From b73d093683db611bec8529358ad31d397c032548 Mon Sep 17 00:00:00 2001
From: Thomas Friedel <tomee6@gmail.com>
Date: Tue, 18 Sep 2018 15:17:04 +0200
Subject: [PATCH] implemented line dash offset

---
 README.md                   |   2 +-
 canvas.go                   |   4 ++++
 canvas_test.go              |  29 +++++++++++++++++++++++++++++
 testdata/LineDashOffset.png | Bin 0 -> 445 bytes
 4 files changed, 34 insertions(+), 1 deletion(-)
 create mode 100755 testdata/LineDashOffset.png

diff --git a/README.md b/README.md
index 19f5e49..8a2130c 100644
--- a/README.md
+++ b/README.md
@@ -111,6 +111,7 @@ These features *should* work just like their HTML5 counterparts, but there are l
 - miterLimit
 - lineDash
 - getLineDash
+- lineDashOffset
 - global alpha
 - drawImage
 - getImageData
@@ -123,7 +124,6 @@ These features *should* work just like their HTML5 counterparts, but there are l
 # Missing features
 
 - globalCompositeOperation
-- lineDashOffset
 - textBaseline
 - isPointInPath
 - isPointInStroke
diff --git a/canvas.go b/canvas.go
index fec495a..2338a6e 100644
--- a/canvas.go
+++ b/canvas.go
@@ -684,6 +684,10 @@ func (cv *Canvas) SetLineDash(dash []float64) {
 	cv.state.lineDashOffset = 0
 }
 
+func (cv *Canvas) SetLineDashOffset(offset float64) {
+	cv.state.lineDashOffset = offset
+}
+
 // GetLineDash gets the line dash style
 func (cv *Canvas) GetLineDash() []float64 {
 	result := make([]float64, len(cv.state.lineDash))
diff --git a/canvas_test.go b/canvas_test.go
index 79bcfa4..8bb79c2 100644
--- a/canvas_test.go
+++ b/canvas_test.go
@@ -239,6 +239,35 @@ func TestLineDash(t *testing.T) {
 	})
 }
 
+func TestLineDashOffset(t *testing.T) {
+	run(t, func(cv *canvas.Canvas) {
+		cv.SetStrokeStyle("#0F0")
+		cv.SetLineWidth(2.5)
+		cv.SetLineDash([]float64{4, 6, 8})
+		cv.SetLineDashOffset(5)
+		cv.BeginPath()
+		cv.MoveTo(20, 20)
+		cv.LineTo(80, 20)
+		cv.LineTo(80, 80)
+		cv.LineTo(50, 80)
+		cv.LineTo(50, 50)
+		cv.LineTo(20, 50)
+		cv.ClosePath()
+		cv.MoveTo(30, 30)
+		cv.LineTo(70, 30)
+		cv.LineTo(70, 70)
+		cv.LineTo(60, 70)
+		cv.LineTo(60, 40)
+		cv.LineTo(30, 40)
+		cv.ClosePath()
+		cv.Stroke()
+		ld := cv.GetLineDash()
+		if ld[0] != 4 || ld[1] != 6 || ld[2] != 8 || ld[3] != 4 || ld[4] != 6 || ld[5] != 8 {
+			t.Fail()
+		}
+	})
+}
+
 func TestCurves(t *testing.T) {
 	run(t, func(cv *canvas.Canvas) {
 		cv.SetStrokeStyle("#00F")
diff --git a/testdata/LineDashOffset.png b/testdata/LineDashOffset.png
new file mode 100755
index 0000000000000000000000000000000000000000..c1c20ae0e3ac563377a54e540a876aad35f93dce
GIT binary patch
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