[opentype] fix variation coordinate format; load cff2 table

harfbuzz/fonts.go

@@ -309,7 +309,7 @@ func (f *Font) ExtentsForDirection(direction Direction) api.FontExtents {
 	return extents
 }
 
-func (font *Font) varCoords() []float32 { return font.face.Coords }
+func (font *Font) varCoords() []tables.Coord { return font.face.Coords }
 
 func (font *Font) getXDelta(varStore tables.ItemVarStore, device tables.DeviceTable) Position {
 	switch device := device.(type) {

harfbuzz/fonts_test.go

@@ -163,7 +163,7 @@ func TestAdvanceTtVarCompV(t *testing.T) {
 
 func TestAdvanceTtVarGvarInfer(t *testing.T) {
 	ft := openFontFile(t, "fonts/TestGVAREight.ttf")
-	coords := []float32{float32(100) / (1 << 14)}
+	coords := []font.VarCoord{100}
 
 	face := &font.Face{Font: ft, Coords: coords}
 	font := NewFont(face)

harfbuzz/ot_shaper.go

@@ -763,7 +763,7 @@ type shaperOpentype struct {
 
 type otShapePlanKey = [2]int // -1 for not found
 
-func newShaperOpentype(tables *font.Font, coords []float32) *shaperOpentype {
+func newShaperOpentype(tables *font.Font, coords []tables.Coord) *shaperOpentype {
 	var out shaperOpentype
 	out.key = otShapePlanKey{
 		0: tables.GSUB.FindVariationIndex(coords),

harfbuzz/shape.go

@@ -2,6 +2,8 @@ package harfbuzz
 
 import (
 	"fmt"
+
+	"github.com/go-text/typesetting/opentype/tables"
 )
 
 // ported from harfbuzz/src/hb-shape.cc, harfbuzz/src/hb-shape-plan.cc Copyright © 2009, 2012 Behdad Esfahbod
@@ -47,7 +49,7 @@ type shapePlan struct {
 }
 
 func (plan *shapePlan) init(copy bool, font *Font, props SegmentProperties,
-	userFeatures []Feature, coords []float32,
+	userFeatures []Feature, coords []tables.Coord,
 ) {
 	plan.props = props
 	if !copy {
@@ -91,7 +93,7 @@ func (plan shapePlan) equal(other shapePlan) bool {
 // plus the variation-space coordinates @coords.
 // See newShapePlanCached for caching support.
 func newShapePlan(font *Font, props SegmentProperties,
-	userFeatures []Feature, coords []float32,
+	userFeatures []Feature, coords []tables.Coord,
 ) *shapePlan {
 	if debugMode {
 		fmt.Printf("NEW SHAPE PLAN: face:%p features:%v coords:%v\n", &font.face, userFeatures, coords)
@@ -126,7 +128,7 @@ func (sp *shapePlan) execute(font *Font, buffer *Buffer, features []Feature) {
 // creates (or returns) a cached shaping plan suitable for reuse, for a combination
 // of `face`, `userFeatures`, `props`, plus the variation-space coordinates `coords`.
 func (b *Buffer) newShapePlanCached(font *Font, props SegmentProperties,
-	userFeatures []Feature, coords []float32,
+	userFeatures []Feature, coords []tables.Coord,
 ) *shapePlan {
 	var key shapePlan
 	key.init(false, font, props, userFeatures, coords)

opentype/api/font/cff/cff2.go

@@ -26,7 +26,7 @@ type CFF2 struct {
 	// otherwise, it can be safely indexed by `fdSelect` output
 	fonts []privateFonts
 
-	varStore tables.ItemVarStore // optional
+	VarStore tables.ItemVarStore // optional
 }
 
 type privateFonts struct {
@@ -54,7 +54,7 @@ func ParseCFF2(src []byte) (*CFF2, error) {
 		psi ps.Machine
 	)
 	if err := psi.Run(topDictSrc, nil, nil, &tp); err != nil {
-		return nil, err
+		return nil, fmt.Errorf("reading top dict: %s", err)
 	}
 
 	var (
@@ -84,7 +84,7 @@ func ParseCFF2(src []byte) (*CFF2, error) {
 		var fd fontDict2
 		err = psi.Run(font, nil, nil, &fd)
 		if err != nil {
-			return nil, err
+			return nil, fmt.Errorf("reading font dict: %s", err)
 		}
 		end := int(fd.privateDictOffset + fd.privateDictSize)
 		if L := len(src); L < end {
@@ -94,7 +94,7 @@ func ParseCFF2(src []byte) (*CFF2, error) {
 		var pd privateDict2
 		err = psi.Run(src[fd.privateDictOffset:end], nil, nil, &pd)
 		if err != nil {
-			return nil, err
+			return nil, fmt.Errorf("reading private dict: %s", err)
 		}
 
