Do a better job at BCE when erasing lines

The `dialog` program relies on this.

term/src/cell.rs

@@ -96,6 +96,17 @@ impl CellAttributes {
     bitfield!(invisible, set_invisible, 8);
     // Allow up to 8 different font values
     //bitfield!(font, set_font, 0b111000000, 6);
+
+    /// Clone the attributes, but exclude fancy extras such
+    /// as hyperlinks or future sprite things
+    pub fn clone_sgr_only(&self) -> Self {
+        Self {
+            attributes: self.attributes,
+            foreground: self.foreground,
+            background: self.background,
+            hyperlink: None,
+        }
+    }
 }
 
 impl Default for CellAttributes {
@@ -196,6 +207,13 @@ impl Cell {
         self.bytes[0] = b' ';
         self.attrs = CellAttributes::default();
     }
+
+    #[inline]
+    pub fn reset_with_attributes(&mut self, attr: &CellAttributes) {
+        self.len = 1;
+        self.bytes[0] = b' ';
+        self.attrs = attr.clone();
+    }
 }
 
 impl From<char> for Cell {

term/src/screen.rs

@@ -143,7 +143,12 @@ impl Screen {
         &line.cells[x]
     }
 
-    pub fn clear_line(&mut self, y: VisibleRowIndex, cols: std::ops::Range<usize>) {
+    pub fn clear_line(
+        &mut self,
+        y: VisibleRowIndex,
+        cols: std::ops::Range<usize>,
+        attr: &CellAttributes,
+    ) {
         let line_idx = self.phys_row(y);
         let line = self.line_mut(line_idx);
         let max_col = line.cells.len();
@@ -151,7 +156,7 @@ impl Screen {
             if x >= max_col {
                 break;
             }
-            line.cells[x].reset();
+            line.cells[x].reset_with_attributes(attr);
         }
     }
 

term/src/terminalstate.rs

@@ -945,37 +945,39 @@ impl TerminalState {
             CSIAction::EraseInLine(erase) => {
                 let cx = self.cursor.x;
                 let cy = self.cursor.y;
+                let pen = self.pen.clone_sgr_only();
                 let mut screen = self.screen_mut();
                 let cols = screen.physical_cols;
                 match erase {
                     LineErase::ToRight => {
-                        screen.clear_line(cy, cx..cols);
+                        screen.clear_line(cy, cx..cols, &pen);
                     }
                     LineErase::ToLeft => {
-                        screen.clear_line(cy, 0..cx);
+                        screen.clear_line(cy, 0..cx, &pen);
                     }
                     LineErase::All => {
-                        screen.clear_line(cy, 0..cols);
+                        screen.clear_line(cy, 0..cols, &pen);
                     }
                 }
             }
             CSIAction::EraseInDisplay(erase) => {
                 let cy = self.cursor.y;
+                let pen = self.pen.clone_sgr_only();
                 let mut screen = self.screen_mut();
                 let cols = screen.physical_cols;
                 let rows = screen.physical_rows as VisibleRowIndex;
                 match erase {
                     DisplayErase::Below => for y in cy..rows {
-                        screen.clear_line(y, 0..cols);
+                        screen.clear_line(y, 0..cols, &pen);
                     },
                     DisplayErase::Above => for y in 0..cy {
-                        screen.clear_line(y, 0..cols);
+                        screen.clear_line(y, 0..cols, &pen);
                     },
                     DisplayErase::All => for y in 0..rows {
-                        screen.clear_line(y, 0..cols);
+                        screen.clear_line(y, 0..cols, &pen);
                     },
                     DisplayErase::SavedLines => {
-                        println!("ed: no support for xterm Erase Saved Lines yet");
+                        println!("TODO: ed: no support for xterm Erase Saved Lines yet");
                     }
                 }
             }

term/src/test/csi.rs

@@ -117,3 +117,31 @@ fn test_cha() {
     term.print("\x1b[100G");
     term.assert_cursor_pos(3, 1, None);
 }
+
+#[test]
+fn test_ed() {
+    let mut term = TestTerm::new(3, 3, 0);
+    term.print("abc\ndef\nghi");
+    term.cup(0, 2);
+    term.print("\x1b[J");
+    assert_visible_contents(&term, &["abc", "def", "   "]);
+
+    // Set background color to blue
+    term.print("\x1b[44m");
+    // Clear whole screen
+    term.print("\x1b[2J");
+
+    // Check that the background color paints all of the cells;
+    // this is also known as BCE - Background Color Erase.
+    let mut attr = CellAttributes::default();
+    attr.background = color::ColorAttribute::PaletteIndex(color::AnsiColor::Navy as u8);
+    let mut line: Line = "   ".into();
+    line.cells[0].attrs = attr.clone();
+    line.cells[1].attrs = attr.clone();
+    line.cells[2].attrs = attr.clone();
+    assert_lines_equal(
+        &term.screen().visible_lines(),
+        &[line.clone(), line.clone(), line],
+        Compare::TEXT | Compare::ATTRS,
+    );
+}