Return point for Z cmd should be the first pair of M coordinates, fixes

#230

svg/pathdata.go

@@ -12,6 +12,7 @@ type PathData struct {
 	o *Minifier
 
 	x, y        float64
+	x0, y0      float64
 	coords      [][]byte
 	coordFloats []float64
 
@@ -36,7 +37,6 @@ func NewPathData(o *Minifier) *PathData {
 // ShortenPathData takes a full pathdata string and returns a shortened version. The original string is overwritten.
 // It parses all commands (M, A, Z, ...) and coordinates (numbers) and calls copyInstruction for each command.
 func (p *PathData) ShortenPathData(b []byte) []byte {
-	var x0, y0 float64
 	var cmd byte
 
 	p.x, p.y = 0.0, 0.0
@@ -52,13 +52,6 @@ func (p *PathData) ShortenPathData(b []byte) []byte {
 		} 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]
@@ -82,6 +75,8 @@ func (p *PathData) copyInstruction(b []byte, cmd byte) int {
 	n := len(p.coords)
 	if n == 0 {
 		if cmd == 'Z' || cmd == 'z' {
+			p.x = p.x0
+			p.y = p.y0
 			b[0] = 'z'
 			return 1
 		}
@@ -191,6 +186,10 @@ func (p *PathData) copyInstruction(b []byte, cmd byte) int {
 			p.x = ax
 			p.y = ay
 		}
+		if i == 0 && (origCmd == 'M' || origCmd == 'm') {
+			p.x0 = p.x
+			p.y0 = p.y
+		}
 	}
 	return j
 }

svg/pathdata_test.go

@@ -54,6 +54,23 @@ func TestPathData(t *testing.T) {
 	}
 }
 
+func TestPathDataTruncated(t *testing.T) {
+	var pathDataTests = []struct {
+		pathData string
+		expected string
+	}{
+		{"m100 0 50 50zM100 0z", "m1e2.0 50 50zm0 0z"},
+	}
+
+	p := NewPathData(&Minifier{Decimals: 3})
+	for _, tt := range pathDataTests {
+		t.Run(tt.pathData, func(t *testing.T) {
+			path := p.ShortenPathData([]byte(tt.pathData))
+			test.Minify(t, tt.pathData, nil, string(path), tt.expected)
+		})
+	}
+}
+
 ////////////////////////////////////////////////////////////////
 
 func BenchmarkShortenPathData(b *testing.B) {