Data commit

Task/Bitmap-Read-an-image-through-a-pipe/Ruby/bitmap-read-an-image-through-a-pipe.rb

@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+require_relative 'raster_graphics'
+
+class Pixmap
+  def self.read_ppm(ios)
+    format = ios.gets.chomp
+    width, height = ios.gets.chomp.split.map(&:to_i)
+    max_colour = ios.gets.chomp
+
+    if !PIXMAP_FORMATS.include?(format) ||
+       (width < 1) || (height < 1) ||
+       (max_colour != '255')
+      ios.close
+      raise StandardError, "file '#{filename}' does not start with the expected header"
+    end
+    ios.binmode if PIXMAP_BINARY_FORMATS.include?(format)
+
+    bitmap = new(width, height)
+    height.times do |y|
+      width.times do |x|
+        # read 3 bytes
+        red, green, blue = case format
+                           when 'P3' then ios.gets.chomp.split
+                           when 'P6' then ios.read(3).unpack('C3')
+                           end
+        bitmap[x, y] = RGBColour.new(red, green, blue)
+      end
+    end
+    ios.close
+    bitmap
+  end
+
+  def self.open(filename)
+    read_ppm(File.open(filename, 'r'))
+  end
+
+  def self.open_from_jpeg(filename)
+    read_ppm(IO.popen("convert jpg:#{filename} ppm:-", 'r'))
+  end
+end
+
+bitmap = Pixmap.open_from_jpeg('foto.jpg')
+bitmap.save('foto.ppm')