feat(xlsx): implement cell style extraction with rich text and worksheet layout

Cargo.toml

@@ -33,8 +33,13 @@ sha2 = "0.10"
 env_logger = "0.11"
 serde_derive = "1.0"
 rstest = { version = "0.26", default-features = false }
+rust_xlsxwriter = "0.93"
 criterion = { version = "0.7", features = ["html_reports"] }
 
+[[example]]
+name = "generate_styles_1M"
+path = "benches/generate_styles_1M.rs"
+
 [[bench]]
 name = "basic"
 harness = false

benches/generate_large_styled_xlsx.rs

@@ -0,0 +1,206 @@
+// SPDX-License-Identifier: MIT
+//
+// Copyright 2016-2025, Johann Tuffe.
+
+//! Generator for large styled xlsx files for benchmarking.
+//!
+//! Run with: cargo run --bin generate_large_styled_xlsx
+//!
+//! This creates `tests/large_styled.xlsx` with 1000 copies of style patterns.
+
+use rust_xlsxwriter::{
+    Color, Format, FormatAlign, FormatBorder, FormatUnderline, Workbook, XlsxError,
+};
+
+fn main() -> Result<(), XlsxError> {
+    let output_path = format!("{}/tests/styles_1M.xlsx", env!("CARGO_MANIFEST_DIR"));
+    println!(
+        "Generating styles_1M.xlsx (1M styled cells) at: {}",
+        output_path
+    );
+
+    let mut workbook = Workbook::new();
+    let worksheet = workbook.add_worksheet();
+    worksheet.set_name("Sheet 1")?;
+
+    // Define formats matching styles.xlsx patterns
+    let bold = Format::new().set_bold();
+    let italic = Format::new().set_italic();
+    let underline = Format::new().set_underline(FormatUnderline::Single);
+    let strikethrough = Format::new().set_font_strikethrough();
+    let red_font = Format::new().set_font_color(Color::Red);
+    let fill_yellow = Format::new().set_background_color(Color::Yellow);
+    let align_center = Format::new().set_align(FormatAlign::Center);
+    let align_right = Format::new().set_align(FormatAlign::Right);
+    let number_format = Format::new().set_num_format("0.00%");
+    let currency_format = Format::new().set_num_format("$#,##0.00");
+    let date_format = Format::new().set_num_format("yyyy-mm-dd");
+
+    // Border formats
+    let thin_border = Format::new()
+        .set_border(FormatBorder::Thin)
+        .set_border_color(Color::Black);
+    let thick_border = Format::new()
+        .set_border(FormatBorder::Thick)
+        .set_border_color(Color::Blue);
+    let dashed_border = Format::new()
+        .set_border(FormatBorder::Dashed)
+        .set_border_color(Color::Green);
+
+    // Combined formats
+    let bold_italic = Format::new().set_bold().set_italic();
+    let bold_red = Format::new().set_bold().set_font_color(Color::Red);
+    let italic_underline = Format::new()
+        .set_italic()
+        .set_underline(FormatUnderline::Single);
+    let center_yellow = Format::new()
+        .set_align(FormatAlign::Center)
+        .set_background_color(Color::Yellow);
+    let bold_border = Format::new().set_bold().set_border(FormatBorder::Thin);
+
+    // Font size variations
+    let size_8 = Format::new().set_font_size(8.0);
+    let size_12 = Format::new().set_font_size(12.0);
+    let size_16 = Format::new().set_font_size(16.0);
+    let size_24 = Format::new().set_font_size(24.0);
+
+    // Font name variations
+    let arial = Format::new().set_font_name("Arial");
+    let times = Format::new().set_font_name("Times New Roman");
+    let courier = Format::new().set_font_name("Courier New");
+
+    // Color variations
+    let blue_font = Format::new().set_font_color(Color::Blue);
+    let green_font = Format::new().set_font_color(Color::Green);
+    let purple_font = Format::new().set_font_color(Color::Purple);
+    let _fill_cyan = Format::new().set_background_color(Color::Cyan);
+    let _fill_magenta = Format::new().set_background_color(Color::Magenta);
+    let _fill_orange = Format::new().set_background_color(Color::Orange);
+
+    // The pattern of styles to repeat (20 columns x 50 rows = 1000 cells per block)
+    // 1000 repetitions = 1M cells, ~3.2MB file
+    let block_rows = 50;
+    let block_cols = 20;
+    let repetitions = 1000;
+
+    println!(
+        "Creating {} blocks of {}x{} = {} total cells",
+        repetitions,
+        block_rows,
+        block_cols,
+        repetitions * block_rows * block_cols
+    );
+
+    for rep in 0..repetitions {
+        let row_offset = (rep * block_rows) as u32;
+
+        for row in 0..block_rows as u32 {
+            let actual_row = row_offset + row;
