v1.0.5

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -63,7 +63,7 @@ body:
     id: gpdf-version
     attributes:
       label: gpdf Version
-      placeholder: "v1.0.4"
+      placeholder: "v1.0.5"
     validations:
       required: true
 

CHANGELOG.md

@@ -7,6 +7,19 @@ and this project adheres to [Semantic Versioning](https://semver.org/).
 
 ## [Unreleased]
 
+## [1.0.5] - 2026-04-19
+
+### Fixed
+- Text alignment precision for Standard 14 fonts — right/center alignment now lands at the true container edge instead of drifting up to ~17pt for large bold text
+  - `template/fontresolver.go`: `MeasureString` and `LineBreak` now use Adobe Core 14 AFM advance widths when no TTF is registered, instead of the `charCount × size × 0.5` approximation
+  - `Resolve` now normalizes an empty `FontFamily` to `Helvetica`, matching the PDF renderer's default
+  - Metrics (Ascender / Descender / CapHeight) from AFM are returned for Standard 14 fonts — previously hard-coded 0.8 / -0.2 / 0.7 fallback
+
+### Added
+- `pdf/font/standard14.go` — Adobe Standard 14 font constants, `IsStandard14`, `Standard14Metrics`, `Standard14Width`, `NewStandard14Font`
+- `pdf/font/standard14_data.go` — AFM-derived width tables and metrics for Helvetica / Times / Courier / Symbol / ZapfDingbats families (14 fonts, printable ASCII coverage)
+- Tests: `pdf/font/standard14_test.go`, `template/fontresolver_test.go`
+
 ## [1.0.4] - 2026-04-07
 
 ### Added
@@ -119,7 +132,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/).
 - Reed-Solomon coefficient order in QR code encoder
 - binary.Write return value handling for errcheck lint
 
-[Unreleased]: https://github.com/gpdf-dev/gpdf/compare/v1.0.4...HEAD
+[Unreleased]: https://github.com/gpdf-dev/gpdf/compare/v1.0.5...HEAD
+[1.0.5]: https://github.com/gpdf-dev/gpdf/compare/v1.0.4...v1.0.5
 [1.0.4]: https://github.com/gpdf-dev/gpdf/compare/v1.0.3...v1.0.4
 [1.0.3]: https://github.com/gpdf-dev/gpdf/compare/v1.0.2...v1.0.3
 [1.0.2]: https://github.com/gpdf-dev/gpdf/compare/v1.0.1...v1.0.2

_benchmark/go.mod

@@ -7,7 +7,7 @@ replace github.com/gpdf-dev/gpdf => ../
 require (
 	github.com/go-pdf/fpdf v1.0.4
 	github.com/johnfercher/maroto/v2 v2.3.3
-	github.com/gpdf-dev/gpdf v1.0.4
+	github.com/gpdf-dev/gpdf v1.0.5
 	github.com/signintech/gopdf v0.36.0
 	golang.org/x/image v0.18.0
 )

internal/buildinfo/version.go

@@ -3,4 +3,4 @@ package buildinfo
 
 // Version is the library version. It is the single source of truth used by
 // the public gpdf.Version constant and the default PDF Producer metadata.
-const Version = "1.0.4"
+const Version = "1.0.5"

