Line wrapping output buffer.. half implemented.

lib/flopp/output/line_wrapper.rb

@@ -0,0 +1,87 @@
+# Copyright, 2016, by Samuel G. D. Williams. <http://www.codeotaku.com>
+# 
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+# 
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+# 
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+
+module Flopp
+	module Output
+		# This is an incomplete implementation of an automatic line wrapping output buffer which handles any kind of output, provided it has special wrapping markers.
+		class LineWrapping
+			MARKER = "\e[0;0m".freeze
+
+			def initialize(output, wrapping_width = 80, minimum_width = 20)
+				@output = output
+				@wrapping_width = wrapping_width
+				@minimum_width = minimum_width
+			end
+
+			ESCAPE_SEQUENCE = /(.*?)(\e\[.*?m|$)/
+
+			def printable_width(text)
+				text.size
+			end
+
+			def wrap(line)
+				wrapping_offset = nil
+				offset = 0
+				buffer = String.new
+				lines = []
+				prefix = nil
+
+				line.scan(ESCAPE_SEQUENCE) do |text, escape_sequence|
+					width = printable_width(text)
+					next_offset = offset + printable_width
+
+					if next_offset > @wrapping_width
+						if wrapping_offset
+							text_wrap_offset = @wrapping_width - offset
+
+							# This text flows past the end of the line and we have a valid wrapping offset. We need to wrap this text.
+							if best_split_index = text.rindex(/\s/, text_wrap_offset) and best_split_index >= @minimum_width
+								# We have enough space to wrap.
+								buffer << text[0...best_split_index]
+								lines << buffer
+								buffer = String.new()
+							else
+								# In this case we can't really wrap on the current line. We fall back to letting the terminal wrap.
+								return line
+							end
+						else
+							# We don't have a specific wrapping offset, and the text flows longer than the wrapping width. We can't do anything - let the terminal wrap.
+							return line
+						end
+					else
+						buffer << text << escape_sequence
+					end
+
+					offset = next_offset
+
+					if wrapping_offset.nil? and offset < @wrapping_width and escape_sequence == MARKER
+						wrapping_offset = offset
+					end
+				end
+			end
+
+			def puts(*lines)
+				lines = lines.flat_map{|line| wrap(line)}
+
+				@output.puts(*lines)
+			end
+		end
+	end
+end