Class: RImageAnalysisTools::Drawing

Inherits:
Object
  • Object
show all
Defined in:
lib/rimageanalysistools/drawing.rb

Overview

A collection of methods for drawing into an existing image.

Instance Method Summary collapse

Instance Method Details

#circle(im, center, radius) ⇒ void

This method returns an undefined value.

Draws a circle into an image.

Parameters:

  • im (WritableImage) —

    the image into which to draw

  • center (Array) —

    an array containing the x,y coordinates of the circle’s center

  • radius (Numeric) —

    the radius of the circle in pixels



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# File 'lib/rimageanalysistools/drawing.rb', line 142

def circle(im, center, radius)

  lower = ImageCoordinate[center[0]-radius-1, center[1]-radius-1, 0,0,0]
  upper = ImageCoordinate[center[0]+radius+1, center[1]+radius+1, 0,0,0]

  im.box_conservative(lower, upper, [:x, :y])

  draw(im) do |ic|
    
    xdiff = ic[:x] - center[0]
    ydiff = ic[:y] - center[1]

    if (Math.hypot(xdiff, ydiff) - radius).abs <= Math.sqrt(2) then
      true
    else
      false
    end

  end

  lower.recycle
  upper.recycle
    
end

#draw(im, draw_value = 255.0) ⇒ void

This method returns an undefined value.

A basic drawing method that iterates through an entire image. At each coordinate, an attached block is evaluated for a boolean response that determines whether that coordinate is overwritten with a specified value. The attached block will be given a single parameter, which is the current ImageCoordinate.

Parameters:

  • im (WritableImage) —

    the image being drawn on

  • draw_value (Numeric) (defaults to: 255.0) —

    the value to which a pixel will be set if the block evaluates to a true value at that coordinate



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# File 'lib/rimageanalysistools/drawing.rb', line 96

def draw(im, draw_value = 255.0)

  im.each do |ic|

    if (yield ic) then

      im.setValue(ic, draw_value)

    end

  end

end

#draw_shape(im, location, shape_name = :circle, shape_parameters = 10) ⇒ void

This method returns an undefined value.

Draws a specified shape into an image.

Parameters:

  • im (WritableImage) —

    the image into which to draw

  • location (Array) —

    an array containing the coordinates of the shape to draw. The exact meaning of this parameter depends on which shape is being drawn.

  • shape_name (Symbol) (defaults to: :circle) —

    the name of the shape to draw. This should correspond to one of the methods of this class.

  • shape_parameters (defaults to: 10) —

    the parameters for drawing the specified shape; the meaning of this parameter depends on the shape.



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# File 'lib/rimageanalysistools/drawing.rb', line 123

def draw_shape(im, location, shape_name=:circle, shape_parameters= 10)

  if self.respond_to?(shape_name) then

    self.send(shape_name, im, location, shape_parameters)

  end

end

#ellipse(im, foci, radius_inc) ⇒ void

This method returns an undefined value.

Draws an ellipse into an image.

Parameters:

  • im (WritableImage) —

    the image into which to draw

  • foci (Array) —

    an array containing two arrays, each of which contains the x,y coordinates of one focus of the ellipse

  • radius_inc (Numeric) —

    the extra amount of distance (in pixels) beyond the distance between the foci that the ellipse should be drawn. (2*radius_inc + dist between foci = major axis length)



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# File 'lib/rimageanalysistools/drawing.rb', line 179

def ellipse(im, foci, radius_inc)

  min_x = foci[0][0]
  max_x = foci[1][0]
  min_y = foci[0][1]
  max_y = foci[1][1]

  if foci[1][0] < min_x then
    min_x = foci[1][0]
    max_x = foci[0][0]
  end

  if foci[1][1] < min_y then
    min_y = foci[1][1]
    max_y = foci[0][1]
  end

  radius = radius_inc + Math.hypot(max_x-min_x, max_y-min_y)
  
  lower = ImageCoordinate[min_x-radius-1, min_y-radius-1, 0,0,0]
  upper = ImageCoordinate[max_x+radius+1, max_y+radius+1, 0,0,0]

  im.box_conservative(lower, upper, [:x, :y])
  
  draw(im) do |ic|
    
    xdiff0 = ic[:x] - foci[0][0]
    ydiff0 = ic[:y] - foci[0][1]
    xdiff1 = ic[:x] - foci[1][0]
    ydiff1 = ic[:y] - foci[1][1]

    if (Math.hypot(xdiff0, ydiff0) + Math.hypot(xdiff1, ydiff1) - radius).abs <= Math.sqrt(2) then
      true
    else
      false
    end

  end


end