pdf/font/standard14.go

@@ -0,0 +1,106 @@
+package font
+
+// Adobe Standard 14 font names. PDF viewers render these without any
+// embedded font data, using their own built-in metrics. gpdf writes text
+// with these fonts as Type1 font entries (see pdf/writer.go:RegisterFont);
+// layout measurement must match the AFM widths that viewers use so that
+// right/center alignment lands at the same coordinate the PDF viewer
+// actually draws the glyphs at.
+const (
+	Helvetica            = "Helvetica"
+	HelveticaBold        = "Helvetica-Bold"
+	HelveticaOblique     = "Helvetica-Oblique"
+	HelveticaBoldOblique = "Helvetica-BoldOblique"
+	TimesRoman           = "Times-Roman"
+	TimesBold            = "Times-Bold"
+	TimesItalic          = "Times-Italic"
+	TimesBoldItalic      = "Times-BoldItalic"
+	Courier              = "Courier"
+	CourierBold          = "Courier-Bold"
+	CourierOblique       = "Courier-Oblique"
+	CourierBoldOblique   = "Courier-BoldOblique"
+	Symbol               = "Symbol"
+	ZapfDingbats         = "ZapfDingbats"
+)
+
+// Standard14EmUnits is the design unit size for all Adobe 14 fonts.
+const Standard14EmUnits = 1000
+
+// IsStandard14 reports whether name is one of the Adobe 14 standard fonts.
+func IsStandard14(name string) bool {
+	_, ok := standard14Data[name]
+	return ok
+}
+
+// Standard14Metrics returns design-unit metrics for a Standard 14 font,
+// or zero Metrics and false if the name is not a Standard 14 font.
+func Standard14Metrics(name string) (Metrics, bool) {
+	d, ok := standard14Data[name]
+	if !ok {
+		return Metrics{}, false
+	}
+	return d.metrics, true
+}
+
+// Standard14Width returns the advance width of r in the named font, in
+// design units (1000 per em). Returns the space glyph's width when r is
+// not present in the font's width table, matching the fallback most PDF
+// viewers apply when asked to measure characters outside the font's
+// encoding.
+func Standard14Width(name string, r rune) (int, bool) {
+	d, ok := standard14Data[name]
+	if !ok {
+		return 0, false
+	}
+	if w, ok := d.widths[r]; ok {
+		return w, true
+	}
+	return d.widths[' '], true
+}
+
+// standard14FontEntry carries the metrics and per-rune advance widths for
+// one Adobe 14 font.
+type standard14FontEntry struct {
+	metrics Metrics
+	widths  map[rune]int
+}
+
+// standard14Font implements Font for layout measurement of Adobe 14 fonts
+// for which no TTF is registered. Encode/Subset are not meaningful for
+// non-embedded Type1 fonts and return empty results.
+type standard14Font struct {
+	name    string
+	metrics Metrics
+	widths  map[rune]int
+}
+
+// NewStandard14Font returns a Font backed by the AFM width tables for the
+// named Adobe 14 font. Returns (nil, false) if name is not a Standard 14
+// font. The returned Font is safe for layout measurement (Metrics and
+// GlyphWidth) but Encode returns the raw UTF-8 bytes and Subset is a
+// no-op — non-embedded Type1 fonts do not require subsetting.
+func NewStandard14Font(name string) (Font, bool) {
+	d, ok := standard14Data[name]
+	if !ok {
+		return nil, false
+	}
+	return &standard14Font{name: name, metrics: d.metrics, widths: d.widths}, true
+}
+
+func (f *standard14Font) Name() string     { return f.name }
+func (f *standard14Font) Metrics() Metrics { return f.metrics }
+
+func (f *standard14Font) GlyphWidth(r rune) (int, bool) {
+	if w, ok := f.widths[r]; ok {
+		return w, true
+	}
+	return 0, false
+}
+
+func (f *standard14Font) Encode(text string) []byte {
+	return []byte(text)
+}
+
+func (f *standard14Font) Subset(_ []rune) ([]byte, error) {
+	return nil, nil
+}

