This adds a new executable called term_plasma

that draws a plasma effect on the console. The program accepts an
optional parameter `-n`, which specifies the refresh interval in
seconds. If this parameter is not provided, the program will exit after
one iteration.

.gitignore

@@ -4,6 +4,7 @@
 .rvmrc
 Gemfile.lock
 coverage
+cscope.out
 errors.lst
 pkg
 tags

README.md

@@ -31,6 +31,9 @@ The following executables are provided with Term::ANSIColor:
 * `term_mandel`: displays the mandelbrot set in the terminal
 * `term_snow`: displays falling snow in the terminal using ANSI movement
   sequences.
+* `term_plasma`: draws a plasma effect on the console, possibly animated and
+  refreshed every `-n seconds`.
+
 
 Additionally the file examples/example.rb in the source/gem-distribution shows
 how this library can be used.

Rakefile

@@ -15,7 +15,7 @@ GemHadar do
 
   test_dir    'tests'
   ignore      '.*.sw[pon]', 'pkg', 'Gemfile.lock', '.rvmrc', 'coverage',
-    'tags', '.bundle', '.byebug_history', 'errors.lst'
+    'tags', '.bundle', '.byebug_history', 'errors.lst', 'cscope.out'
 
   readme      'README.md'
   executables.merge Dir['bin/*'].map { |x| File.basename(x) }

bin/term_plasma

@@ -0,0 +1,97 @@
+#!/usr/bin/env ruby
+
+require 'tins/go'
+include Tins::GO
+require 'term/ansicolor'
+include Term::ANSIColor
+Term::ANSIColor.true_coloring = ENV['COLORTERM'] =~ /\A(truecolor|24bit)\z/
+include Math
+
+# Generates a palette of 256 colors based on sine waves
+#
+# @return [Array<Array<Integer>>] An array of arrays, each containing
+#    three integers representing the RGB values of a color.
+def generate_palette
+  (0..255).map { |i|
+    [
+      128 + 128 * sin(PI * i / 32.0),
+      128 + 128 * sin(PI * i / 64.0),
+      128 + 128 * sin(PI * i / 128.0),
+    ].map { _1.clamp(0, 255).round }
+  }
+end
+
+# Resets the terminal to its original state, and assigns width $w and height
+# $h.
+def full_reset
+  $w, $h = Tins::Terminal.cols, Tins::Terminal.lines
+  $h *= 2
+  print reset, clear_screen, move_home, hide_cursor
+end
+
+# Generates a screen based on a plasma.
+#
+# @param plasma [Array<Array<Integer>>] An array of arrays, each containing
+#    three integers representing the RGB values of a color.
+# @return [String] The string representation of the screen, each character
+#    representing a pixel on the screen with the corresponding color.
+def generate_screen(plasma)
+  screen = ''
+  0.step($h - 1, 2) do |y|
+    0.upto($w - 1) do |x|
+      screen << color(plasma[y][x]) + on_color(plasma[y + 1][x]) + ?▀
+    end
+  end
+  screen
+end
+
+# Generates a plasma generated based on sine waves
+#
+# @param now [Float] A value based on the current time in seconds
+# @return [Array<Array<Integer>>] An array of arrays, each containing
+#    three integers representing the RGB values of a color.
+def generate_plasma(now)
+  plasma = Array.new($h) { [ nil ] * $w }
+  0.upto($h - 1) do |y|
+    0.upto($w - 1) do |x|
+      x, y = x.to_f, y.to_f
+      color = (
+        128.0 + (128.0 * sin((x / 7.0) - 3.0 * cos(now / 2.0))) +
+        128.0 + (128.0 * sin((y / 13.0) - 2.0 * sin(now))) +
+        128.0 + (128.0 * sin(hypot((x - $w / 3.0), (y - $h / 2.0)) / 5.0)) +
+        128.0 + (128.0 * sin((hypot(x, y) / 5.0) - sin(now / 3.0)))
+      ) / 4.0
+      plasma[y][x] = $palette[(color + now).round % $palette.size]
+    end
+  end
+  plasma
+end
+
+$opts = go('n:')
+
+$palette = generate_palette
+
+begin
+  $full_reset = true
+  trap(:SIGWINCH) { $full_reset = true }
+
+  loop do
+    if $full_reset
+      $full_reset = false
+      full_reset
+    end
+
+    now    = Time.now.to_f / ($opts[?n]&.to_f || 1)
+    plasma = generate_plasma(now)
+    print move_home, generate_screen(plasma), reset
+
+    if n = $opts[?n]&.to_f
+      sleep n
+    else
+      print move_to_column(1), erase_in_line, show_cursor
+      exit
+    end
+  end
+rescue Interrupt
+  print reset, clear_screen, move_home, show_cursor
+end

