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Fix cursor movements on long lines in editor #521

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merged 4 commits into from
Jul 26, 2023
Merged

Fix cursor movements on long lines in editor #521

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f848ddc
Fix cursor horizontal move on long lines
vinc Jul 24, 2023
a56dc81
Fix cursor alignment on long lines
vinc Jul 24, 2023
04cf1dd
Increase diagram size in comment
vinc Jul 24, 2023
7e81348
Fix insertion
vinc Jul 25, 2023
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53 changes: 32 additions & 21 deletions src/usr/editor.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -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();
Expand Down Expand Up @@ -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;
Expand All @@ -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
Expand All @@ -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;
Expand All @@ -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;
}
Expand Down Expand Up @@ -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
}
Expand Down