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version: "1.0.1" name: pptx-debug-workflow description: Systematic debugging workflow for python-pptx presentation generation
PPTX Debugging Workflow
A systematic approach to creating and debugging PowerPoint presentations using the python-pptx library. This workflow ensures reliable presentation generation through iterative verification and error resolution.
Step 1: Verify Installation
Before writing any code, verify that python-pptx is installed:
pip show python-pptx
If not installed:
pip install python-pptx
Step 2: Test Minimal PPTX Creation
Create and run a minimal test script to verify the library works:
from pptx import Presentationprs = Presentation()slide = prs.slides.add_slide(prs.slide_layouts[0])slide.shapes.title.text = "Test Slide"prs.save("test.pptx")print("Test presentation created successfully")
Run this first to confirm basic functionality before building complex presentations.
Step 3: Write Full Script to File
Always write your presentation script to a `.py` file instead of using heredoc or inline execution. This enables:
- Better error messages with line numbers
- Easier iteration and debugging
- Preserved state between error fixes
Example structure:
from pptx import Presentationfrom pptx.util import Inches, Ptfrom pptx.enum.shapes import MSO_SHAPEfrom pptx.enum.chart import XL_CHART_TYPE, XL_LEGEND_POSITIONfrom pptx.chart.data import CategoryChartDatadef create_presentation():prs = Presentation()# Build slides hereprs.save("output.pptx")print("Presentation saved successfully")if __name__ == "__main__":create_presentation()
Step 4: Execute and Capture Full Traceback
Run the script with full error output:
python your_script.py 2>&1 | tee debug_output.log
This captures the complete Python traceback including:
- Error type and message
- Line numbers where errors occurred
- Stack trace for debugging
Step 5: Fix API Errors Iteratively
Common python-pptx API patterns to remember:
Chart Legend Positioning
Use XL_LEGEND_POSITION (NOT XL_CHART_TYPE) for legend positioning:
from pptx.enum.chart import XL_LEGEND_POSITIONchart.chart.has_legend = Truechart.chart.legend.position = XL_LEGEND_POSITION.RIGHT
Table Cell Access
Access table cells through row iteration pattern:
table = slide.shapes.add_table(rows=5, cols=4, left=Inches(1), top=Inches(2), width=Inches(6), height=Inches(3)).table# Correct pattern - iterate through rows, then cellsfor row_idx, row in enumerate(table.rows):for cell_idx, cell in enumerate(row.cells):cell.text = f"Row {row_idx}, Cell {cell_idx}"# Or direct accesstable.rows[0].cells[0].text = "Header"
Chart Data Format
For pie charts, use category-based data:
chart_data = CategoryChartData()chart_data.categories = ['Category A', 'Category B', 'Category C']chart_data.add_series('Series 1', (30, 45, 25))x, y, cx, cy = Inches(2), Inches(2), Inches(6), Inches(4.5)slide.shapes.add_chart(XL_CHART_TYPE.PIE, x, y, cx, cy, chart_data)
Step 6: Validate Output
After successful execution:
- Verify the
.pptxfile was created - Open in PowerPoint or compatible viewer
- Check that all slides, tables, and charts render correctly
Common Troubleshooting
| Issue | Solution | |
|---|---|---|
| Module not found | pip install python-pptx | |
| AttributeError on chart | Check XL_LEGEND_POSITION vs XL_CHART_TYPE | |
| Table cell access fails | Use table.rows[row].cells[cell] pattern | |
| Chart doesn't display | Verify chart_data format matches chart type | |
| Import errors | Check enum imports from pptx.enum.* |
Quick Reference Script Template
from pptx import Presentationfrom pptx.util import Inches, Ptfrom pptx.enum.chart import XL_CHART_TYPE, XL_LEGEND_POSITIONfrom pptx.chart.data import CategoryChartDatadef main():prs = Presentation()# Add title slideslide = prs.slides.add_slide(prs.slide_layouts[0])slide.shapes.title.text = "Title"# Add content slide with tableslide = prs.slides.add_slide(prs.slide_layouts[1])table = slide.shapes.add_table(3, 3, Inches(1), Inches(2), Inches(8), Inches(2)).tablefor row in table.rows:for cell in row.cells:cell.text = "Data"prs.save("presentation.pptx")print("Done!")if __name__ == "__main__":main()