1771 lines
43 KiB
Go
1771 lines
43 KiB
Go
// Copyright 2012 The Freetype-Go Authors. All rights reserved.
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// Use of this source code is governed by your choice of either the
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// FreeType License or the GNU General Public License version 2 (or
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// any later version), both of which can be found in the LICENSE file.
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package truetype
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// This file implements a Truetype bytecode interpreter.
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// The opcodes are described at https://developer.apple.com/fonts/TTRefMan/RM05/Chap5.html
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import (
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"errors"
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"math"
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"golang.org/x/image/math/fixed"
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)
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const (
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twilightZone = 0
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glyphZone = 1
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numZone = 2
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)
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type pointType uint32
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const (
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current pointType = 0
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unhinted pointType = 1
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inFontUnits pointType = 2
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numPointType = 3
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)
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// callStackEntry is a bytecode call stack entry.
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type callStackEntry struct {
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program []byte
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pc int
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loopCount int32
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}
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// hinter implements bytecode hinting. A hinter can be re-used to hint a series
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// of glyphs from a Font.
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type hinter struct {
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stack, store []int32
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// functions is a map from function number to bytecode.
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functions map[int32][]byte
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// font and scale are the font and scale last used for this hinter.
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// Changing the font will require running the new font's fpgm bytecode.
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// Changing either will require running the font's prep bytecode.
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font *Font
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scale fixed.Int26_6
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// gs and defaultGS are the current and default graphics state. The
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// default graphics state is the global default graphics state after
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// the font's fpgm and prep programs have been run.
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gs, defaultGS graphicsState
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// points and ends are the twilight zone's points, glyph's points
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// and glyph's contour boundaries.
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points [numZone][numPointType][]Point
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ends []int
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// scaledCVT is the lazily initialized scaled Control Value Table.
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scaledCVTInitialized bool
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scaledCVT []fixed.Int26_6
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}
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// graphicsState is described at https://developer.apple.com/fonts/TTRefMan/RM04/Chap4.html
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type graphicsState struct {
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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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// Reference points and zone pointers.
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rp, zp [3]int32
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// Control Value / Single Width Cut-In.
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controlValueCutIn, singleWidthCutIn, singleWidth fixed.Int26_6
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// Delta base / shift.
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deltaBase, deltaShift int32
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// Minimum distance.
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minDist fixed.Int26_6
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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 fixed.Int26_6
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roundSuper45 bool
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// Auto-flip.
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autoFlip bool
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}
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var globalDefaultGS = graphicsState{
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pv: [2]f2dot14{0x4000, 0}, // Unit vector along the X axis.
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fv: [2]f2dot14{0x4000, 0},
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dv: [2]f2dot14{0x4000, 0},
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zp: [3]int32{1, 1, 1},
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controlValueCutIn: (17 << 6) / 16, // 17/16 as a fixed.Int26_6.
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deltaBase: 9,
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deltaShift: 3,
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minDist: 1 << 6, // 1 as a fixed.Int26_6.
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loop: 1,
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roundPeriod: 1 << 6, // 1 as a fixed.Int26_6.
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roundThreshold: 1 << 5, // 1/2 as a fixed.Int26_6.
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roundSuper45: false,
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autoFlip: true,
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}
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func resetTwilightPoints(f *Font, p []Point) []Point {
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if n := int(f.maxTwilightPoints) + 4; n <= cap(p) {
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p = p[:n]
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for i := range p {
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p[i] = Point{}
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}
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} else {
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p = make([]Point, n)
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}
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return p
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}
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func (h *hinter) init(f *Font, scale fixed.Int26_6) error {
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h.points[twilightZone][0] = resetTwilightPoints(f, h.points[twilightZone][0])
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h.points[twilightZone][1] = resetTwilightPoints(f, h.points[twilightZone][1])
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h.points[twilightZone][2] = resetTwilightPoints(f, h.points[twilightZone][2])
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rescale := h.scale != scale
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if h.font != f {
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h.font, rescale = f, true
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if h.functions == nil {
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h.functions = make(map[int32][]byte)
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} else {
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for k := range h.functions {
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delete(h.functions, k)
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}
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}
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if x := int(f.maxStackElements); x > len(h.stack) {
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x += 255
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x &^= 255
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h.stack = make([]int32, x)
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}
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if x := int(f.maxStorage); x > len(h.store) {
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x += 15
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x &^= 15
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h.store = make([]int32, x)
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}
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if len(f.fpgm) != 0 {
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if err := h.run(f.fpgm, nil, nil, nil, nil); err != nil {
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return err
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}
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}
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}
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if rescale {
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h.scale = scale
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h.scaledCVTInitialized = false
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h.defaultGS = globalDefaultGS
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if len(f.prep) != 0 {
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if err := h.run(f.prep, nil, nil, nil, nil); err != nil {
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return err
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}
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h.defaultGS = h.gs
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// The MS rasterizer doesn't allow the following graphics state
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// variables to be modified by the CVT program.
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h.defaultGS.pv = globalDefaultGS.pv
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h.defaultGS.fv = globalDefaultGS.fv
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h.defaultGS.dv = globalDefaultGS.dv
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h.defaultGS.rp = globalDefaultGS.rp
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h.defaultGS.zp = globalDefaultGS.zp
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h.defaultGS.loop = globalDefaultGS.loop
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}
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}
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return nil
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}
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func (h *hinter) run(program []byte, pCurrent, pUnhinted, pInFontUnits []Point, ends []int) error {
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h.gs = h.defaultGS
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h.points[glyphZone][current] = pCurrent
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h.points[glyphZone][unhinted] = pUnhinted
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h.points[glyphZone][inFontUnits] = pInFontUnits
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h.ends = ends
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if len(program) > 50000 {
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return errors.New("truetype: hinting: too many instructions")
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}
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var (
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steps, pc, top int
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opcode uint8
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callStack [32]callStackEntry
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callStackTop int
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)
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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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}
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opcode = program[pc]
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if top < int(popCount[opcode]) {
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return errors.New("truetype: hinting: stack underflow")
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}
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switch opcode {
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case opSVTCA0:
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h.gs.pv = [2]f2dot14{0, 0x4000}
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h.gs.fv = [2]f2dot14{0, 0x4000}
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h.gs.dv = [2]f2dot14{0, 0x4000}
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case opSVTCA1:
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h.gs.pv = [2]f2dot14{0x4000, 0}
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h.gs.fv = [2]f2dot14{0x4000, 0}
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h.gs.dv = [2]f2dot14{0x4000, 0}
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case opSPVTCA0:
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h.gs.pv = [2]f2dot14{0, 0x4000}
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h.gs.dv = [2]f2dot14{0, 0x4000}
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case opSPVTCA1:
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h.gs.pv = [2]f2dot14{0x4000, 0}
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h.gs.dv = [2]f2dot14{0x4000, 0}
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case opSFVTCA0:
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h.gs.fv = [2]f2dot14{0, 0x4000}
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case opSFVTCA1:
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h.gs.fv = [2]f2dot14{0x4000, 0}
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case opSPVTL0, opSPVTL1, opSFVTL0, opSFVTL1:
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top -= 2
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p1 := h.point(0, current, h.stack[top+0])
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p2 := h.point(0, current, h.stack[top+1])
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if p1 == nil || p2 == nil {
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return errors.New("truetype: hinting: point out of range")
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}
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dx := f2dot14(p1.X - p2.X)
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dy := f2dot14(p1.Y - p2.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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v := normalize(dx, dy)
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if opcode < opSFVTL0 {
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h.gs.pv = v
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h.gs.dv = v
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} else {
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h.gs.fv = v
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}
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case opSPVFS:
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top -= 2
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h.gs.pv = normalize(f2dot14(h.stack[top]), f2dot14(h.stack[top+1]))
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h.gs.dv = h.gs.pv
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case opSFVFS:
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top -= 2
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h.gs.fv = normalize(f2dot14(h.stack[top]), f2dot14(h.stack[top+1]))
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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.gs.pv[0])
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h.stack[top+1] = int32(h.gs.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.gs.fv[0])
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h.stack[top+1] = int32(h.gs.fv[1])
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top += 2
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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 + fixed.Int26_6(rx)
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p.Y = a0.Y + fixed.Int26_6(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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case opSZP0, opSZP1, opSZP2:
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top--
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h.gs.zp[opcode-opSZP0] = h.stack[top]
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case opSZPS:
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top--
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h.gs.zp[0] = h.stack[top]
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h.gs.zp[1] = h.stack[top]
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h.gs.zp[2] = h.stack[top]
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case opSLOOP:
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top--
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// https://developer.apple.com/fonts/TrueType-Reference-Manual/RM05/Chap5.html#SLOOP
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// says that "Setting the loop variable to zero is an error". In
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// theory, the inequality on the next line should be "<=" instead
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// of "<". In practice, some font files' bytecode, such as the '2'
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// glyph in the DejaVuSansMono.ttf that comes with Ubuntu 14.04,
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// issue SLOOP with a zero on top of the stack. Just like the C
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// Freetype code, we allow the zero.
