diff --git a/src/usr/editor.rs b/src/usr/editor.rs index 074169c45..eb39d2935 100644 --- a/src/usr/editor.rs +++ b/src/usr/editor.rs @@ -236,6 +236,31 @@ impl Editor { self.highlighted.clear(); } + // Align cursor that is past the end of the line, to the end + // of the line. + // + // If the cursor is somewhere on the long line on the second + // screen in the following diagram, going down should move + // the cursor to the end of the short line and display the + // first screen instead of the second screen. + // + // +----------------------------+----------------------------+ + // | | | + // | This is a loooooooooooooooo|oooooong line | + // | This is a short line | ^ | + // | ^ | | + // +----------------------------+----------------------------+ + fn align_cursor(&mut self) { + let x = self.offset.x + self.cursor.x; + let y = self.offset.y + self.cursor.y; + let eol = self.lines[y].chars().count(); + if x > eol { + let n = self.cols(); + self.offset.x = (eol / n) * n; + self.cursor.x = eol % n; + } + } + pub fn run(&mut self) -> Result<(), ExitCode> { print!("\x1b[2J\x1b[1;1H"); // Clear screen and move cursor to top self.print_screen(); @@ -317,9 +342,9 @@ impl Editor { self.cursor.y -= 1 } else if self.offset.y > 0 { self.offset.y -= 1; - self.print_screen(); } - self.cursor.x = self.next_pos(self.cursor.x, self.cursor.y); + self.align_cursor(); + self.print_screen(); }, 'B' if csi => { // Arrow Down let is_eof = self.offset.y + self.cursor.y == self.lines.len() - 1; @@ -328,12 +353,12 @@ impl Editor { if is_bottom || is_eof { if !is_eof { self.offset.y += 1; - self.print_screen(); } } else { self.cursor.y += 1; } - self.cursor.x = self.next_pos(self.cursor.x, self.cursor.y); + self.align_cursor(); + self.print_screen(); } }, 'C' if csi => { // Arrow Right @@ -344,8 +369,8 @@ impl Editor { csi = false; continue } else if self.cursor.x == self.cols() - 1 { - self.cursor.x = self.offset.x; self.offset.x += self.cols(); + self.cursor.x -= self.cols() - 1; self.print_screen(); } else { self.cursor.x += 1; @@ -358,10 +383,10 @@ impl Editor { csi = false; continue; } else if self.cursor.x == 0 { - self.cursor.x = self.offset.x - 1; self.offset.x -= self.cols(); + self.cursor.x += self.cols() - 1; + self.align_cursor(); self.print_screen(); - self.cursor.x = self.next_pos(self.cursor.x, self.cursor.y); } else { self.cursor.x -= 1; } @@ -521,20 +546,6 @@ impl Editor { Ok(()) } - // Move cursor past end of line to end of line or left of the screen - fn next_pos(&self, x: usize, y: usize) -> usize { - let eol = self.lines[self.offset.y + y].chars().count(); - if eol <= self.offset.x + x { - if eol <= self.offset.x { - 0 - } else { - eol - 1 - } - } else { - x - } - } - fn rows(&self) -> usize { sys::console::rows() - 1 // Leave out one line for status line }