freetype/truetype: vector set/gets, store ops, roll/max/min ops.
R=bsiegert CC=golang-dev http://codereview.appspot.com/6354080
This commit is contained in:
Nigel Tao
parent
9e927de79b
commit
2bf22ccf6b
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@ -13,12 +13,34 @@ import (
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)
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type hinter struct {
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// TODO: variable sized stack and store slices based on the maxp section?
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// Should the arrays for the stack and store be combined? For now, fixed
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// maximum sizes seem to work in practice.
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stack [800]int32
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// The graphics state is described at https://developer.apple.com/fonts/TTRefMan/RM04/Chap4.html
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roundPeriod, roundPhase, roundThreshold int32
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store [128]int32
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// The fields below constitue the graphics state, which is described at
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// https://developer.apple.com/fonts/TTRefMan/RM04/Chap4.html
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// Projection vector, freedom vector and dual projection vector.
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pv, fv, dv [2]f2dot14
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// Minimum distance.
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minDist f26dot6
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// Loop count.
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loop int32
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// Rounding policy.
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roundPeriod, roundPhase, roundThreshold f26dot6
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}
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func (h *hinter) run(program []byte) error {
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// The default vectors are along the X axis.
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h.pv = [2]f2dot14{0x4000, 0}
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h.fv = [2]f2dot14{0x4000, 0}
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h.dv = [2]f2dot14{0x4000, 0}
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// The default minimum distance is 1.
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h.minDist = 1 << 6
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// The default loop count is 1.
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h.loop = 1
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// The default rounding policy is round to grid.
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h.roundPeriod = 1 << 6
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h.roundPhase = 0
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@ -31,7 +53,7 @@ func (h *hinter) run(program []byte) error {
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steps, pc, top int
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opcode uint8
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)
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for 0 <= pc && int(pc) < len(program) {
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for 0 <= pc && pc < len(program) {
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steps++
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if steps == 100000 {
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return errors.New("truetype: hinting: too many steps")
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@ -45,6 +67,69 @@ func (h *hinter) run(program []byte) error {
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}
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switch opcode {
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case opSVTCA0:
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h.pv = [2]f2dot14{0, 0x4000}
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h.fv = [2]f2dot14{0, 0x4000}
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// TODO: h.dv = h.pv ??
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case opSVTCA1:
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h.pv = [2]f2dot14{0x4000, 0}
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h.fv = [2]f2dot14{0x4000, 0}
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// TODO: h.dv = h.pv ??
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case opSPVTCA0:
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h.pv = [2]f2dot14{0, 0x4000}
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// TODO: h.dv = h.pv ??
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case opSPVTCA1:
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h.pv = [2]f2dot14{0x4000, 0}
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// TODO: h.dv = h.pv ??
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case opSFVTCA0:
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h.fv = [2]f2dot14{0, 0x4000}
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case opSFVTCA1:
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h.fv = [2]f2dot14{0x4000, 0}
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case opSPVFS:
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top -= 2
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h.pv[0] = f2dot14(h.stack[top+0])
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h.pv[1] = f2dot14(h.stack[top+1])
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// TODO: normalize h.pv ??
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// TODO: h.dv = h.pv ??
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case opSFVFS:
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top -= 2
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h.fv[0] = f2dot14(h.stack[top+0])
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h.fv[1] = f2dot14(h.stack[top+1])
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// TODO: normalize h.fv ??
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case opGPV:
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if top+1 >= len(h.stack) {
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return errors.New("truetype: hinting: stack overflow")
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}
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h.stack[top+0] = int32(h.pv[0])
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h.stack[top+1] = int32(h.pv[1])
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top += 2
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case opGFV:
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if top+1 >= len(h.stack) {
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return errors.New("truetype: hinting: stack overflow")
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}
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h.stack[top+0] = int32(h.fv[0])
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h.stack[top+1] = int32(h.fv[1])
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top += 2
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case opSFVTPV:
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h.fv = h.pv
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case opSLOOP:
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top--
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if h.stack[top] <= 0 {
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return errors.New("truetype: hinting: invalid data")
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}
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h.loop = h.stack[top]
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case opRTG:
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h.roundPeriod = 1 << 6
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h.roundPhase = 0
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@ -55,6 +140,10 @@ func (h *hinter) run(program []byte) error {
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h.roundPhase = 1 << 5
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h.roundThreshold = 1 << 5
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case opSMD:
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top--
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h.minDist = f26dot6(h.stack[top])
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case opELSE:
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opcode = 1
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goto ifelse
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@ -65,7 +154,7 @@ func (h *hinter) run(program []byte) error {
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continue
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case opDUP:
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if int(top) >= len(h.stack) {
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if top >= len(h.stack) {
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return errors.New("truetype: hinting: stack overflow")
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}
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h.stack[top] = h.stack[top-1]
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@ -81,7 +170,7 @@ func (h *hinter) run(program []byte) error {
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h.stack[top-1], h.stack[top-2] = h.stack[top-2], h.stack[top-1]
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case opDEPTH:
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if int(top) >= len(h.stack) {
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if top >= len(h.stack) {
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return errors.New("truetype: hinting: stack overflow")
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}
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h.stack[top] = int32(top)
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@ -111,6 +200,21 @@ func (h *hinter) run(program []byte) error {
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opcode = 0x80
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goto push
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case opWS:
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top -= 2
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i := int(h.stack[top])
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if i < 0 || len(h.store) <= i {
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return errors.New("truetype: hinting: invalid data")
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}
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h.store[i] = h.stack[top+1]
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case opRS:
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i := int(h.stack[top-1])
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if i < 0 || len(h.store) <= i {
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return errors.New("truetype: hinting: invalid data")
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}
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h.stack[top-1] = h.store[i]
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case opDEBUG:
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// No-op.
