feat: PNG writer based on Stumpy libs

Hacefile.yml

@@ -113,3 +113,11 @@ tasks:
       kcov --clean --include-path=./src ${PWD}/coverage ./bin/run_tests
     outputs:
       - coverage/index.html
+
+  loc:
+    phony: true
+    always_run: true
+    dependencies:
+      - src
+    commands: |
+      tokei src -e src/constants/

shard.yml

@@ -18,6 +18,10 @@ dependencies:
     github: ralsina/sixteen
   docopt:
     github: chenkovsky/docopt.cr
+  stumpy_utils:
+    github: stumpycr/stumpy_utils
+  stumpy_png:
+    github: stumpycr/stumpy_png
 
 crystal: ">= 1.13.0"
 

src/formatters/png.cr

@@ -0,0 +1,113 @@
+require "../formatter"
+require "stumpy_png"
+require "stumpy_utils"
+require "compress/gzip"
+
+module Tartrazine
+  def self.to_png(text : String, language : String,
+                  theme : String = "default-dark",
+                  line_numbers : Bool = false) : String
+    Tartrazine::Png.new(
+      theme: Tartrazine.theme(theme),
+      line_numbers: line_numbers
+    ).format(text, Tartrazine.lexer(name: language))
+  end
+
+  class FontFiles
+    extend BakedFileSystem
+    bake_folder "../../fonts", __DIR__
+  end
+
+  class Png < Formatter
+    include StumpyPNG
+    property? line_numbers : Bool = false
+    @font_regular : PCFParser::Font
+    @font_bold : PCFParser::Font
+    @font_oblique : PCFParser::Font
+    @font_bold_oblique : PCFParser::Font
+    @font_width = 15
+    @font_height = 24
+
+    def initialize(@theme : Theme = Tartrazine.theme("default-dark"), @line_numbers : Bool = false)
+      @font_regular = load_font("/courier-regular.pcf.gz")
+      @font_bold = load_font("/courier-bold.pcf.gz")
+      @font_oblique = load_font("/courier-oblique.pcf.gz")
+      @font_bold_oblique = load_font("/courier-bold-oblique.pcf.gz")
+    end
+
+    private def load_font(name : String) : PCFParser::Font
+      compressed = FontFiles.get(name)
+      uncompressed = Compress::Gzip::Reader.open(compressed) do |gzip|
+        gzip.gets_to_end
+      end
+      PCFParser::Font.new(IO::Memory.new uncompressed)
+    end
+
+    private def line_label(i : Int32) : String
+      "#{i + 1}".rjust(4).ljust(5)
+    end
+
+    def format(text : String, lexer : BaseLexer, outp : IO) : Nil
+      # Create canvas of correct size
+      lines = text.split("\n")
+      canvas_height = lines.size * @font_height
+      canvas_width = lines.max_of(&.size)
+      canvas_width += 5 if line_numbers?
+      canvas_width *= @font_width
+
+      bg_color = RGBA.from_hex("##{theme.styles["Background"].background.try &.hex}")
+      canvas = Canvas.new(canvas_width, canvas_height, bg_color)
+
+      tokenizer = lexer.tokenizer(text)
+      x = 0
+      y = @font_height
+      i = 0
+      if line_numbers?
+        canvas.text(x, y, line_label(i), @font_regular, RGBA.from_hex("##{theme.styles["Background"].color.try &.hex}"))
+        x += 5 * @font_width
+      end
+
+      tokenizer.each do |token|
+        font, color = token_style(token[:type])
+        # These fonts are very limited
+        t = token[:value].gsub(/[^[:ascii:]]/, "?")
+        canvas.text(x, y, t.rstrip("\n"), font, color)
+        if token[:value].includes?("\n")
+          x = 0
+          y += @font_height
+          i += 1
+          if line_numbers?
+            canvas.text(x, y, line_label(i), @font_regular, RGBA.from_hex("##{theme.styles["Background"].color.try &.hex}"))
+            x += 4 * @font_width
+          end
+        end
+
+        x += token[:value].size * @font_width
+      end
+
+      StumpyPNG.write(canvas, outp)
+    end
+
+    def token_style(token : String) : {PCFParser::Font, RGBA}
+      if theme.styles.has_key?(token)
+        s = theme.styles[token]
+      else
+        # Themes don't contain information for each specific
+        # token type. However, they may contain information
+        # for a parent style. Worst case, we go to the root
+        # (Background) style.
+        s = theme.styles[theme.style_parents(token).reverse.find { |parent|
+          theme.styles.has_key?(parent)
+        }]
+      end
+
+      color = RGBA.from_hex("##{theme.styles["Background"].color.try &.hex}")
+      color = RGBA.from_hex("##{s.color.try &.hex}") if s.color
+
+      return {@font_bold_oblique, color} if s.bold && s.italic
+      return {@font_bold, color} if s.bold
+      return {@font_oblique, color} if s.italic
+      return {@font_regular, color}
+    end
+  end
+end

src/main.cr

@@ -4,6 +4,10 @@ require "./tartrazine"
 HELP = <<-HELP
 tartrazine: a syntax highlighting tool
 
+You can use the CLI to generate HTML, terminal, JSON or SVG output
+from a source file using different themes.
+Keep in mind that not all formatters support all features.
+
 Usage:
   tartrazine (-h, --help)
   tartrazine FILE -f html [-t theme][--standalone][--line-numbers]
@@ -13,6 +17,8 @@ Usage:
                               [-o output]
   tartrazine FILE -f svg  [-t theme][--standalone][--line-numbers]
                           [-l lexer][-o output]
+  tartrazine FILE -f png  [-t theme][--line-numbers]
+                          [-l lexer][-o output]
   tartrazine FILE -f json [-o output]
   tartrazine --list-themes
   tartrazine --list-lexers
@@ -78,6 +84,10 @@ if options["-f"]
     formatter.standalone = options["--standalone"] != nil
     formatter.line_numbers = options["--line-numbers"] != nil
     formatter.theme = theme
+  when "png"
+    formatter = Tartrazine::Png.new
+    formatter.line_numbers = options["--line-numbers"] != nil
+    formatter.theme = theme
   else
     puts "Invalid formatter: #{formatter}"
     exit 1