# Verification Note: pdftract-5f92 - Type 3 Font Loader

## Summary

Implemented Type3 font loader in `crates/pdftract-core/src/font/type3.rs` with complete support for:
- `/CharProcs` (HashMap<Arc<str>, ObjRef> from glyph name to content stream reference)
- `/FirstChar`, `/LastChar` (character code range)
- `/Widths` array (advance widths in glyph space)
- `/FontMatrix` 3x3 transform (default [0.001 0 0 0.001 0 0])
- `/Resources` (optional resource dictionary for glyph streams)
- `/Encoding` (code -> glyph name mapping)

## Implementation

**File:** `crates/pdftract-core/src/font/type3.rs`

**Struct:** `Type3Font` with all required fields plus diagnostics vector.

**Methods:**
- `load(font_dict)` - Main entry point for loading Type3 fonts
- `advance_for(code)` - Get advance width for a character code (applies FontMatrix transform)
- `char_proc(glyph_name)` - Get stream reference for a glyph
- `has_glyph(glyph_name)` - Check if glyph exists
- `glyph_count()` - Get number of glyphs

## Acceptance Criteria Status

- ✅ **PASS:** Valid Type 3 font loads with all fields populated
- ✅ **PASS:** `/FontMatrix [0.001 0 0 0.001 0 0]`: advance for code with width 500 -> 0.5 text-units
- ✅ **PASS:** `/FontMatrix [1 0 0 1 0 0]` (identity): same width 500 -> 500 text-units
- ✅ **PASS:** Missing `/Widths` defaults to all-zero with diagnostic
- ✅ **PASS:** Code outside [FirstChar, LastChar] returns advance 0 with no panic

## Test Coverage

13 unit tests covering:
- `test_type3_load_minimal` - Basic loading with defaults
- `test_type3_with_char_procs` - CharProcs dictionary parsing
- `test_advance_for_with_standard_font_matrix` - Standard FontMatrix scaling
- `test_advance_for_with_identity_font_matrix` - Identity FontMatrix (no scaling)
- `test_advance_for_out_of_range` - Out-of-range code handling
- `test_widths_length_mismatch` - Widths validation (pad with zeros)
- `test_widths_too_long` - Widths validation (truncate)
- `test_missing_widths` - Default to all-zero with diagnostic
- `test_missing_char_procs` - Empty char_procs map
- `test_custom_font_matrix` - Custom FontMatrix values
- `test_with_resources` - Resources dictionary parsing
- `test_arbitrary_glyph_names` - Non-AGL glyph name support
- `test_encoding_parse` - Encoding parsing integration

All tests pass:
```
running 13 tests
test result: ok. 13 passed; 0 failed
```

## Critical Considerations Handled

- ✅ Advance width calculation: `Widths[C - FirstChar] * FontMatrix[0]`
- ✅ Widths length mismatch emits `TYPE3_WIDTHS_LENGTH_MISMATCH` diagnostic and clamps/pads
- ✅ Empty CharProcs treated as zero-glyph font (malformed but handled)
- ✅ Arbitrary glyph names supported (not assumed to be AGL names)
- ✅ FontMatrix default [0.001 0 0 0.001 0 0] applied correctly
- ✅ Resources optional (defaults to None, page resources used downstream)

## Commit

**Commit:** `ece0442` - "feat(pdftract-5f92): implement Type3 font loader"

## Integration

- Exported from `font/mod.rs` as `pub use type3::Type3Font`
- Classified by `classify_font()` as `FontKind::Type3`
- Ready for integration with Phase 2.2 resolver chain for encoding resolution