Class: ImageScience

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

Overview

Provides a clean and simple API to generate thumbnails using FreeImage as the underlying mechanism.

For more information or if you have build issues with FreeImage, see seattlerb.rubyforge.org/ImageScience.html

Constant Summary collapse

VERSION = 
'1.2.1.tdd'
JPEG_DEFAULT =

These actually come from FreeImage.h.

0
JPEG_FAST =

75%

1
JPEG_ACCURATE = 
2
JPEG_QUALITYSUPERB =

100%

0x80
JPEG_QUALITYGOOD =

75%

0x100
JPEG_QUALITYNORMAL =

50%

0x200
JPEG_QUALITYAVERAGE =

25%

0x400
JPEG_QUALITYBAD =

10%

0x800
JPEG_PROGRESSIVE =

save as a progressive-JPEG (use | to combine with other flags)

0x2000

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.with_image(path) ⇒ Object

The top-level image loader opens path and then yields the image.



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# File 'lib/image_science.rb', line 30

def self.with_image(path) # :yields: image
end

.with_image_from_memory(data) ⇒ Object

The top-level image loader, opens an image from the string data and then yields the image.



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# File 'lib/image_science.rb', line 36

def self.with_image_from_memory(data) # :yields: image
end

Instance Method Details

#cropped_thumbnail(size) ⇒ Object

Creates a square thumbnail of the image cropping the longest edge to match the shortest edge, resizes to size, and yields the new image.



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# File 'lib/image_science.rb', line 91

def cropped_thumbnail(size) # :yields: image
  w, h = width, height
  l, t, r, b, half = 0, 0, w, h, (w - h).abs / 2

  l, r = half, half + h if w > h
  t, b = half, half + w if h > w

  with_crop(l, t, r, b) do |img|
    img.thumbnail(size) do |thumb|
      yield thumb
    end
  end
end

#height ⇒ Object

Returns the height of the image, in pixels.



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# File 'lib/image_science.rb', line 54

def height; end

#resize(width, height) ⇒ Object

Resizes the image to width and height using a cubic-bspline filter and yields the new image.



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# File 'lib/image_science.rb', line 70

def resize(width, height) # :yields: image
end

#save(path, jpeg_quality = JPEG_QUALITYSUPERB) ⇒ Object

Saves the image out to path. Changing the file extension will convert the file type to the appropriate format.



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# File 'lib/image_science.rb', line 60

def save(path, jpeg_quality = JPEG_QUALITYSUPERB)
  save_with_quality(path, jpeg_quality)
end

#save_with_quality(path, jpeg_quality) ⇒ Object 



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# File 'lib/image_science.rb', line 64

def save_with_quality(path, jpeg_quality); end

#thumbnail(size) ⇒ Object

Creates a proportional thumbnail of the image scaled so its longest edge is resized to size and yields the new image.



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# File 'lib/image_science.rb', line 77

def thumbnail(size) # :yields: image
  w, h = width, height
  scale = size.to_f / (w > h ? w : h)

  self.resize((w * scale).to_i, (h * scale).to_i) do |image|
    yield image
  end
end

#width ⇒ Object

Returns the width of the image, in pixels.



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# File 'lib/image_science.rb', line 49

def width; end

#with_crop(left, top, right, bottom) ⇒ Object

Crops an image to left, top, right, and bottom and then yields the new image.



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# File 'lib/image_science.rb', line 43

def with_crop(left, top, right, bottom) # :yields: image
end