all: introduce no-err New plot function

align_example_test.go

@@ -26,10 +26,7 @@ func ExampleAlign() {
 				continue
 			}
 
-			p, err := plot.New()
-			if err != nil {
-				panic(err)
-			}
+			p := plot.New()
 
 			if j == 0 && i == 2 {
 				// This shows what happens when the axis padding
@@ -93,11 +90,7 @@ func ExampleAlign() {
 }
 
 func ExampleAxis_labelsPosition() {
-	p, err := plot.New()
-	if err != nil {
-		log.Fatalf("could not create plot: %+v", err)
-	}
-
+	p := plot.New()
 	p.Title.Text = "Title"
 	p.X.Label.Text = "X [mm]"
 	p.Y.Label.Text = "Y [A.U.]"
@@ -108,7 +101,7 @@ func ExampleAxis_labelsPosition() {
 	p.Y.Min = -10
 	p.Y.Max = +10
 
-	err = p.Save(10*vg.Centimeter, 10*vg.Centimeter, "testdata/axis_labels.png")
+	err := p.Save(10*vg.Centimeter, 10*vg.Centimeter, "testdata/axis_labels.png")
 	if err != nil {
 		log.Fatalf("could not save plot: %+v", err)
 	}

axis_test.go

@@ -156,19 +156,15 @@ func TestAxisPadding(t *testing.T) {
 	for _, padding := range []int{0, 5, 10} {
 		t.Run(fmt.Sprintf("padding-%d", padding), func(t *testing.T) {
 			cmpimg.CheckPlot(func() {
-				p, err := New()
-				if err != nil {
-					t.Fatalf("error: %+v", err)
-				}
-
+				p := New()
 				p.Title.Text = fmt.Sprintf("padding=%d", padding)
 				p.X.Label.Text = "X-Axis"
 				p.X.Label.Padding = vg.Points(float64(padding))
 				p.Y.Label.Text = "Y-Axis"
 				p.Y.Label.Padding = vg.Points(float64(padding))
 
 				const size = 5 * vg.Centimeter
-				err = p.Save(size, size, fmt.Sprintf("testdata/axis_padding_%02d.png", padding))
+				err := p.Save(size, size, fmt.Sprintf("testdata/axis_padding_%02d.png", padding))
 				if err != nil {
 					t.Fatalf("error: %+v", err)
 				}

gob/gob_test.go

@@ -33,11 +33,7 @@ func TestPersistency(t *testing.T) {
 	lineData := randomPoints(n, rnd)
 	linePointsData := randomPoints(n, rnd)
 
-	p, err := plot.New()
-	if err != nil {
-		t.Fatalf("error creating plot: %v\n", err)
-	}
-
+	p := plot.New()
 	p.Title.Text = "Plot Example"
 	p.X.Label.Text = "X"
 	p.Y.Label.Text = "Y"

palette/moreland/example_test.go

@@ -119,10 +119,7 @@ func Example() {
 
 		h := plotter.NewHeatMap(m, plte.cmap)
 
-		p, err := plot.New()
-		if err != nil {
-			log.Panic(err)
-		}
+		p := plot.New()
 		p.Title.Text = plte.name
 
 		p.Add(h)

palette/reverse_example_test.go

@@ -17,10 +17,7 @@ import (
 // This example creates a color bar and a second color bar where the
 // direction of the colors are reversed.
 func ExampleReverse() {
-	p, err := plot.New()
-	if err != nil {
-		log.Panic(err)
-	}
+	p := plot.New()
 	l := &plotter.ColorBar{ColorMap: moreland.Kindlmann()}
 	l2 := &plotter.ColorBar{ColorMap: palette.Reverse(moreland.Kindlmann())}
 	l.ColorMap.SetMin(0.5)
@@ -33,17 +30,14 @@ func ExampleReverse() {
 	p.X.Padding = 0
 	p.Title.Text = "A ColorMap and its Reverse"
 
-	if err = p.Save(300, 48, "testdata/reverse.png"); err != nil {
+	if err := p.Save(300, 48, "testdata/reverse.png"); err != nil {
 		log.Panic(err)
 	}
 }
 
 // This example creates a color palette from a reversed ColorMap.
 func ExampleReverse_palette() {
-	p, err := plot.New()
-	if err != nil {
-		log.Panic(err)
-	}
+	p := plot.New()
 	thumbs := plotter.PaletteThumbnailers(palette.Reverse(moreland.Kindlmann()).Palette(10))
 	for i, t := range thumbs {
 		p.Legend.Add(fmt.Sprint(i), t)
@@ -52,7 +46,7 @@ func ExampleReverse_palette() {
 	p.X.Padding = 0
 	p.Y.Padding = 0
 
