Use a regex for faster filtering of uinicode data

kitty/screen.py

@@ -12,7 +12,8 @@ from PyQt5.QtCore import QObject, pyqtSignal
 
 from pyte import charsets as cs, control as ctrl, graphics as g, modes as mo
 from .data_types import Line, Cursor, rewrap_lines
-from .utils import wcwidth
+from .utils import wcwidth, is_simple_string
+from .unicode import ignore_pat
 
 
 #: A container for screen's scroll margins.
@@ -28,7 +29,6 @@ Savepoint = namedtuple("Savepoint", [
     "origin",
     "wrap"
 ])
-IGNORED_CATEGORIES = ('Cc', 'Cf', 'Cn', 'Cs')
 
 
 class Screen(QObject):
@@ -292,17 +292,11 @@ class Screen(QObject):
             return self.utf8_decoder.decode(data)
         return "".join(self.g0_charset[b] for b in data)
 
-    def draw(self, data: bytes):
-        """ Displays decoded characters at the current cursor position and
-        creates new lines as need if DECAWM is set.  """
-        orig_x, orig_y = self.cursor.x, self.cursor.y
-        self._notify_cursor_position = False
-        try:
-            for char in self._decode(data):
-                if unicodedata.category(char) in IGNORED_CATEGORIES:
-                    continue
-                char_width = wcwidth(char)
+    def _fast_draw(self, data: str) -> None:
+        while data:
+            pass  # TODO: Implement me
 
+    def _draw_char(self, char: str, char_width: int) -> None:
         # If this was the last column in a line and auto wrap mode is
         # enabled, move the cursor to the beginning of the next line,
         # otherwise replace characters already displayed with newly
@@ -350,6 +344,23 @@ class Screen(QObject):
             self.cursor.x = min(self.cursor.x + char_width, self.columns - 1)
             if not do_insert:
                 self.update_cell_range(self.cursor.y, cx, self.cursor.x)
+
+    def draw(self, data: bytes) -> None:
+        """ Displays decoded characters at the current cursor position and
+        creates new lines as need if DECAWM is set.  """
+        orig_x, orig_y = self.cursor.x, self.cursor.y
+        self._notify_cursor_position = False
+        data = self._decode(data)
+        try:
+            if is_simple_string(data):
+                return self._fast_draw(data)
+            data = ignore_pat.sub('', data)
+            if data:
+                widths = list(map(wcwidth, data))
+                if sum(widths) == len(data):
+                    return self._fast_draw(data)
+                for char, char_width in zip(data, widths):
+                    self._draw_char(char, char_width)
         finally:
             self._notify_cursor_position = True
         if orig_x != self.cursor.x or orig_y != self.cursor.y:
@@ -527,6 +538,7 @@ class Screen(QObject):
             x = self.cursor.x
             num = min(self.columns - x, count)
             line = self.linebuf[y]
+            # TODO: Handle wide chars that get split at the right edge.
             line.right_shift(x, num)
             line.apply_cursor(self.cursor, x, num, clear_char=True)
             self.update_cell_range(y, x, self.columns)
@@ -546,6 +558,7 @@ class Screen(QObject):
         if top <= y <= bottom:
             x = self.cursor.x
             num = min(self.columns - x, count)
+            # TODO: Handle deletion of wide chars
             line = self.linebuf[y]
             line.left_shift(x, num)
             line.apply_cursor(self.cursor, self.columns - num, num, clear_char=True)