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.

1 files changed, 2 insertions, 3 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<_>>();