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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.gs.loop = h.stack[top]
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case opRTG:
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h.gs.roundPeriod = 1 << 6
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h.gs.roundPhase = 0
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h.gs.roundThreshold = 1 << 5
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h.gs.roundSuper45 = false
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case opRTHG:
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h.gs.roundPeriod = 1 << 6
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h.gs.roundPhase = 1 << 5
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h.gs.roundThreshold = 1 << 5
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h.gs.roundSuper45 = false
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case opSMD:
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top--
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h.gs.minDist = fixed.Int26_6(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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case opJMPR:
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top--
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pc += int(h.stack[top])
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continue
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case opSCVTCI:
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top--
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h.gs.controlValueCutIn = fixed.Int26_6(h.stack[top])
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case opSSWCI:
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top--
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h.gs.singleWidthCutIn = fixed.Int26_6(h.stack[top])
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case opSSW:
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top--
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h.gs.singleWidth = h.font.scale(h.scale * fixed.Int26_6(h.stack[top]))
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case opDUP:
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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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top++
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case opPOP:
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top--
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case opCLEAR:
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top = 0
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case opSWAP:
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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 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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top++
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case opCINDEX, opMINDEX:
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x := int(h.stack[top-1])
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if x <= 0 || x >= top {
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return errors.New("truetype: hinting: invalid data")
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}
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h.stack[top-1] = h.stack[top-1-x]
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if opcode == opMINDEX {
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copy(h.stack[top-1-x:top-1], h.stack[top-x:top])
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top--
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}
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case opALIGNPTS:
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top -= 2
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p := h.point(1, current, h.stack[top])
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q := h.point(0, current, 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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d := dotProduct(fixed.Int26_6(q.X-p.X), fixed.Int26_6(q.Y-p.Y), h.gs.pv) / 2
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h.move(p, +d, true)
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h.move(q, -d, true)
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case opUTP:
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top--
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p := h.point(0, current, h.stack[top])
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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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p.Flags &^= flagTouchedX | flagTouchedY
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case opLOOPCALL, opCALL:
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if callStackTop >= len(callStack) {
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return errors.New("truetype: hinting: call stack overflow")
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}
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top--
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f, ok := h.functions[h.stack[top]]
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if !ok {
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return errors.New("truetype: hinting: undefined function")
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}
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callStack[callStackTop] = callStackEntry{program, pc, 1}
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if opcode == opLOOPCALL {
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top--
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if h.stack[top] == 0 {
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break
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}
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callStack[callStackTop].loopCount = h.stack[top]
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}
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callStackTop++
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program, pc = f, 0
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continue
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case opFDEF:
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// Save all bytecode up until the next ENDF.
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startPC := pc + 1
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fdefloop:
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for {
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pc++
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if pc >= len(program) {
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return errors.New("truetype: hinting: unbalanced FDEF")
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}
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switch program[pc] {
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case opFDEF:
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return errors.New("truetype: hinting: nested FDEF")
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case opENDF:
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top--
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h.functions[h.stack[top]] = program[startPC : pc+1]
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break fdefloop
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default:
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var ok bool
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pc, ok = skipInstructionPayload(program, pc)
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if !ok {
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return errors.New("truetype: hinting: unbalanced FDEF")
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}
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}
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}
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case opENDF:
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if callStackTop == 0 {
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return errors.New("truetype: hinting: call stack underflow")
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}
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callStackTop--
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callStack[callStackTop].loopCount--
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if callStack[callStackTop].loopCount != 0 {
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callStackTop++
|
|
pc = 0
|
|
continue
|
|
}
|
|
program, pc = callStack[callStackTop].program, callStack[callStackTop].pc
|
|
|
|
case opMDAP0, opMDAP1:
|
|
top--
|
|
i := h.stack[top]
|
|
p := h.point(0, current, i)
|
|
if p == nil {
|
|
return errors.New("truetype: hinting: point out of range")
|
|
}
|
|
distance := fixed.Int26_6(0)
|
|
if opcode == opMDAP1 {
|
|
distance = dotProduct(p.X, p.Y, h.gs.pv)
|
|
// TODO: metrics compensation.
|
|
distance = h.round(distance) - distance
|
|
}
|
|
h.move(p, distance, true)
|
|
h.gs.rp[0] = i
|
|
h.gs.rp[1] = i
|
|
|
|
case opIUP0, opIUP1:
|
|
iupY, mask := opcode == opIUP0, uint32(flagTouchedX)
|
|
if iupY {
|
|
mask = flagTouchedY
|
|
}
|
|
prevEnd := 0
|
|
for _, end := range h.ends {
|
|
for i := prevEnd; i < end; i++ {
|
|
for i < end && h.points[glyphZone][current][i].Flags&mask == 0 {
|
|
i++
|
|
}
|
|
if i == end {
|
|
break
|
|
}
|
|
firstTouched, curTouched := i, i
|
|
i++
|
|
for ; i < end; i++ {
|
|
if h.points[glyphZone][current][i].Flags&mask != 0 {
|
|
h.iupInterp(iupY, curTouched+1, i-1, curTouched, i)
|
|
curTouched = i
|
|
}
|
|
}
|
|
if curTouched == firstTouched {
|
|
h.iupShift(iupY, prevEnd, end, curTouched)
|
|
} else {
|
|
h.iupInterp(iupY, curTouched+1, end-1, curTouched, firstTouched)
|
|
if firstTouched > 0 {
|
|
h.iupInterp(iupY, prevEnd, firstTouched-1, curTouched, firstTouched)
|
|
}
|
|
}
|
|
}
|
|
prevEnd = end
|
|
}
|
|
|
|
case opSHP0, opSHP1:
|
|
if top < int(h.gs.loop) {
|
|
return errors.New("truetype: hinting: stack underflow")
|
|
}
|
|
_, _, d, ok := h.displacement(opcode&1 == 0)
|
|
if !ok {
|
|
return errors.New("truetype: hinting: point out of range")
|
|
}
|
|
for ; h.gs.loop != 0; h.gs.loop-- {
|
|
top--
|
|
p := h.point(2, current, h.stack[top])
|
|
if p == nil {
|
|
return errors.New("truetype: hinting: point out of range")
|
|
}
|
|
h.move(p, d, true)
|
|
}
|
|
h.gs.loop = 1
|
|
|
|
case opSHC0, opSHC1:
|
|
top--
|
|
zonePointer, i, d, ok := h.displacement(opcode&1 == 0)
|
|
if !ok {
|
|
return errors.New("truetype: hinting: point out of range")
|
|
}
|
|
if h.gs.zp[2] == 0 {
|
|
// TODO: implement this when we have a glyph that does this.