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@ -172,11 +276,11 @@ func (h *hinter) run(program []byte) error {
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if h.stack[top] == 0 {
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return errors.New("truetype: hinting: division by zero")
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}
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h.stack[top-1] = div(h.stack[top-1], h.stack[top])
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h.stack[top-1] = int32(f26dot6(h.stack[top-1]).div(f26dot6(h.stack[top])))
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case opMUL:
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top--
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h.stack[top-1] = mul(h.stack[top-1], h.stack[top])
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h.stack[top-1] = int32(f26dot6(h.stack[top-1]).mul(f26dot6(h.stack[top])))
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case opABS:
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if h.stack[top-1] < 0 {
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@ -196,7 +300,7 @@ func (h *hinter) run(program []byte) error {
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case opROUND00, opROUND01, opROUND10, opROUND11:
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// The four flavors of opROUND are equivalent. See the comment below on
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// opNROUND for the rationale.
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h.stack[top-1] = h.round(h.stack[top-1])
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h.stack[top-1] = int32(h.round(f26dot6(h.stack[top-1])))
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case opNROUND00, opNROUND01, opNROUND10, opNROUND11:
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// No-op. The spec says to add one of four "compensations for the engine
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@ -221,9 +325,9 @@ func (h *hinter) run(program []byte) error {
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h.roundPeriod *= 46341
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h.roundPeriod /= 65536
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}
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h.roundPhase = h.roundPeriod * ((h.stack[top] >> 4) & 0x03) / 4
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h.roundPhase = h.roundPeriod * f26dot6((h.stack[top]>>4)&0x03) / 4
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if x := h.stack[top] & 0x0f; x != 0 {
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h.roundThreshold = h.roundPeriod * (x - 4) / 8
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h.roundThreshold = h.roundPeriod * f26dot6(x-4) / 8
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} else {
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h.roundThreshold = h.roundPeriod - 1
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}
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@ -257,6 +361,29 @@ func (h *hinter) run(program []byte) error {
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h.roundPhase = 0
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h.roundThreshold = 0
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case opSANGW, opAA:
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// These ops are "anachronistic" and no longer used.
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top--
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case opIDEF:
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// IDEF is for ancient versions of the bytecode interpreter, and is no longer used.
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return errors.New("truetype: hinting: unsupported IDEF instruction")
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case opROLL:
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h.stack[top-1], h.stack[top-3], h.stack[top-2] = h.stack[top-3], h.stack[top-2], h.stack[top-1]
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case opMAX:
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top--
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if h.stack[top-1] < h.stack[top] {
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h.stack[top-1] = h.stack[top]
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}
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case opMIN:
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top--
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if h.stack[top-1] > h.stack[top] {
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h.stack[top-1] = h.stack[top]
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}
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case opPUSHB000, opPUSHB001, opPUSHB010, opPUSHB011, opPUSHB100, opPUSHB101, opPUSHB110, opPUSHB111:
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opcode -= opPUSHB000 - 1
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goto push
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@ -332,7 +459,7 @@ func (h *hinter) run(program []byte) error {
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}
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if opcode == 0 {
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pc++
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if int(pc) >= len(program) {
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if pc >= len(program) {
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return errors.New("truetype: hinting: insufficient data")
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}
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opcode = program[pc]
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@ -359,19 +486,25 @@ func (h *hinter) run(program []byte) error {
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return nil
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}
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// f2dot14 is a 2.14 fixed point number.
