[MRG] Add syntax highlighting to code blocks

README.md

@@ -118,8 +118,10 @@ Note: You can use high resolution images and tweak the terminal font size to get
 
 ### Code blocks
 
+To specify your language for syntax highlighting, put it on the first line after the backticks. If no language is specified, no highlighting will be applied.
+
 <pre>
-```
+```python
 import os
 
 os.getcwd()

examples/sample.md

@@ -64,7 +64,7 @@ columns, rows = shutil.get_terminal_size()
 
 ## Images
 
-```
+```md
 ![RC](images/recurse.png)
 ```
 

present/effects.py

@@ -13,7 +13,12 @@
     ColourImageFile,
     DynamicRenderer,
 )
+from asciimatics.parsers import AnsiTerminalParser
+from asciimatics.strings import ColouredText
 
+from pygments import highlight
+from pygments.lexers import get_lexer_by_name
+from pygments.formatters import Terminal256Formatter
 
 ATTRS = {
     "bold": Screen.A_BOLD,
@@ -34,6 +39,35 @@
 EFFECTS = ["fireworks", "explosions", "stars", "matrix", "plasma"]
 
 
+class HighlightedCode(StaticRenderer):
+    def __init__(self, code, lang):
+        super(HighlightedCode, self).__init__()
+        self._images = [code]
+        self.lang = lang
+
+    @property
+    def rendered_text(self):
+        if self.lang is None:
+            return super().rendered_text
+
+        if len(self._plain_images) <= 0:
+            self._convert_images()
+
+        lexer = get_lexer_by_name(self.lang)
+        highlighted_block = []
+        colour_map = []
+
+        # We're only expecting this renderer to have one code block
+        for line in self._plain_images[0]:
+            highlighted_line = highlight(line, lexer, Terminal256Formatter())
+            encoded_text = ColouredText(highlighted_line, AnsiTerminalParser())
+
+            highlighted_block.append(encoded_text)
+            colour_map.append(encoded_text.colour_map)
+
+        return (highlighted_block, colour_map)
+
+
 class Text(StaticRenderer):
     def __init__(self, text):
         super(Text, self).__init__()
@@ -139,10 +173,12 @@ def _base(screen, element, row, fg_color, bg_color, attr=0):
 
 
 def _code(screen, element, row):
+    column = int(screen.dimensions[1] / 3)
     code = Print(
         screen,
-        Text(element.render()),
+        HighlightedCode(element.render(), element.lang()),
         row,
+        column,
         colour=Screen.COLOUR_WHITE,
         bg=Screen.COLOUR_BLACK,
         transparent=False,

present/slide.py

@@ -98,6 +98,9 @@ def pad(s, fill=" "):
     def size(self):
         return len(self.obj["text"].splitlines())
 
+    def lang(self):
+        return self.obj["info"]
+
     def render(self):
         return self.pad(self.obj["text"])
 

setup.py

@@ -17,6 +17,7 @@
     "Click>=7.0",
     "mistune>=2.0.0a4",
     "pyfiglet>=0.8.post1",
+    "Pygments>=2.10.0",
     "PyYAML>=5.3.1",
 ]
 dev_requires = ["black>=20.8b1", "Sphinx>=2.2.1"]