changedetection.io/changedetectionio/content_fetchers/helpers.py

105 wiersze
4.1 KiB
Python

# Pages with a vertical height longer than this will use the 'stitch together' method.
# - Many GPUs have a max texture size of 16384x16384px (or lower on older devices).
# - If a page is taller than ~8000–10000px, it risks exceeding GPU memory limits.
# - This is especially important on headless Chromium, where Playwright may fail to allocate a massive full-page buffer.
# The size at which we will switch to stitching method
SCREENSHOT_SIZE_STITCH_THRESHOLD=8000
from loguru import logger
def capture_stitched_together_full_page(page):
import io
import os
import time
from PIL import Image, ImageDraw, ImageFont
MAX_TOTAL_HEIGHT = SCREENSHOT_SIZE_STITCH_THRESHOLD*4 # Maximum total height for the final image (When in stitch mode)
MAX_CHUNK_HEIGHT = 4000 # Height per screenshot chunk
WARNING_TEXT_HEIGHT = 20 # Height of the warning text overlay
# Save the original viewport size
original_viewport = page.viewport_size
now = time.time()
try:
viewport = page.viewport_size
page_height = page.evaluate("document.documentElement.scrollHeight")
# Limit the total capture height
capture_height = min(page_height, MAX_TOTAL_HEIGHT)
images = []
total_captured_height = 0
for offset in range(0, capture_height, MAX_CHUNK_HEIGHT):
# Ensure we do not exceed the total height limit
chunk_height = min(MAX_CHUNK_HEIGHT, MAX_TOTAL_HEIGHT - total_captured_height)
# Adjust viewport size for this chunk
page.set_viewport_size({"width": viewport["width"], "height": chunk_height})
# Scroll to the correct position
page.evaluate(f"window.scrollTo(0, {offset})")
# Capture screenshot chunk
screenshot_bytes = page.screenshot(type='jpeg', quality=int(os.getenv("SCREENSHOT_QUALITY", 30)))
images.append(Image.open(io.BytesIO(screenshot_bytes)))
total_captured_height += chunk_height
# Stop if we reached the maximum total height
if total_captured_height >= MAX_TOTAL_HEIGHT:
break
# Create the final stitched image
stitched_image = Image.new('RGB', (viewport["width"], total_captured_height))
y_offset = 0
# Stitch the screenshot chunks together
for img in images:
stitched_image.paste(img, (0, y_offset))
y_offset += img.height
logger.debug(f"Screenshot stitched together in {time.time()-now:.2f}s")
# Overlay warning text if the screenshot was trimmed
if page_height > MAX_TOTAL_HEIGHT:
draw = ImageDraw.Draw(stitched_image)
warning_text = f"WARNING: Screenshot was {page_height}px but trimmed to {MAX_TOTAL_HEIGHT}px because it was too long"
# Load font (default system font if Arial is unavailable)
try:
font = ImageFont.truetype("arial.ttf", WARNING_TEXT_HEIGHT) # Arial (Windows/Mac)
except IOError:
font = ImageFont.load_default() # Default font if Arial not found
# Get text bounding box (correct method for newer Pillow versions)
text_bbox = draw.textbbox((0, 0), warning_text, font=font)
text_width = text_bbox[2] - text_bbox[0] # Calculate text width
text_height = text_bbox[3] - text_bbox[1] # Calculate text height
# Define background rectangle (top of the image)
draw.rectangle([(0, 0), (viewport["width"], WARNING_TEXT_HEIGHT)], fill="white")
# Center text horizontally within the warning area
text_x = (viewport["width"] - text_width) // 2
text_y = (WARNING_TEXT_HEIGHT - text_height) // 2
# Draw the warning text in red
draw.text((text_x, text_y), warning_text, fill="red", font=font)
# Save or return the final image
output = io.BytesIO()
stitched_image.save(output, format="JPEG", quality=int(os.getenv("SCREENSHOT_QUALITY", 30)))
screenshot = output.getvalue()
finally:
# Restore the original viewport size
page.set_viewport_size(original_viewport)
return screenshot