Line.clear_text()

kitty/data-types.h

@@ -24,6 +24,7 @@ typedef unsigned int index_type;
 
 #define CHAR_MASK 0xFFFFFF
 #define ATTRS_SHIFT 24
+#define ATTRS_MASK_WITHOUT_WIDTH 0xFC000000
 #define WIDTH_MASK  0xFF
 #define DECORATION_SHIFT  2
 #define BOLD_SHIFT 4

kitty/line.c

@@ -159,6 +159,20 @@ cursor_from(Line* self, PyObject *args) {
     return (PyObject*)ans;
 }
 
+static PyObject*
+clear_text(Line* self, PyObject *args) {
+#define clear_text_doc "clear_text(at, num, ch=' ') -> Clear characters in the specified range, preserving formatting."
+    unsigned int at, num;
+    int ch = 32;
+    if (!PyArg_ParseTuple(args, "II|C", &at, &num, &ch)) return NULL;
+    const char_type repl = ((char_type)ch & CHAR_MASK) | (1 << ATTRS_SHIFT);
+    for (index_type i = at; i < MIN(self->xnum, at + num); i++) {
+        self->chars[i] = (self->chars[i] & ATTRS_MASK_WITHOUT_WIDTH) | repl;
+    }
+    memset(self->combining_chars + at, 0, MIN(num, self->xnum - at) * sizeof(combining_type));
+    Py_RETURN_NONE;
+}
+
 static PyObject*
 apply_cursor(Line* self, PyObject *args) {
 #define apply_cursor_doc "apply_cursor(cursor, at=0, num=1, clear_char=False) -> Apply the formatting attributes from cursor to the specified characters in this line."
@@ -293,6 +307,7 @@ static PyMethodDef methods[] = {
     METHOD(set_text, METH_VARARGS)
     METHOD(cursor_from, METH_VARARGS)
     METHOD(apply_cursor, METH_VARARGS)
+    METHOD(clear_text, METH_VARARGS)
     METHOD(copy_char, METH_VARARGS)
     METHOD(right_shift, METH_VARARGS)
     METHOD(left_shift, METH_VARARGS)

kitty/screen.py

@@ -607,7 +607,7 @@ class Screen:
             # TODO: Check what to do if x is on the second char of a wide char
             # pair.
             num = min(self.columns - x, count)
-            line = self.linebuf[y]
+            line = self.linebuf.line(y)
             line.right_shift(x, num)
             line.apply_cursor(self.cursor, x, num, clear_char=True)
             self.update_cell_range(y, x, self.columns - 1)
@@ -631,7 +631,7 @@ class Screen:
             # for this control code. Also, what happens if we start deleting
             # at the second cell of a wide character, or delete only the first
             # cell of a wide character?
-            line = self.linebuf[y]
+            line = self.linebuf.line(y)
             line.left_shift(x, num)
             line.apply_cursor(self.cursor, self.columns - num, num, clear_char=True)
             self.update_cell_range(y, x, self.columns - 1)
@@ -654,7 +654,8 @@ class Screen:
         x, y = self.cursor.x, self.cursor.y
         # TODO: Same set of wide character questions as for delete_characters()
         num = min(self.columns - x, count)
-        self.linebuf[y].apply_cursor(self.cursor, x, num, clear_char=True)
+        l = self.linebuf.line(y)
+        l.apply_cursor(self.cursor, x, num, clear_char=True)
         self.update_cell_range(y, x, min(x + num, self.columns) - 1)
 
     def erase_in_line(self, how=0, private=False):
@@ -685,7 +686,7 @@ class Screen:
         if n - s:
             # TODO: Same set of questions as for delete_characters()
             y = self.cursor.y
-            line = self.linebuf[y]
+            line = self.linebuf.line(y)
             c = None if private else self.cursor
             if private:
                 line.clear_text(s, n)
@@ -723,9 +724,9 @@ class Screen:
         if interval[1] > interval[0]:
             for line in range(*interval):
                 if private:
-                    self.linebuf[line].clear_text(0, self.columns)
+                    self.linebuf.line(line).clear_text(0, self.columns)
                 else:
-                    self.linebuf[line].apply_cursor(self.cursor, 0, self.columns, clear_char=True)
+                    self.linebuf.line(line).apply_cursor(self.cursor, 0, self.columns, clear_char=True)
             self.update_line_range(interval[0], interval[1] - 1)
 
         # In case of 0 or 1 we have to erase the line with the cursor also
@@ -894,7 +895,7 @@ class Screen:
     def alignment_display(self):
         """Fills screen with uppercase E's for screen focus and alignment."""
         for i in range(self.lines):
-            self.linebuf[i].clear_text(0, self.columns, 'E')
+            self.linebuf.line(i).clear_text(0, self.columns, 'E')
 
     def select_graphic_rendition(self, *attrs):
         """Set display attributes.

kitty_tests/datatypes.py

@@ -107,6 +107,13 @@ class TestDataTypes(BaseTest):
         self.ae(lb.line(3), lb2.line(0))
         self.ae(lb.line(4), clb.line(4))
 
+        lb = filled_line_buf(5, 5, filled_cursor())
+        l = lb.line(0)
+        l.add_combining_char(1, 'a')
+        l.clear_text(1, 2)
+        self.ae(str(l), '0  00')
+        self.assertEqualAttributes(l.cursor_from(1), l.cursor_from(0))
+
     def test_line(self):
         lb = LineBuf(2, 3)
         for y in range(lb.ynum):