816 lines
19 KiB
Go
816 lines
19 KiB
Go
// Copyright 2011 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package coding implements low-level QR coding details.
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package coding // import "rsc.io/qr/coding"
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import (
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"fmt"
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"strconv"
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"strings"
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"rsc.io/qr/gf256"
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)
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// Field is the field for QR error correction.
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var Field = gf256.NewField(0x11d, 2)
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// A Version represents a QR version.
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// The version specifies the size of the QR code:
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// a QR code with version v has 4v+17 pixels on a side.
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// Versions number from 1 to 40: the larger the version,
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// the more information the code can store.
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type Version int
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const MinVersion = 1
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const MaxVersion = 40
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func (v Version) String() string {
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return strconv.Itoa(int(v))
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}
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func (v Version) sizeClass() int {
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if v <= 9 {
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return 0
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}
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if v <= 26 {
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return 1
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}
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return 2
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}
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// DataBytes returns the number of data bytes that can be
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// stored in a QR code with the given version and level.
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func (v Version) DataBytes(l Level) int {
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vt := &vtab[v]
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lev := &vt.level[l]
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return vt.bytes - lev.nblock*lev.check
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}
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// Encoding implements a QR data encoding scheme.
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// The implementations--Numeric, Alphanumeric, and String--specify
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// the character set and the mapping from UTF-8 to code bits.
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// The more restrictive the mode, the fewer code bits are needed.
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type Encoding interface {
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Check() error
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Bits(v Version) int
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Encode(b *Bits, v Version)
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}
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type Bits struct {
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b []byte
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nbit int
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}
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func (b *Bits) Reset() {
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b.b = b.b[:0]
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b.nbit = 0
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}
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func (b *Bits) Bits() int {
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return b.nbit
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}
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func (b *Bits) Bytes() []byte {
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if b.nbit%8 != 0 {
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panic("fractional byte")
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}
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return b.b
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}
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func (b *Bits) Append(p []byte) {
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if b.nbit%8 != 0 {
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panic("fractional byte")
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}
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b.b = append(b.b, p...)
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b.nbit += 8 * len(p)
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}
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func (b *Bits) Write(v uint, nbit int) {
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for nbit > 0 {
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n := nbit
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if n > 8 {
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n = 8
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}
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if b.nbit%8 == 0 {
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b.b = append(b.b, 0)
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} else {
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m := -b.nbit & 7
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if n > m {
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n = m
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}
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}
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b.nbit += n
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sh := uint(nbit - n)
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b.b[len(b.b)-1] |= uint8(v >> sh << uint(-b.nbit&7))
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v -= v >> sh << sh
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nbit -= n
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}
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}
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// Num is the encoding for numeric data.
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// The only valid characters are the decimal digits 0 through 9.
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type Num string
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func (s Num) String() string {
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return fmt.Sprintf("Num(%#q)", string(s))
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}
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func (s Num) Check() error {
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for _, c := range s {
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if c < '0' || '9' < c {
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return fmt.Errorf("non-numeric string %#q", string(s))
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}
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}
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return nil
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}
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var numLen = [3]int{10, 12, 14}
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func (s Num) Bits(v Version) int {
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return 4 + numLen[v.sizeClass()] + (10*len(s)+2)/3
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}
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func (s Num) Encode(b *Bits, v Version) {
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b.Write(1, 4)
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b.Write(uint(len(s)), numLen[v.sizeClass()])
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var i int
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for i = 0; i+3 <= len(s); i += 3 {
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w := uint(s[i]-'0')*100 + uint(s[i+1]-'0')*10 + uint(s[i+2]-'0')
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b.Write(w, 10)
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}
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switch len(s) - i {
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case 1:
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w := uint(s[i] - '0')
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b.Write(w, 4)
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case 2:
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w := uint(s[i]-'0')*10 + uint(s[i+1]-'0')
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b.Write(w, 7)
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}
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}
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// Alpha is the encoding for alphanumeric data.
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// The valid characters are 0-9A-Z$%*+-./: and space.