 		out.fonts[i].defaultVSIndex = pd.vsindex
@@ -136,7 +136,7 @@ func ParseCFF2(src []byte) (*CFF2, error) {
 			return nil, fmt.Errorf("reading variation store: EOF: expected length: %d, got %d", end, L)
 		}
 		vstore := src[tp.vstore+2 : end]
-		out.varStore, _, err = tables.ParseItemVarStore(vstore)
+		out.VarStore, _, err = tables.ParseItemVarStore(vstore)
 		if err != nil {
 			return nil, err
 		}
@@ -173,22 +173,22 @@ func (tp *topDict2) Apply(state *ps.Machine, op ps.Operator) error {
 		if state.ArgStack.Top < 1 {
 			return fmt.Errorf("invalid number of arguments for operator %s in Top Dict", op)
 		}
-		tp.charStrings = state.ArgStack.Pop()
+		tp.charStrings = int32(state.ArgStack.Pop())
 	case ps.Operator{Operator: 36, IsEscaped: true}: // FDArray
 		if state.ArgStack.Top < 1 {
 			return fmt.Errorf("invalid number of arguments for operator %s in Top Dict", op)
 		}
-		tp.fdArray = state.ArgStack.Pop()
+		tp.fdArray = int32(state.ArgStack.Pop())
 	case ps.Operator{Operator: 37, IsEscaped: true}: // FDSelect
 		if state.ArgStack.Top < 1 {
 			return fmt.Errorf("invalid number of arguments for operator %s in Top Dict", op)
 		}
-		tp.fdSelect = state.ArgStack.Pop()
+		tp.fdSelect = int32(state.ArgStack.Pop())
 	case ps.Operator{Operator: 24, IsEscaped: false}: // vstore
 		if state.ArgStack.Top < 1 {
 			return fmt.Errorf("invalid number of arguments for operator %s in Top Dict", op)
 		}
-		tp.vstore = state.ArgStack.Pop()
+		tp.vstore = int32(state.ArgStack.Pop())
 	default:
 		return fmt.Errorf("invalid operator %s in Top Dict", op)
 	}
@@ -208,8 +208,8 @@ func (fd *fontDict2) Apply(state *ps.Machine, op ps.Operator) error {
 		if state.ArgStack.Top < 2 {
 			return fmt.Errorf("invalid number of arguments for operator %s in Font Dict", op)
 		}
-		fd.privateDictOffset = state.ArgStack.Pop()
-		fd.privateDictSize = state.ArgStack.Pop()
+		fd.privateDictOffset = int32(state.ArgStack.Pop())
+		fd.privateDictSize = int32(state.ArgStack.Pop())
 		return nil
 	default:
 		return fmt.Errorf("invalid operator %s in Font Dict", op)
@@ -237,13 +237,13 @@ func (priv *privateDict2) Apply(state *ps.Machine, op ps.Operator) error {
 			if state.ArgStack.Top < 1 {
 				return errors.New("invalid stack size for 'subrs' in private Dict charstring")
 			}
-			priv.subrsOffset = state.ArgStack.Pop()
+			priv.subrsOffset = int32(state.ArgStack.Pop())
 			return nil
 		case 22: // "vsindex"
 			if state.ArgStack.Top < 1 {
 				return fmt.Errorf("invalid stack size for %s in private Dict", op)
 			}
-			priv.vsindex = state.ArgStack.Pop()
+			priv.vsindex = int32(state.ArgStack.Pop())
 			return nil
 		case 23: // "blend"
 			return nil

opentype/api/font/cff/charstring.go

@@ -5,7 +5,6 @@ package cff
 import (
 	"errors"
 	"fmt"
-	"math"
 
 	"github.com/go-text/typesetting/opentype/api"
 	ps "github.com/go-text/typesetting/opentype/api/font/cff/interpreter"
@@ -44,8 +43,8 @@ type type2CharstringHandler struct {
 	// found in private DICT, needed since we can't differenciate
 	// no width set from 0 width
 	// `width` must be initialized to default width
-	nominalWidthX int32
-	width         int32
+	nominalWidthX float64
+	width         float64
 }
 
 func (type2CharstringHandler) Context() ps.Context { return ps.Type2Charstring }
@@ -143,8 +142,9 @@ func (met *type2CharstringHandler) Apply(state *ps.Machine, op ps.Operator) erro
 // LoadGlyph parses the glyph charstring to compute segments and path bounds.
 // It returns an error if the glyph is invalid or if decoding the charstring fails.
 //
-// [coords] must either have the same length as the variations axis, or be empty
-func (f *CFF2) LoadGlyph(glyph tables.GlyphID, coords []float32) ([]api.Segment, ps.PathBounds, error) {
+// [coords] must either have the same length as the variations axis, or be empty,
+// and be normalized
+func (f *CFF2) LoadGlyph(glyph tables.GlyphID, coords []tables.Coord) ([]api.Segment, ps.PathBounds, error) {
 	if int(glyph) >= len(f.Charstrings) {
 		return nil, ps.PathBounds{}, errGlyph
 	}
@@ -165,18 +165,19 @@ func (f *CFF2) LoadGlyph(glyph tables.GlyphID, coords []float32) ([]api.Segment,
 	font := f.fonts[index]
 
 	loader.coords = coords
-	loader.vars = f.varStore
+	loader.vars = f.VarStore
 	loader.setVSIndex(int(font.defaultVSIndex))
 
 	err = psi.Run(f.Charstrings[glyph], font.localSubrs, f.globalSubrs, &loader)
+
 	return loader.cs.Segments, loader.cs.Bounds, err
 }
 
