Bitmap/Read an image through a pipe: Difference between revisions

Content added Content deleted
(→‎{{header|Lua}}: added Lua solution)
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=={{header|Ruby}}==
=={{header|Ruby}}==
Uses [[Raster graphics operations/Ruby]].
Extending [[Read ppm file#Ruby]] and [[PPM conversion through a pipe#Ruby]]. Uses the ImageMagick <code>convert</code> tool.


<lang ruby>class Pixmap
<lang ruby># frozen_string_literal: true

require_relative 'raster_graphics'

class Pixmap
def self.read_ppm(ios)
def self.read_ppm(ios)
format = ios.gets.chomp
format = ios.gets.chomp
width, height = ios.gets.chomp.split.map {|n| n.to_i }
width, height = ios.gets.chomp.split.map(&:to_i)
max_colour = ios.gets.chomp
max_colour = ios.gets.chomp


if (not PIXMAP_FORMATS.include?(format)) or
if !PIXMAP_FORMATS.include?(format) ||
width < 1 or height < 1 or
(width < 1) || (height < 1) ||
max_colour != '255'
(max_colour != '255')
then
ios.close
ios.close
raise StandardError, "file '#{filename}' does not start with the expected header"
raise StandardError, "file '#{filename}' does not start with the expected header"
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ios.binmode if PIXMAP_BINARY_FORMATS.include?(format)
ios.binmode if PIXMAP_BINARY_FORMATS.include?(format)


bitmap = self.new(width, height)
bitmap = new(width, height)
height.times do |y|
height.times do |y|
width.times do |x|
width.times do |x|
# read 3 bytes
# read 3 bytes
red, green, blue = case format
red, green, blue = case format
when 'P3' then ios.gets.chomp.split
when 'P3' then ios.gets.chomp.split
when 'P6' then ios.read(3).unpack('C3')
when 'P6' then ios.read(3).unpack('C3')
end
end
bitmap[x,y] = RGBColour.new(red, green, blue)
bitmap[x, y] = RGBColour.new(red, green, blue)
end
end
end
end
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end
end


bitmap = Pixmap.open_from_jpeg('file.jpg')</lang>
bitmap = Pixmap.open_from_jpeg('foto.jpg')
bitmap.save('foto.ppm')
</lang>


=={{header|Tcl}}==
=={{header|Tcl}}==
Retrieved from "https://rosettacode.org/wiki/Bitmap/Read_an_image_through_a_pipe"