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type Alpha string
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const alphabet = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ $%*+-./:"
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func (s Alpha) String() string {
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return fmt.Sprintf("Alpha(%#q)", string(s))
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}
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func (s Alpha) Check() error {
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for _, c := range s {
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if strings.IndexRune(alphabet, c) < 0 {
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return fmt.Errorf("non-alphanumeric string %#q", string(s))
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}
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}
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return nil
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}
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var alphaLen = [3]int{9, 11, 13}
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func (s Alpha) Bits(v Version) int {
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return 4 + alphaLen[v.sizeClass()] + (11*len(s)+1)/2
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}
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func (s Alpha) Encode(b *Bits, v Version) {
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b.Write(2, 4)
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b.Write(uint(len(s)), alphaLen[v.sizeClass()])
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var i int
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for i = 0; i+2 <= len(s); i += 2 {
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w := uint(strings.IndexRune(alphabet, rune(s[i])))*45 +
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uint(strings.IndexRune(alphabet, rune(s[i+1])))
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b.Write(w, 11)
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}
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if i < len(s) {
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w := uint(strings.IndexRune(alphabet, rune(s[i])))
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b.Write(w, 6)
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}
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}
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// String is the encoding for 8-bit data. All bytes are valid.
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type String string
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func (s String) String() string {
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return fmt.Sprintf("String(%#q)", string(s))
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}
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func (s String) Check() error {
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return nil
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}
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var stringLen = [3]int{8, 16, 16}
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func (s String) Bits(v Version) int {
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return 4 + stringLen[v.sizeClass()] + 8*len(s)
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}
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func (s String) Encode(b *Bits, v Version) {
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b.Write(4, 4)
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b.Write(uint(len(s)), stringLen[v.sizeClass()])
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for i := 0; i < len(s); i++ {
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b.Write(uint(s[i]), 8)
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}
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}
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// A Pixel describes a single pixel in a QR code.
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type Pixel uint32
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const (
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Black Pixel = 1 << iota
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Invert
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)
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func (p Pixel) Offset() uint {
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return uint(p >> 6)
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}
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func OffsetPixel(o uint) Pixel {
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return Pixel(o << 6)
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}
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func (r PixelRole) Pixel() Pixel {
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return Pixel(r << 2)
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}
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func (p Pixel) Role() PixelRole {
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return PixelRole(p>>2) & 15
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}
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func (p Pixel) String() string {
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s := p.Role().String()
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if p&Black != 0 {
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s += "+black"
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}
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if p&Invert != 0 {
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s += "+invert"
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}
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s += "+" + strconv.FormatUint(uint64(p.Offset()), 10)
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return s
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}
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// A PixelRole describes the role of a QR pixel.
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type PixelRole uint32
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const (
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_ PixelRole = iota
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Position // position squares (large)
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Alignment // alignment squares (small)
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Timing // timing strip between position squares
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Format // format metadata
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PVersion // version pattern
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Unused // unused pixel
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Data // data bit
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Check // error correction check bit
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Extra
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)
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var roles = []string{
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"",
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"position",
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"alignment",
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"timing",
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"format",
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"pversion",
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"unused",
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"data",
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"check",
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"extra",
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}
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func (r PixelRole) String() string {
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if Position <= r && r <= Check {
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return roles[r]
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}
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return strconv.Itoa(int(r))
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}
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// A Level represents a QR error correction level.
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// From least to most tolerant of errors, they are L, M, Q, H.
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type Level int
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const (
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L Level = iota
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M
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Q
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H
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)
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func (l Level) String() string {
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if L <= l && l <= H {
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return "LMQH"[l : l+1]
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}
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return strconv.Itoa(int(l))
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}
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// A Code is a square pixel grid.
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type Code struct {
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Bitmap []byte // 1 is black, 0 is white
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Size int // number of pixels on a side
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Stride int // number of bytes per row
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}
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func (c *Code) Black(x, y int) bool {
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return 0 <= x && x < c.Size && 0 <= y && y < c.Size &&
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c.Bitmap[y*c.Stride+x/8]&(1<<uint(7-x&7)) != 0
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}
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// A Mask describes a mask that is applied to the QR
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// code to avoid QR artifacts being interpreted as
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// alignment and timing patterns (such as the squares
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// in the corners). Valid masks are integers from 0 to 7.
