From 963b266cce1cbb81a88fba2175f2d70be86559e4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Ekl=C3=B6f?= <daniel@ekloef.se>
Date: Mon, 17 Jun 2019 20:53:05 +0200
Subject: [PATCH] vt: handle cursor-at-right-edge

When printing to the right-most-cell, don't advance the
cursor. Instead, set a flag that indicates that the *next* print
should line-wrap.
---
 grid.c     |  1 +
 terminal.h |  1 +
 vt.c       | 11 +++++++++--
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/grid.c b/grid.c
index dc94ceae..3954b64f 100644
--- a/grid.c
+++ b/grid.c
@@ -25,6 +25,7 @@ grid_cursor_move(struct grid *grid, int cols)
     grid->cells[new_cursor].dirty = true;
     grid->cursor = new_cursor;
     grid->dirty = true;
+    grid->print_needs_wrap = false;
 }
 
 void
diff --git a/terminal.h b/terminal.h
index bc0bca56..e6a2e1f2 100644
--- a/terminal.h
+++ b/terminal.h
@@ -29,6 +29,7 @@ struct grid {
     int cell_height;
 
     int cursor;
+    bool print_needs_wrap;
     struct cell *cells;
 
     uint32_t foreground;
diff --git a/vt.c b/vt.c
index 21630292..e1fe0f03 100644
--- a/vt.c
+++ b/vt.c
@@ -177,7 +177,10 @@ action(struct terminal *term, enum action action, uint8_t c)
         memset(&term->vt.utf8, 0, sizeof(term->vt.utf8));
         break;
 
-    case ACTION_PRINT:{
+    case ACTION_PRINT: {
+        if (term->grid.print_needs_wrap)
+            grid_cursor_move(&term->grid, 1);
+
         struct cell *cell = &term->grid.cells[term->grid.cursor];
 
         cell->dirty = true;
@@ -194,7 +197,11 @@ action(struct terminal *term, enum action action, uint8_t c)
 
         cell->attrs = term->vt.attrs;
 
-        grid_cursor_move(&term->grid, 1);
+        if ((term->grid.cursor + 1) % term->grid.cols)
+            grid_cursor_move(&term->grid, 1);
+        else
+            term->grid.print_needs_wrap = true;
+
         term->grid.dirty = true;
         break;
     }