From cce162bd72945165b212a0a1c923b3c17fb3d0ff Mon Sep 17 00:00:00 2001
From: pjht <pterpstra@pterpstra.com>
Date: Mon, 9 Sep 2024 11:05:26 -0500
Subject: [PATCH] Fix erasing the old cursor

---
 src/main.rs | 35 +++++++++++++++++------------------
 1 file changed, 17 insertions(+), 18 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index d272886..3b2e704 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -21,7 +21,7 @@
 
 use core::str;
 use std::{
-    borrow::Cow, collections::HashMap, fmt::{self, Write}, os::mikros::{address_space::ACTIVE_SPACE, ipc, syscalls}
+    borrow::Cow, collections::HashMap, fmt::{self, Write}, os::mikros::{address_space::ACTIVE_SPACE, ipc, syscalls}, usize
 };
 
 use fontdue::{layout::{CoordinateSystem, GlyphRasterConfig, Layout, LayoutSettings, TextStyle, WrapStyle}, Font, FontSettings};
@@ -162,7 +162,8 @@ pub struct FramebufferWriter {
     layout: Layout,
     next_line_y: usize,
     glyph_cache: HashMap<GlyphRasterConfig, Vec<u8>>,
-    cursor_height: usize,
+    cursor_top: usize,
+    cursor_bot: usize,
 }
 
 impl FramebufferWriter {
@@ -180,7 +181,8 @@ impl FramebufferWriter {
             layout,
             next_line_y: 0,
             glyph_cache: HashMap::new(),
-            cursor_height: 0,
+            cursor_top: 0,
+            cursor_bot: 0,
         }
     }
 
@@ -190,6 +192,10 @@ impl FramebufferWriter {
         let text_height = self.layout.height();
         self.layout.append(&[&self.font], &TextStyle::new("\u{2588}", 12.0, 0));
 
+        for row in self.cursor_top..self.cursor_bot {
+            fbuf.clear_row(row);
+        }
+
         if (self.next_line_y + self.layout.height() as usize) > fbuf.yres {
             let excess_y =
                 self.layout.height() as usize - (fbuf.yres - self.next_line_y);
@@ -197,25 +203,13 @@ impl FramebufferWriter {
             self.next_line_y -= excess_y;
         } 
 
-        for row in 0..usize::max(self.cursor_height+5,text_height as usize) {
-            fbuf.clear_row(self.next_line_y + row);
-        }
-
-        //for row in 0..(fbuf.yres - self.next_line_y) {
-        //    fbuf.clear_row(self.next_line_y + row);
-        //}
-
-        self.cursor_height = (self.layout.height() - text_height) as usize;
-
         let glyphs = self.layout.glyphs();
+        let lines = self.layout.lines().unwrap();
 
-        let mut first_line_top_offset = None;
+        let first_line = lines[0];
+        let first_line_top_offset = (first_line.baseline_y - first_line.max_ascent) as usize;
 
         for line in self.layout.lines().unwrap() {
-            if first_line_top_offset.is_none() {
-                first_line_top_offset = Some((line.baseline_y - line.max_ascent) as usize);
-            }
-            let first_line_top_offset = first_line_top_offset.unwrap();
             for glyph_pos in &glyphs[line.glyph_start..=line.glyph_end] {
                 if glyph_pos.width == 0 || glyph_pos.height == 0 {
                     continue;
@@ -239,6 +233,11 @@ impl FramebufferWriter {
             }
         }
 
+        let cursor_glyph = glyphs.last().unwrap();
+
+        self.cursor_top = cursor_glyph.y as usize - first_line_top_offset + self.next_line_y;
+        self.cursor_bot = cursor_glyph.y as usize - first_line_top_offset + self.next_line_y + cursor_glyph.height;
+
         let last_line = self.layout.lines().unwrap().last().unwrap();
         fbuf.update_screen();