Class: Magick::Image

Inherits:
Object
  • Object
show all
Defined in:
lib/extensions/resize_matte.rb

Overview

Add Magick::Image#resize_matte method, to resize with a colored matte, if needed (instead of cropping image).

Instance Method Summary collapse

Instance Method Details

#resize_matte(width, height, bg_color = "white", to_png = false) ⇒ Object

Resizes and adds background to full dimensions Returns a new image



7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
 
# File 'lib/extensions/resize_matte.rb', line 7

def resize_matte(width, height, bg_color = "white", to_png = false)

  bg_color = "white" if bg_color.nil?
  
  new_cols = 0
  new_rows = 0
  
  # http://www.imagemagick.org/RMagick/doc/image1.html#change_geometry
  new_image = self.change_geometry(Magick::Geometry.new(width, height)) do |cols, rows, img|
    new_cols = cols; new_rows = rows; 
    img.resize(cols, rows)
  end
  
  bg_color = "none" if to_png

  canvas = Magick::Image.new(width, height) { self.background_color = bg_color }
  if to_png
    canvas.format = "PNG" 
    new_image.format = "PNG"
  end
  
  # http://www.imagemagick.org/RMagick/doc/image1.html#composite
  # http://www.imagemagick.org/RMagick/doc/constants.html#CompositeOperator
  composited = canvas.composite(new_image, Magick::CenterGravity, Magick::OverCompositeOp)
  composited.format = "PNG" if to_png
  composited
end