|
|
return errors.New("hinting: unimplemented SHC instruction")
|
|
}
|
|
contour := h.stack[top]
|
|
if contour < 0 || len(ends) <= int(contour) {
|
|
return errors.New("truetype: hinting: contour out of range")
|
|
}
|
|
j0, j1 := int32(0), int32(h.ends[contour])
|
|
if contour > 0 {
|
|
j0 = int32(h.ends[contour-1])
|
|
}
|
|
move := h.gs.zp[zonePointer] != h.gs.zp[2]
|
|
for j := j0; j < j1; j++ {
|
|
if move || j != i {
|
|
h.move(h.point(2, current, j), d, true)
|
|
}
|
|
}
|
|
|
|
case opSHZ0, opSHZ1:
|
|
top--
|
|
zonePointer, i, d, ok := h.displacement(opcode&1 == 0)
|
|
if !ok {
|
|
return errors.New("truetype: hinting: point out of range")
|
|
}
|
|
|
|
// As per C Freetype, SHZ doesn't move the phantom points, or mark
|
|
// the points as touched.
|
|
limit := int32(len(h.points[h.gs.zp[2]][current]))
|
|
if h.gs.zp[2] == glyphZone {
|
|
limit -= 4
|
|
}
|
|
for j := int32(0); j < limit; j++ {
|
|
if i != j || h.gs.zp[zonePointer] != h.gs.zp[2] {
|
|
h.move(h.point(2, current, j), d, false)
|
|
}
|
|
}
|
|
|
|
case opSHPIX:
|
|
top--
|
|
d := fixed.Int26_6(h.stack[top])
|
|
if top < int(h.gs.loop) {
|
|
return errors.New("truetype: hinting: stack underflow")
|
|
}
|
|
for ; h.gs.loop != 0; h.gs.loop-- {
|
|
top--
|
|
p := h.point(2, current, h.stack[top])
|
|
if p == nil {
|
|
return errors.New("truetype: hinting: point out of range")
|
|
}
|
|
h.move(p, d, true)
|
|
}
|
|
h.gs.loop = 1
|
|
|
|
case opIP:
|
|
if top < int(h.gs.loop) {
|
|
return errors.New("truetype: hinting: stack underflow")
|
|
}
|
|
pointType := inFontUnits
|
|
twilight := h.gs.zp[0] == 0 || h.gs.zp[1] == 0 || h.gs.zp[2] == 0
|
|
if twilight {
|
|
pointType = unhinted
|
|
}
|
|
p := h.point(1, pointType, h.gs.rp[2])
|
|
oldP := h.point(0, pointType, h.gs.rp[1])
|
|
oldRange := dotProduct(p.X-oldP.X, p.Y-oldP.Y, h.gs.dv)
|
|
|
|
p = h.point(1, current, h.gs.rp[2])
|
|
curP := h.point(0, current, h.gs.rp[1])
|
|
curRange := dotProduct(p.X-curP.X, p.Y-curP.Y, h.gs.pv)
|
|
for ; h.gs.loop != 0; h.gs.loop-- {
|
|
top--
|
|
i := h.stack[top]
|
|
p = h.point(2, pointType, i)
|
|
oldDist := dotProduct(p.X-oldP.X, p.Y-oldP.Y, h.gs.dv)
|
|
p = h.point(2, current, i)
|
|
curDist := dotProduct(p.X-curP.X, p.Y-curP.Y, h.gs.pv)
|
|
newDist := fixed.Int26_6(0)
|
|
if oldDist != 0 {
|
|
if oldRange != 0 {
|
|
newDist = fixed.Int26_6(mulDiv(int64(oldDist), int64(curRange), int64(oldRange)))
|
|
} else {
|
|
newDist = -oldDist
|
|
}
|
|
}
|
|
h.move(p, newDist-curDist, true)
|
|
}
|
|
h.gs.loop = 1
|
|
|
|
case opMSIRP0, opMSIRP1:
|
|
top -= 2
|
|
i := h.stack[top]
|
|
distance := fixed.Int26_6(h.stack[top+1])
|
|
|
|
// TODO: special case h.gs.zp[1] == 0 in C Freetype.
|
|
ref := h.point(0, current, h.gs.rp[0])
|
|
p := h.point(1, current, i)
|
|
if ref == nil || p == nil {
|
|
return errors.New("truetype: hinting: point out of range")
|
|
}
|
|
curDist := dotProduct(p.X-ref.X, p.Y-ref.Y, h.gs.pv)
|
|
|
|
// Set-RP0 bit.
|
|
if opcode == opMSIRP1 {
|
|
h.gs.rp[0] = i
|
|
}
|
|
h.gs.rp[1] = h.gs.rp[0]
|
|
h.gs.rp[2] = i
|
|
|
|
// Move the point.
|
|
h.move(p, distance-curDist, true)
|
|
|
|
case opALIGNRP:
|
|
if top < int(h.gs.loop) {
|
|
return errors.New("truetype: hinting: stack underflow")
|
|
}
|
|
ref := h.point(0, current, h.gs.rp[0])
|
|
if ref == nil {
|
|
return errors.New("truetype: hinting: point out of range")
|
|
}
|
|
for ; h.gs.loop != 0; h.gs.loop-- {
|
|
top--
|
|
p := h.point(1, current, h.stack[top])
|
|
if p == nil {
|
|
return errors.New("truetype: hinting: point out of range")
|
|
}
|
|
h.move(p, -dotProduct(p.X-ref.X, p.Y-ref.Y, h.gs.pv), true)
|
|
}
|
|
h.gs.loop = 1
|
|
|
|
case opRTDG:
|
|
h.gs.roundPeriod = 1 << 5
|
|
h.gs.roundPhase = 0
|
|
h.gs.roundThreshold = 1 << 4
|
|
h.gs.roundSuper45 = false
|
|
|
|
case opMIAP0, opMIAP1:
|
|
top -= 2
|
|
i := h.stack[top]
|
|
distance := h.getScaledCVT(h.stack[top+1])
|
|
if h.gs.zp[0] == 0 {
|
|
p := h.point(0, unhinted, i)
|
|
q := h.point(0, current, i)
|
|
p.X = fixed.Int26_6((int64(distance) * int64(h.gs.fv[0])) >> 14)
|
|
p.Y = fixed.Int26_6((int64(distance) * int64(h.gs.fv[1])) >> 14)
|
|
*q = *p
|
|
}
|
|
p := h.point(0, current, i)
|
|
oldDist := dotProduct(p.X, p.Y, h.gs.pv)
|
|
if opcode == opMIAP1 {
|
|
if fabs(distance-oldDist) > h.gs.controlValueCutIn {
|
|
distance = oldDist
|
|
}
|
|
// TODO: metrics compensation.
|
|
distance = h.round(distance)
|
|
}
|
|
h.move(p, distance-oldDist, true)
|
|
h.gs.rp[0] = i
|
|
h.gs.rp[1] = i
|
|
|
|
case opNPUSHB:
|
|
opcode = 0
|
|
goto push
|
|
|
|
case opNPUSHW:
|
|
opcode = 0x80
|
|
goto push
|
|
|
|
case opWS:
|
|
top -= 2
|
|
i := int(h.stack[top])
|
|
if i < 0 || len(h.store) <= i {
|
|
return errors.New("truetype: hinting: invalid data")
|
|
}
|
|
h.store[i] = h.stack[top+1]
|
|
|
|
case opRS:
|
|
i := int(h.stack[top-1])
|
|
if i < 0 || len(h.store) <= i {
|
|
return errors.New("truetype: hinting: invalid data")
|
|
}
|
|
h.stack[top-1] = h.store[i]
|
|
|
|
case opWCVTP:
|
|
top -= 2
|
|
h.setScaledCVT(h.stack[top], fixed.Int26_6(h.stack[top+1]))
|
|
|
|
case opRCVT:
|
|
h.stack[top-1] = int32(h.getScaledCVT(h.stack[top-1]))
|
|
|
|
case opGC0, opGC1:
|
|
i := h.stack[top-1]
|
|
if opcode == opGC0 {
|
|
p := h.point(2, current, i)
|
|
h.stack[top-1] = int32(dotProduct(p.X, p.Y, h.gs.pv))
|
|
} else {
|
|
p := h.point(2, unhinted, i)
|
|
// Using dv as per C Freetype.
