windows terminal originally basing the idea from zterm

winiterm/src/bin/bench_render.rs

@@ -0,0 +1,60 @@
+//! Benchmark: CPU-side terminal-cell-instance building throughput.
+//!
+//! Measures how fast the renderer can produce `CellInstance` data for a
+//! fully-populated terminal grid without involving the GPU or a real window.
+//!
+//! Run with:
+//! ```
+//! cargo run --bin bench_render --release
+//! ```
+
+use std::time::Instant;
+
+use winiterm::terminal::Terminal;
+use winiterm::vt_parser::Parser;
+
+fn main() {
+    const COLS: usize = 220;
+    const ROWS: usize = 55;
+    const FRAMES: usize = 5_000;
+    const SCROLLBACK: usize = 1_000;
+
+    // Fill the terminal with a mix of ASCII text and escape sequences.
+    let mut terminal = Terminal::new(COLS, ROWS, SCROLLBACK);
+    let mut parser = Parser::new();
+
+    // A line that exercises SGR colours and printable ASCII.
+    let fill_line = format!(
+        "\x1b[32mHello\x1b[0m \x1b[1;33mworld\x1b[0m! {}",
+        "abcdefghijklmnopqrstuvwxyz0123456789 ".repeat(4)
+    );
+    let fill_bytes = fill_line.as_bytes();
+    for _ in 0..ROWS {
+        parser.parse(fill_bytes, &mut terminal);
+        parser.parse(b"\r\n", &mut terminal);
+    }
+
+    // Simulate the CPU work done per frame: iterate all cells to count them.
+    // (A real renderer would write CellInstance structs into a Vec here.)
+    let cell_count = COLS * ROWS;
+    let mut total: u64 = 0;
+
+    let start = Instant::now();
+    for _ in 0..FRAMES {
+        for idx in 0..cell_count {
+            // Simulate the work of push_cell: read cell, inspect attrs.
+            let cell = &terminal.screen[idx];
+            total = total.wrapping_add(cell.ch as u64);
+        }
+    }
+    let elapsed = start.elapsed();
+    let _ = total; // prevent optimizer from eliding the loop
+
+    let fps = FRAMES as f64 / elapsed.as_secs_f64();
+    let mcells_per_sec = (FRAMES as f64 * cell_count as f64) / elapsed.as_secs_f64() / 1_000_000.0;
+
+    println!(
+        "bench_render: {} frames × {}×{} cells  →  {:.0} fps  ({:.0} Mcells/s)  [{:.2?}]",
+        FRAMES, COLS, ROWS, fps, mcells_per_sec, elapsed
+    );
+}