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type f2dot14 int16
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// f26dot6 is a 26.6 fixed point number.
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type f26dot6 int32
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// div returns x/y in 26.6 fixed point arithmetic.
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func div(x, y int32) int32 {
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return int32((int64(x) << 6) / int64(y))
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func (x f26dot6) div(y f26dot6) f26dot6 {
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return f26dot6((int64(x) << 6) / int64(y))
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}
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// mul returns x*y in 26.6 fixed point arithmetic.
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func mul(x, y int32) int32 {
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return int32(int64(x) * int64(y) >> 6)
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func (x f26dot6) mul(y f26dot6) f26dot6 {
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return f26dot6(int64(x) * int64(y) >> 6)
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}
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// round rounds the given number. The rounding algorithm is described at
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// https://developer.apple.com/fonts/TTRefMan/RM02/Chap2.html#rounding
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func (h *hinter) round(x int32) int32 {
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func (h *hinter) round(x f26dot6) f26dot6 {
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if h.roundPeriod == 0 {
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return x
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}
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@ -48,6 +48,25 @@ func TestBytecode(t *testing.T) {
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nil,
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"unbalanced",
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},
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{
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"vector set/gets",
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[]byte{
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opSVTCA1, // []
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opGPV, // [ 0x4000, 0 ]
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opSVTCA0, // [ 0x4000, 0 ]
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opGFV, // [ 0x4000, 0, 0, 0x4000 ]
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opNEG, // [ 0x4000, 0, 0, -0x4000 ]
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opSPVFS, // [ 0x4000, 0 ]
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opSFVTPV, // [ 0x4000, 0 ]
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opPUSHB000, // [ 0x4000, 0, 1 ]
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1,
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opGFV, // [ 0x4000, 0, 1, 0, -0x4000 ]
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opPUSHB000, // [ 0x4000, 0, 1, 0, -0x4000, 2 ]
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2,
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},
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[]int32{0x4000, 0, 1, 0, -0x4000, 2},
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"",
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},
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{
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"jumps",
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[]byte{
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@ -126,6 +145,23 @@ func TestBytecode(t *testing.T) {
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[]int32{255, -2, 253, 1, 2, 0x0405, 0x0607, 0x0809},
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"",
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},
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{
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"store ops",
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[]byte{
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opPUSHB011, // [1, 22, 3, 44]
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1,
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22,
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3,
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44,
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opWS, // [1, 22]
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opWS, // []
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opPUSHB000, // [3]
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3,
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opRS, // [44]
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},
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[]int32{44},
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"",
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},
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{
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"comparison ops",
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[]byte{
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@ -418,6 +454,37 @@ func TestBytecode(t *testing.T) {
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[]int32{-112, -48, -48, -48, 16, 16, 16, 80},
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"",
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},
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{
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"roll",
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[]byte{
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opPUSHB010, // [1, 2, 3]
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1,
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2,
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3,
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opROLL, // [2, 3, 1]
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},
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[]int32{2, 3, 1},
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"",
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},
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{
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"max/min",
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[]byte{
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opPUSHW001, // [-2, -3]
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0xff,
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0xfe,
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0xff,
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0xfd,
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opMAX, // [-2]
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opPUSHW001, // [-2, -4, -5]
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0xff,
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0xfc,
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0xff,
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0xfb,
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opMIN, // [-2, -5]
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},
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[]int32{-2, -5},
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"",
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},
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}
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for _, tc := range testCases {
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@ -10,21 +10,21 @@ package truetype
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// TODO: the opXXX constants without end-of-line comments are not yet implemented.
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const (
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opSVTCA0 = 0x00
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opSVTCA1 = 0x01
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opSPVTCA0 = 0x02
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opSPVTCA1 = 0x03
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opSFVTCA0 = 0x04
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opSFVTCA1 = 0x05
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opSVTCA0 = 0x00 // Set freedom and projection Vectors To Coordinate Axis
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opSVTCA1 = 0x01 // .
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opSPVTCA0 = 0x02 // Set Projection Vector To Coordinate Axis
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opSPVTCA1 = 0x03 // .
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opSFVTCA0 = 0x04 // Set Freedom Vector to Coordinate Axis
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opSFVTCA1 = 0x05 // .
