diff --git a/grid_line.go b/grid_line.go
index 63fafb6..80274bd 100644
--- a/grid_line.go
+++ b/grid_line.go
@@ -7,10 +7,9 @@ type GridLineProvider interface {
 
 // GridLine is a line on a graph canvas.
 type GridLine struct {
-	IsMinor    bool
-	IsVertical bool
-	Style      Style
-	Value      float64
+	IsMinor bool
+	Style   Style
+	Value   float64
 }
 
 // Major returns if the gridline is a `major` line.
@@ -23,23 +22,13 @@ func (gl GridLine) Minor() bool {
 	return gl.IsMinor
 }
 
-// Vertical returns if the line is vertical line or not.
-func (gl GridLine) Vertical() bool {
-	return gl.IsVertical
-}
-
-// Horizontal returns if the line is horizontal line or not.
-func (gl GridLine) Horizontal() bool {
-	return !gl.IsVertical
-}
-
 // Render renders the gridline
-func (gl GridLine) Render(r Renderer, canvasBox Box, ra Range, defaults Style) {
+func (gl GridLine) Render(r Renderer, canvasBox Box, ra Range, isVertical bool, defaults Style) {
 	r.SetStrokeColor(gl.Style.GetStrokeColor(defaults.GetStrokeColor()))
 	r.SetStrokeWidth(gl.Style.GetStrokeWidth(defaults.GetStrokeWidth()))
 	r.SetStrokeDashArray(gl.Style.GetStrokeDashArray(defaults.GetStrokeDashArray()))
 
-	if gl.IsVertical {
+	if isVertical {
 		lineLeft := canvasBox.Left + ra.Translate(gl.Value)
 		lineBottom := canvasBox.Bottom
 		lineTop := canvasBox.Top
@@ -59,7 +48,7 @@ func (gl GridLine) Render(r Renderer, canvasBox Box, ra Range, defaults Style) {
 }
 
 // GenerateGridLines generates grid lines.
-func GenerateGridLines(ticks []Tick, majorStyle, minorStyle Style, isVertical bool) []GridLine {
+func GenerateGridLines(ticks []Tick, majorStyle, minorStyle Style) []GridLine {
 	var gl []GridLine
 	isMinor := false
 
@@ -73,10 +62,9 @@ func GenerateGridLines(ticks []Tick, majorStyle, minorStyle Style, isVertical bo
 			s = minorStyle
 		}
 		gl = append(gl, GridLine{
-			Style:      s,
-			IsMinor:    isMinor,
-			IsVertical: isVertical,
-			Value:      t.Value,
+			Style:   s,
+			IsMinor: isMinor,
+			Value:   t.Value,
 		})
 		isMinor = !isMinor
 	}
diff --git a/xaxis.go b/xaxis.go
index 10f8c5f..f1326db 100644
--- a/xaxis.go
+++ b/xaxis.go
@@ -63,7 +63,7 @@ func (xa XAxis) GetGridLines(ticks []Tick) []GridLine {
 	if len(xa.GridLines) > 0 {
 		return xa.GridLines
 	}
-	return GenerateGridLines(ticks, xa.GridMajorStyle, xa.GridMinorStyle, true)
+	return GenerateGridLines(ticks, xa.GridMajorStyle, xa.GridMinorStyle)
 }
 
 // Measure returns the bounds of the axis.
@@ -183,7 +183,7 @@ func (xa XAxis) Render(r Renderer, canvasBox Box, ra Range, defaults Style, tick
 				if gl.IsMinor {
 					defaults = xa.GridMinorStyle
 				}
-				gl.Render(r, canvasBox, ra, gl.Style.InheritFrom(defaults))
+				gl.Render(r, canvasBox, ra, true, gl.Style.InheritFrom(defaults))
 			}
 		}
 	}
diff --git a/yaxis.go b/yaxis.go
index 458d0ca..fe7ab44 100644
--- a/yaxis.go
+++ b/yaxis.go
@@ -63,7 +63,7 @@ func (ya YAxis) GetGridLines(ticks []Tick) []GridLine {
 	if len(ya.GridLines) > 0 {
 		return ya.GridLines
 	}
-	return GenerateGridLines(ticks, ya.GridMajorStyle, ya.GridMinorStyle, false)
+	return GenerateGridLines(ticks, ya.GridMajorStyle, ya.GridMinorStyle)
 }
 
 // Measure returns the bounds of the axis.
@@ -190,7 +190,7 @@ func (ya YAxis) Render(r Renderer, canvasBox Box, ra Range, defaults Style, tick
 	}
 
 	if ya.Zero.Style.Show {
-		ya.Zero.Render(r, canvasBox, ra, Style{})
+		ya.Zero.Render(r, canvasBox, ra, false, Style{})
 	}
 
 	if ya.GridMajorStyle.Show || ya.GridMinorStyle.Show {
@@ -200,7 +200,7 @@ func (ya YAxis) Render(r Renderer, canvasBox Box, ra Range, defaults Style, tick
 				if gl.IsMinor {
 					defaults = ya.GridMinorStyle
 				}
-				gl.Render(r, canvasBox, ra, gl.Style.InheritFrom(defaults))
+				gl.Render(r, canvasBox, ra, false, gl.Style.InheritFrom(defaults))
 			}
 		}
 	}