Module: Prawn::Graphics

Includes:
CapStyle, Color, Dash, Gradient, JoinStyle, Transformation, Transparency
Included in:
Document
Defined in:
lib/prawn/graphics.rb,
lib/prawn/graphics/dash.rb,
lib/prawn/graphics/color.rb,
lib/prawn/graphics/gradient.rb,
lib/prawn/graphics/cap_style.rb,
lib/prawn/graphics/join_style.rb,
lib/prawn/graphics/transparency.rb,
lib/prawn/graphics/transformation.rb

Overview

Implements the drawing facilities for Prawn::Document. Use this to draw the most beautiful imaginable things.

This file lifts and modifies several of PDF::Writer's graphics functions ruby-pdf.rubyforge.org

Defined Under Namespace

Modules: CapStyle, Color, Dash, Gradient, JoinStyle, Transformation, Transparency

Constant Summary

KAPPA =

This constant is used to approximate a symmetrical arc using a cubic Bezier curve.

4.0 * ((Math.sqrt(2) - 1.0) / 3.0)

Constants included from JoinStyle

JoinStyle::JOIN_STYLES

Constants included from CapStyle

CapStyle::CAP_STYLES

Constants included from Color

Color::COLOR_SPACES

Instance Method Summary (collapse)

Methods included from Gradient

#fill_gradient, #stroke_gradient

Methods included from Transformation

#rotate, #scale, #transformation_matrix, #translate

Methods included from Transparency

#transparent

Methods included from JoinStyle

#join_style

Methods included from CapStyle

#cap_style

Methods included from Dash

#dash, #dashed?, #undash, #write_stroke_dash

Methods included from Color

#fill_color, #hex2rgb, #rgb2hex, #stroke_color

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

- (Object) method_missing(id, *args, &block)

Provides the following shortcuts:

stroke_some_method(*args) #=> some_method(*args); stroke
fill_some_method(*args) #=> some_method(*args); fill
fill_and_stroke_some_method(*args) #=> some_method(*args); fill_and_stroke


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# File 'lib/prawn/graphics.rb', line 346

def method_missing(id,*args,&block)
  case(id.to_s)
  when /^fill_and_stroke_(.*)/
    send($1,*args,&block); fill_and_stroke
  when /^stroke_(.*)/
    send($1,*args,&block); stroke
  when /^fill_(.*)/
    send($1,*args,&block); fill
  else
    super
  end
end

Instance Method Details

- (Object) circle(center, radius)

Draws a circle of radius radius with the centre-point at point as a complete subpath. The drawing point will be moved to the centre-point upon completion of the drawing the circle.

pdf.circle [100,100], 25


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# File 'lib/prawn/graphics.rb', line 197

def circle(center, radius)
  ellipse(center, radius, radius)
end

- (Object) circle_at(point, options)

DEPRECATED: Please use circle instead.



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# File 'lib/prawn/graphics.rb', line 185

def circle_at(point, options)
  warn "[DEPRECATION] 'circle_at' is deprecated in favor of 'circle'. " +
       "'circle_at' will be removed in release 1.1"
  circle(point, options[:radius])
end

- (Object) close_and_stroke

Closes and strokes the current path. If a block is provided, yields to the block before closing the path. See Graphics::Color for color details.



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# File 'lib/prawn/graphics.rb', line 297

def close_and_stroke
  yield if block_given?
  add_content "s"
end

- (Object) close_path

Closes the current path.



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# File 'lib/prawn/graphics.rb', line 336

def close_path
  add_content "h"
end

- (Object) curve(origin, dest, options = {})

Draws a Bezier curve between two points, bounded by two additional points

pdf.curve [50,100], [100,100], :bounds => [[90,90],[75,75]]


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# File 'lib/prawn/graphics.rb', line 174

def curve(origin,dest, options={})
  move_to(*origin)
  curve_to(dest,options)
end

- (Object) curve_to(dest, options = {})

Draws a Bezier curve from the current drawing position to the specified point, bounded by two additional points.

pdf.curve_to [100,100], :bounds => [[90,90],[75,75]]


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# File 'lib/prawn/graphics.rb', line 66

def curve_to(dest,options={})
   options[:bounds] or raise Prawn::Errors::InvalidGraphicsPath,
     "Bounding points for bezier curve must be specified "+
     "as :bounds => [[x1,y1],[x2,y2]]"

   curve_points = (options[:bounds] << dest).map { |e| map_to_absolute(e) }
   add_content("%.3f %.3f %.3f %.3f %.3f %.3f c" %
                 curve_points.flatten )
end

- (Object) ellipse(point, r1, r2 = r1)

Draws an ellipse of x radius r1 and y radius r2 with the centre-point at point as a complete subpath. The drawing point will be moved to the centre-point upon completion of the drawing the ellipse.