|
|
h.stack[top-1] = int32(dotProduct(p.X, p.Y, h.gs.dv))
|
|
}
|
|
|
|
case opSCFS:
|
|
top -= 2
|
|
i := h.stack[top]
|
|
p := h.point(2, current, i)
|
|
if p == nil {
|
|
return errors.New("truetype: hinting: point out of range")
|
|
}
|
|
c := dotProduct(p.X, p.Y, h.gs.pv)
|
|
h.move(p, fixed.Int26_6(h.stack[top+1])-c, true)
|
|
if h.gs.zp[2] != 0 {
|
|
break
|
|
}
|
|
q := h.point(2, unhinted, i)
|
|
if q == nil {
|
|
return errors.New("truetype: hinting: point out of range")
|
|
}
|
|
q.X = p.X
|
|
q.Y = p.Y
|
|
|
|
case opMD0, opMD1:
|
|
top--
|
|
pt, v, scale := pointType(0), [2]f2dot14{}, false
|
|
if opcode == opMD0 {
|
|
pt = current
|
|
v = h.gs.pv
|
|
} else if h.gs.zp[0] == 0 || h.gs.zp[1] == 0 {
|
|
pt = unhinted
|
|
v = h.gs.dv
|
|
} else {
|
|
pt = inFontUnits
|
|
v = h.gs.dv
|
|
scale = true
|
|
}
|
|
p := h.point(0, pt, h.stack[top-1])
|
|
q := h.point(1, pt, h.stack[top])
|
|
if p == nil || q == nil {
|
|
return errors.New("truetype: hinting: point out of range")
|
|
}
|
|
d := int32(dotProduct(p.X-q.X, p.Y-q.Y, v))
|
|
if scale {
|
|
d = int32(int64(d*int32(h.scale)) / int64(h.font.fUnitsPerEm))
|
|
}
|
|
h.stack[top-1] = d
|
|
|
|
case opMPPEM, opMPS:
|
|
if top >= len(h.stack) {
|
|
return errors.New("truetype: hinting: stack overflow")
|
|
}
|
|
// For MPS, point size should be irrelevant; we return the PPEM.
|
|
h.stack[top] = int32(h.scale) >> 6
|
|
top++
|
|
|
|
case opFLIPON, opFLIPOFF:
|
|
h.gs.autoFlip = opcode == opFLIPON
|
|
|
|
case opDEBUG:
|
|
// No-op.
|
|
|
|
case opLT:
|
|
top--
|
|
h.stack[top-1] = bool2int32(h.stack[top-1] < h.stack[top])
|
|
|
|
case opLTEQ:
|
|
top--
|
|
h.stack[top-1] = bool2int32(h.stack[top-1] <= h.stack[top])
|
|
|
|
case opGT:
|
|
top--
|
|
h.stack[top-1] = bool2int32(h.stack[top-1] > h.stack[top])
|
|
|
|
case opGTEQ:
|
|
top--
|
|
h.stack[top-1] = bool2int32(h.stack[top-1] >= h.stack[top])
|
|
|
|
case opEQ:
|
|
top--
|
|
h.stack[top-1] = bool2int32(h.stack[top-1] == h.stack[top])
|
|
|
|
case opNEQ:
|
|
top--
|
|
h.stack[top-1] = bool2int32(h.stack[top-1] != h.stack[top])
|
|
|
|
case opODD, opEVEN:
|
|
i := h.round(fixed.Int26_6(h.stack[top-1])) >> 6
|
|
h.stack[top-1] = int32(i&1) ^ int32(opcode-opODD)
|
|
|
|
case opIF:
|
|
top--
|
|
if h.stack[top] == 0 {
|
|
opcode = 0
|
|
goto ifelse
|
|
}
|
|
|
|
case opEIF:
|
|
// No-op.
|
|
|
|
case opAND:
|
|
top--
|
|
h.stack[top-1] = bool2int32(h.stack[top-1] != 0 && h.stack[top] != 0)
|
|
|
|
case opOR:
|
|
top--
|
|
h.stack[top-1] = bool2int32(h.stack[top-1]|h.stack[top] != 0)
|
|
|
|
case opNOT:
|
|
h.stack[top-1] = bool2int32(h.stack[top-1] == 0)
|
|
|
|
case opDELTAP1:
|
|
goto delta
|
|
|
|
case opSDB:
|
|
top--
|
|
h.gs.deltaBase = h.stack[top]
|
|
|
|
case opSDS:
|
|
top--
|
|
h.gs.deltaShift = h.stack[top]
|
|
|
|
case opADD:
|
|
top--
|
|
h.stack[top-1] += h.stack[top]
|
|
|
|
case opSUB:
|
|
top--
|
|
h.stack[top-1] -= h.stack[top]
|
|
|
|
case opDIV:
|
|
top--
|
|
if h.stack[top] == 0 {
|
|
return errors.New("truetype: hinting: division by zero")
|
|
}
|
|
h.stack[top-1] = int32(fdiv(fixed.Int26_6(h.stack[top-1]), fixed.Int26_6(h.stack[top])))
|
|
|
|
case opMUL:
|
|
top--
|
|
h.stack[top-1] = int32(fmul(fixed.Int26_6(h.stack[top-1]), fixed.Int26_6(h.stack[top])))
|
|
|
|
case opABS:
|
|
if h.stack[top-1] < 0 {
|
|
h.stack[top-1] = -h.stack[top-1]
|
|
}
|
|
|
|
case opNEG:
|
|
h.stack[top-1] = -h.stack[top-1]
|
|
|
|
case opFLOOR:
|
|
h.stack[top-1] &^= 63
|
|
|
|
case opCEILING:
|
|
h.stack[top-1] += 63
|
|
h.stack[top-1] &^= 63
|
|
|
|
case opROUND00, opROUND01, opROUND10, opROUND11:
|
|
// The four flavors of opROUND are equivalent. See the comment below on
|
|
// opNROUND for the rationale.
|
|
h.stack[top-1] = int32(h.round(fixed.Int26_6(h.stack[top-1])))
|
|
|
|
case opNROUND00, opNROUND01, opNROUND10, opNROUND11:
|
|
// No-op. The spec says to add one of four "compensations for the engine
|
|
// characteristics", to cater for things like "different dot-size printers".
|
|
// https://developer.apple.com/fonts/TTRefMan/RM02/Chap2.html#engine_compensation
|
|
// This code does not implement engine compensation, as we don't expect to
|
|
// be used to output on dot-matrix printers.
|
|
|
|
case opWCVTF:
|
|
top -= 2
|
|
h.setScaledCVT(h.stack[top], h.font.scale(h.scale*fixed.Int26_6(h.stack[top+1])))
|
|
|
|
case opDELTAP2, opDELTAP3, opDELTAC1, opDELTAC2, opDELTAC3:
|
|
goto delta
|
|
|
|
case opSROUND, opS45ROUND:
|
|
top--
|
|
switch (h.stack[top] >> 6) & 0x03 {
|
|
case 0:
|
|
h.gs.roundPeriod = 1 << 5
|
|
case 1, 3:
|
|
h.gs.roundPeriod = 1 << 6
|
|
case 2:
|
|
h.gs.roundPeriod = 1 << 7
|
|
}
|
|
h.gs.roundSuper45 = opcode == opS45ROUND
|
|
if h.gs.roundSuper45 {
|
|
// The spec says to multiply by √2, but the C Freetype code says 1/√2.
|
|
// We go with 1/√2.