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type Mask int
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// http://www.swetake.com/qr/qr5_en.html
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var mfunc = []func(int, int) bool{
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func(i, j int) bool { return (i+j)%2 == 0 },
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func(i, j int) bool { return i%2 == 0 },
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func(i, j int) bool { return j%3 == 0 },
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func(i, j int) bool { return (i+j)%3 == 0 },
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func(i, j int) bool { return (i/2+j/3)%2 == 0 },
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func(i, j int) bool { return i*j%2+i*j%3 == 0 },
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func(i, j int) bool { return (i*j%2+i*j%3)%2 == 0 },
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func(i, j int) bool { return (i*j%3+(i+j)%2)%2 == 0 },
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}
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func (m Mask) Invert(y, x int) bool {
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if m < 0 {
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return false
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}
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return mfunc[m](y, x)
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}
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// A Plan describes how to construct a QR code
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// with a specific version, level, and mask.
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type Plan struct {
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Version Version
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Level Level
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Mask Mask
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DataBytes int // number of data bytes
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CheckBytes int // number of error correcting (checksum) bytes
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Blocks int // number of data blocks
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Pixel [][]Pixel // pixel map
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}
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// NewPlan returns a Plan for a QR code with the given
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// version, level, and mask.
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func NewPlan(version Version, level Level, mask Mask) (*Plan, error) {
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p, err := vplan(version)
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if err != nil {
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return nil, err
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}
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if err := fplan(level, mask, p); err != nil {
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return nil, err
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}
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if err := lplan(version, level, p); err != nil {
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return nil, err
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}
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if err := mplan(mask, p); err != nil {
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return nil, err
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}
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return p, nil
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}
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func (b *Bits) Pad(n int) {
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if n < 0 {
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panic("qr: invalid pad size")
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}
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if n <= 4 {
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b.Write(0, n)
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} else {
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b.Write(0, 4)
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n -= 4
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n -= -b.Bits() & 7
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b.Write(0, -b.Bits()&7)
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pad := n / 8
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for i := 0; i < pad; i += 2 {
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b.Write(0xec, 8)
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if i+1 >= pad {
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break
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}
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b.Write(0x11, 8)
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}
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}
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}
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func (b *Bits) AddCheckBytes(v Version, l Level) {
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nd := v.DataBytes(l)
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if b.nbit < nd*8 {
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b.Pad(nd*8 - b.nbit)
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}
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if b.nbit != nd*8 {
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panic("qr: too much data")
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}
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dat := b.Bytes()
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vt := &vtab[v]
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lev := &vt.level[l]
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db := nd / lev.nblock
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extra := nd % lev.nblock
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chk := make([]byte, lev.check)
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rs := gf256.NewRSEncoder(Field, lev.check)
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for i := 0; i < lev.nblock; i++ {
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if i == lev.nblock-extra {
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db++
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}
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rs.ECC(dat[:db], chk)
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b.Append(chk)
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dat = dat[db:]
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}
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if len(b.Bytes()) != vt.bytes {
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panic("qr: internal error")
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}
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}
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func (p *Plan) Encode(text ...Encoding) (*Code, error) {
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var b Bits
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for _, t := range text {
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if err := t.Check(); err != nil {
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return nil, err
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}
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t.Encode(&b, p.Version)
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}
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if b.Bits() > p.DataBytes*8 {
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return nil, fmt.Errorf("cannot encode %d bits into %d-bit code", b.Bits(), p.DataBytes*8)
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}
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b.AddCheckBytes(p.Version, p.Level)
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bytes := b.Bytes()
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// Now we have the checksum bytes and the data bytes.
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// Construct the actual code.
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c := &Code{Size: len(p.Pixel), Stride: (len(p.Pixel) + 7) &^ 7}
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c.Bitmap = make([]byte, c.Stride*c.Size)
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crow := c.Bitmap
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for _, row := range p.Pixel {
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for x, pix := range row {
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switch pix.Role() {
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case Data, Check:
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o := pix.Offset()
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if bytes[o/8]&(1<<uint(7-o&7)) != 0 {
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pix ^= Black
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}
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}
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if pix&Black != 0 {
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crow[x/8] |= 1 << uint(7-x&7)
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}
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}
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crow = crow[c.Stride:]
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}
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return c, nil
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}
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// A version describes metadata associated with a version.