# draws an ellipse with x-radius 25 and y-radius 50
pdf.ellipse [100,100], 25, 50


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# File 'lib/prawn/graphics.rb', line 216

def ellipse(point, r1, r2 = r1)
  x, y = point
  l1 = r1 * KAPPA
  l2 = r2 * KAPPA

  move_to(x + r1, y)

  # Upper right hand corner
  curve_to [x,  y + r2],
    :bounds => [[x + r1, y + l2], [x + l1, y + r2]]

  # Upper left hand corner
  curve_to [x - r1, y],
    :bounds => [[x - l1, y + r2], [x - r1, y + l2]]

  # Lower left hand corner
  curve_to [x, y - r2],
    :bounds => [[x - r1, y - l2], [x - l1, y - r2]]

  # Lower right hand corner
  curve_to [x + r1, y],
    :bounds => [[x + l1, y - r2], [x + r1, y - l2]]

  move_to(x, y)
end

- (Object) ellipse_at(point, r1, r2 = r1)

DEPRECATED: Please use ellipse instead.



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# File 'lib/prawn/graphics.rb', line 202

def ellipse_at(point, r1, r2=r1)
  warn "[DEPRECATION] 'ellipse_at' is deprecated in favor of 'ellipse'. " +
       "'ellipse_at' will be removed in release 1.1"
  ellipse(point, r1, r2)
end

- (Object) fill(options = {})

Closes and fills the current path. See Graphics::Color for color details.

If the option :fill_rule => :even_odd is specified, Prawn will use the even-odd rule to fill the path. Otherwise, the nonzero winding number rule will be used. See the PDF reference, "Graphics -> Path Construction and Painting -> Clipping Path Operators" for details on the difference.



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# File 'lib/prawn/graphics.rb', line 315

def fill(options={})
  yield if block_given?
  add_content(options[:fill_rule] == :even_odd ? "f*" : "f")
end

- (Object) fill_and_stroke(options = {})

Closes, fills, and strokes the current path. If a block is provided, yields to the block before closing the path. See Graphics::Color for color details.

If the option :fill_rule => :even_odd is specified, Prawn will use the even-odd rule to fill the path. Otherwise, the nonzero winding number rule will be used. See the PDF reference, "Graphics -> Path Construction and Painting -> Clipping Path Operators" for details on the difference.



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# File 'lib/prawn/graphics.rb', line 329

def fill_and_stroke(options={})
  yield if block_given?
  add_content(options[:fill_rule] == :even_odd ? "b*" : "b")
end

- (Object) horizontal_line(x1, x2, options = {})

Draws a horizontal line from x1 to x2 at the current y position, or the position specified by the :at option.

# draw a line from [25, 75] to [100, 75]
horizontal_line 25, 100, :at => 75


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# File 'lib/prawn/graphics.rb', line 143

def horizontal_line(x1,x2,options={})
  if options[:at]
    y1 = options[:at]
  else
    y1 = y - bounds.absolute_bottom
  end
  
  line(x1,y1,x2,y1)
end

- (Object) horizontal_rule

Draws a horizontal line from the left border to the right border of the bounding box at the current y position.



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# File 'lib/prawn/graphics.rb', line 156

def horizontal_rule
  horizontal_line(bounds.left, bounds.right)
end

- (Object) line(*points)

Draws a line from one point to another. Points may be specified as tuples or flattened argument list:

pdf.line [100,100], [200,250]
pdf.line(100,100,200,250)


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# File 'lib/prawn/graphics.rb', line 131

def line(*points)
  x0,y0,x1,y1 = points.flatten
  move_to(x0, y0)
  line_to(x1, y1)
end

- (Object) line_to(*point)

Draws a line from the current drawing position to the specified point. The destination may be described as a tuple or a flattened list:

pdf.line_to [50,50]
pdf.line_to(50,50)


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# File 'lib/prawn/graphics.rb', line 56

def line_to(*point)
  x,y = map_to_absolute(point)
  add_content("%.3f %.3f l" % [ x, y ])
end

- (Object) line_width(width = nil)

When called without an argument, returns the current line thickness. When called with an argument, sets the line thickness to the specified value (in PDF points)

pdf.line_width #=> 1
pdf.line_width(5)
pdf.line_width #=> 5


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# File 'lib/prawn/graphics.rb', line 117

def line_width(width=nil)
  if width
    self.line_width = width
  else
    current_line_width
  end
end

- (Object) line_width=(width)

Sets line thickness to the width specified.



