Unify the grid line indexing types

Previously Alacritty was using two different ways to reference lines in
the terminal. Either a `usize`, or a `Line(usize)`. These indexing
systems both served different purposes, but made it difficult to reason
about logic involving these systems because of its inconsistency.

To resolve this issue, a single new `Line(i32)` type has been
introduced.  All existing references to lines and points now rely on
this definition of a line.

The indexing starts at the top of the terminal region with the line 0,
which matches the line 1 used by escape sequences. Each line in the
history becomes increasingly negative and the bottommost line is equal
to the number of visible lines minus one.

Having a system which goes into the negatives allows following the
escape sequence's indexing system closely, while at the same time making
it trivial to implement `Ord` for points.

The Alacritty UI crate is the only place which has a different indexing
system, since rendering and input puts the zero line at the top of the
viewport, rather than the top of the terminal region.

All instances which refer to a number of lines/columns instead of just a
single Line/Column have also been changed to use a `usize` instead. This
way a Line/Column will always refer to a specific place in the grid and
no confusion is created by having a count of lines as a possible index
into the grid storage.

2 files changed, 11 insertions, 11 deletions

diff --git a/alacritty/src/renderer/mod.rs b/alacritty/src/renderer/mod.rs
index 4d752463..414d9bd5 100644
--- a/alacritty/src/renderer/mod.rs
+++ b/alacritty/src/renderer/mod.rs
@@ -481,7 +481,7 @@ impl Batch {
 
         self.instances.push(InstanceData {
             col: cell.point.column.0 as u16,
-            row: cell.point.line.0 as u16,
+            row: cell.point.line as u16,
 
             top: glyph.top,
             left: glyph.left,
@@ -830,7 +830,7 @@ impl<'a> RenderApi<'a> {
     pub fn render_string(
         &mut self,
         glyph_cache: &mut GlyphCache,
-        point: Point,
+        point: Point<usize>,
         fg: Rgb,
         bg: Rgb,
         string: &str,
@@ -846,7 +846,6 @@ impl<'a> RenderApi<'a> {
                 bg_alpha: 1.0,
                 fg,
                 bg,
-                is_match: false,
             })
             .collect::<Vec<_>>();
 
diff --git a/alacritty/src/renderer/rects.rs b/alacritty/src/renderer/rects.rs
index fd966d27..591c9f46 100644
--- a/alacritty/src/renderer/rects.rs
+++ b/alacritty/src/renderer/rects.rs
@@ -3,6 +3,7 @@ use std::mem;
 
 use crossfont::Metrics;
 
+use alacritty_terminal::grid::Dimensions;
 use alacritty_terminal::index::{Column, Point};
 use alacritty_terminal::term::cell::Flags;
 use alacritty_terminal::term::color::Rgb;
@@ -31,8 +32,8 @@ impl RenderRect {
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
 pub struct RenderLine {
-    pub start: Point,
-    pub end: Point,
+    pub start: Point<usize>,
+    pub end: Point<usize>,
     pub color: Rgb,
 }
 
@@ -42,7 +43,7 @@ impl RenderLine {
 
         let mut start = self.start;
         while start.line < self.end.line {
-            let end = Point::new(start.line, size.cols() - 1);
+            let end = Point::new(start.line, size.last_column());
             Self::push_rects(&mut rects, metrics, size, flag, start, end, self.color);
             start = Point::new(start.line + 1, Column(0));
         }
@@ -57,8 +58,8 @@ impl RenderLine {
         metrics: &Metrics,
         size: &SizeInfo,
         flag: Flags,
-        start: Point,
-        end: Point,
+        start: Point<usize>,
+        end: Point<usize>,
         color: Rgb,
     ) {
         let (position, thickness) = match flag {
@@ -99,8 +100,8 @@ impl RenderLine {
     fn create_rect(
         size: &SizeInfo,
         descent: f32,
-        start: Point,
-        end: Point,
+        start: Point<usize>,
+        end: Point<usize>,
         position: f32,
         mut thickness: f32,
         color: Rgb,
@@ -112,7 +113,7 @@ impl RenderLine {
         // Make sure lines are always visible.
         thickness = thickness.max(1.);
 
-        let line_bottom = (start.line.0 as f32 + 1.) * size.cell_height();
+        let line_bottom = (start.line as f32 + 1.) * size.cell_height();
         let baseline = line_bottom + descent;
 
         let mut y = (baseline - position - thickness / 2.).ceil();