-	if err = p.Save(35, 120, "testdata/reverse_palette.png"); err != nil {
+	if err := p.Save(35, 120, "testdata/reverse_palette.png"); err != nil {
 		log.Panic(err)
 	}
 }

plot.go

@@ -92,9 +92,8 @@ const (
 	vertical
 )
 
-// New returns a new plot with some reasonable
-// default settings.
-func New() (*Plot, error) {
+// New returns a new plot with some reasonable default settings.
+func New() *Plot {
 	hdlr := DefaultTextHandler
 	p := &Plot{
 		BackgroundColor: color.White,
@@ -110,7 +109,7 @@ func New() (*Plot, error) {
 		YAlign:  draw.YTop,
 		Handler: hdlr,
 	}
-	return p, nil
+	return p
 }
 
 // Add adds a Plotters to the plot.

plot_test.go

@@ -88,11 +88,7 @@ func TestIssue514(t *testing.T) {
 			go func() {
 				defer close(done)
 
-				p, err := plot.New()
-				if err != nil {
-					t.Errorf("could not create plot: %v", err)
-					return
-				}
+				p := plot.New()
 
 				var (
 					y1 = 100.0

plotter/barchart_example_test.go

@@ -22,10 +22,7 @@ func ExampleBarChart() {
 	horizontalLabels := []string{"Label A", "Label B", "Label C", "Label D"}
 
 	// Create a vertical BarChart
-	p1, err := plot.New()
-	if err != nil {
-		log.Panic(err)
-	}
+	p1 := plot.New()
 	verticalBarChart, err := plotter.NewBarChart(values, 0.5*vg.Centimeter)
 	if err != nil {
 		log.Panic(err)
@@ -38,10 +35,7 @@ func ExampleBarChart() {
 	}
 
 	// Create a horizontal BarChart
-	p2, err := plot.New()
-	if err != nil {
-		log.Panic(err)
-	}
+	p2 := plot.New()
 	horizontalBarChart, err := plotter.NewBarChart(values, 0.5*vg.Centimeter)
 	horizontalBarChart.Horizontal = true // Specify a horizontal BarChart.
 	if err != nil {
@@ -60,10 +54,7 @@ func ExampleBarChart() {
 	groupC := plotter.Values{12, 28, 15, 21, 8}
 	groupD := plotter.Values{30, 42, 6, 9, 12}
 
-	p, err := plot.New()
-	if err != nil {
-		log.Panic(err)
-	}
+	p := plot.New()
 	p.Title.Text = "Bar chart"
 	p.Y.Label.Text = "Heights"
 
@@ -115,10 +106,7 @@ func ExampleBarChart() {
 	}
 
 	// Now, make a stacked BarChart.
-	p, err = plot.New()
-	if err != nil {
-		log.Panic(err)
-	}
+	p = plot.New()
 	p.Title.Text = "Bar chart"
 	p.Y.Label.Text = "Heights"
 
@@ -243,10 +231,7 @@ func ExampleBarChart_positiveNegative() {
 		log.Panic(err)
 	}
 
-	p, err := plot.New()
-	if err != nil {
-		log.Panic(err)
-	}
+	p := plot.New()
 	p.Add(zero, pos1, pos2, neg1, neg2, netDots)
 	p.NominalY("Alpha", "Bravo", "Charlie", "Echo", "Foxtrot", "Golf")
 

plotter/boxplot_example_test.go

@@ -60,10 +60,7 @@ func ExampleBoxPlot() {
 		log.Panic(err)
 	}
 
-	p1, err := plot.New()
-	if err != nil {
-		log.Panic(err)
-	}
+	p1 := plot.New()
 	p1.Title.Text = "Vertical Box Plot"
 	p1.Y.Label.Text = "plotter.Values"
 	p1.Y.Max = 6
@@ -97,10 +94,7 @@ func ExampleBoxPlot() {
 		log.Panic(err)
 	}
 
-	p2, err := plot.New()
-	if err != nil {
-		log.Panic(err)
-	}
+	p2 := plot.New()
 	p2.Title.Text = "Horizontal Box Plot"
 	p2.X.Label.Text = "plotter.Values"
 
@@ -117,10 +111,7 @@ func ExampleBoxPlot() {
 	}
 
 	// Now, make a grouped box plot.
-	p3, err := plot.New()
-	if err != nil {
-		log.Panic(err)
-	}
+	p3 := plot.New()
 	p3.Title.Text = "Box Plot"
 	p3.Y.Label.Text = "plotter.Values"
 

plotter/bubbles_example_test.go

@@ -52,10 +52,7 @@ func ExampleScatter_bubbles() {
 		}
 	}
 
-	p, err := plot.New()
-	if err != nil {
-		log.Panic(err)
-	}
+	p := plot.New()
 	p.Title.Text = "Bubbles"
 	p.X.Label.Text = "X"
 	p.Y.Label.Text = "Y"

plotter/colorbar_example_test.go

@@ -14,29 +14,24 @@ import (
 )
 
 func ExampleColorBar_horizontal() {
-	p, err := plot.New()
-	if err != nil {
-		log.Panic(err)
-	}
+	p := plot.New()
+	p.HideY()
+	p.X.Padding = 0
+	p.Title.Text = "Title"
+
 	l := &plotter.ColorBar{ColorMap: moreland.ExtendedBlackBody()}
 	l.ColorMap.SetMin(0.5)
 	l.ColorMap.SetMax(1.5)
 	p.Add(l)
-	p.HideY()
-	p.X.Padding = 0
-	p.Title.Text = "Title"
 
