Fix Ruby 4 compatibility

lib/scalebar.rb

@@ -1,4 +1,4 @@
 require "scalebar/version"
 require "scalebar/scalebar"
-require 'trollop'
-require 'dimensions'
+require 'optimist'
+require 'dimensions'

lib/scalebar/scalebar.rb

@@ -39,7 +39,7 @@ def initialize(output, argv = ARGV)
 	  end
 
 	  def cmd_options(argv=ARGV)
-	    Trollop::options(argv) do
+	    Optimist::options(argv) do
 	        # banner "  Usage: scalebar imagefile"
 	      banner  <<"EOS"
 NAME
@@ -244,7 +244,7 @@ def y_range
 	  end
 
 	  def parse_option
-	    Trollop::die "invalid args" if argv.size < 1
+	    Optimist::die "invalid args" if argv.size < 1
 	    @image_path = argv.shift
 	    @dirname = File.dirname(@image_path)
 	    @basename = File.basename(@image_path, ".*")
@@ -276,7 +276,7 @@ def parse_option
 
 	  def run
 	    parse_option
-	    if File.exists?(output_path)
+	    if File.exist?(output_path)
 	      STDERR.puts "|#{output_path}| already exists."
 	    else
 	      generate_tex(params[:grid])

scalebar.gemspec

@@ -22,6 +22,6 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency "rake", ">= 12.3.3"
   spec.add_development_dependency "rspec", "~> 3.1"  
 
-  spec.add_dependency "trollop", "~> 2.1"
+  spec.add_dependency "optimist", "~> 3.0"
   spec.add_dependency "dimensions", "~> 1.3"  
 end

spec/scalebar/scalebar_spec.rb

@@ -185,7 +185,7 @@ module Scalebar
 
 		it "generate tex" do
 			cui.run
-			expect(File.exists?(tex_path)).to be_truthy
+			expect(File.exist?(tex_path)).to be_truthy
 		end
 
 
@@ -211,7 +211,7 @@ module Scalebar
 
 		it "generate tex with grid" do
 			cui.run
-			expect(File.exists?(tex_path)).to be_truthy
+			expect(File.exist?(tex_path)).to be_truthy
 			expect(File.open(tex_path).read).to match(/Grids of \|\S+\| micro meter pitch are drawn\./)
 			expect(File.open(tex_path).read).to match(/multiput/)
 		end
@@ -236,11 +236,11 @@ module Scalebar
 
 		it "generate tex without grid" do
 			cui.run
-			expect(File.exists?(tex_path)).to be_truthy
+			expect(File.exist?(tex_path)).to be_truthy
 			expect(File.open(tex_path).read).not_to match(/Grids of \|\S+\| micro meter pitch are drawn\./)
 			expect(File.open(tex_path).read).not_to match(/multiput/)
 		end
 	end
 
 end
-end
+end

spec/spec_helper.rb

@@ -1,3 +1,5 @@
+require 'fileutils'
+
 #require 'scalebar'
 class Output
   def messages