From ae56f78075ea1f033ab27fef0b3fa6b28e058b42 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?I=C3=B1aki=20Dom=C3=ADnguez=20Ochoa?= <inakidomoc@gmail.com>
Date: Sat, 26 Apr 2025 20:31:15 +0200
Subject: [PATCH] fixed some issues with text rendering and line wrapping

---
 src/app/rendering/terminal_text/mod.rs | 59 ++++++++++++++++++++++----
 1 file changed, 51 insertions(+), 8 deletions(-)

diff --git a/src/app/rendering/terminal_text/mod.rs b/src/app/rendering/terminal_text/mod.rs
index d11656d..0f6f8d8 100644
--- a/src/app/rendering/terminal_text/mod.rs
+++ b/src/app/rendering/terminal_text/mod.rs
@@ -198,13 +198,45 @@ impl TerminalText {
 
     fn get_line_bounds(&self, line: usize) -> TextBounds {
         // Calculate the bounds for a specific line
+        if line >= self.buffer.lines.len() {
+            // Return default bounds for invalid line
+            return TextBounds {
+                left: 0,
+                top: 0,
+                right: 0,
+                bottom: 0,
+            };
+        }
 
         let line_height = self.buffer.metrics().line_height;
         let viewport_width = self.viewport.resolution().width;
 
-        // Calculate floating point values first
-        let top_f32 = (line as f32 * line_height).floor();
-        let bottom_f32 = ((line as f32 + 1.0) * line_height).ceil();
+        // Use layout_runs to get information about wrapped lines
+        let layout_iter = self.buffer.layout_runs();
+        let mut top_line = 0;
+        let mut bottom_line = 0;
+        let mut found_line = false;
+
+        // Iterate through layout runs to find our target line
+        for (visual_line_count, run) in layout_iter.enumerate() {
+            if run.line_i == line {
+                // This run belongs to our target line
+                if !found_line {
+                    // First run of our target line
+                    top_line = visual_line_count;
+                    found_line = true;
+                }
+                // Update bottom line for each run we find for this line
+                bottom_line = visual_line_count + 1;
+            } else if found_line {
+                // We've processed all runs for our target line
+                break;
+            }
+        }
+
+        // Calculate bounds based on visual line positions
+        let top_f32 = (top_line as f32 * line_height).floor();
+        let bottom_f32 = (bottom_line as f32 * line_height).ceil();
 
         // Safe conversions with overflow checks
         let top = if top_f32 > i32::MAX as f32 {
@@ -241,15 +273,26 @@ impl TerminalText {
         // Start from line 0 (no scrolling yet)
         let start_line = 0;
 
-        // Calculate how many complete lines fit in the viewport
-        // Add 1 to include partially visible lines at the bottom
-        let visible_lines = (viewport_height / line_height).ceil() as usize + 1;
+        // Calculate visible lines based on wrapped text
+        let layout_iter = self.buffer.layout_runs();
+        let mut last_logical_line = 0;
 
-        // Make sure we don't go beyond the actual number of lines
+        // Count how many visual lines we have and map to logical lines
+        for (visual_line_count, run) in layout_iter.enumerate() {
+            last_logical_line = run.line_i;
+
+            // If we've exceeded the viewport height, we can stop counting
+            if ((start_line + visual_line_count) as f32 * line_height) > viewport_height {
+                break;
+            }
+        }
+
+        // Add 1 to include partially visible lines at the bottom
         let end_line = if self.buffer.lines.is_empty() {
             0
         } else {
-            (start_line + visible_lines).min(self.buffer.lines.len())
+            // Make sure we include at least the last logical line that has content in the viewport
+            (last_logical_line + 1).min(self.buffer.lines.len())
         };
 
         trace!("visible line range goes from {start_line} to {end_line}");