crosspoint-reader-mod/scripts/preview_placeholder_cover.py

#!/usr/bin/env python3
"""Generate a preview of the placeholder cover layout at full cover size (480x800).
This mirrors the C++ PlaceholderCoverGenerator layout logic for visual verification.
"""

from PIL import Image, ImageDraw, ImageFont
import sys
import os

# Reuse the book icon generator
sys.path.insert(0, os.path.dirname(__file__))
from generate_book_icon import generate_book_icon


def create_preview(width=480, height=800, title="The Great Gatsby", author="F. Scott Fitzgerald"):
    img = Image.new("1", (width, height), 1)  # White
    draw = ImageDraw.Draw(img)

    # Proportional layout constants
    edge_padding = max(3, width // 48)      # ~10px at 480w
    border_width = max(2, width // 96)      # ~5px at 480w
    inner_padding = max(4, width // 32)     # ~15px at 480w

    title_scale = 2 if height >= 600 else 1
    author_scale = 2 if height >= 600 else 1  # Author also larger on full covers
    icon_scale = 2 if height >= 600 else (1 if height >= 350 else 0)

    # Draw border inset from edge
    bx = edge_padding
    by = edge_padding
    bw = width - 2 * edge_padding
    bh = height - 2 * edge_padding
    for i in range(border_width):
        draw.rectangle([bx + i, by + i, bx + bw - 1 - i, by + bh - 1 - i], outline=0)

    # Content area
    content_x = edge_padding + border_width + inner_padding
    content_y = edge_padding + border_width + inner_padding
    content_w = width - 2 * content_x
    content_h = height - 2 * content_y

    # Zones
    title_zone_h = content_h * 2 // 3
    author_zone_h = content_h - title_zone_h
    author_zone_y = content_y + title_zone_h

    # Separator
    sep_w = content_w // 3
    sep_x = content_x + (content_w - sep_w) // 2
    draw.line([sep_x, author_zone_y, sep_x + sep_w, author_zone_y], fill=0)

    # Use a basic font for the preview (won't match exact Ubuntu metrics, but shows layout)
    try:
        title_font = ImageFont.truetype("/System/Library/Fonts/Helvetica.ttc", 12 * title_scale)
        author_font = ImageFont.truetype("/System/Library/Fonts/Helvetica.ttc", 10 * author_scale)
    except (OSError, IOError):
        title_font = ImageFont.load_default()
        author_font = ImageFont.load_default()

    # Icon dimensions (needed for title text wrapping)
    icon_w_px = 48 * icon_scale if icon_scale > 0 else 0
    icon_h_px = 48 * icon_scale if icon_scale > 0 else 0
    icon_gap = max(8, width // 40) if icon_scale > 0 else 0
    title_text_w = content_w - icon_w_px - icon_gap  # Title wraps in narrower area beside icon

    # Wrap title (within the narrower area to the right of the icon)
    title_lines = []
    words = title.split()
    current_line = ""
    for word in words:
        test = f"{current_line} {word}".strip()
        bbox = draw.textbbox((0, 0), test, font=title_font)
        if bbox[2] - bbox[0] <= title_text_w:
            current_line = test
        else:
            if current_line:
                title_lines.append(current_line)
            current_line = word
    if current_line:
        title_lines.append(current_line)
    title_lines = title_lines[:5]

    # Line spacing: 75% of advanceY (tighter so 2-3 lines fit within icon height)
    title_line_h = 29 * title_scale * 3 // 4  # Based on C++ ubuntu_12_bold advanceY

    # Measure actual single-line height from the PIL font for accurate centering
    sample_bbox = draw.textbbox((0, 0), "Ag", font=title_font)  # Tall + descender chars
    single_line_visual_h = sample_bbox[3] - sample_bbox[1]

    # Visual height: line spacing between lines + actual height of last line's glyphs
    num_title_lines = len(title_lines)
    title_visual_h = (num_title_lines - 1) * title_line_h + single_line_visual_h if num_title_lines > 0 else 0
    title_block_h = max(icon_h_px, title_visual_h)

    title_start_y = content_y + (title_zone_h - title_block_h) // 2
    if title_start_y < content_y:
        title_start_y = content_y

    # If title fits within icon height, center it vertically against the icon.
    # Otherwise top-align so extra lines overflow below.
    icon_y = title_start_y
    if icon_h_px > 0 and title_visual_h <= icon_h_px:
        title_text_y = title_start_y + (icon_h_px - title_visual_h) // 2
    else:
        title_text_y = title_start_y

    # Horizontal centering: measure widest title line, center icon+gap+text block
    max_title_line_w = 0
    for line in title_lines:
        bbox = draw.textbbox((0, 0), line, font=title_font)
        w = bbox[2] - bbox[0]
        if w > max_title_line_w:
            max_title_line_w = w
    title_block_w = icon_w_px + icon_gap + max_title_line_w
    title_block_x = content_x + (content_w - title_block_w) // 2

    # Draw icon
    if icon_scale > 0:
        icon_img = generate_book_icon(48)
        scaled_icon = icon_img.resize((icon_w_px, icon_h_px), Image.NEAREST)
        for iy in range(scaled_icon.height):
            for ix in range(scaled_icon.width):
                if not scaled_icon.getpixel((ix, iy)):
                    img.putpixel((title_block_x + ix, icon_y + iy), 0)

    # Draw title (to the right of the icon)
    title_text_x = title_block_x + icon_w_px + icon_gap
    current_y = title_text_y
    for line in title_lines:
        draw.text((title_text_x, current_y), line, fill=0, font=title_font)
        current_y += title_line_h

    # Wrap author
    author_lines = []
    words = author.split()
    current_line = ""
    for word in words:
        test = f"{current_line} {word}".strip()
        bbox = draw.textbbox((0, 0), test, font=author_font)
        if bbox[2] - bbox[0] <= content_w:
            current_line = test
        else:
            if current_line:
                author_lines.append(current_line)
            current_line = word
    if current_line:
        author_lines.append(current_line)
    author_lines = author_lines[:3]

    # Draw author centered in bottom 1/3
    author_line_h = 24 * author_scale  # Ubuntu 10 regular advanceY ~24
    author_block_h = len(author_lines) * author_line_h
    author_start_y = author_zone_y + (author_zone_h - author_block_h) // 2

    for line in author_lines:
        bbox = draw.textbbox((0, 0), line, font=author_font)
        line_w = bbox[2] - bbox[0]
        line_x = content_x + (content_w - line_w) // 2
        draw.text((line_x, author_start_y), line, fill=0, font=author_font)
        author_start_y += author_line_h

    return img


if __name__ == "__main__":
    # Full cover
    img = create_preview(480, 800, "A Really Long Book Title That Should Wrap", "Jane Doe")
    img.save("mod/preview_cover_480x800.png")
    print("Saved mod/preview_cover_480x800.png", file=sys.stderr)

    # Medium thumbnail
    img2 = create_preview(240, 400, "A Really Long Book Title That Should Wrap", "Jane Doe")
    img2.save("mod/preview_thumb_240x400.png")
    print("Saved mod/preview_thumb_240x400.png", file=sys.stderr)

    # Small thumbnail
    img3 = create_preview(136, 226, "A Really Long Book Title", "Jane Doe")
    img3.save("mod/preview_thumb_136x226.png")
    print("Saved mod/preview_thumb_136x226.png", file=sys.stderr)