Rmagick each_pixel,它是如何工作的？

Question

我需要在rmagick中操纵图像的每个像素.我在IRB(互动红宝石)中这样做这就是我所拥有的:

require 'Rmagick'
include Magick
f = Image.new(100,100)
f.display #so far so good. A 100x100 white image is displayed

f.each_pixel {|pixel, c, r| pixel.red = 0}
f.display #the image is still white. It should really be a shade of blue.

我究竟做错了什么？

Answer 1

问题是,您从each_pixel返回的数组是一个新数据集.需要将数据存储回图像.

改为使用get_pixels和store_pixels:

img = Magick::ImageList.new('img.jpg').first
pixels = img.get_pixels(0,0,img.columns,img.rows)

for pixel in pixels
    avg = (pixel.red + pixel.green + pixel.blue) / 3
    pixel.red = avg
    pixel.blue = avg
    pixel.green = avg
end

img.store_pixels(0,0, img.columns, img.rows, pixels)
img.display