Syntax highlighting for the diff view

src/calibre/gui2/tweak_book/diff.py

@@ -9,19 +9,76 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 import sys
 from functools import partial
 
-from PyQt4.Qt import (QSplitter, QApplication)
+from PyQt4.Qt import (QSplitter, QApplication, QPlainTextDocumentLayout, QTextDocument, QTextCursor, QTextCharFormat)
 
-from calibre.gui2.tweak_book.editor.text import PlainTextEdit
+from calibre.gui2.tweak_book import tprefs
+from calibre.gui2.tweak_book.editor.text import PlainTextEdit, get_highlighter, default_font_family
+from calibre.gui2.tweak_book.editor.themes import THEMES, default_theme, theme_color
 from calibre.utils.diff import get_sequence_matcher
 
+def get_theme():
+    theme = THEMES.get(tprefs['editor_theme'], None)
+    if theme is None:
+        theme = THEMES[default_theme()]
+    return theme
+
 class TextBrowser(PlainTextEdit):
 
     def __init__(self, parent=None):
         PlainTextEdit.__init__(self, parent)
         self.setReadOnly(True)
-        self.setLineWrapMode(self.NoWrap)
+        w = self.fontMetrics()
+        self.space_width = w.width(' ')
+        self.setLineWrapMode(self.WidgetWidth if tprefs['editor_line_wrap'] else self.NoWrap)
+        self.setTabStopWidth(tprefs['editor_tab_stop_width'] * self.space_width)
+        font = self.font()
+        ff = tprefs['editor_font_family']
+        if ff is None:
+            ff = default_font_family()
+        font.setFamily(ff)
+        font.setPointSize(tprefs['editor_font_size'])
+        self.setFont(font)
+        theme = get_theme()
+        pal = self.palette()
+        pal.setColor(pal.Base, theme_color(theme, 'Normal', 'bg'))
+        pal.setColor(pal.AlternateBase, theme_color(theme, 'CursorLine', 'bg'))
+        pal.setColor(pal.Text, theme_color(theme, 'Normal', 'fg'))
+        pal.setColor(pal.Highlight, theme_color(theme, 'Visual', 'bg'))
+        pal.setColor(pal.HighlightedText, theme_color(theme, 'Visual', 'fg'))
+        self.setPalette(pal)
 
-class DiffView(QSplitter):
+class Highlight(QTextDocument):
+
+    def __init__(self, parent, text, syntax):
+        QTextDocument.__init__(self, parent)
+        self.l = QPlainTextDocumentLayout(self)
+        self.setDocumentLayout(self.l)
+        self.highlighter = get_highlighter(syntax)(self)
+        self.highlighter.apply_theme(get_theme())
+        self.highlighter.setDocument(self)
+        self.setPlainText(text)
+
+    def copy_lines(self, lo, hi, cursor):
+        ''' Copy specified lines from the syntax highlighted buffer into the
+        destination cursor, preserving all formatting created by the syntax
+        highlighter. '''
+        num = hi - lo
+        if num > 0:
+            block = self.findBlockByNumber(lo + 1)
+            while num > 0:
+                num -= 1
+                cursor.insertText(block.text())
+                dest_block = cursor.block()
+                c = QTextCursor(dest_block)
+                for af in block.layout().additionalFormats():
+                    start = dest_block.position() + af.start
+                    c.setPosition(start), c.setPosition(start + af.length, c.KeepAnchor)
+                    c.setCharFormat(af.format)
+                cursor.insertBlock()
+                cursor.setCharFormat(QTextCharFormat())
+                block = block.next()
+
+class TextDiffView(QSplitter):
 
     def __init__(self, parent=None):
         QSplitter.__init__(self, parent)
@@ -32,10 +89,11 @@ class DiffView(QSplitter):
     def __call__(self, left_text, right_text, context=None, syntax=None):
         left_lines = left_text.splitlines()
         right_lines = right_text.splitlines()
+        self.left_highlight, self.right_highlight = Highlight(self, left_text, syntax), Highlight(self, right_text, syntax)
         self.context = context
 
-        self.left_insert = partial(self.do_insert, self.left.textCursor(), left_lines)
+        self.left_insert = partial(self.do_insert, self.left.textCursor(), self.left_highlight)
-        self.right_insert = partial(self.do_insert, self.right.textCursor(), right_lines)
+        self.right_insert = partial(self.do_insert, self.right.textCursor(), self.right_highlight)
         self.cruncher = get_sequence_matcher()(None, left_lines, right_lines)
         self.do_layout(context)
 
@@ -44,19 +102,22 @@ class DiffView(QSplitter):
 
     def do_layout(self, context=None):
         self.left.clear(), self.right.clear()
-        opcodes = self.cruncher.get_opcodes() if context is None else self.cruncher.get_grouped_opcodes(context)
+        if context is None:
-        for tag, alo, ahi, blo, bhi in opcodes:
+            for tag, alo, ahi, blo, bhi in self.cruncher.get_opcodes():
                 getattr(self, tag)(alo, ahi, blo, bhi)
+        else:
+            for group in self.cruncher.get_grouped_opcodes():
+                for tag, alo, ahi, blo, bhi in group:
+                    getattr(self, tag)(alo, ahi, blo, bhi)
+
         for v in (self.left, self.right):
             c = v.textCursor()
             c.movePosition(c.Start)
             v.setTextCursor(c)
 
-    def do_insert(self, cursor, lines, lo, hi):
+    def do_insert(self, cursor, highlighter, lo, hi):
         start_block = cursor.blockNumber()
-        if lo != hi:
+        highlighter.copy_lines(lo, hi, cursor)
-            cursor.insertText('\n'.join(lines[lo:hi]))
-            cursor.insertBlock()
         return start_block, cursor.blockNumber()
 
     def equal(self, alo, ahi, blo, bhi):
@@ -76,8 +137,8 @@ if __name__ == '__main__':
     app = QApplication([])
     raw1 = open(sys.argv[-2], 'rb').read().decode('utf-8')
     raw2 = open(sys.argv[-1], 'rb').read().decode('utf-8')
-    w = DiffView()
+    w = TextDiffView()
-    w(raw1, raw2)
+    w(raw1, raw2, syntax='html', context=None)
     w.show()
     app.exec_()
 

src/calibre/gui2/tweak_book/editor/text.py

@@ -27,6 +27,9 @@ from calibre.gui2.tweak_book.editor.syntax.css import CSSHighlighter
 PARAGRAPH_SEPARATOR = '\u2029'
 entity_pat = re.compile(r'&(#{0,1}[a-zA-Z0-9]{1,8});')
 
+def get_highlighter(syntax):
+    return {'html':HTMLHighlighter, 'css':CSSHighlighter, 'xml':XMLHighlighter}.get(syntax, SyntaxHighlighter)
+
 _dff = None
 def default_font_family():
     global _dff
@@ -180,7 +183,7 @@ class TextEdit(PlainTextEdit):
 
     def load_text(self, text, syntax='html', process_template=False):
         self.syntax = syntax
-        self.highlighter = {'html':HTMLHighlighter, 'css':CSSHighlighter, 'xml':XMLHighlighter}.get(syntax, SyntaxHighlighter)(self)
+        self.highlighter = get_highlighter(syntax)(self)
         self.highlighter.apply_theme(self.theme)
         self.highlighter.setDocument(self.document())
         self.setPlainText(unicodedata.normalize('NFC', text))