feat: Implement OTF to terminal half-block rendering pipeline including font loading, text rasterization, word-wrap, and gradient coloring.

engine/render.py

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+"""
+OTF → terminal half-block rendering pipeline.
+Font loading, text rasterization, word-wrap, gradient coloring, headline block assembly.
+Depends on: config, terminal, sources, translate.
+"""
+
+import re
+import random
+
+from PIL import Image, ImageDraw, ImageFont
+
+from engine import config
+from engine.terminal import RST, W_COOL
+from engine.sources import SCRIPT_FONTS, SOURCE_LANGS, NO_UPPER
+from engine.translate import detect_location_language, translate_headline
+
+# ─── GRADIENT ─────────────────────────────────────────────
+# Left → right: white-hot leading edge fades to near-black
+GRAD_COLS = [
+    "\033[1;38;5;231m",  # white
+    "\033[1;38;5;195m",  # pale cyan-white
+    "\033[38;5;123m",    # bright cyan
+    "\033[38;5;118m",    # bright lime
+    "\033[38;5;82m",     # lime
+    "\033[38;5;46m",     # bright green
+    "\033[38;5;40m",     # green
+    "\033[38;5;34m",     # medium green
+    "\033[38;5;28m",     # dark green
+    "\033[38;5;22m",     # deep green
+    "\033[2;38;5;22m",   # dim deep green
+    "\033[2;38;5;235m",  # near black
+]
+
+# ─── FONT LOADING ─────────────────────────────────────────
+_FONT_OBJ = None
+_FONT_CACHE = {}
+
+
+def font():
+    """Lazy-load the primary OTF font."""
+    global _FONT_OBJ
+    if _FONT_OBJ is None:
+        _FONT_OBJ = ImageFont.truetype(config.FONT_PATH, config.FONT_SZ)
+    return _FONT_OBJ
+
+
+def font_for_lang(lang=None):
+    """Get appropriate font for a language."""
+    if lang is None or lang not in SCRIPT_FONTS:
+        return font()
+    if lang not in _FONT_CACHE:
+        try:
+            _FONT_CACHE[lang] = ImageFont.truetype(SCRIPT_FONTS[lang], config.FONT_SZ)
+        except Exception:
+            _FONT_CACHE[lang] = font()
+    return _FONT_CACHE[lang]
+
+
+# ─── RASTERIZATION ────────────────────────────────────────
+def render_line(text, fnt=None):
+    """Render a line of text as terminal rows using OTF font + half-blocks."""
+    if fnt is None:
+        fnt = font()
+    bbox = fnt.getbbox(text)
+    if not bbox or bbox[2] <= bbox[0]:
+        return [""]
+    pad = 4
+    img_w = bbox[2] - bbox[0] + pad * 2
+    img_h = bbox[3] - bbox[1] + pad * 2
+    img = Image.new('L', (img_w, img_h), 0)
+    draw = ImageDraw.Draw(img)
+    draw.text((-bbox[0] + pad, -bbox[1] + pad), text, fill=255, font=fnt)
+    pix_h = config.RENDER_H * 2
+    scale = pix_h / max(img_h, 1)
+    new_w = max(1, int(img_w * scale))
+    img = img.resize((new_w, pix_h), Image.Resampling.LANCZOS)
+    data = img.tobytes()
+    thr = 80
+    rows = []
+    for y in range(0, pix_h, 2):
+        row = []
+        for x in range(new_w):
+            top = data[y * new_w + x] > thr
+            bot = data[(y + 1) * new_w + x] > thr if y + 1 < pix_h else False
+            if top and bot:
+                row.append("█")
+            elif top:
+                row.append("▀")
+            elif bot:
+                row.append("▄")
+            else:
+                row.append(" ")
+        rows.append("".join(row))
+    while rows and not rows[-1].strip():
+        rows.pop()
+    while rows and not rows[0].strip():
+        rows.pop(0)
+    return rows if rows else [""]
+
+
+def big_wrap(text, max_w, fnt=None):
+    """Word-wrap text and render with OTF font."""
+    if fnt is None:
+        fnt = font()
+    words = text.split()
+    lines, cur = [], ""
+    for word in words:
+        test = f"{cur} {word}".strip() if cur else word
+        bbox = fnt.getbbox(test)
+        if bbox:
+            img_h = bbox[3] - bbox[1] + 8
+            pix_h = config.RENDER_H * 2
+            scale = pix_h / max(img_h, 1)
+            term_w = int((bbox[2] - bbox[0] + 8) * scale)
+        else:
+            term_w = 0
+        if term_w > max_w - 4 and cur:
+            lines.append(cur)
+            cur = word
+        else:
+            cur = test
+    if cur:
+        lines.append(cur)
+    out = []
+    for i, ln in enumerate(lines):
+        out.extend(render_line(ln, fnt))
+        if i < len(lines) - 1:
+            out.append("")
+    return out
+
+
+def lr_gradient(rows):
+    """Color each non-space block character with a left-to-right gradient."""
+    n = len(GRAD_COLS)
+    max_x = max((len(r.rstrip()) for r in rows if r.strip()), default=1)
+    out = []
+    for row in rows:
+        if not row.strip():
+            out.append(row)
+            continue
+        buf = []
+        for x, ch in enumerate(row):
+            if ch == ' ':
+                buf.append(' ')
+            else:
+                idx = min(round(x / max(max_x - 1, 1) * (n - 1)), n - 1)
+                buf.append(f"{GRAD_COLS[idx]}{ch}\033[0m")
+        out.append("".join(buf))
+    return out
+
+
+# ─── HEADLINE BLOCK ASSEMBLY ─────────────────────────────
+def make_block(title, src, ts, w):
+    """Render a headline into a content block with color."""
+    target_lang = (SOURCE_LANGS.get(src) or detect_location_language(title)) if config.MODE == 'news' else None
+    lang_font = font_for_lang(target_lang)
+    if target_lang:
+        title = translate_headline(title, target_lang)
+    # Don't uppercase scripts that have no case (CJK, Arabic, etc.)
+    if target_lang and target_lang in NO_UPPER:
+        title_up = re.sub(r"\s+", " ", title)
+    else:
+        title_up = re.sub(r"\s+", " ", title.upper())
+    for old, new in [("\u2019","'"), ("\u2018","'"), ("\u201c",'"'),
+                     ("\u201d",'"'), ("\u2013","-"), ("\u2014","-")]:
+        title_up = title_up.replace(old, new)
+    big_rows = big_wrap(title_up, w - 4, lang_font)
+    big_rows = lr_gradient(big_rows)
+    hc = random.choice([
+        "\033[38;5;46m",    # matrix green
+        "\033[38;5;34m",    # dark green
+        "\033[38;5;82m",    # lime
+        "\033[38;5;48m",    # sea green
+        "\033[38;5;37m",    # teal
+        "\033[38;5;44m",    # cyan
+        "\033[38;5;87m",    # sky
+        "\033[38;5;117m",   # ice blue
+        "\033[38;5;250m",   # cool white
+        "\033[38;5;156m",   # pale green
+        "\033[38;5;120m",   # mint
+        "\033[38;5;80m",    # dark cyan
+        "\033[38;5;108m",   # grey-green
+        "\033[38;5;115m",   # sage
+        "\033[1;38;5;46m",  # bold green
+        "\033[1;38;5;250m", # bold white
+    ])
+    content = ["  " + r for r in big_rows]
+    content.append("")
+    meta = f"\u2591 {src} \u00b7 {ts}"
+    content.append(" " * max(2, w - len(meta) - 2) + meta)
+    return content, hc, len(content) - 1  # (rows, color, meta_row_index)