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type version struct {
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apos int
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astride int
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bytes int
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pattern int
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level [4]level
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}
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type level struct {
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nblock int
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check int
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}
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var vtab = []version{
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{},
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{100, 100, 26, 0x0, [4]level{{1, 7}, {1, 10}, {1, 13}, {1, 17}}}, // 1
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{16, 100, 44, 0x0, [4]level{{1, 10}, {1, 16}, {1, 22}, {1, 28}}}, // 2
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{20, 100, 70, 0x0, [4]level{{1, 15}, {1, 26}, {2, 18}, {2, 22}}}, // 3
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{24, 100, 100, 0x0, [4]level{{1, 20}, {2, 18}, {2, 26}, {4, 16}}}, // 4
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{28, 100, 134, 0x0, [4]level{{1, 26}, {2, 24}, {4, 18}, {4, 22}}}, // 5
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{32, 100, 172, 0x0, [4]level{{2, 18}, {4, 16}, {4, 24}, {4, 28}}}, // 6
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{20, 16, 196, 0x7c94, [4]level{{2, 20}, {4, 18}, {6, 18}, {5, 26}}}, // 7
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{22, 18, 242, 0x85bc, [4]level{{2, 24}, {4, 22}, {6, 22}, {6, 26}}}, // 8
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{24, 20, 292, 0x9a99, [4]level{{2, 30}, {5, 22}, {8, 20}, {8, 24}}}, // 9
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{26, 22, 346, 0xa4d3, [4]level{{4, 18}, {5, 26}, {8, 24}, {8, 28}}}, // 10
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{28, 24, 404, 0xbbf6, [4]level{{4, 20}, {5, 30}, {8, 28}, {11, 24}}}, // 11
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{30, 26, 466, 0xc762, [4]level{{4, 24}, {8, 22}, {10, 26}, {11, 28}}}, // 12
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{32, 28, 532, 0xd847, [4]level{{4, 26}, {9, 22}, {12, 24}, {16, 22}}}, // 13
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{24, 20, 581, 0xe60d, [4]level{{4, 30}, {9, 24}, {16, 20}, {16, 24}}}, // 14
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{24, 22, 655, 0xf928, [4]level{{6, 22}, {10, 24}, {12, 30}, {18, 24}}}, // 15
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{24, 24, 733, 0x10b78, [4]level{{6, 24}, {10, 28}, {17, 24}, {16, 30}}}, // 16
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{28, 24, 815, 0x1145d, [4]level{{6, 28}, {11, 28}, {16, 28}, {19, 28}}}, // 17
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{28, 26, 901, 0x12a17, [4]level{{6, 30}, {13, 26}, {18, 28}, {21, 28}}}, // 18
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{28, 28, 991, 0x13532, [4]level{{7, 28}, {14, 26}, {21, 26}, {25, 26}}}, // 19
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{32, 28, 1085, 0x149a6, [4]level{{8, 28}, {16, 26}, {20, 30}, {25, 28}}}, // 20
