thumbnail generator for recipes in presentation

thumbnail.py

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+#!/usr/bin/env python3
+"""
+thumbnail.py — generate a link-preview card thumbnail from a screenshot.
+
+Usage:
+    python3 thumbnail.py <screenshot> <url> <title> [-o output.png] [--width 800]
+
+Example:
+    python3 thumbnail.py page.png "souschef.wahwa.com" "Chana Masala" -o thumb.png
+"""
+
+import argparse
+import sys
+
+try:
+    from PIL import Image, ImageDraw, ImageFont, ImageFilter
+except ImportError:
+    sys.exit("Install Pillow:  pip install Pillow")
+
+# Render at 2× then downsample — gives crisp text and sharp edges.
+RENDER_SCALE = 2
+
+# ── visual constants (all at 1× display size) ─────────────────────────────────
+BG_COLOR      = (255, 251, 235)    # warm cream
+CARD_COLOR    = (255, 255, 255)
+URL_COLOR     = (37,  99,  235)    # blue-600
+TITLE_COLOR   = (17,  24,  39)     # gray-900
+DIVIDER_COLOR = (229, 231, 235)    # gray-200
+ICON_BG_COLOR = (240, 241, 243)    # gray-100
+ICON_FG_COLOR = (100, 108, 120)    # gray-500
+
+CORNER_RADIUS = 16
+CARD_PADDING  = 24
+HEADER_V_PAD  = 20
+ICON_SIZE     = 44    # circle diameter
+TEXT_GAP      = 14
+CANVAS_PAD    = 44
+MAX_CONTENT_H = 640
+
+
+# ── fonts ─────────────────────────────────────────────────────────────────────
+def _load_font(paths, size):
+    for p in paths:
+        try:
+            return ImageFont.truetype(p, size)
+        except (IOError, OSError):
+            pass
+    return ImageFont.load_default()
+
+
+def get_font(size, bold=False):
+    if bold:
+        paths = [
+            "/System/Library/Fonts/Supplemental/Arial Bold.ttf",
+            "/Library/Fonts/Arial Bold.ttf",
+            "/usr/share/fonts/truetype/dejavu/DejaVuSans-Bold.ttf",
+            "/usr/share/fonts/truetype/liberation/LiberationSans-Bold.ttf",
+        ]
+    else:
+        paths = [
+            "/System/Library/Fonts/Supplemental/Arial.ttf",
+            "/Library/Fonts/Arial.ttf",
+            "/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf",
+            "/usr/share/fonts/truetype/liberation/LiberationSans-Regular.ttf",
+        ]
+    return _load_font(paths, size)
+
+
+# ── text measurement ──────────────────────────────────────────────────────────
+def tw(f, s):
+    bb = f.getbbox(s)
+    return bb[2] - bb[0]
+
+
+def th(f, s="Ag"):
+    bb = f.getbbox(s)
+    return bb[3] - bb[1]
+
+
+# ── paperclip icon ────────────────────────────────────────────────────────────
+def draw_paperclip_icon(draw, cx, cy, r, color, lw):
+    """
+    Two concentric rounded-rectangle outlines sharing the same top arc —
+    the classic paperclip silhouette.
+    """
+    # Outer pill
+    ow = int(r * 0.50)    # half-width
+    oh = int(r * 0.82)    # half-height
+    draw.rounded_rectangle(
+        [cx - ow, cy - oh, cx + ow, cy + oh],
+        radius=ow,          # = half-width → perfect semicircular ends
+        outline=color,
+        width=lw,
+    )
+    # Inner clip: same top, ends ~55% down
+    iw = int(r * 0.21)
+    i_top = cy - oh + lw + max(2, lw // 2)   # just clear of outer top arc
+    i_bot = cy + int(r * 0.46)
+    draw.rounded_rectangle(
+        [cx - iw, i_top, cx + iw, i_bot],
+        radius=iw,
+        outline=color,
+        width=lw,
+    )
+
+
+def draw_icon(draw, cx, cy, r):
+    """Paperclip inside a light circle."""
+    draw.ellipse([cx - r, cy - r, cx + r, cy + r], fill=ICON_BG_COLOR)
+    lw = max(2, r // 9)
+    draw_paperclip_icon(draw, cx, cy, r, ICON_FG_COLOR, lw)
+
+
+# ── external-link glyph ───────────────────────────────────────────────────────
+def draw_ext_link(draw, x, y, s, color, lw):
+    """
+    Classic external-link indicator: small box (lower-left) with an arrow
+    exiting through the upper-right corner.
