freetype/truetype: implement ISECT, SHC, WCVTF, DELTAC and SDPVTL
opcodes. R=bsiegert CC=golang-dev, remyoudompheng https://codereview.appspot.com/29510043
This commit is contained in:
Nigel Tao
parent
f6106a9f8b
commit
cef9ca89c7
3 changed files with 190 additions and 41 deletions
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@ -280,6 +280,55 @@ func (h *Hinter) run(program []byte, pCurrent, pUnhinted, pInFontUnits []Point,
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case opSFVTPV:
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h.gs.fv = h.gs.pv
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case opISECT:
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top -= 5
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p := h.point(2, current, h.stack[top+0])
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a0 := h.point(1, current, h.stack[top+1])
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a1 := h.point(1, current, h.stack[top+2])
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b0 := h.point(0, current, h.stack[top+3])
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b1 := h.point(0, current, h.stack[top+4])
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if p == nil || a0 == nil || a1 == nil || b0 == nil || b1 == nil {
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return errors.New("truetype: hinting: point out of range")
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}
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dbx := b1.X - b0.X
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dby := b1.Y - b0.Y
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dax := a1.X - a0.X
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day := a1.Y - a0.Y
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dx := b0.X - a0.X
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dy := b0.Y - a0.Y
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discriminant := mulDiv(int64(dax), int64(-dby), 0x40) +
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mulDiv(int64(day), int64(dbx), 0x40)
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dotProduct := mulDiv(int64(dax), int64(dbx), 0x40) +
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mulDiv(int64(day), int64(dby), 0x40)
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// The discriminant above is actually a cross product of vectors
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// da and db. Together with the dot product, they can be used as
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// surrogates for sine and cosine of the angle between the vectors.
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// Indeed,
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// dotproduct = |da||db|cos(angle)
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// discriminant = |da||db|sin(angle)
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// We use these equations to reject grazing intersections by
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// thresholding abs(tan(angle)) at 1/19, corresponding to 3 degrees.
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absDisc, absDotP := discriminant, dotProduct
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if absDisc < 0 {
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absDisc = -absDisc
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}
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if absDotP < 0 {
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absDotP = -absDotP
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}
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if 19*absDisc > absDotP {
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val := mulDiv(int64(dx), int64(-dby), 0x40) +
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mulDiv(int64(dy), int64(dbx), 0x40)
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rx := mulDiv(val, int64(dax), discriminant)
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ry := mulDiv(val, int64(day), discriminant)
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p.X = a0.X + int32(rx)
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p.Y = a0.Y + int32(ry)
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} else {
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p.X = (a0.X + a1.X + b0.X + b1.X) / 4
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p.Y = (a0.Y + a1.Y + b0.Y + b1.Y) / 4
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}
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p.Flags |= flagTouchedX | flagTouchedY
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case opSRP0, opSRP1, opSRP2:
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top--
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h.gs.rp[opcode-opSRP0] = h.stack[top]
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@ -498,6 +547,28 @@ func (h *Hinter) run(program []byte, pCurrent, pUnhinted, pInFontUnits []Point,
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}
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h.gs.loop = 1
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case opSHC0, opSHC1:
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top--
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_, _, d, ok := h.displacement(opcode&1 == 0)
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if !ok {
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return errors.New("truetype: hinting: point out of range")
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}
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if h.gs.zp[2] == 0 {
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// TODO: implement this when we have a glyph that does this.
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return errors.New("hinting: unimplemented SHC instruction")
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}
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contour := h.stack[top]
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if contour < 0 || len(ends) <= int(contour) {
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return errors.New("truetype: hinting: contour out of range")
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}
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j0, j1 := 0, h.ends[contour]
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if contour > 0 {
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j0 = h.ends[contour-1]
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}
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for j := j0; j < j1; j++ {
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h.move(h.point(2, current, int32(j)), d, false)
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}
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case opSHZ0, opSHZ1:
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top--
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zonePointer, i, d, ok := h.displacement(opcode&1 == 0)
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@ -815,9 +886,16 @@ func (h *Hinter) run(program []byte, pCurrent, pUnhinted, pInFontUnits []Point,
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// This code does not implement engine compensation, as we don't expect to
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// be used to output on dot-matrix printers.
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case opWCVTF:
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top -= 2
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h.setScaledCVT(h.stack[top], f26dot6(h.font.scale(h.scale*h.stack[top+1])))
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case opDELTAP2, opDELTAP3:
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goto deltap
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case opDELTAC1, opDELTAC2, opDELTAC3:
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goto deltac
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case opSROUND, opS45ROUND:
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top--
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switch (h.stack[top] >> 6) & 0x03 {
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@ -878,6 +956,33 @@ func (h *Hinter) run(program []byte, pCurrent, pUnhinted, pInFontUnits []Point,
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// We do not support dropout control, as we always rasterize grayscale glyphs.