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# File 'lib/prawn/graphics.rb', line 104

def line_width=(width)
  self.current_line_width = width
  write_line_width
end

- (Object) move_to(*point)

Moves the drawing position to a given point. The point can be specified as a tuple or a flattened argument list

pdf.move_to [100,50]
pdf.move_to(100,50)


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# File 'lib/prawn/graphics.rb', line 45

def move_to(*point)
  x,y = map_to_absolute(point)
  add_content("%.3f %.3f m" % [ x, y ])
end

- (Object) polygon(*points)

Draws a polygon from the specified points.

# draws a snazzy triangle
pdf.polygon [100,100], [100,200], [200,200]


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# File 'lib/prawn/graphics.rb', line 247

def polygon(*points)
  move_to points[0]
  (points[1..-1] << points[0]).each do |point|
    line_to(*point)
  end
  # close the path
  add_content "h"
end

- (Object) rectangle(point, width, height)

Draws a rectangle given point, width and height. The rectangle is bounded by its upper-left corner.

pdf.rectangle [300,300], 100, 200


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# File 'lib/prawn/graphics.rb', line 81

def rectangle(point,width,height)
  x,y = map_to_absolute(point)
  add_content("%.3f %.3f %.3f %.3f re" % [ x, y - height, width, height ])
end

- (Object) rounded_polygon(radius, *points)

Draws a rounded polygon from specified points using the radius to define bezier curves

# draws a rounded filled in polygon
 pdf.fill_and_stroke_rounded_polygon(10, [100, 250], [200, 300], [300, 250],
               [300, 150], [200, 100], [100, 150])


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# File 'lib/prawn/graphics.rb', line 261

def rounded_polygon(radius, *points)
  move_to point_on_line(radius, points[1], points[0])
  sides = points.size
  points << points[0] << points[1]
  (sides).times do |i|
    rounded_vertex(radius, points[i], points[i + 1], points[i + 2])
  end
  # close the path
  add_content "h"
end

- (Object) rounded_rectangle(point, width, height, radius)

Draws a rounded rectangle given point, width and height and radius for the rounded corner. The rectangle is bounded by its upper-left corner.

pdf.rounded_rectangle [300,300], 100, 200, 10


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# File 'lib/prawn/graphics.rb', line 92

def rounded_rectangle(point,width,height,radius)
  x, y = point
  rounded_polygon(radius, point, [x + width, y], [x + width, y - height], [x, y - height])
end

- (Object) rounded_vertex(radius, *points)

Creates a rounded vertex for a line segment used for building a rounded polygon requires a radius to define bezier curve and three points. The first two points define the line segment and the third point helps define the curve for the vertex.



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# File 'lib/prawn/graphics.rb', line 276

def rounded_vertex(radius, *points)
  x0,y0,x1,y1,x2,y2 = points.flatten
  radial_point_1 = point_on_line(radius, points[0], points[1])
  bezier_point_1 = point_on_line((radius - radius*KAPPA), points[0], points[1] )
  radial_point_2 = point_on_line(radius, points[2], points[1])
  bezier_point_2 = point_on_line((radius - radius*KAPPA), points[2], points[1])
  line_to(radial_point_1)
  curve_to(radial_point_2, :bounds => [bezier_point_1, bezier_point_2])
end

- (Object) stroke

Strokes the current path. If a block is provided, yields to the block before closing the path. See Graphics::Color for color details.



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# File 'lib/prawn/graphics.rb', line 289

def stroke
  yield if block_given?
  add_content "S"
end

- (Object) stroke_bounds

Draws and strokes a rectangle represented by the current bounding box



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# File 'lib/prawn/graphics.rb', line 304

def stroke_bounds
  stroke_rectangle bounds.top_left, bounds.width, bounds.height
end

- (Object) vertical_line(y1, y2, params)

Draws a vertical line at the x cooordinate given by :at from y1 to y2.

# draw a line from [25, 100] to [25, 300]
vertical_line 100, 300, :at => 25


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# File 'lib/prawn/graphics.rb', line 165

def vertical_line(y1,y2,params)
  line(params[:at],y1,params[:at],y2)
end