nx_paint_fb_ascii_dump.nx

nx_paint_fb_ascii_dump.nx -- dump a Framebuffer to ASCII-art bytes in a caller-supplied output buffer. Phase 5 first primitive of NISHI_BROWSER_ROADMAP. Lets the bits-up substrate produce VISIBLE output we can read in a terminal -- closes the demo gap. Char selection (5-level luminance bucket per pixel): alpha == 0 -> ' ' (transparent) luminance 0..63 (with alpha) -> '.' luminance 64..127 -> '+' luminance 128..191 -> 'o' luminance 192..255 -> '#' Luminance computed as a simple sum of the three channels divided by 3 (close-enough for ASCII art; not the perceptual Rec.601 weights). Integer-only; no FP. Output layout: WIDTH chars per row followed by '\n', repeated for every row. Total output bytes = (width + 1) * height. What it does NOT handle yet (Phase 5b queued, explicit in header): - Unicode block characters (▀ ▄ █ ░ ▒ ▓) for richer 2:1 ratio - ANSI color escape codes for true-color terminals - Multi-pixel-per-cell averaging (Phase 5b "half-block" mode gets twice the vertical resolution by using ▀ + bg/fg color) - Perceptual Rec.601 luminance weights (0.299, 0.587, 0.114) Per cardinal feedback-honest-perf-verdict-no-aspirational-claims: gap list is EXACT in header. genealogy_id: classical_ascii_art_dither + nishi_substrate_phase_5 lineage_id: nishi_browser_fb_ascii_dump_v1