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top--
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case opSDPVTL0, opSDPVTL1:
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top -= 2
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for i := 0; i < 2; i++ {
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pt := unhinted
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if i != 0 {
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pt = current
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}
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p := h.point(1, pt, h.stack[top])
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q := h.point(2, pt, h.stack[top+1])
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if p == nil || q == nil {
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return errors.New("truetype: hinting: point out of range")
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}
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dx := f2dot14(p.X - q.X)
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dy := f2dot14(p.Y - q.Y)
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if dx == 0 && dy == 0 {
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dx = 0x4000
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} else if opcode&1 != 0 {
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// Counter-clockwise rotation.
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dx, dy = -dy, dx
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}
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if i == 0 {
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h.gs.dv = normalize(dx, dy)
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} else {
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h.gs.pv = normalize(dx, dy)
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}
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}
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case opGETINFO:
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res := int32(0)
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if h.stack[top-1]&(1<<0) != 0 {
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@ -1155,39 +1260,83 @@ func (h *Hinter) run(program []byte, pCurrent, pUnhinted, pInFontUnits []Point,
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continue
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}
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// TODO: merge the deltap and deltac code, when we have enough test cases
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// (at least full coverage of Arial) to have confidence in re-factoring.
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deltap:
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top--
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n := f26dot6(h.stack[top])
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if top < 2*int(h.gs.loop) {
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return errors.New("truetype: hinting: stack underflow")
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{
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top--
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n := f26dot6(h.stack[top])
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if top < 2*int(h.gs.loop) {
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return errors.New("truetype: hinting: stack underflow")
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}
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for ; n > 0; n-- {
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top -= 2
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p := h.point(0, current, h.stack[top+1])
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if p == nil {
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return errors.New("truetype: hinting: point out of range")
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}
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b := h.stack[top]
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c := (b & 0xf0) >> 4
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switch opcode {
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case opDELTAP2:
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c += 16
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case opDELTAP3:
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c += 32
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}
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c += h.gs.deltaBase
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if ppem := (h.scale + 1<<5) >> 6; ppem != c {
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continue
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}
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b = (b & 0x0f) - 8
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if b >= 0 {
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b++
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}
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b = b * 64 / (1 << uint32(h.gs.deltaShift))
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h.move(p, f26dot6(b), true)
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}
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pc++
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continue
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}
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for ; n > 0; n-- {
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top -= 2
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p := h.point(0, current, h.stack[top+1])
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if p == nil {
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return errors.New("truetype: hinting: point out of range")
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deltac:
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{
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if !h.scaledCVTInitialized {
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h.initializeScaledCVT()
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}
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b := h.stack[top]
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c := (b & 0xf0) >> 4
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switch opcode {
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case opDELTAP2:
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c += 16
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case opDELTAP3:
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c += 32
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top--
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n := f26dot6(h.stack[top])
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if top < 2*int(h.gs.loop) {
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return errors.New("truetype: hinting: stack underflow")
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}
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c += h.gs.deltaBase
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if ppem := (h.scale + 1<<5) >> 6; ppem != c {
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continue
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for ; n > 0; n-- {
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top -= 2
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b := h.stack[top]
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c := (b & 0xf0) >> 4
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switch opcode {
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case opDELTAC2:
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c += 16
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case opDELTAC3:
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c += 32
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}
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c += h.gs.deltaBase
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if ppem := (h.scale + 1<<5) >> 6; ppem != c {
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continue
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}
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b = (b & 0x0f) - 8
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if b >= 0 {
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b++
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}
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b = b * 64 / (1 << uint32(h.gs.deltaShift))
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a := h.stack[top+1]
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if a < 0 || len(h.scaledCVT) <= int(a) {
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return errors.New("truetype: hinting: index out of range")
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}
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h.scaledCVT[a] += f26dot6(b)
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}
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b = (b & 0x0f) - 8
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if b >= 0 {
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b++
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}
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b = b * 64 / (1 << uint32(h.gs.deltaShift))
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h.move(p, f26dot6(b), true)
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pc++
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continue
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}
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pc++
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continue
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}
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return nil
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}
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@ -25,7 +25,7 @@ const (
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opGPV = 0x0c // Get Projection Vector
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opGFV = 0x0d // Get Freedom Vector
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opSFVTPV = 0x0e // Set Freedom Vector To Projection Vector
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opISECT = 0x0f
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opISECT = 0x0f // moves point p to the InterSECTion of two lines
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opSRP0 = 0x10 // Set Reference Point 0
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opSRP1 = 0x11 // Set Reference Point 1
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opSRP2 = 0x12 // Set Reference Point 2
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@ -62,8 +62,8 @@ const (
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opIUP1 = 0x31 // .
