UPDATE: Text spills now to adjacent cells if needed

base/src/test/user_model/mod.rs

@@ -11,6 +11,7 @@ mod test_evaluation;
 mod test_general;
 mod test_grid_lines;
 mod test_keyboard_navigation;
+mod test_last_empty_cell;
 mod test_on_area_selection;
 mod test_on_expand_selected_range;
 mod test_on_paste_styles;

base/src/test/user_model/test_last_empty_cell.rs

@@ -0,0 +1,55 @@
+#![allow(clippy::unwrap_used)]
+
+use crate::constants::LAST_ROW;
+use crate::expressions::types::Area;
+use crate::test::util::new_empty_model;
+use crate::UserModel;
+
+#[test]
+fn basic_tests() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    // This is the first row, column 5
+    model.set_user_input(0, 3, 5, "todo").unwrap();
+
+    // Row 3 before column 5 should be empty
+    assert_eq!(
+        model
+            .get_last_non_empty_in_row_before_column(0, 3, 4)
+            .unwrap(),
+        None
+    );
+    // Row 3 before column 5 should be 5
+    assert_eq!(
+        model
+            .get_last_non_empty_in_row_before_column(0, 3, 7)
+            .unwrap(),
+        Some(5)
+    );
+}
+
+#[test]
+fn test_last_empty_cell() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+
+    let column_g_range = Area {
+        sheet: 0,
+        row: 1,
+        column: 7,
+        width: 1,
+        height: LAST_ROW,
+    };
+
+    model
+        .update_range_style(&column_g_range, "fill.bg_color", "#333444")
+        .unwrap();
+
+    // Column 7 has a style but it is empty
+    assert_eq!(
+        model
+            .get_last_non_empty_in_row_before_column(0, 3, 14)
+            .unwrap(),
+        None
+    );
+}

base/src/user_model/common.rs

@@ -13,8 +13,8 @@ use crate::{
     },
     model::Model,
     types::{
-        Alignment, BorderItem, CellType, Col, HorizontalAlignment, SheetProperties, SheetState,
-        Style, VerticalAlignment,
+        Alignment, BorderItem, Cell, CellType, Col, HorizontalAlignment, SheetProperties,
+        SheetState, Style, VerticalAlignment,
     },
     utils::is_valid_hex_color,
 };
@@ -1602,6 +1602,64 @@ impl UserModel {
         Ok(self.model.workbook.worksheet(sheet)?.show_grid_lines)
     }
 
+    /// Returns the largest column in the row less than a column whose cell has a non empty value.
+    /// If the row is empty, it returns `None`.
+    /// This is useful when rendering a part of a worksheet to know which cells spill over
+    pub fn get_last_non_empty_in_row_before_column(
+        &self,
+        sheet: u32,
+        row: i32,
+        column: i32,
+    ) -> Result<Option<i32>, String> {
+        let worksheet = self.model.workbook.worksheet(sheet)?;
+        let data = worksheet.sheet_data.get(&row);
+        if let Some(row_data) = data {
+            let mut last_column = None;
+            let mut columns: Vec<i32> = row_data.keys().copied().collect();
+            columns.sort_unstable();
+            for col in columns {
+                if col < column {
+                    if let Some(cell) = worksheet.cell(row, col) {
+                        if matches!(cell, Cell::EmptyCell { .. }) {
+                            continue;
+                        }
+                    }
+                    last_column = Some(col);
+                }
+            }
+            Ok(last_column)
+        } else {
+            Ok(None)
+        }
+    }
+
+    /// Returns the largest column in the row greater than a column whose cell has a non empty value.
+    pub fn get_first_non_empty_in_row_after_column(
+        &self,
+        sheet: u32,
+        row: i32,
+        column: i32,
+    ) -> Result<Option<i32>, String> {
+        let worksheet = self.model.workbook.worksheet(sheet)?;
+        let data = worksheet.sheet_data.get(&row);
+        if let Some(row_data) = data {
+            let mut columns: Vec<i32> = row_data.keys().copied().collect();
+            // We sort the keys to ensure we are going from left to right
+            columns.sort_unstable();
+            for col in columns {
+                if col > column {
+                    if let Some(cell) = worksheet.cell(row, col) {
+                        if matches!(cell, Cell::EmptyCell { .. }) {
+                            continue;
+                        }
+                    }
+                    return Ok(Some(col));
+                }
+            }
+        }
+        Ok(None)
+    }
+
     /// Returns a copy of the selected area
     pub fn copy_to_clipboard(&self) -> Result<Clipboard, String> {
         let selected_area = self.get_selected_view();