package_tab_points)
  return [0, 0, 1, 1] if points.empty?

  xs = points.map(&:first)
  ys = points.map(&:last)
  min_x = xs.min || 0
  min_y = ys.min || 0
  [
    min_x,
    min_y,
    (xs.max - min_x) + INSET_LEFT + INSET_RIGHT,
    (ys.max - min_y) + INSET_TOP + INSET_BOTTOM
  ]
end