 // cff2CharstringHandler implements operators needed to fetch CFF2 charstring metrics
 type cff2CharstringHandler struct {
 	cs ps.CharstringReader
 
-	coords []float32 // variation coordinates
+	coords []tables.Coord // normalized variation coordinates
 	vars   tables.ItemVarStore
 
 	// the currently active ItemVariationData subtable (default to 0)
@@ -214,7 +215,7 @@ func (met *cff2CharstringHandler) blend(state *ps.Machine) error {
 	if state.ArgStack.Top < 1 {
 		return errors.New("missing n argument for blend operator")
 	}
-	n := state.ArgStack.Pop()
+	n := int32(state.ArgStack.Pop())
 	k := int32(len(met.scalars))
 	if state.ArgStack.Top < n*(k+1) {
 		return errors.New("missing arguments for blend operator")
@@ -224,12 +225,13 @@ func (met *cff2CharstringHandler) blend(state *ps.Machine) error {
 		args := state.ArgStack.Vals[state.ArgStack.Top-n*(k+1) : state.ArgStack.Top]
 		// the first n values are the 'default' arguments
 		for i := int32(0); i < n; i++ {
-			baseValue := math.Float32frombits(uint32(args[i]))
+			baseValue := args[i]
 			deltas := args[n+i*k : n+(i+1)*k] // all the regions, for one operand
+			v := 0.
 			for ik, delta := range deltas {
-				baseValue += met.scalars[ik] * math.Float32frombits(uint32(delta))
+				v += float64(met.scalars[ik]) * delta
 			}
-			args[i] = int32(math.Round(float64(baseValue))) // upadte the stack with the blended value
+			args[i] = baseValue + v // update the stack with the blended value
 		}
 	}
 

opentype/api/font/cff/interpreter/charstrings.go

@@ -5,6 +5,7 @@ package psinterpreter
 import (
 	"errors"
 	"fmt"
+	"math"
 
 	"github.com/go-text/typesetting/opentype/api"
 )
@@ -33,19 +34,20 @@ func (b *PathBounds) Enlarge(pt Point) {
 
 // ToExtents converts a path bounds to the corresponding glyph extents.
 func (b *PathBounds) ToExtents() api.GlyphExtents {
+	xBearing, yBearing := math.Round(b.Min.X), math.Round(b.Max.Y)
 	return api.GlyphExtents{
-		XBearing: float32(b.Min.X),
-		YBearing: float32(b.Max.Y),
-		Width:    float32(b.Max.X - b.Min.X),
-		Height:   float32(b.Min.Y - b.Max.Y),
+		XBearing: float32(xBearing),
+		YBearing: float32(yBearing),
+		Width:    float32(math.Round(b.Max.X - xBearing)),
+		Height:   float32(math.Round(b.Min.Y - yBearing)),
 	}
 }
 
 // Point is a 2D Point in font units.
-type Point struct{ X, Y int32 }
+type Point struct{ X, Y float64 }
 
 // Move translates the Point.
-func (p *Point) Move(dx, dy int32) {
+func (p *Point) Move(dx, dy float64) {
 	p.X += dx
 	p.Y += dy
 }
@@ -165,21 +167,14 @@ func (out *CharstringReader) ensureClosePath() {
 	}
 }
 
-func abs(x int32) int32 {
-	if x < 0 {
-		return -x
-	}
-	return x
-}
-
 // ------------------------------------------------------------
 
 // LocalSubr pops the subroutine index and call it
 func LocalSubr(state *Machine) error {
 	if state.ArgStack.Top < 1 {
 		return errors.New("invalid callsubr operator (empty stack)")
 	}
-	index := state.ArgStack.Pop()
+	index := int32(state.ArgStack.Pop())
 	return state.CallSubroutine(index, true)
 }
 
@@ -188,7 +183,7 @@ func GlobalSubr(state *Machine) error {
 	if state.ArgStack.Top < 1 {
 		return errors.New("invalid callgsubr operator (empty stack)")
 	}
-	index := state.ArgStack.Pop()
+	index := int32(state.ArgStack.Pop())
 	return state.CallSubroutine(index, false)
 }
 
@@ -578,7 +573,7 @@ func (out *CharstringReader) Flex1(state *Machine) error {
 	pt5.Move(state.ArgStack.Vals[8], state.ArgStack.Vals[9])
 	pt6 := pt5
 
-	if abs(d.X) > abs(d.Y) {
+	if math.Abs(d.X) > math.Abs(d.Y) {
 		pt6.X += state.ArgStack.Vals[10]
 		pt6.Y = out.CurrentPoint.Y
 	} else {