|
|
h.gs.roundPeriod *= 46341
|
|
h.gs.roundPeriod /= 65536
|
|
}
|
|
h.gs.roundPhase = h.gs.roundPeriod * fixed.Int26_6((h.stack[top]>>4)&0x03) / 4
|
|
if x := h.stack[top] & 0x0f; x != 0 {
|
|
h.gs.roundThreshold = h.gs.roundPeriod * fixed.Int26_6(x-4) / 8
|
|
} else {
|
|
h.gs.roundThreshold = h.gs.roundPeriod - 1
|
|
}
|
|
|
|
case opJROT:
|
|
top -= 2
|
|
if h.stack[top+1] != 0 {
|
|
pc += int(h.stack[top])
|
|
continue
|
|
}
|
|
|
|
case opJROF:
|
|
top -= 2
|
|
if h.stack[top+1] == 0 {
|
|
pc += int(h.stack[top])
|
|
continue
|
|
}
|
|
|
|
case opROFF:
|
|
h.gs.roundPeriod = 0
|
|
h.gs.roundPhase = 0
|
|
h.gs.roundThreshold = 0
|
|
h.gs.roundSuper45 = false
|
|
|
|
case opRUTG:
|
|
h.gs.roundPeriod = 1 << 6
|
|
h.gs.roundPhase = 0
|
|
h.gs.roundThreshold = 1<<6 - 1
|
|
h.gs.roundSuper45 = false
|
|
|
|
case opRDTG:
|
|
h.gs.roundPeriod = 1 << 6
|
|
h.gs.roundPhase = 0
|
|
h.gs.roundThreshold = 0
|
|
h.gs.roundSuper45 = false
|
|
|
|
case opSANGW, opAA:
|
|
// These ops are "anachronistic" and no longer used.
|
|
top--
|
|
|
|
case opFLIPPT:
|
|
if top < int(h.gs.loop) {
|
|
return errors.New("truetype: hinting: stack underflow")
|
|
}
|
|
points := h.points[glyphZone][current]
|
|
for ; h.gs.loop != 0; h.gs.loop-- {
|
|
top--
|
|
i := h.stack[top]
|
|
if i < 0 || len(points) <= int(i) {
|
|
return errors.New("truetype: hinting: point out of range")
|
|
}
|
|
points[i].Flags ^= flagOnCurve
|
|
}
|
|
h.gs.loop = 1
|
|
|
|
case opFLIPRGON, opFLIPRGOFF:
|
|
top -= 2
|
|
i, j, points := h.stack[top], h.stack[top+1], h.points[glyphZone][current]
|
|
if i < 0 || len(points) <= int(i) || j < 0 || len(points) <= int(j) {
|
|
return errors.New("truetype: hinting: point out of range")
|
|
}
|
|
for ; i <= j; i++ {
|
|
if opcode == opFLIPRGON {
|
|
points[i].Flags |= flagOnCurve
|
|
} else {
|
|
points[i].Flags &^= flagOnCurve
|
|
}
|
|
}
|
|
|
|
case opSCANCTRL:
|
|
// We do not support dropout control, as we always rasterize grayscale glyphs.
|
|
top--
|
|
|
|
case opSDPVTL0, opSDPVTL1:
|
|
top -= 2
|
|
for i := 0; i < 2; i++ {
|
|
pt := unhinted
|
|
if i != 0 {
|
|
pt = current
|
|
}
|
|
p := h.point(1, pt, h.stack[top])
|
|
q := h.point(2, pt, h.stack[top+1])
|
|
if p == nil || q == nil {
|
|
return errors.New("truetype: hinting: point out of range")
|
|
}
|
|
dx := f2dot14(p.X - q.X)
|
|
dy := f2dot14(p.Y - q.Y)
|
|
if dx == 0 && dy == 0 {
|
|
dx = 0x4000
|
|
} else if opcode&1 != 0 {
|
|
// Counter-clockwise rotation.
|
|
dx, dy = -dy, dx
|
|
}
|
|
if i == 0 {
|
|
h.gs.dv = normalize(dx, dy)
|
|
} else {
|
|
h.gs.pv = normalize(dx, dy)
|
|
}
|
|
}
|
|
|
|
case opGETINFO:
|
|
res := int32(0)
|
|
if h.stack[top-1]&(1<<0) != 0 {
|
|
// Set the engine version. We hard-code this to 35, the same as
|
|
// the C freetype code, which says that "Version~35 corresponds
|
|
// to MS rasterizer v.1.7 as used e.g. in Windows~98".
|
|
res |= 35
|
|
}
|
|
if h.stack[top-1]&(1<<5) != 0 {
|
|
// Set that we support grayscale.
|
|
res |= 1 << 12
|
|
}
|
|
// We set no other bits, as we do not support rotated or stretched glyphs.
|
|
h.stack[top-1] = res
|
|
|
|
case opIDEF:
|
|
// IDEF is for ancient versions of the bytecode interpreter, and is no longer used.
|
|
return errors.New("truetype: hinting: unsupported IDEF instruction")
|
|
|
|
case opROLL:
|
|
h.stack[top-1], h.stack[top-3], h.stack[top-2] =
|
|
h.stack[top-3], h.stack[top-2], h.stack[top-1]
|
|
|
|
case opMAX:
|
|
top--
|
|
if h.stack[top-1] < h.stack[top] {
|
|
h.stack[top-1] = h.stack[top]
|
|
}
|
|
|
|
case opMIN:
|
|
top--
|
|
if h.stack[top-1] > h.stack[top] {
|
|
h.stack[top-1] = h.stack[top]
|
|
}
|
|
|
|
case opSCANTYPE:
|
|
// We do not support dropout control, as we always rasterize grayscale glyphs.
|
|
top--
|
|
|
|
case opINSTCTRL:
|
|
// TODO: support instruction execution control? It seems rare, and even when
|
|
// nominally used (e.g. Source Sans Pro), it seems conditional on extreme or
|
|
// unusual rasterization conditions. For example, the code snippet at
|
|
// https://developer.apple.com/fonts/TTRefMan/RM05/Chap5.html#INSTCTRL
|
|
// uses INSTCTRL when grid-fitting a rotated or stretched glyph, but
|
|
// freetype-go does not support rotated or stretched glyphs.
|
|
top -= 2
|
|
|
|
default:
|
|
if opcode < opPUSHB000 {
|
|
return errors.New("truetype: hinting: unrecognized instruction")
|
|
}
|
|
|
|
if opcode < opMDRP00000 {
|
|
// PUSHxxxx opcode.
|
|
|
|
if opcode < opPUSHW000 {
|
|
opcode -= opPUSHB000 - 1
|
|
} else {
|
|
opcode -= opPUSHW000 - 1 - 0x80
|
|
}
|
|
goto push
|
|
}
|
|
|
|
if opcode < opMIRP00000 {
|
|
// MDRPxxxxx opcode.
|
|
|
|
top--
|
|
i := h.stack[top]
|
|
ref := h.point(0, current, h.gs.rp[0])
|
|
p := h.point(1, current, i)
|
|
if ref == nil || p == nil {
|
|
return errors.New("truetype: hinting: point out of range")
|
|
}
|
|
|
|
oldDist := fixed.Int26_6(0)
|
|
if h.gs.zp[0] == 0 || h.gs.zp[1] == 0 {
|
|
p0 := h.point(1, unhinted, i)
|
|
p1 := h.point(0, unhinted, h.gs.rp[0])
|
|
oldDist = dotProduct(p0.X-p1.X, p0.Y-p1.Y, h.gs.dv)
|
|
} else {
|
|
p0 := h.point(1, inFontUnits, i)
|
|
p1 := h.point(0, inFontUnits, h.gs.rp[0])
|
|
oldDist = dotProduct(p0.X-p1.X, p0.Y-p1.Y, h.gs.dv)
|
|
oldDist = h.font.scale(h.scale * oldDist)
|
|
}
|
|
|
|
// Single-width cut-in test.