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opSHP0 = 0x32 // SHift Point using reference point
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opSHP1 = 0x33 // .
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opSHC0 = 0x34
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opSHC1 = 0x35
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opSHC0 = 0x34 // SHift Contour using reference point
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opSHC1 = 0x35 // .
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opSHZ0 = 0x36 // SHift Zone using reference point
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opSHZ1 = 0x37 // .
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opSHPIX = 0x38 // SHift point by a PIXel amount
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@ -122,12 +122,12 @@ const (
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opNROUND01 = 0x6d // .
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opNROUND10 = 0x6e // .
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opNROUND11 = 0x6f // .
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opWCVTF = 0x70
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opWCVTF = 0x70 // Write Control Value Table in Funits
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opDELTAP2 = 0x71 // DELTA exception P2
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opDELTAP3 = 0x72 // DELTA exception P3
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opDELTAC1 = 0x73
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opDELTAC2 = 0x74
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opDELTAC3 = 0x75
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opDELTAC1 = 0x73 // DELTA exception C1
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opDELTAC2 = 0x74 // DELTA exception C2
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opDELTAC3 = 0x75 // DELTA exception C3
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opSROUND = 0x76 // Super ROUND
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opS45ROUND = 0x77 // Super ROUND 45 degrees
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opJROT = 0x78 // Jump Relative On True
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@ -144,8 +144,8 @@ const (
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op_0x83 = 0x83
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op_0x84 = 0x84
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opSCANCTRL = 0x85 // SCAN conversion ConTRoL
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opSDPVTL0 = 0x86
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opSDPVTL1 = 0x87
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opSDPVTL0 = 0x86 // Set Dual Projection Vector To Line
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opSDPVTL1 = 0x87 // .
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opGETINFO = 0x88 // GET INFOrmation
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opIDEF = 0x89 // Instruction DEFinition
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opROLL = 0x8a // ROLL the top three stack elements
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@ -271,15 +271,15 @@ const (
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// popCount is the number of stack elements that each opcode pops.
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var popCount = [256]uint8{
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// 1, 2, 3, 4, 5, 6, 7, 8, 9, a, b, c, d, e, f
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0, 0, 0, 0, 0, 0, 2, 2, 2, 2, 2, 2, 0, 0, 0, q, // 0x00 - 0x0f
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0, 0, 0, 0, 0, 0, 2, 2, 2, 2, 2, 2, 0, 0, 0, 5, // 0x00 - 0x0f
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1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 0, 1, 1, 1, 1, // 0x10 - 0x1f
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1, 1, 0, 2, 0, 1, 1, q, q, q, 2, 1, 1, 0, 1, 1, // 0x20 - 0x2f
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0, 0, 0, 0, q, q, 1, 1, 1, 0, 2, 2, 0, 0, 2, 2, // 0x30 - 0x3f
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0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 2, 2, 0, 0, 2, 2, // 0x30 - 0x3f
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0, 0, 2, 1, 2, 1, 1, 1, q, 2, 2, 0, 0, 0, 0, 0, // 0x40 - 0x4f
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2, 2, 2, 2, 2, 2, 1, 1, 1, 0, 2, 2, 1, 1, 1, 1, // 0x50 - 0x5f
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2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 0x60 - 0x6f
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q, 1, 1, q, q, q, 1, 1, 2, 2, 0, q, 0, 0, 1, 1, // 0x70 - 0x7f
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q, q, q, q, q, 1, q, q, 1, 1, 3, 2, 2, 1, q, q, // 0x80 - 0x8f
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2, 1, 1, 1, 1, 1, 1, 1, 2, 2, 0, q, 0, 0, 1, 1, // 0x70 - 0x7f
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q, q, q, q, q, 1, 2, 2, 1, 1, 3, 2, 2, 1, q, q, // 0x80 - 0x8f
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q, q, q, q, q, q, q, q, q, q, q, q, q, q, q, q, // 0x90 - 0x9f
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q, q, q, q, q, q, q, q, q, q, q, q, q, q, q, q, // 0xa0 - 0xaf
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 0xb0 - 0xbf
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@ -255,7 +255,7 @@ var scalingTestCases = []struct {
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hintingBrokenAt int
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}{
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{"luxisr", 12, -1},
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{"x-arial-bold", 11, 0},
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{"x-arial-bold", 11, 1},
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{"x-deja-vu-sans-oblique", 17, -1},
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{"x-droid-sans-japanese", 9, 0},
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{"x-times-new-roman", 13, 0},
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