package svg import ( strconvStdlib "strconv" "github.com/tdewolff/minify" "github.com/tdewolff/parse" "github.com/tdewolff/strconv" ) type PathData struct { o *Minifier x, y float64 coords [][]byte coordFloats []float64 state PathDataState curBuffer []byte altBuffer []byte coordBuffer []byte } type PathDataState struct { cmd byte prevDigit bool prevDigitIsInt bool } func NewPathData(o *Minifier) *PathData { return &PathData{o: o} } func (p *PathData) ShortenPathData(b []byte) []byte { var x0, y0 float64 var cmd byte p.x, p.y = 0.0, 0.0 p.coords = p.coords[:0] p.coordFloats = p.coordFloats[:0] p.state = PathDataState{} j := 0 for i := 0; i < len(b); i++ { c := b[i] if c == ' ' || c == ',' || c == '\n' || c == '\r' || c == '\t' { continue } else if c >= 'A' && (cmd == 0 || cmd != c || c == 'M' || c == 'm') { // any command if cmd != 0 { j += p.copyInstruction(b[j:], cmd) if cmd == 'M' || cmd == 'm' { x0 = p.x y0 = p.y } else if cmd == 'Z' || cmd == 'z' { p.x = x0 p.y = y0 } } cmd = c p.coords = p.coords[:0] p.coordFloats = p.coordFloats[:0] } else if n := parse.Number(b[i:]); n > 0 { f, _ := strconv.ParseFloat(b[i : i+n]) p.coords = append(p.coords, b[i:i+n]) p.coordFloats = append(p.coordFloats, f) i += n - 1 } } if cmd != 0 { j += p.copyInstruction(b[j:], cmd) } return b[:j] } func (p *PathData) copyInstruction(b []byte, cmd byte) int { n := len(p.coords) if n == 0 { if cmd == 'Z' || cmd == 'z' { b[0] = 'z' return 1 } return 0 } isRelCmd := cmd >= 'a' // get new cursor coordinates di := 0 if (cmd == 'M' || cmd == 'm' || cmd == 'L' || cmd == 'l' || cmd == 'T' || cmd == 't') && n%2 == 0 { di = 2 // reprint M always, as the first pair is a move but subsequent pairs are L if cmd == 'M' || cmd == 'm' { p.state.cmd = byte(0) } } else if cmd == 'H' || cmd == 'h' || cmd == 'V' || cmd == 'v' { di = 1 } else if (cmd == 'S' || cmd == 's' || cmd == 'Q' || cmd == 'q') && n%4 == 0 { di = 4 } else if (cmd == 'C' || cmd == 'c') && n%6 == 0 { di = 6 } else if (cmd == 'A' || cmd == 'a') && n%7 == 0 { di = 7 } else { return 0 } j := 0 origCmd := cmd ax, ay := 0.0, 0.0 for i := 0; i < n; i += di { // subsequent coordinate pairs for M are really L if i > 0 && (origCmd == 'M' || origCmd == 'm') { origCmd = 'L' + (origCmd - 'M') } cmd = origCmd coords := p.coords[i : i+di] coordFloats := p.coordFloats[i : i+di] if cmd == 'H' || cmd == 'h' { ax = coordFloats[di-1] if isRelCmd { ay = 0 } else { ay = p.y } } else if cmd == 'V' || cmd == 'v' { if isRelCmd { ax = 0 } else { ax = p.x } ay = coordFloats[di-1] } else { ax = coordFloats[di-2] ay = coordFloats[di-1] } // switch from L to H or V whenever possible if cmd == 'L' || cmd == 'l' { if isRelCmd { if coordFloats[0] == 0 { cmd = 'v' coords = coords[1:] coordFloats = coordFloats[1:] } else if coordFloats[1] == 0 { cmd = 'h' coords = coords[:1] coordFloats = coordFloats[:1] } } else { if coordFloats[0] == p.x { cmd = 'V' coords = coords[1:] coordFloats = coordFloats[1:] } else if coordFloats[1] == p.y { cmd = 'H' coords = coords[:1] coordFloats = coordFloats[:1] } } } // make a current and alternated path with absolute/relative altered var curState, altState PathDataState curState = p.shortenCurPosInstruction(cmd, coords) if isRelCmd { altState = p.shortenAltPosInstruction(cmd-'a'+'A', coordFloats, p.x, p.y) } else { altState = p.shortenAltPosInstruction(cmd-'A'+'a', coordFloats, -p.x, -p.y) } // choose shortest, relative or absolute path? if len(p.altBuffer) < len(p.curBuffer) { j += copy(b[j:], p.altBuffer) p.state = altState } else { j += copy(b[j:], p.curBuffer) p.state = curState } if isRelCmd { p.x += ax p.y += ay } else { p.x = ax p.y = ay } } return j } func (p *PathData) shortenCurPosInstruction(cmd byte, coords [][]byte) PathDataState { state := p.state p.curBuffer = p.curBuffer[:0] if cmd != state.cmd && !(state.cmd == 'M' && cmd == 'L' || state.cmd == 'm' && cmd == 'l') { p.curBuffer = append(p.curBuffer, cmd) state.cmd = cmd state.prevDigit = false state.prevDigitIsInt = false } for _, coord := range coords { coord = minify.Number(coord, p.o.Decimals) state.copyNumber(&p.curBuffer, coord) } return state } func (p *PathData) shortenAltPosInstruction(cmd byte, coordFloats []float64, x, y float64) PathDataState { state := p.state p.altBuffer = p.altBuffer[:0] if cmd != state.cmd && !(state.cmd == 'M' && cmd == 'L' || state.cmd == 'm' && cmd == 'l') { p.altBuffer = append(p.altBuffer, cmd) state.cmd = cmd state.prevDigit = false state.prevDigitIsInt = false } for i, f := range coordFloats { if cmd == 'L' || cmd == 'l' || cmd == 'C' || cmd == 'c' || cmd == 'S' || cmd == 's' || cmd == 'Q' || cmd == 'q' || cmd == 'T' || cmd == 't' || cmd == 'M' || cmd == 'm' { if i%2 == 0 { f += x } else { f += y } } else if cmd == 'H' || cmd == 'h' { f += x } else if cmd == 'V' || cmd == 'v' { f += y } else if cmd == 'A' || cmd == 'a' { if i%7 == 5 { f += x } else if i%7 == 6 { f += y } } p.coordBuffer = strconvStdlib.AppendFloat(p.coordBuffer[:0], f, 'g', -1, 64) coord := minify.Number(p.coordBuffer, p.o.Decimals) state.copyNumber(&p.altBuffer, coord) } return state } func (state *PathDataState) copyNumber(buffer *[]byte, coord []byte) { if state.prevDigit && (coord[0] >= '0' && coord[0] <= '9' || coord[0] == '.' && state.prevDigitIsInt) { if coord[0] == '0' && !state.prevDigitIsInt { // if the first digit is zero, it is always just zero *buffer = append(*buffer, '.', '0') // prevDigit and prevDigitIsInt stay true return } else { *buffer = append(*buffer, ' ') } } state.prevDigit = true state.prevDigitIsInt = true if len(coord) > 2 && coord[len(coord)-2] == '0' && coord[len(coord)-1] == '0' { coord[len(coord)-2] = 'e' coord[len(coord)-1] = '2' state.prevDigitIsInt = false } else { for _, c := range coord { if c == '.' || c == 'e' || c == 'E' { state.prevDigitIsInt = false break } } } *buffer = append(*buffer, coord...) }