+
+            // Column 0: Bold text
+            worksheet.write_string_with_format(actual_row, 0, "Bold", &bold)?;
+
+            // Column 1: Italic text
+            worksheet.write_string_with_format(actual_row, 1, "Italic", &italic)?;
+
+            // Column 2: Underline text
+            worksheet.write_string_with_format(actual_row, 2, "Underline", &underline)?;
+
+            // Column 3: Strikethrough
+            worksheet.write_string_with_format(actual_row, 3, "Strike", &strikethrough)?;
+
+            // Column 4: Red font
+            worksheet.write_string_with_format(actual_row, 4, "Red", &red_font)?;
+
+            // Column 5: Yellow fill
+            worksheet.write_string_with_format(actual_row, 5, "Yellow", &fill_yellow)?;
+
+            // Column 6: Center aligned
+            worksheet.write_string_with_format(actual_row, 6, "Center", &align_center)?;
+
+            // Column 7: Right aligned
+            worksheet.write_string_with_format(actual_row, 7, "Right", &align_right)?;
+
+            // Column 8: Number with percentage format
+            worksheet.write_number_with_format(
+                actual_row,
+                8,
+                0.1234 + (row as f64 * 0.001),
+                &number_format,
+            )?;
+
+            // Column 9: Currency format
+            worksheet.write_number_with_format(
+                actual_row,
+                9,
+                1234.56 + (row as f64),
+                &currency_format,
+            )?;
+
+            // Column 10: Date format
+            worksheet.write_number_with_format(
+                actual_row,
+                10,
+                45000.0 + (row as f64),
+                &date_format,
+            )?;
+
+            // Column 11: Thin border
+            worksheet.write_string_with_format(actual_row, 11, "Thin", &thin_border)?;
+
+            // Column 12: Thick border
+            worksheet.write_string_with_format(actual_row, 12, "Thick", &thick_border)?;
+
+            // Column 13: Dashed border
+            worksheet.write_string_with_format(actual_row, 13, "Dashed", &dashed_border)?;
+
+            // Column 14: Bold + Italic
+            worksheet.write_string_with_format(actual_row, 14, "Bold+Ital", &bold_italic)?;
+
+            // Column 15: Bold + Red
+            worksheet.write_string_with_format(actual_row, 15, "Bold+Red", &bold_red)?;
+
+            // Column 16: Italic + Underline
+            worksheet.write_string_with_format(actual_row, 16, "Ital+Uline", &italic_underline)?;
+
+            // Column 17: Center + Yellow
+            worksheet.write_string_with_format(actual_row, 17, "Ctr+Yellow", &center_yellow)?;
+
+            // Column 18: Bold + Border
+            worksheet.write_string_with_format(actual_row, 18, "Bold+Bdr", &bold_border)?;
+
+            // Column 19: Mixed - rotate through variations
+            match row % 10 {
+                0 => worksheet.write_string_with_format(actual_row, 19, "Size8", &size_8)?,
+                1 => worksheet.write_string_with_format(actual_row, 19, "Size12", &size_12)?,
+                2 => worksheet.write_string_with_format(actual_row, 19, "Size16", &size_16)?,
+                3 => worksheet.write_string_with_format(actual_row, 19, "Size24", &size_24)?,
+                4 => worksheet.write_string_with_format(actual_row, 19, "Arial", &arial)?,
+                5 => worksheet.write_string_with_format(actual_row, 19, "Times", &times)?,
+                6 => worksheet.write_string_with_format(actual_row, 19, "Courier", &courier)?,
+                7 => worksheet.write_string_with_format(actual_row, 19, "Blue", &blue_font)?,
+                8 => worksheet.write_string_with_format(actual_row, 19, "Green", &green_font)?,
+                _ => worksheet.write_string_with_format(actual_row, 19, "Purple", &purple_font)?,
+            };
+        }
+
+        if rep % 100 == 0 {
+            println!("Progress: {}/{} blocks", rep, repetitions);
+        }
+    }
+
+    // Set some column widths
+    for col in 0..block_cols as u16 {
+        worksheet.set_column_width(col, 12.0)?;
+    }
+
+    workbook.save(&output_path)?;
+
+    println!("Done! File saved to: {}", output_path);
+    println!(
+        "Total cells with styles: {}",
+        repetitions * block_rows * block_cols
+    );
+
+    Ok(())
+}