pdf/font/standard14_data.go

@@ -0,0 +1,221 @@
+package font
+
+// Advance widths and metrics for the Adobe Core 14 fonts in 1000 em units.
+//
+// Values transcribed from the Adobe Font Metrics (AFM) files published by
+// Adobe as part of the Core Font Program. Coverage is printable ASCII
+// (0x20-0x7E); characters outside this range fall back to the space
+// glyph's width — which matches how PDF viewers render unmapped runes for
+// non-embedded Type1 fonts.
+
+// printableASCIIWidths maps rune positions 0x20..0x7E (space through ~) to
+// their advance widths. Helper to expand a compact [95]uint16 into the
+// rune-keyed map stored on each font entry.
+func printableASCIIWidths(ws [95]uint16) map[rune]int {
+	m := make(map[rune]int, 95)
+	for i, w := range ws {
+		m[rune(0x20+i)] = int(w)
+	}
+	return m
+}
+
+// monospaceWidths returns a 95-entry table where every printable ASCII
+// glyph has the same advance width — used for the Courier family.
+func monospaceWidths(w uint16) [95]uint16 {
+	var arr [95]uint16
+	for i := range arr {
+		arr[i] = w
+	}
+	return arr
+}
+
+var helveticaASCII = [95]uint16{
+	// 0x20..0x27:   ! " # $ % & '
+	278, 278, 355, 556, 556, 889, 667, 191,
+	// 0x28..0x2F: ( ) * + , - . /
+	333, 333, 389, 584, 278, 333, 278, 278,
+	// 0x30..0x37: 0 1 2 3 4 5 6 7
+	556, 556, 556, 556, 556, 556, 556, 556,
+	// 0x38..0x3F: 8 9 : ; < = > ?
+	556, 556, 278, 278, 584, 584, 584, 556,
+	// 0x40..0x47: @ A B C D E F G
+	1015, 667, 667, 722, 722, 667, 611, 778,
+	// 0x48..0x4F: H I J K L M N O
+	722, 278, 500, 667, 556, 833, 722, 778,
+	// 0x50..0x57: P Q R S T U V W
+	667, 778, 722, 667, 611, 722, 667, 944,
+	// 0x58..0x5F: X Y Z [ \ ] ^ _
+	667, 667, 611, 278, 278, 278, 469, 556,
+	// 0x60..0x67: ` a b c d e f g
+	333, 556, 556, 500, 556, 556, 278, 556,
+	// 0x68..0x6F: h i j k l m n o
+	556, 222, 222, 500, 222, 833, 556, 556,
+	// 0x70..0x77: p q r s t u v w
+	556, 556, 333, 500, 278, 556, 500, 722,
+	// 0x78..0x7E: x y z { | } ~
+	500, 500, 500, 334, 260, 334, 584,
+}
+
+var helveticaBoldASCII = [95]uint16{
+	278, 333, 474, 556, 556, 889, 722, 238,
+	333, 333, 389, 584, 278, 333, 278, 278,
+	556, 556, 556, 556, 556, 556, 556, 556,
+	556, 556, 333, 333, 584, 584, 584, 611,
+	975, 722, 722, 722, 722, 667, 611, 778,
+	722, 278, 556, 722, 611, 833, 722, 778,
+	667, 778, 722, 667, 611, 722, 667, 944,
+	667, 667, 611, 333, 278, 333, 584, 556,
+	333, 556, 611, 556, 611, 556, 333, 611,
+	611, 278, 278, 556, 278, 889, 611, 611,
+	611, 611, 389, 556, 333, 611, 556, 778,
+	556, 556, 500, 389, 280, 389, 584,
+}
+
+var timesRomanASCII = [95]uint16{
+	250, 333, 408, 500, 500, 833, 778, 180,
+	333, 333, 500, 564, 250, 333, 250, 278,
+	500, 500, 500, 500, 500, 500, 500, 500,
+	500, 500, 278, 278, 564, 564, 564, 444,
+	921, 722, 667, 667, 722, 611, 556, 722,
+	722, 333, 389, 722, 611, 889, 722, 722,
+	556, 722, 667, 556, 611, 722, 722, 944,
+	722, 722, 611, 333, 278, 333, 469, 500,
+	333, 444, 500, 444, 500, 444, 333, 500,
+	500, 278, 278, 500, 278, 778, 500, 500,