term-ansicolor.gemspec

@@ -8,12 +8,12 @@ Gem::Specification.new do |s|
   s.required_rubygems_version = Gem::Requirement.new(">= 0".freeze) if s.respond_to? :required_rubygems_version=
   s.require_paths = ["lib".freeze]
   s.authors = ["Florian Frank".freeze]
-  s.date = "2024-07-15"
+  s.date = "2024-07-16"
   s.description = "This library uses ANSI escape sequences to control the attributes of terminal output".freeze
   s.email = "[email protected]".freeze
-  s.executables = ["term_cdiff".freeze, "term_colortab".freeze, "term_decolor".freeze, "term_display".freeze, "term_mandel".freeze, "term_snow".freeze]
+  s.executables = ["term_cdiff".freeze, "term_colortab".freeze, "term_decolor".freeze, "term_display".freeze, "term_mandel".freeze, "term_plasma".freeze, "term_snow".freeze]
   s.extra_rdoc_files = ["README.md".freeze, "lib/term/ansicolor.rb".freeze, "lib/term/ansicolor/attribute.rb".freeze, "lib/term/ansicolor/attribute/color256.rb".freeze, "lib/term/ansicolor/attribute/color8.rb".freeze, "lib/term/ansicolor/attribute/intense_color8.rb".freeze, "lib/term/ansicolor/attribute/text.rb".freeze, "lib/term/ansicolor/attribute/underline.rb".freeze, "lib/term/ansicolor/hsl_triple.rb".freeze, "lib/term/ansicolor/hyperlink.rb".freeze, "lib/term/ansicolor/movement.rb".freeze, "lib/term/ansicolor/ppm_reader.rb".freeze, "lib/term/ansicolor/rgb_color_metrics.rb".freeze, "lib/term/ansicolor/rgb_triple.rb".freeze, "lib/term/ansicolor/version.rb".freeze]
-  s.files = [".all_images.yml".freeze, ".gitignore".freeze, ".utilsrc".freeze, "CHANGES".freeze, "COPYING".freeze, "Gemfile".freeze, "README.md".freeze, "Rakefile".freeze, "VERSION".freeze, "bin/term_cdiff".freeze, "bin/term_colortab".freeze, "bin/term_decolor".freeze, "bin/term_display".freeze, "bin/term_mandel".freeze, "bin/term_snow".freeze, "examples/example.rb".freeze, "examples/lambda-red-plain.ppm".freeze, "examples/lambda-red.png".freeze, "examples/lambda-red.ppm".freeze, "lib/term/ansicolor.rb".freeze, "lib/term/ansicolor/.keep".freeze, "lib/term/ansicolor/attribute.rb".freeze, "lib/term/ansicolor/attribute/color256.rb".freeze, "lib/term/ansicolor/attribute/color8.rb".freeze, "lib/term/ansicolor/attribute/intense_color8.rb".freeze, "lib/term/ansicolor/attribute/text.rb".freeze, "lib/term/ansicolor/attribute/underline.rb".freeze, "lib/term/ansicolor/hsl_triple.rb".freeze, "lib/term/ansicolor/hyperlink.rb".freeze, "lib/term/ansicolor/movement.rb".freeze, "lib/term/ansicolor/ppm_reader.rb".freeze, "lib/term/ansicolor/rgb_color_metrics.rb".freeze, "lib/term/ansicolor/rgb_triple.rb".freeze, "lib/term/ansicolor/version.rb".freeze, "term-ansicolor.gemspec".freeze, "tests/ansicolor_test.rb".freeze, "tests/attribute_test.rb".freeze, "tests/hsl_triple_test.rb".freeze, "tests/hyperlink_test.rb".freeze, "tests/ppm_reader_test.rb".freeze, "tests/rgb_color_metrics_test.rb".freeze, "tests/rgb_triple_test.rb".freeze, "tests/test_helper.rb".freeze]
+  s.files = [".all_images.yml".freeze, ".gitignore".freeze, ".utilsrc".freeze, "CHANGES".freeze, "COPYING".freeze, "Gemfile".freeze, "README.md".freeze, "Rakefile".freeze, "VERSION".freeze, "bin/term_cdiff".freeze, "bin/term_colortab".freeze, "bin/term_decolor".freeze, "bin/term_display".freeze, "bin/term_mandel".freeze, "bin/term_plasma".freeze, "bin/term_snow".freeze, "examples/example.rb".freeze, "examples/lambda-red-plain.ppm".freeze, "examples/lambda-red.png".freeze, "examples/lambda-red.ppm".freeze, "lib/term/ansicolor.rb".freeze, "lib/term/ansicolor/.keep".freeze, "lib/term/ansicolor/attribute.rb".freeze, "lib/term/ansicolor/attribute/color256.rb".freeze, "lib/term/ansicolor/attribute/color8.rb".freeze, "lib/term/ansicolor/attribute/intense_color8.rb".freeze, "lib/term/ansicolor/attribute/text.rb".freeze, "lib/term/ansicolor/attribute/underline.rb".freeze, "lib/term/ansicolor/hsl_triple.rb".freeze, "lib/term/ansicolor/hyperlink.rb".freeze, "lib/term/ansicolor/movement.rb".freeze, "lib/term/ansicolor/ppm_reader.rb".freeze, "lib/term/ansicolor/rgb_color_metrics.rb".freeze, "lib/term/ansicolor/rgb_triple.rb".freeze, "lib/term/ansicolor/version.rb".freeze, "term-ansicolor.gemspec".freeze, "tests/ansicolor_test.rb".freeze, "tests/attribute_test.rb".freeze, "tests/hsl_triple_test.rb".freeze, "tests/hyperlink_test.rb".freeze, "tests/ppm_reader_test.rb".freeze, "tests/rgb_color_metrics_test.rb".freeze, "tests/rgb_triple_test.rb".freeze, "tests/test_helper.rb".freeze]
   s.homepage = "https://github.com/flori/term-ansicolor".freeze
   s.licenses = ["Apache-2.0".freeze]
   s.rdoc_options = ["--title".freeze, "Term-ansicolor - Ruby library that colors strings using ANSI escape sequences".freeze, "--main".freeze, "README.md".freeze]