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{26, 22, 1156, 0x15683, [4]level{{8, 28}, {17, 26}, {23, 28}, {25, 30}}}, // 21
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{24, 24, 1258, 0x168c9, [4]level{{9, 28}, {17, 28}, {23, 30}, {34, 24}}}, // 22
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{28, 24, 1364, 0x177ec, [4]level{{9, 30}, {18, 28}, {25, 30}, {30, 30}}}, // 23
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{26, 26, 1474, 0x18ec4, [4]level{{10, 30}, {20, 28}, {27, 30}, {32, 30}}}, // 24
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{30, 26, 1588, 0x191e1, [4]level{{12, 26}, {21, 28}, {29, 30}, {35, 30}}}, // 25
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{28, 28, 1706, 0x1afab, [4]level{{12, 28}, {23, 28}, {34, 28}, {37, 30}}}, // 26
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{32, 28, 1828, 0x1b08e, [4]level{{12, 30}, {25, 28}, {34, 30}, {40, 30}}}, // 27
|
|
{24, 24, 1921, 0x1cc1a, [4]level{{13, 30}, {26, 28}, {35, 30}, {42, 30}}}, // 28
|
|
{28, 24, 2051, 0x1d33f, [4]level{{14, 30}, {28, 28}, {38, 30}, {45, 30}}}, // 29
|
|
{24, 26, 2185, 0x1ed75, [4]level{{15, 30}, {29, 28}, {40, 30}, {48, 30}}}, // 30
|
|
{28, 26, 2323, 0x1f250, [4]level{{16, 30}, {31, 28}, {43, 30}, {51, 30}}}, // 31
|
|
{32, 26, 2465, 0x209d5, [4]level{{17, 30}, {33, 28}, {45, 30}, {54, 30}}}, // 32
|
|
{28, 28, 2611, 0x216f0, [4]level{{18, 30}, {35, 28}, {48, 30}, {57, 30}}}, // 33
|
|
{32, 28, 2761, 0x228ba, [4]level{{19, 30}, {37, 28}, {51, 30}, {60, 30}}}, // 34
|
|
{28, 24, 2876, 0x2379f, [4]level{{19, 30}, {38, 28}, {53, 30}, {63, 30}}}, // 35
|
|
{22, 26, 3034, 0x24b0b, [4]level{{20, 30}, {40, 28}, {56, 30}, {66, 30}}}, // 36
|
|
{26, 26, 3196, 0x2542e, [4]level{{21, 30}, {43, 28}, {59, 30}, {70, 30}}}, // 37
|
|
{30, 26, 3362, 0x26a64, [4]level{{22, 30}, {45, 28}, {62, 30}, {74, 30}}}, // 38
|
|
{24, 28, 3532, 0x27541, [4]level{{24, 30}, {47, 28}, {65, 30}, {77, 30}}}, // 39
|
|
{28, 28, 3706, 0x28c69, [4]level{{25, 30}, {49, 28}, {68, 30}, {81, 30}}}, // 40
|
|
}
|
|
|
|
func grid(siz int) [][]Pixel {
|
|
m := make([][]Pixel, siz)
|
|
pix := make([]Pixel, siz*siz)
|
|
for i := range m {
|
|
m[i], pix = pix[:siz], pix[siz:]
|
|
}
|
|
return m
|
|
}
|
|
|
|
// vplan creates a Plan for the given version.
|
|
func vplan(v Version) (*Plan, error) {
|
|
p := &Plan{Version: v}
|
|
if v < 1 || v > 40 {
|
|
return nil, fmt.Errorf("invalid QR version %d", int(v))
|
|
}
|
|
siz := 17 + int(v)*4
|
|
m := grid(siz)
|
|
p.Pixel = m
|
|
|
|
// Timing markers (overwritten by boxes).
|
|
const ti = 6 // timing is in row/column 6 (counting from 0)
|
|
for i := range m {
|
|
p := Timing.Pixel()
|
|
if i&1 == 0 {
|
|
p |= Black
|
|
}
|
|
m[i][ti] = p
|
|
m[ti][i] = p
|
|
}
|
|
|
|
// Position boxes.
|
|
posBox(m, 0, 0)
|
|
posBox(m, siz-7, 0)
|
|
posBox(m, 0, siz-7)
|
|
|
|
// Alignment boxes.
|
|
info := &vtab[v]
|
|
for x := 4; x+5 < siz; {
|
|
for y := 4; y+5 < siz; {
|
|
// don't overwrite timing markers
|
|
if (x < 7 && y < 7) || (x < 7 && y+5 >= siz-7) || (x+5 >= siz-7 && y < 7) {
|
|
} else {
|
|
alignBox(m, x, y)
|
|
}
|
|
if y == 4 {
|
|
y = info.apos
|
|
} else {
|
|
y += info.astride
|
|
}
|
|
}
|
|
if x == 4 {
|
|
x = info.apos
|
|
} else {
|
|
x += info.astride
|
|
}
|
|
}
|
|
|
|
// Version pattern.
