run2-pdf-visual-extraction

name	run2_pdf-visual-extraction
description	Extract calendar event times by analyzing visual block positions relative to hour markers

PDF Visual Extraction for Calendar Events

Purpose

Accurately extract event times from calendar PDF by measuring visual block heights and positions relative to hour markers on the timeline axis.

Key Strategy

1. Identify Hour Marker Positions

• Calendar PDFs typically list hours on the left axis (12am, 1am, ..., 11pm)
• Use pdfplumber to extract text and identify hour positions
• Calculate pixel-to-time conversion using hour positions

import pdfplumber
import re

def get_hour_positions(pdf_path):
    """Extract positions of hour markers"""
    with pdfplumber.open(pdf_path) as pdf:
        page = pdf.pages[0]
        text = page.extract_text()

        # Find all hour markers
        hours = {}
        for line in text.split('\n'):
            match = re.match(r'(\d{1,2}(?:am|pm))', line, re.IGNORECASE)
            if match:
                hour_str = match.group(1)
                # Note: Would need OCR or position data to get pixel y-coordinates

        return hours

2. Identify Colored Blocks Using OCR/Text Extraction

• Use pdfplumber to extract all text elements
• Match event names with their labels
• Identify block color types:
  • Red blocks (RGB ~200, 100, 100): Busy/important (fixed)
  • Blue blocks (RGB ~100, 100, 200): Flexible/low-priority (can override)
  • Gray blocks (RGB ~150, 150, 150): Unavailable (fixed)
  • Yellow/Green blocks (RGB high-G): Semi-busy (fixed)

3. Visual Measurement Approach (Manual Inspection)

When automated extraction is insufficient, measure block heights manually:

def estimate_block_duration(visual_inspection):
    """
    Based on visual inspection of PDF:

    Measure each block's height relative to hour markers:
    - If block spans exactly from one hour line to next = 1 hour
    - If block is half the height of 1-hour span = 30 minutes
    - If block is 2 hour-spans tall = 2 hours

    Cross-check by comparing block heights:
    - Blocks of similar visual height likely have similar durations
    - Use known 1-hour blocks as reference
    """
    pass

4. Cross-validation Strategy

def validate_event_times(events, constraints):
    """
    Validate extracted times make sense:

    1. Events don't overlap (except where explicitly flexible)
    2. Events fit within business hours shown on calendar
    3. Event durations are reasonable (not 20+ hours)
    4. Sequence is correct (no events starting before earlier events)
    """
    pass

Implementation Notes

For this PDF format:

• Calendar shows: "Mon Mar 9, 2026 (Eastern Time - New York)"
• Timeline: 12am through 11pm (24-hour period)
• Events visible: Out of office, Weekly Group Meeting, Busy with task B, Project A Discussion, Coffee Chat, Out of office
• Blue blocks are flexible; all others are fixed

Visual Inspection Checklist:

• Identify all hour markers (12am through 11pm on left axis)
• For each colored block, note start time (which hour line it touches)
• For each colored block, estimate height relative to hour-spans
• Identify block colors and map to priority level
• Cross-check total timeline adds up to 24 hours

Example Output

events = [
    {"name": "Out of office", "start": "00:00", "end": "09:00", "color": "gray", "flexible": False},
    {"name": "Weekly Group Meeting", "start": "10:00", "end": "11:00", "color": "red", "flexible": False},
    {"name": "Busy with task B", "start": "11:00", "end": "13:00", "color": "blue", "flexible": True},
    {"name": "Project A Discussion", "start": "14:00", "end": "15:00", "color": "red", "flexible": False},
    {"name": "Coffee Chat with someone", "start": "15:00", "end": "15:45", "color": "yellow", "flexible": False},
    {"name": "Out of office", "start": "18:00", "end": , : , : },
]