|
|
if x := fabs(oldDist - h.gs.singleWidth); x < h.gs.singleWidthCutIn {
|
|
if oldDist >= 0 {
|
|
oldDist = +h.gs.singleWidth
|
|
} else {
|
|
oldDist = -h.gs.singleWidth
|
|
}
|
|
}
|
|
|
|
// Rounding bit.
|
|
// TODO: metrics compensation.
|
|
distance := oldDist
|
|
if opcode&0x04 != 0 {
|
|
distance = h.round(oldDist)
|
|
}
|
|
|
|
// Minimum distance bit.
|
|
if opcode&0x08 != 0 {
|
|
if oldDist >= 0 {
|
|
if distance < h.gs.minDist {
|
|
distance = h.gs.minDist
|
|
}
|
|
} else {
|
|
if distance > -h.gs.minDist {
|
|
distance = -h.gs.minDist
|
|
}
|
|
}
|
|
}
|
|
|
|
// Set-RP0 bit.
|
|
h.gs.rp[1] = h.gs.rp[0]
|
|
h.gs.rp[2] = i
|
|
if opcode&0x10 != 0 {
|
|
h.gs.rp[0] = i
|
|
}
|
|
|
|
// Move the point.
|
|
oldDist = dotProduct(p.X-ref.X, p.Y-ref.Y, h.gs.pv)
|
|
h.move(p, distance-oldDist, true)
|
|
|
|
} else {
|
|
// MIRPxxxxx opcode.
|
|
|
|
top -= 2
|
|
i := h.stack[top]
|
|
cvtDist := h.getScaledCVT(h.stack[top+1])
|
|
if fabs(cvtDist-h.gs.singleWidth) < h.gs.singleWidthCutIn {
|
|
if cvtDist >= 0 {
|
|
cvtDist = +h.gs.singleWidth
|
|
} else {
|
|
cvtDist = -h.gs.singleWidth
|
|
}
|
|
}
|
|
|
|
if h.gs.zp[1] == 0 {
|
|
// TODO: implement once we have a .ttf file that triggers
|
|
// this, so that we can step through C's freetype.
|
|
return errors.New("truetype: hinting: unimplemented twilight point adjustment")
|
|
}
|
|
|
|
ref := h.point(0, unhinted, h.gs.rp[0])
|
|
p := h.point(1, unhinted, i)
|
|
if ref == nil || p == nil {
|
|
return errors.New("truetype: hinting: point out of range")
|
|
}
|
|
oldDist := dotProduct(p.X-ref.X, p.Y-ref.Y, h.gs.dv)
|
|
|
|
ref = h.point(0, current, h.gs.rp[0])
|
|
p = h.point(1, current, i)
|
|
if ref == nil || p == nil {
|
|
return errors.New("truetype: hinting: point out of range")
|
|
}
|
|
curDist := dotProduct(p.X-ref.X, p.Y-ref.Y, h.gs.pv)
|
|
|
|
if h.gs.autoFlip && oldDist^cvtDist < 0 {
|
|
cvtDist = -cvtDist
|
|
}
|
|
|
|
// Rounding bit.
|
|
// TODO: metrics compensation.
|
|
distance := cvtDist
|
|
if opcode&0x04 != 0 {
|
|
// The CVT value is only used if close enough to oldDist.
|
|
if (h.gs.zp[0] == h.gs.zp[1]) &&
|
|
(fabs(cvtDist-oldDist) > h.gs.controlValueCutIn) {
|
|
|
|
distance = oldDist
|
|
}
|
|
distance = h.round(distance)
|
|
}
|
|
|
|
// Minimum distance bit.
|
|
if opcode&0x08 != 0 {
|
|
if oldDist >= 0 {
|
|
if distance < h.gs.minDist {
|
|
distance = h.gs.minDist
|
|
}
|
|
} else {
|
|
if distance > -h.gs.minDist {
|
|
distance = -h.gs.minDist
|
|
}
|
|
}
|
|
}
|
|
|
|
// Set-RP0 bit.
|
|
h.gs.rp[1] = h.gs.rp[0]
|
|
h.gs.rp[2] = i
|
|
if opcode&0x10 != 0 {
|
|
h.gs.rp[0] = i
|
|
}
|
|
|
|
// Move the point.
|
|
h.move(p, distance-curDist, true)
|
|
}
|
|
}
|
|
pc++
|
|
continue
|
|
|
|
ifelse:
|
|
// Skip past bytecode until the next ELSE (if opcode == 0) or the
|
|
// next EIF (for all opcodes). Opcode == 0 means that we have come
|
|
// from an IF. Opcode == 1 means that we have come from an ELSE.
|
|
{
|
|
ifelseloop:
|
|
for depth := 0; ; {
|
|
pc++
|
|
if pc >= len(program) {
|
|
return errors.New("truetype: hinting: unbalanced IF or ELSE")
|
|
}
|
|
switch program[pc] {
|
|
case opIF:
|
|
depth++
|
|
case opELSE:
|
|
if depth == 0 && opcode == 0 {
|
|
break ifelseloop
|
|
}
|
|
case opEIF:
|
|
depth--
|
|
if depth < 0 {
|
|
break ifelseloop
|
|
}
|
|
default:
|
|
var ok bool
|
|
pc, ok = skipInstructionPayload(program, pc)
|
|
if !ok {
|
|
return errors.New("truetype: hinting: unbalanced IF or ELSE")
|
|
}
|
|
}
|
|
}
|
|
pc++
|
|
continue
|
|
}
|
|
|
|
push:
|
|
// Push n elements from the program to the stack, where n is the low 7 bits of
|
|
// opcode. If the low 7 bits are zero, then n is the next byte from the program.
|
|
// The high bit being 0 means that the elements are zero-extended bytes.
|
|
// The high bit being 1 means that the elements are sign-extended words.
|
|
{
|
|
width := 1
|
|
if opcode&0x80 != 0 {
|
|
opcode &^= 0x80
|
|
width = 2
|
|
}
|
|
if opcode == 0 {
|
|
pc++
|
|
if pc >= len(program) {
|
|
return errors.New("truetype: hinting: insufficient data")
|
|
}
|
|
opcode = program[pc]
|
|
}
|
|
pc++
|
|
if top+int(opcode) > len(h.stack) {
|
|
return errors.New("truetype: hinting: stack overflow")
|
|
}
|
|
if pc+width*int(opcode) > len(program) {
|
|
return errors.New("truetype: hinting: insufficient data")
|
|
}
|
|
for ; opcode > 0; opcode-- {
|
|
if width == 1 {
|
|
h.stack[top] = int32(program[pc])
|
|
} else {
|
|
h.stack[top] = int32(int8(program[pc]))<<8 | int32(program[pc+1])
|
|
}
|
|
top++
|
|
pc += width
|
|
}
|
|
continue
|
|
}
|
|
|
|
delta:
|
|
{
|
|
if opcode >= opDELTAC1 && !h.scaledCVTInitialized {
|
|
h.initializeScaledCVT()
|
|
}
|
|
top--
|
|
n := h.stack[top]
|
|
if int32(top) < 2*n {
|
|
return errors.New("truetype: hinting: stack underflow")
|
|
}
|
|
for ; n > 0; n-- {
|
|
top -= 2
|
|
b := h.stack[top]
|
|
c := (b & 0xf0) >> 4
|
|
switch opcode {
|
|
case opDELTAP2, opDELTAC2:
|
|
c += 16
|
|
case opDELTAP3, opDELTAC3:
|
|
c += 32
|
|
}
|
|
c += h.gs.deltaBase
|
|
if ppem := (int32(h.scale) + 1<<5) >> 6; ppem != c {
|
|
continue
|
|
}
|
|
b = (b & 0x0f) - 8
|
|
if b >= 0 {
|
|
b++
|
|
}
|
|
b = b * 64 / (1 << uint32(h.gs.deltaShift))
|
|
if opcode >= opDELTAC1 {
|
|
a := h.stack[top+1]
|
|
if a < 0 || len(h.scaledCVT) <= int(a) {
|
|
return errors.New("truetype: hinting: index out of range")
|
|
}
|
|
h.scaledCVT[a] += fixed.Int26_6(b)
|
|
} else {
|
|
p := h.point(0, current, h.stack[top+1])
|
|
if p == nil {
|
|
return errors.New("truetype: hinting: point out of range")
|
|
}
|
|
h.move(p, fixed.Int26_6(b), true)
|
|
}
|
|
}
|
|
pc++
|
|
continue
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (h *hinter) initializeScaledCVT() {
|
|
h.scaledCVTInitialized = true
|
|
if n := len(h.font.cvt) / 2; n <= cap(h.scaledCVT) {
|
|
h.scaledCVT = h.scaledCVT[:n]
|
|
} else {
|
|
if n < 32 {
|
|
n = 32
|
|
}
|
|
h.scaledCVT = make([]fixed.Int26_6, len(h.font.cvt)/2, n)
|
|
}
|
|
for i := range h.scaledCVT {
|
|
unscaled := uint16(h.font.cvt[2*i])<<8 | uint16(h.font.cvt[2*i+1])
|
|
h.scaledCVT[i] = h.font.scale(h.scale * fixed.Int26_6(int16(unscaled)))
|
|
}
|
|
}
|
|
|
|
// getScaledCVT returns the scaled value from the font's Control Value Table.