|
|
pat := vtab[v].pattern
|
|
if pat != 0 {
|
|
v := pat
|
|
for x := 0; x < 6; x++ {
|
|
for y := 0; y < 3; y++ {
|
|
p := PVersion.Pixel()
|
|
if v&1 != 0 {
|
|
p |= Black
|
|
}
|
|
m[siz-11+y][x] = p
|
|
m[x][siz-11+y] = p
|
|
v >>= 1
|
|
}
|
|
}
|
|
}
|
|
|
|
// One lonely black pixel
|
|
m[siz-8][8] = Unused.Pixel() | Black
|
|
|
|
return p, nil
|
|
}
|
|
|
|
// fplan adds the format pixels
|
|
func fplan(l Level, m Mask, p *Plan) error {
|
|
// Format pixels.
|
|
fb := uint32(l^1) << 13 // level: L=01, M=00, Q=11, H=10
|
|
fb |= uint32(m) << 10 // mask
|
|
const formatPoly = 0x537
|
|
rem := fb
|
|
for i := 14; i >= 10; i-- {
|
|
if rem&(1<<uint(i)) != 0 {
|
|
rem ^= formatPoly << uint(i-10)
|
|
}
|
|
}
|
|
fb |= rem
|
|
invert := uint32(0x5412)
|
|
siz := len(p.Pixel)
|
|
for i := uint(0); i < 15; i++ {
|
|
pix := Format.Pixel() + OffsetPixel(i)
|
|
if (fb>>i)&1 == 1 {
|
|
pix |= Black
|
|
}
|
|
if (invert>>i)&1 == 1 {
|
|
pix ^= Invert | Black
|
|
}
|
|
// top left
|
|
switch {
|
|
case i < 6:
|
|
p.Pixel[i][8] = pix
|
|
case i < 8:
|
|
p.Pixel[i+1][8] = pix
|
|
case i < 9:
|
|
p.Pixel[8][7] = pix
|
|
default:
|
|
p.Pixel[8][14-i] = pix
|
|
}
|
|
// bottom right
|
|
switch {
|
|
case i < 8:
|
|
p.Pixel[8][siz-1-int(i)] = pix
|
|
default:
|
|
p.Pixel[siz-1-int(14-i)][8] = pix
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// lplan edits a version-only Plan to add information
|
|
// about the error correction levels.
|
|
func lplan(v Version, l Level, p *Plan) error {
|
|
p.Level = l
|
|
|
|
nblock := vtab[v].level[l].nblock
|
|
ne := vtab[v].level[l].check
|
|
nde := (vtab[v].bytes - ne*nblock) / nblock
|
|
extra := (vtab[v].bytes - ne*nblock) % nblock
|
|
dataBits := (nde*nblock + extra) * 8
|
|
checkBits := ne * nblock * 8
|
|
|
|
p.DataBytes = vtab[v].bytes - ne*nblock
|
|
p.CheckBytes = ne * nblock
|
|
p.Blocks = nblock
|
|
|
|
// Make data + checksum pixels.
|
|
data := make([]Pixel, dataBits)
|
|
for i := range data {
|
|
data[i] = Data.Pixel() | OffsetPixel(uint(i))
|
|
}
|
|
check := make([]Pixel, checkBits)
|
|
for i := range check {
|
|
check[i] = Check.Pixel() | OffsetPixel(uint(i+dataBits))
|
|
}
|
|
|
|
// Split into blocks.
|
|
dataList := make([][]Pixel, nblock)
|
|
checkList := make([][]Pixel, nblock)
|
|
for i := 0; i < nblock; i++ {
|
|
// The last few blocks have an extra data byte (8 pixels).
|
|
nd := nde
|
|
if i >= nblock-extra {
|
|
nd++
|
|
}
|
|
dataList[i], data = data[0:nd*8], data[nd*8:]
|
|
checkList[i], check = check[0:ne*8], check[ne*8:]
|
|
}
|
|
if len(data) != 0 || len(check) != 0 {
|
|
panic("data/check math")
|
|
}
|
|
|
|
// Build up bit sequence, taking first byte of each block,
|
|
// then second byte, and so on. Then checksums.