+	500, 500, 333, 389, 278, 500, 500, 722,
+	500, 500, 444, 480, 200, 480, 541,
+}
+
+var timesBoldASCII = [95]uint16{
+	250, 333, 555, 500, 500, 1000, 833, 278,
+	333, 333, 500, 570, 250, 333, 250, 278,
+	500, 500, 500, 500, 500, 500, 500, 500,
+	500, 500, 333, 333, 570, 570, 570, 500,
+	930, 722, 667, 722, 722, 667, 611, 778,
+	778, 389, 500, 778, 667, 944, 722, 778,
+	611, 778, 722, 556, 667, 722, 722, 1000,
+	722, 722, 667, 333, 278, 333, 581, 500,
+	333, 500, 556, 444, 556, 444, 333, 500,
+	556, 278, 333, 556, 278, 833, 556, 500,
+	556, 556, 444, 389, 333, 556, 500, 722,
+	500, 500, 444, 394, 220, 394, 520,
+}
+
+var timesItalicASCII = [95]uint16{
+	250, 333, 420, 500, 500, 833, 778, 214,
+	333, 333, 500, 675, 250, 333, 250, 278,
+	500, 500, 500, 500, 500, 500, 500, 500,
+	500, 500, 333, 333, 675, 675, 675, 500,
+	920, 611, 611, 667, 722, 611, 611, 722,
+	722, 333, 444, 667, 556, 833, 667, 722,
+	611, 722, 611, 500, 556, 722, 611, 833,
+	611, 556, 556, 389, 278, 389, 422, 500,
+	333, 500, 500, 444, 500, 444, 278, 500,
+	500, 278, 278, 444, 278, 722, 500, 500,
+	500, 500, 389, 389, 278, 500, 444, 667,
+	444, 444, 389, 400, 275, 400, 541,
+}
+
+var timesBoldItalicASCII = [95]uint16{
+	250, 389, 555, 500, 500, 833, 778, 278,
+	333, 333, 500, 570, 250, 333, 250, 278,
+	500, 500, 500, 500, 500, 500, 500, 500,
+	500, 500, 333, 333, 570, 570, 570, 500,
+	832, 667, 667, 667, 722, 667, 667, 722,
+	778, 389, 500, 667, 611, 889, 722, 722,
+	611, 722, 667, 556, 611, 722, 667, 889,
+	667, 611, 611, 333, 278, 333, 570, 500,
+	333, 500, 500, 444, 500, 444, 333, 500,
+	556, 278, 278, 500, 278, 778, 556, 500,
+	500, 500, 389, 389, 278, 556, 444, 667,
+	500, 444, 389, 348, 220, 348, 570,
+}
+
+// Symbol and ZapfDingbats use specialized encodings that don't map to
+// printable ASCII in the usual way. For layout measurement we return a
+// plausible average width — users generally don't set body text in these
+// fonts, and any mismatch only affects alignment within those contexts.
+var symbolFallbackWidth = uint16(500)
+var zapfDingbatsFallbackWidth = uint16(788)
+
+// standard14Data holds per-font metrics and ASCII width tables.
+// Helvetica-Oblique / Helvetica-BoldOblique share widths with their upright
+// counterparts (obliquing does not alter advance widths). Courier-* are all
+// 600 em units wide (monospace).
+var standard14Data = map[string]standard14FontEntry{
+	Helvetica: {
+		metrics: Metrics{UnitsPerEm: 1000, Ascender: 718, Descender: -207, CapHeight: 718, XHeight: 523, LineGap: 0},
+		widths:  printableASCIIWidths(helveticaASCII),
+	},
+	HelveticaBold: {
+		metrics: Metrics{UnitsPerEm: 1000, Ascender: 718, Descender: -207, CapHeight: 718, XHeight: 532, LineGap: 0},
+		widths:  printableASCIIWidths(helveticaBoldASCII),
+	},
+	HelveticaOblique: {
+		metrics: Metrics{UnitsPerEm: 1000, Ascender: 718, Descender: -207, CapHeight: 718, XHeight: 523, LineGap: 0, ItalicAngle: -12},
+		widths:  printableASCIIWidths(helveticaASCII),
+	},