|
|
func (h *hinter) getScaledCVT(i int32) fixed.Int26_6 {
|
|
if !h.scaledCVTInitialized {
|
|
h.initializeScaledCVT()
|
|
}
|
|
if i < 0 || len(h.scaledCVT) <= int(i) {
|
|
return 0
|
|
}
|
|
return h.scaledCVT[i]
|
|
}
|
|
|
|
// setScaledCVT overrides the scaled value from the font's Control Value Table.
|
|
func (h *hinter) setScaledCVT(i int32, v fixed.Int26_6) {
|
|
if !h.scaledCVTInitialized {
|
|
h.initializeScaledCVT()
|
|
}
|
|
if i < 0 || len(h.scaledCVT) <= int(i) {
|
|
return
|
|
}
|
|
h.scaledCVT[i] = v
|
|
}
|
|
|
|
func (h *hinter) point(zonePointer uint32, pt pointType, i int32) *Point {
|
|
points := h.points[h.gs.zp[zonePointer]][pt]
|
|
if i < 0 || len(points) <= int(i) {
|
|
return nil
|
|
}
|
|
return &points[i]
|
|
}
|
|
|
|
func (h *hinter) move(p *Point, distance fixed.Int26_6, touch bool) {
|
|
fvx := int64(h.gs.fv[0])
|
|
pvx := int64(h.gs.pv[0])
|
|
if fvx == 0x4000 && pvx == 0x4000 {
|
|
p.X += fixed.Int26_6(distance)
|
|
if touch {
|
|
p.Flags |= flagTouchedX
|
|
}
|
|
return
|
|
}
|
|
|
|
fvy := int64(h.gs.fv[1])
|
|
pvy := int64(h.gs.pv[1])
|
|
if fvy == 0x4000 && pvy == 0x4000 {
|
|
p.Y += fixed.Int26_6(distance)
|
|
if touch {
|
|
p.Flags |= flagTouchedY
|
|
}
|
|
return
|
|
}
|
|
|
|
fvDotPv := (fvx*pvx + fvy*pvy) >> 14
|
|
|
|
if fvx != 0 {
|
|
p.X += fixed.Int26_6(mulDiv(fvx, int64(distance), fvDotPv))
|
|
if touch {
|
|
p.Flags |= flagTouchedX
|
|
}
|
|
}
|
|
|
|
if fvy != 0 {
|
|
p.Y += fixed.Int26_6(mulDiv(fvy, int64(distance), fvDotPv))
|
|
if touch {
|
|
p.Flags |= flagTouchedY
|
|
}
|
|
}
|
|
}
|
|
|
|
func (h *hinter) iupInterp(interpY bool, p1, p2, ref1, ref2 int) {
|
|
if p1 > p2 {
|
|
return
|
|
}
|
|
if ref1 >= len(h.points[glyphZone][current]) ||
|
|
ref2 >= len(h.points[glyphZone][current]) {
|
|
return
|
|
}
|
|
|
|
var ifu1, ifu2 fixed.Int26_6
|
|
if interpY {
|
|
ifu1 = h.points[glyphZone][inFontUnits][ref1].Y
|
|
ifu2 = h.points[glyphZone][inFontUnits][ref2].Y
|
|
} else {
|
|
ifu1 = h.points[glyphZone][inFontUnits][ref1].X
|
|
ifu2 = h.points[glyphZone][inFontUnits][ref2].X
|
|
}
|
|
if ifu1 > ifu2 {
|
|
ifu1, ifu2 = ifu2, ifu1
|
|
ref1, ref2 = ref2, ref1
|
|
}
|
|
|
|
var unh1, unh2, delta1, delta2 fixed.Int26_6
|
|
if interpY {
|
|
unh1 = h.points[glyphZone][unhinted][ref1].Y
|
|
unh2 = h.points[glyphZone][unhinted][ref2].Y
|
|
delta1 = h.points[glyphZone][current][ref1].Y - unh1
|
|
delta2 = h.points[glyphZone][current][ref2].Y - unh2
|
|
} else {
|
|
unh1 = h.points[glyphZone][unhinted][ref1].X
|
|
unh2 = h.points[glyphZone][unhinted][ref2].X
|
|
delta1 = h.points[glyphZone][current][ref1].X - unh1
|
|
delta2 = h.points[glyphZone][current][ref2].X - unh2
|
|
}
|
|
|
|
var xy, ifuXY fixed.Int26_6
|
|
if ifu1 == ifu2 {
|
|
for i := p1; i <= p2; i++ {
|
|
if interpY {
|
|
xy = h.points[glyphZone][unhinted][i].Y
|
|
} else {
|
|
xy = h.points[glyphZone][unhinted][i].X
|
|
}
|
|
|
|
if xy <= unh1 {
|
|
xy += delta1
|
|
} else {
|
|
xy += delta2
|
|
}
|
|
|
|
if interpY {
|
|
h.points[glyphZone][current][i].Y = xy
|
|
} else {
|
|
h.points[glyphZone][current][i].X = xy
|
|
}
|
|
}
|
|
return
|
|
}
|
|
|
|
scale, scaleOK := int64(0), false
|
|
for i := p1; i <= p2; i++ {
|
|
if interpY {
|
|
xy = h.points[glyphZone][unhinted][i].Y
|
|
ifuXY = h.points[glyphZone][inFontUnits][i].Y
|
|
} else {
|
|
xy = h.points[glyphZone][unhinted][i].X
|
|
ifuXY = h.points[glyphZone][inFontUnits][i].X
|
|
}
|
|
|
|
if xy <= unh1 {
|
|
xy += delta1
|
|
} else if xy >= unh2 {
|
|
xy += delta2
|
|
} else {
|
|
if !scaleOK {
|
|
scaleOK = true
|
|
scale = mulDiv(int64(unh2+delta2-unh1-delta1), 0x10000, int64(ifu2-ifu1))
|
|
}
|
|
numer := int64(ifuXY-ifu1) * scale
|
|
if numer >= 0 {
|
|
numer += 0x8000
|
|
} else {
|
|
numer -= 0x8000
|
|
}
|
|
xy = unh1 + delta1 + fixed.Int26_6(numer/0x10000)
|
|
}
|
|
|
|
if interpY {
|
|
h.points[glyphZone][current][i].Y = xy
|
|
} else {
|
|
h.points[glyphZone][current][i].X = xy
|
|
}
|
|
}
|
|
}
|
|
|
|
func (h *hinter) iupShift(interpY bool, p1, p2, p int) {
|
|
var delta fixed.Int26_6
|
|
if interpY {
|
|
delta = h.points[glyphZone][current][p].Y - h.points[glyphZone][unhinted][p].Y
|
|
} else {
|
|
delta = h.points[glyphZone][current][p].X - h.points[glyphZone][unhinted][p].X
|
|
}
|
|
if delta == 0 {
|
|
return
|
|
}
|
|
for i := p1; i < p2; i++ {
|
|
if i == p {
|
|
continue
|
|
}
|
|
if interpY {
|
|
h.points[glyphZone][current][i].Y += delta
|
|
} else {
|
|
h.points[glyphZone][current][i].X += delta
|
|
}
|
|
}
|
|
}
|
|
|
|
func (h *hinter) displacement(useZP1 bool) (zonePointer uint32, i int32, d fixed.Int26_6, ok bool) {
|
|
zonePointer, i = uint32(0), h.gs.rp[1]
|
|
if useZP1 {
|
|
zonePointer, i = 1, h.gs.rp[2]
|
|
}
|
|
p := h.point(zonePointer, current, i)
|
|
q := h.point(zonePointer, unhinted, i)
|
|
if p == nil || q == nil {
|
|
return 0, 0, 0, false
|
|
}
|
|
d = dotProduct(p.X-q.X, p.Y-q.Y, h.gs.pv)
|
|
return zonePointer, i, d, true
|
|
}
|
|
|
|
// skipInstructionPayload increments pc by the extra data that follows a
|
|
// variable length PUSHB or PUSHW instruction.