+    """
+    m = lw
+    # Box occupies the lower-left ~60% of the bounding square
+    bx2 = x + int(s * 0.62)
+    by1 = y + int(s * 0.38)
+    draw.rounded_rectangle(
+        [x + m, by1, bx2, y + s - m],
+        radius=max(1, s // 7),
+        outline=color,
+        width=lw,
+    )
+    # Diagonal shaft from inside the box toward upper-right
+    ax1, ay1 = x + int(s * 0.34), y + int(s * 0.66)
+    ax2, ay2 = x + s - m,         y + m
+    draw.line([(ax1, ay1), (ax2, ay2)], fill=color, width=lw)
+    # Arrowhead (two orthogonal tails at the tip)
+    aw = int(s * 0.30)
+    draw.line([(ax2 - aw, ay2), (ax2, ay2)], fill=color, width=lw)
+    draw.line([(ax2, ay2),      (ax2, ay2 + aw)], fill=color, width=lw)
+
+
+# ── main ──────────────────────────────────────────────────────────────────────
+def create_thumbnail(screenshot_path, url, title,
+                     output_path="thumbnail.png", card_width=800):
+    S = RENDER_SCALE
+
+    screenshot = Image.open(screenshot_path).convert("RGB")
+
+    url_f   = get_font(17 * S)
+    title_f = get_font(22 * S, bold=True)
+
+    uh = th(url_f,   url)
+    th_ = th(title_f, title)
+    text_block_h = uh + 8 * S + th_
+
+    # Scaled geometry
+    CW   = card_width * S
+    CP   = CARD_PADDING * S
+    HVP  = HEADER_V_PAD * S
+    IS   = ICON_SIZE * S
+    TG   = TEXT_GAP * S
+    CR   = CORNER_RADIUS * S
+    CNVP = CANVAS_PAD * S
+    MCH  = MAX_CONTENT_H * S
+
+    header_h = HVP + max(IS, text_block_h) + HVP
+
+    # Scale screenshot to fill card width; crop height
+    raw_h     = int(screenshot.height * CW / screenshot.width)
+    content_h = min(raw_h, MCH)
+    ss = screenshot.resize((CW, raw_h), Image.LANCZOS).crop((0, 0, CW, content_h))
+
+    card_h   = header_h + S + content_h
+    canvas_w = CW + CNVP * 2
+    canvas_h = card_h + CNVP * 2
+
+    canvas = Image.new("RGBA", (canvas_w, canvas_h), BG_COLOR + (255,))
+
+    # Drop shadow
+    shadow = Image.new("RGBA", (canvas_w, canvas_h), (0, 0, 0, 0))
+    sd = ImageDraw.Draw(shadow)
+    off = 6 * S
+    sd.rounded_rectangle(
+        [CNVP + off, CNVP + off, CNVP + CW + off, CNVP + card_h + off],
+        radius=CR, fill=(0, 0, 0, 38),
+    )
+    shadow = shadow.filter(ImageFilter.GaussianBlur(11 * S))
+    canvas.alpha_composite(shadow)
+
+    # White card
+    card_l = Image.new("RGBA", (canvas_w, canvas_h), (0, 0, 0, 0))
+    ImageDraw.Draw(card_l).rounded_rectangle(
+        [CNVP, CNVP, CNVP + CW, CNVP + card_h],
+        radius=CR, fill=CARD_COLOR + (255,),
+    )
+    canvas.alpha_composite(card_l)
+
+    draw = ImageDraw.Draw(canvas)
+
+    # Icon (vertically centred in header)
+    icx = CNVP + CP + IS // 2
+    icy = CNVP + header_h // 2
+    draw_icon(draw, icx, icy, IS // 2)
+
+    # URL text
+    tx    = CNVP + CP + IS + TG
+    ty_url = CNVP + (header_h - text_block_h) // 2
+    draw.text((tx, ty_url), url, font=url_f, fill=URL_COLOR)
+
+    # External-link glyph (same height as URL text, a little larger)
+    uw      = tw(url_f, url)
+    glyph_s = int(uh * 1.05)
+    glyph_lw = max(2, S)
+    draw_ext_link(
+        draw,
+        tx + uw + 6 * S,
+        ty_url + (uh - glyph_s) // 2,
+        glyph_s, URL_COLOR, glyph_lw,
+    )
+
+    # Title
+    draw.text((tx, ty_url + uh + 8 * S), title, font=title_f, fill=TITLE_COLOR)
+
+    # Divider
+    div_y = CNVP + header_h
+    draw.line([(CNVP, div_y), (CNVP + CW, div_y)], fill=DIVIDER_COLOR, width=S)
+
+    # Screenshot (edge-to-edge inside card)
+    rgb = canvas.convert("RGB")
+    rgb.paste(ss, (CNVP, div_y + S))
+
+    # Clip to rounded card shape
+    mask = Image.new("L", (canvas_w, canvas_h), 0)
+    ImageDraw.Draw(mask).rounded_rectangle(
+        [CNVP, CNVP, CNVP + CW, CNVP + card_h], radius=CR, fill=255,
+    )
+    bg = Image.new("RGB", (canvas_w, canvas_h), BG_COLOR)
+    bg.paste(rgb, mask=mask)
+
+    # Downsample to 1× for crisp output
+    out_w, out_h = canvas_w // S, canvas_h // S
+    bg.resize((out_w, out_h), Image.LANCZOS).save(output_path)
+    print(f"Saved: {output_path}  ({out_w} × {out_h})")
+
+
+if __name__ == "__main__":
+    ap = argparse.ArgumentParser(description="Generate a link-preview thumbnail card")
+    ap.add_argument("screenshot", help="Path to the input screenshot")
+    ap.add_argument("url",        help='URL label, e.g. "souschef.wahwa.com"')
+    ap.add_argument("title",      help="Page title displayed in bold")
+    ap.add_argument("-o", "--output", default="thumbnail.png",
+                    help="Output image path (default: thumbnail.png)")
+    ap.add_argument("--width", type=int, default=800,
+                    help="Card width in pixels (default: 800)")
+    args = ap.parse_args()
+    create_thumbnail(args.screenshot, args.url, args.title, args.output, args.width)