fix: restore PDF marker visibility by fixing coordinate transformation (fixes #986) #988
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fixes #986) ## Root Cause Analysis PDF markers were missing due to coordinate transformation regression where aspect ratio preservation placed markers at incorrect positions, often outside the visible plot area. **Issue**: Same coordinate transformation bug that caused scale regression (#985) also affected marker positioning in `normalize_to_pdf_coords()`. ## Technical Fix Restored independent axis scaling in PDF coordinate transformation: 1. **normalize_to_pdf_coords()**: Use separate x_scale/y_scale instead of common_scale 2. **safe_coordinate_transform()**: Remove aspect ratio preservation logic 3. **Result**: Markers positioned correctly within visible plot area ## Changes Made - Modified `src/backends/vector/fortplot_pdf_coordinate.f90`: - Remove `common_scale = min(x_scale, y_scale)` logic - Use independent scaling: `x_scale` and `y_scale` - Transform markers directly to correct plot coordinates - Maintain epsilon protection for edge cases ## Validation - Created regression test demonstrating missing markers issue and fix - Tested multiple marker types: circles, squares, triangles, crosses - Verified markers appear correctly in PDF output after fix - Confirmed marker_demo example works properly - All existing tests continue to pass ## Test Plan - [x] Run marker regression test to verify fix - [x] Test marker_demo example (all marker types) - [x] Verify markers visible in PDF output - [x] Confirm no regressions in existing functionality 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <noreply@anthropic.com>
This was referenced Aug 31, 2025
…in per-axis scaling and bounds clamping
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Summary
Fixes missing markers in PDF output caused by coordinate transformation regression. Markers were being positioned outside the visible plot area due to aspect ratio preservation logic introduced ~2 weeks ago.
Root Cause
Same underlying issue as PDF scale regression #985:
normalize_to_pdf_coords()common_scale = min(x_scale, y_scale)Technical Fix
Applied same coordinate transformation fix as scale regression:
Modified Functions
normalize_to_pdf_coords(): Restored independent X/Y scalingsafe_coordinate_transform(): Removed aspect ratio preservationKey Changes
Validation
test_missing_markers_986.f90demonstrates issue/fixmarker_demoworks correctly after fixFiles Changed
src/backends/vector/fortplot_pdf_coordinate.f90: Coordinate transformation fixexample/test_missing_markers_986.f90: Regression test for verificationRelationship to Other Issues
This fix resolves the same coordinate transformation bug as #985 (PDF scale regression):
Test Plan
🤖 Generated with Claude Code