|
|
func skipInstructionPayload(program []byte, pc int) (newPC int, ok bool) {
|
|
switch program[pc] {
|
|
case opNPUSHB:
|
|
pc++
|
|
if pc >= len(program) {
|
|
return 0, false
|
|
}
|
|
pc += int(program[pc])
|
|
case opNPUSHW:
|
|
pc++
|
|
if pc >= len(program) {
|
|
return 0, false
|
|
}
|
|
pc += 2 * int(program[pc])
|
|
case opPUSHB000, opPUSHB001, opPUSHB010, opPUSHB011,
|
|
opPUSHB100, opPUSHB101, opPUSHB110, opPUSHB111:
|
|
pc += int(program[pc] - (opPUSHB000 - 1))
|
|
case opPUSHW000, opPUSHW001, opPUSHW010, opPUSHW011,
|
|
opPUSHW100, opPUSHW101, opPUSHW110, opPUSHW111:
|
|
pc += 2 * int(program[pc]-(opPUSHW000-1))
|
|
}
|
|
return pc, true
|
|
}
|
|
|
|
// f2dot14 is a 2.14 fixed point number.
|
|
type f2dot14 int16
|
|
|
|
func normalize(x, y f2dot14) [2]f2dot14 {
|
|
fx, fy := float64(x), float64(y)
|
|
l := 0x4000 / math.Hypot(fx, fy)
|
|
fx *= l
|
|
if fx >= 0 {
|
|
fx += 0.5
|
|
} else {
|
|
fx -= 0.5
|
|
}
|
|
fy *= l
|
|
if fy >= 0 {
|
|
fy += 0.5
|
|
} else {
|
|
fy -= 0.5
|
|
}
|
|
return [2]f2dot14{f2dot14(fx), f2dot14(fy)}
|
|
}
|
|
|
|
// fabs returns abs(x) in 26.6 fixed point arithmetic.
|
|
func fabs(x fixed.Int26_6) fixed.Int26_6 {
|
|
if x < 0 {
|
|
return -x
|
|
}
|
|
return x
|
|
}
|
|
|
|
// fdiv returns x/y in 26.6 fixed point arithmetic.
|
|
func fdiv(x, y fixed.Int26_6) fixed.Int26_6 {
|
|
return fixed.Int26_6((int64(x) << 6) / int64(y))
|
|
}
|
|
|
|
// fmul returns x*y in 26.6 fixed point arithmetic.
|
|
func fmul(x, y fixed.Int26_6) fixed.Int26_6 {
|
|
return fixed.Int26_6((int64(x)*int64(y) + 1<<5) >> 6)
|
|
}
|
|
|
|
// dotProduct returns the dot product of [x, y] and q. It is almost the same as
|
|
// px := int64(x)
|
|
// py := int64(y)
|
|
// qx := int64(q[0])
|
|
// qy := int64(q[1])
|
|
// return fixed.Int26_6((px*qx + py*qy + 1<<13) >> 14)
|
|
// except that the computation is done with 32-bit integers to produce exactly
|
|
// the same rounding behavior as C Freetype.
|
|
func dotProduct(x, y fixed.Int26_6, q [2]f2dot14) fixed.Int26_6 {
|
|
// Compute x*q[0] as 64-bit value.
|
|
l := uint32((int32(x) & 0xFFFF) * int32(q[0]))
|
|
m := (int32(x) >> 16) * int32(q[0])
|
|
|
|
lo1 := l + (uint32(m) << 16)
|
|
hi1 := (m >> 16) + (int32(l) >> 31) + bool2int32(lo1 < l)
|
|
|
|
// Compute y*q[1] as 64-bit value.
|
|
l = uint32((int32(y) & 0xFFFF) * int32(q[1]))
|
|
m = (int32(y) >> 16) * int32(q[1])
|
|
|
|
lo2 := l + (uint32(m) << 16)
|
|
hi2 := (m >> 16) + (int32(l) >> 31) + bool2int32(lo2 < l)
|
|
|
|
// Add them.
|
|
lo := lo1 + lo2
|
|
hi := hi1 + hi2 + bool2int32(lo < lo1)
|
|
|
|
// Divide the result by 2^14 with rounding.
|
|
s := hi >> 31
|
|
l = lo + uint32(s)
|
|
hi += s + bool2int32(l < lo)
|
|
lo = l
|
|
|
|
l = lo + 0x2000
|
|
hi += bool2int32(l < lo)
|
|
|
|
return fixed.Int26_6((uint32(hi) << 18) | (l >> 14))
|
|
}
|
|
|
|
// mulDiv returns x*y/z, rounded to the nearest integer.
|
|
func mulDiv(x, y, z int64) int64 {
|
|
xy := x * y
|
|
if z < 0 {
|
|
xy, z = -xy, -z
|
|
}
|
|
if xy >= 0 {
|
|
xy += z / 2
|
|
} else {
|
|
xy -= z / 2
|
|
}
|
|
return xy / z
|
|
}
|
|
|
|
// round rounds the given number. The rounding algorithm is described at
|
|
// https://developer.apple.com/fonts/TTRefMan/RM02/Chap2.html#rounding
|
|
func (h *hinter) round(x fixed.Int26_6) fixed.Int26_6 {
|
|
if h.gs.roundPeriod == 0 {
|
|
// Rounding is off.
|
|
return x
|
|
}
|
|
if x >= 0 {
|
|
ret := x - h.gs.roundPhase + h.gs.roundThreshold
|
|
if h.gs.roundSuper45 {
|
|
ret /= h.gs.roundPeriod
|
|
ret *= h.gs.roundPeriod
|
|
} else {
|
|
ret &= -h.gs.roundPeriod
|
|
}
|
|
if x != 0 && ret < 0 {
|
|
ret = 0
|
|
}
|
|
return ret + h.gs.roundPhase
|
|
}
|
|
ret := -x - h.gs.roundPhase + h.gs.roundThreshold
|
|
if h.gs.roundSuper45 {
|
|
ret /= h.gs.roundPeriod
|
|
ret *= h.gs.roundPeriod
|
|
} else {
|
|
ret &= -h.gs.roundPeriod
|
|
}
|
|
if ret < 0 {
|
|
ret = 0
|
|
}
|
|
return -ret - h.gs.roundPhase
|
|
}
|
|
|
|
func bool2int32(b bool) int32 {
|
|
if b {
|
|
return 1
|
|
}
|
|
return 0
|
|
}
|