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opSPVTL0 = 0x06
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opSPVTL1 = 0x07
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opSFVTL0 = 0x08
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opSFVTL1 = 0x09
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opSFVFS = 0x0b
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opSPVFS = 0x0a
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opGPV = 0x0c
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opGFV = 0x0d
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opSFVTPV = 0x0e
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opSPVFS = 0x0a // Set Projection Vector From Stack
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opSFVFS = 0x0b // Set Freedom Vector From Stack
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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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opSRP0 = 0x10
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opSRP1 = 0x11
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@ -33,10 +33,10 @@ const (
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opSZP1 = 0x14
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opSZP2 = 0x15
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opSZPS = 0x16
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opSLOOP = 0x17
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opSLOOP = 0x17 // Set LOOP variable
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opRTG = 0x18 // Round To Grid
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opRTHG = 0x19 // Round To Half Grid
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opSMD = 0x1a
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opSMD = 0x1a // Set Minimum Distance
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opELSE = 0x1b // ELSE clause
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opJMPR = 0x1c // JuMP Relative
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opSCVTCI = 0x1d
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@ -76,8 +76,8 @@ const (
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opMIAP1 = 0x3f
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opNPUSHB = 0x40 // PUSH N Bytes
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opNPUSHW = 0x41 // PUSH N Words
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opWS = 0x42
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opRS = 0x43
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opWS = 0x42 // Write Store
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opRS = 0x43 // Read Store
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opWCVTP = 0x44
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opRCVT = 0x45
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opGC0 = 0x46
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@ -136,8 +136,8 @@ const (
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op_0x7b = 0x7b
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opRUTG = 0x7c // Round Up To Grid
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opRDTG = 0x7d // Round Down To Grid
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opSANGW = 0x7e
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opAA = 0x7f
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opSANGW = 0x7e // Set ANGle Weight
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opAA = 0x7f // Adjust Angle
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opFLIPPT = 0x80
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opFLIPRGON = 0x81
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opFLIPRGOFF = 0x82
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@ -147,10 +147,10 @@ const (
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opSDPVTL0 = 0x86
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opSDPVTL1 = 0x87
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opGETINFO = 0x88
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opIFDEF = 0x89
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opROLL = 0x8a
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opMAX = 0x8b
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opMIN = 0x8c
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opIDEF = 0x89 // Instruction DEFinition
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opROLL = 0x8a // ROLL the top three stack elements
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opMAX = 0x8b // MAXimum of top two stack elements
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opMIN = 0x8c // MINimum of top two stack elements
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opSCANTYPE = 0x8d
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opINSTCTRL = 0x8e
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op_0x8f = 0x8f
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@ -271,15 +271,15 @@ const (
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// popCount is the number of stack elements that each opcode pops.
|
||||
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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||||
q, q, q, q, q, q, q, q, q, q, q, q, q, q, q, q, // 0x00 - 0x0f
|
||||
q, q, q, q, q, q, q, q, 0, 0, q, 0, 1, q, q, q, // 0x10 - 0x1f
|
||||
0, 0, 0, 0, 0, 0, q, q, q, q, 2, 2, 0, 0, 0, q, // 0x00 - 0x0f
|
||||
q, q, q, q, q, q, q, 1, 0, 0, 1, 0, 1, q, q, q, // 0x10 - 0x1f
|
||||
1, 1, 0, 2, 0, 1, 1, q, q, q, q, q, q, q, q, q, // 0x20 - 0x2f
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||||
q, q, q, q, q, q, q, q, q, q, q, q, q, 0, q, q, // 0x30 - 0x3f
|
||||
0, 0, q, q, q, q, q, q, q, q, q, q, q, q, q, 0, // 0x40 - 0x4f
|
||||
0, 0, 2, 1, q, q, q, q, q, q, q, q, q, q, q, 0, // 0x40 - 0x4f
|
||||
2, 2, 2, 2, 2, 2, q, q, 1, 0, 2, 2, 1, q, q, q, // 0x50 - 0x5f
|
||||
2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 0x60 - 0x6f
|
||||
q, q, q, q, q, q, 1, 1, 2, 2, 0, q, 0, 0, q, q, // 0x70 - 0x7f
|
||||
q, q, q, q, q, q, q, q, q, q, q, q, q, q, q, q, // 0x80 - 0x8f
|
||||
q, q, q, q, q, q, 1, 1, 2, 2, 0, q, 0, 0, 1, 1, // 0x70 - 0x7f
|
||||
q, q, q, q, q, q, q, q, q, 1, 3, 2, 2, q, q, q, // 0x80 - 0x8f
|
||||
q, q, q, q, q, q, q, q, q, q, q, q, q, q, q, q, // 0x90 - 0x9f
|
||||
q, q, q, q, q, q, q, q, q, q, q, q, q, q, q, q, // 0xa0 - 0xaf
|
||||
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 0xb0 - 0xbf
|
||||
|
|
|
|||
Loading…
Reference in New Issue