-	if err = p.Save(300, 48, "testdata/colorBarHorizontal.png"); err != nil {
+	if err := p.Save(300, 48, "testdata/colorBarHorizontal.png"); err != nil {
 		log.Panic(err)
 	}
 }
 
 // This example shows how to create a ColorBar on a log-transformed axis.
 func ExampleColorBar_horizontal_log() {
-	p, err := plot.New()
-	if err != nil {
-		log.Panic(err)
-	}
+	p := plot.New()
 	colorMap, err := moreland.NewLuminance([]color.Color{color.Black, color.White})
 	if err != nil {
 		log.Panic(err)
@@ -57,10 +52,7 @@ func ExampleColorBar_horizontal_log() {
 }
 
 func ExampleColorBar_vertical() {
-	p, err := plot.New()
-	if err != nil {
-		log.Panic(err)
-	}
+	p := plot.New()
 	l := &plotter.ColorBar{ColorMap: moreland.ExtendedBlackBody()}
 	l.ColorMap.SetMin(0.5)
 	l.ColorMap.SetMax(1.5)
@@ -70,7 +62,7 @@ func ExampleColorBar_vertical() {
 	p.Y.Padding = 0
 	p.Title.Text = "Title"
 
-	if err = p.Save(40, 300, "testdata/colorBarVertical.png"); err != nil {
+	if err := p.Save(40, 300, "testdata/colorBarVertical.png"); err != nil {
 		log.Panic(err)
 	}
 }

plotter/contour_example_test.go

@@ -42,11 +42,7 @@ func ExampleContour() {
 		)
 	)
 
-	p, err := plot.New()
-	if err != nil {
-		log.Fatalf("could not create plot: %+v", err)
-	}
-
+	p := plot.New()
 	p.Title.Text = "Contour"
 	p.X.Padding = 0
 	p.Y.Padding = 0
@@ -55,7 +51,7 @@ func ExampleContour() {
 
 	p.Add(c)
 
-	err = p.Save(10*vg.Centimeter, 10*vg.Centimeter, "testdata/contour.png")
+	err := p.Save(10*vg.Centimeter, 10*vg.Centimeter, "testdata/contour.png")
 	if err != nil {
 		log.Fatalf("could not save plot: %+v", err)
 	}

plotter/contour_test.go

@@ -56,11 +56,7 @@ func TestHeatMapWithContour(t *testing.T) {
 	c := NewContour(m, levels, palette.Rainbow(10, palette.Blue, palette.Red, 1, 1, 1))
 	c.LineStyles[0].Width *= 5
 
-	plt, err := plot.New()
-	if err != nil {
-		t.Fatalf("could not create plot: %+v", err)
-	}
-
+	plt := plot.New()
 	plt.Add(h)
 	plt.Add(c)
 	plt.Add(NewGlyphBoxes())
@@ -69,7 +65,8 @@ func TestHeatMapWithContour(t *testing.T) {
 	plt.Y.Padding = 0
 	plt.X.Max = 3.5
 	plt.Y.Max = 2.5
-	err = plt.Save(7, 7, "heat.svg")
+
+	err := plt.Save(7, 7, "heat.svg")
 	if err != nil {
 		t.Fatalf("could not save plot: %+v", err)
 	}
@@ -95,18 +92,15 @@ func TestComplexContours(t *testing.T) {
 		levels := []float64{-1, 3, 7, 9, 13, 15, 19, 23, 27, 31}
 		c := NewContour(m, levels, palette.Rainbow(10, palette.Blue, palette.Red, 1, 1, 1))
 
-		plt, err := plot.New()
-		if err != nil {
-			t.Fatalf("could not create plot: %+v", err)
-		}
-
-		plt.Add(c)
-
+		plt := plot.New()
 		plt.X.Padding = 0
 		plt.Y.Padding = 0
 		plt.X.Max = 79.5
 		plt.Y.Max = 79.5
-		err = plt.Save(7, 7, fmt.Sprintf("complex_contour-%v.svg", n))
+
+		plt.Add(c)
+
+		err := plt.Save(7, 7, fmt.Sprintf("complex_contour-%v.svg", n))
 		if err != nil {
 			t.Fatalf("could not save plot: %+v", err)
 		}