feat: Introduce visual effects module, enhance text rendering with SSAA, and add shifting gradient support.

engine/render.py

@@ -71,8 +71,11 @@ def render_line(text, fnt=None):
     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))
+    hi_h = pix_h * config.SSAA
+    scale = hi_h / max(img_h, 1)
+    new_w_hi = max(1, int(img_w * scale))
+    img = img.resize((new_w_hi, hi_h), Image.Resampling.LANCZOS)
+    new_w = max(1, int(new_w_hi / config.SSAA))
     img = img.resize((new_w, pix_h), Image.Resampling.LANCZOS)
     data = img.tobytes()
     thr = 80
@@ -129,8 +132,8 @@ def big_wrap(text, max_w, fnt=None):
     return out
 
 
-def lr_gradient(rows):
-    """Color each non-space block character with a left-to-right gradient."""
+def lr_gradient(rows, offset=0.0):
+    """Color each non-space block character with a shifting left-to-right gradient."""
     n = len(GRAD_COLS)
     max_x = max((len(r.rstrip()) for r in rows if r.strip()), default=1)
     out = []
@@ -143,7 +146,8 @@ def lr_gradient(rows):
             if ch == ' ':
                 buf.append(' ')
             else:
-                idx = min(round(x / max(max_x - 1, 1) * (n - 1)), n - 1)
+                shifted = (x / max(max_x - 1, 1) + offset) % 1.0
+                idx = min(round(shifted * (n - 1)), n - 1)
                 buf.append(f"{GRAD_COLS[idx]}{ch}\033[0m")
         out.append("".join(buf))
     return out
@@ -165,7 +169,6 @@ def make_block(title, src, ts, w):
                      ("\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