ticks refactor.

grid_line.go

@@ -1,31 +1,8 @@
 package chart
 
-// GenerateGridLines generates grid lines.
-func GenerateGridLines(ticks []Tick, isVertical bool) []GridLine {
-	var gl []GridLine
-	isMinor := false
-	minorStyle := Style{
-		StrokeColor: DefaultGridLineColor.WithAlpha(100),
-		StrokeWidth: 1.0,
-	}
-	majorStyle := Style{
-		StrokeColor: DefaultGridLineColor,
-		StrokeWidth: 1.0,
-	}
-	for _, t := range ticks {
-		s := majorStyle
-		if isMinor {
-			s = minorStyle
-		}
-		gl = append(gl, GridLine{
-			Style:      s,
-			IsMinor:    isMinor,
-			IsVertical: isVertical,
-			Value:      t.Value,
-		})
-		isMinor = !isMinor
-	}
-	return gl
+// GridLineProvider is a type that provides grid lines.
+type GridLineProvider interface {
+	GetGridLines(ticks []Tick, isVertical bool) []GridLine
 }
 
 // GridLine is a line on a graph canvas.
@@ -82,3 +59,31 @@ func (gl GridLine) Render(r Renderer, canvasBox Box, ra Range) {
 		r.Stroke()
 	}
 }
+
+// GenerateGridLines generates grid lines.
+func GenerateGridLines(ticks []Tick, isVertical bool) []GridLine {
+	var gl []GridLine
+	isMinor := false
+	minorStyle := Style{
+		StrokeColor: DefaultGridLineColor.WithAlpha(100),
+		StrokeWidth: 1.0,
+	}
+	majorStyle := Style{
+		StrokeColor: DefaultGridLineColor,
+		StrokeWidth: 1.0,
+	}
+	for _, t := range ticks {
+		s := majorStyle
+		if isMinor {
+			s = minorStyle
+		}
+		gl = append(gl, GridLine{
+			Style:      s,
+			IsMinor:    isMinor,
+			IsVertical: isVertical,
+			Value:      t.Value,
+		})
+		isMinor = !isMinor
+	}
+	return gl
+}