+	HelveticaBoldOblique: {
+		metrics: Metrics{UnitsPerEm: 1000, Ascender: 718, Descender: -207, CapHeight: 718, XHeight: 532, LineGap: 0, ItalicAngle: -12},
+		widths:  printableASCIIWidths(helveticaBoldASCII),
+	},
+	TimesRoman: {
+		metrics: Metrics{UnitsPerEm: 1000, Ascender: 683, Descender: -217, CapHeight: 662, XHeight: 450, LineGap: 0},
+		widths:  printableASCIIWidths(timesRomanASCII),
+	},
+	TimesBold: {
+		metrics: Metrics{UnitsPerEm: 1000, Ascender: 683, Descender: -217, CapHeight: 676, XHeight: 461, LineGap: 0},
+		widths:  printableASCIIWidths(timesBoldASCII),
+	},
+	TimesItalic: {
+		metrics: Metrics{UnitsPerEm: 1000, Ascender: 683, Descender: -217, CapHeight: 653, XHeight: 441, LineGap: 0, ItalicAngle: -15.5},
+		widths:  printableASCIIWidths(timesItalicASCII),
+	},
+	TimesBoldItalic: {
+		metrics: Metrics{UnitsPerEm: 1000, Ascender: 683, Descender: -217, CapHeight: 669, XHeight: 462, LineGap: 0, ItalicAngle: -15},
+		widths:  printableASCIIWidths(timesBoldItalicASCII),
+	},
+	Courier: {
+		metrics: Metrics{UnitsPerEm: 1000, Ascender: 629, Descender: -157, CapHeight: 562, XHeight: 426, LineGap: 0},
+		widths:  printableASCIIWidths(monospaceWidths(600)),
+	},
+	CourierBold: {
+		metrics: Metrics{UnitsPerEm: 1000, Ascender: 629, Descender: -157, CapHeight: 562, XHeight: 439, LineGap: 0},
+		widths:  printableASCIIWidths(monospaceWidths(600)),
+	},
+	CourierOblique: {
+		metrics: Metrics{UnitsPerEm: 1000, Ascender: 629, Descender: -157, CapHeight: 562, XHeight: 426, LineGap: 0, ItalicAngle: -12},
+		widths:  printableASCIIWidths(monospaceWidths(600)),
+	},
+	CourierBoldOblique: {
+		metrics: Metrics{UnitsPerEm: 1000, Ascender: 629, Descender: -157, CapHeight: 562, XHeight: 439, LineGap: 0, ItalicAngle: -12},
+		widths:  printableASCIIWidths(monospaceWidths(600)),
+	},
+	Symbol: {
+		metrics: Metrics{UnitsPerEm: 1000, Ascender: 1010, Descender: -293, CapHeight: 729, XHeight: 525, LineGap: 0},
+		widths:  printableASCIIWidths(monospaceWidths(symbolFallbackWidth)),
+	},
+	ZapfDingbats: {
+		metrics: Metrics{UnitsPerEm: 1000, Ascender: 820, Descender: -143, CapHeight: 820, XHeight: 456, LineGap: 0},
+		widths:  printableASCIIWidths(monospaceWidths(zapfDingbatsFallbackWidth)),
+	},
+}
+
+// Variant aliases: template.buildFontVariantID emits generic "-Italic"
+// suffixes regardless of family, but the Adobe Core 14 canonical names use
+// "-Oblique" for Helvetica/Courier (and "-Roman" as the base form of
+// Times). Map those variants so layout lookups find the same metrics the
+// PDF renderer writes out via base14Variants in pdftarget.go.
+func init() {
+	for alias, canonical := range map[string]string{
+		"Helvetica-Italic":     HelveticaOblique,
+		"Helvetica-BoldItalic": HelveticaBoldOblique,
+		"Courier-Italic":       CourierOblique,
+		"Courier-BoldItalic":   CourierBoldOblique,
+		"Times":                TimesRoman,
+	} {
+		if _, exists := standard14Data[alias]; !exists {
+			standard14Data[alias] = standard14Data[canonical]
+		}
+	}
+}