|
|
bits := make([]Pixel, dataBits+checkBits)
|
|
dst := bits
|
|
for i := 0; i < nde+1; i++ {
|
|
for _, b := range dataList {
|
|
if i*8 < len(b) {
|
|
copy(dst, b[i*8:(i+1)*8])
|
|
dst = dst[8:]
|
|
}
|
|
}
|
|
}
|
|
for i := 0; i < ne; i++ {
|
|
for _, b := range checkList {
|
|
if i*8 < len(b) {
|
|
copy(dst, b[i*8:(i+1)*8])
|
|
dst = dst[8:]
|
|
}
|
|
}
|
|
}
|
|
if len(dst) != 0 {
|
|
panic("dst math")
|
|
}
|
|
|
|
// Sweep up pair of columns,
|
|
// then down, assigning to right then left pixel.
|
|
// Repeat.
|
|
// See Figure 2 of http://www.pclviewer.com/rs2/qrtopology.htm
|
|
siz := len(p.Pixel)
|
|
rem := make([]Pixel, 7)
|
|
for i := range rem {
|
|
rem[i] = Extra.Pixel()
|
|
}
|
|
src := append(bits, rem...)
|
|
for x := siz; x > 0; {
|
|
for y := siz - 1; y >= 0; y-- {
|
|
if p.Pixel[y][x-1].Role() == 0 {
|
|
p.Pixel[y][x-1], src = src[0], src[1:]
|
|
}
|
|
if p.Pixel[y][x-2].Role() == 0 {
|
|
p.Pixel[y][x-2], src = src[0], src[1:]
|
|
}
|
|
}
|
|
x -= 2
|
|
if x == 7 { // vertical timing strip
|
|
x--
|
|
}
|
|
for y := 0; y < siz; y++ {
|
|
if p.Pixel[y][x-1].Role() == 0 {
|
|
p.Pixel[y][x-1], src = src[0], src[1:]
|
|
}
|
|
if p.Pixel[y][x-2].Role() == 0 {
|
|
p.Pixel[y][x-2], src = src[0], src[1:]
|
|
}
|
|
}
|
|
x -= 2
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// mplan edits a version+level-only Plan to add the mask.
|
|
func mplan(m Mask, p *Plan) error {
|
|
p.Mask = m
|
|
for y, row := range p.Pixel {
|
|
for x, pix := range row {
|
|
if r := pix.Role(); (r == Data || r == Check || r == Extra) && p.Mask.Invert(y, x) {
|
|
row[x] ^= Black | Invert
|
|
}
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// posBox draws a position (large) box at upper left x, y.
|
|
func posBox(m [][]Pixel, x, y int) {
|
|
pos := Position.Pixel()
|
|
// box
|
|
for dy := 0; dy < 7; dy++ {
|
|
for dx := 0; dx < 7; dx++ {
|
|
p := pos
|
|
if dx == 0 || dx == 6 || dy == 0 || dy == 6 || 2 <= dx && dx <= 4 && 2 <= dy && dy <= 4 {
|
|
p |= Black
|
|
}
|
|
m[y+dy][x+dx] = p
|
|
}
|
|
}
|
|
// white border
|
|
for dy := -1; dy < 8; dy++ {
|
|
if 0 <= y+dy && y+dy < len(m) {
|
|
if x > 0 {
|
|
m[y+dy][x-1] = pos
|
|
}
|
|
if x+7 < len(m) {
|
|
m[y+dy][x+7] = pos
|
|
}
|
|
}
|
|
}
|
|
for dx := -1; dx < 8; dx++ {
|
|
if 0 <= x+dx && x+dx < len(m) {
|
|
if y > 0 {
|
|
m[y-1][x+dx] = pos
|
|
}
|
|
if y+7 < len(m) {
|
|
m[y+7][x+dx] = pos
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// alignBox draw an alignment (small) box at upper left x, y.
|
|
func alignBox(m [][]Pixel, x, y int) {
|
|
// box
|
|
align := Alignment.Pixel()
|
|
for dy := 0; dy < 5; dy++ {
|
|
for dx := 0; dx < 5; dx++ {
|
|
p := align
|
|
if dx == 0 || dx == 4 || dy == 0 || dy == 4 || dx == 2 && dy == 2 {
|
|
p |= Black
|
|
}
|
|
m[y+dy][x+dx] = p
|
|
}
|
|
}
|
|
}
|