LineChart defaults to 0 mix and max when these are NaN

Signed-off-by: Xabier Larrakoetxea <slok69@gmail.com>

widgets/linechart/linechart.go

@@ -57,7 +57,7 @@ func newSeriesValues(values []float64) *seriesValues {
 	v := make([]float64, len(values))
 	copy(v, values)
 
-	min, max := numbers.MinMax(v)
+	min, max := minMax(v)
 	return &seriesValues{
 		values: v,
 		min:    min,
@@ -176,8 +176,9 @@ func (lc *LineChart) yMinMax() (float64, float64) {
 		maximums = append(maximums, lc.opts.yAxisCustomScale.max)
 	}
 
-	min, _ := numbers.MinMax(minimums)
+	min, _ := minMax(minimums)
-	_, max := numbers.MinMax(maximums)
+	_, max := minMax(maximums)
+
 	return min, max
 }
 
@@ -530,3 +531,22 @@ func (lc *LineChart) maxXValue() int {
 	}
 	return maxLen - 1
 }
+
+const (
+	defMin = 0
+	defMax = 0
+)
+
+// minMax is a wrapper around numbers.MinMax that controls
+// the output if the values are NaN and sets defaults if it's
+// the case.
+func minMax(values []float64) (x, y float64) {
+	min, max := numbers.MinMax(values)
+	if math.IsNaN(min) {
+		min = defMin
+	}
+	if math.IsNaN(max) {
+		max = defMax
+	}
+	return min, max
+}

widgets/linechart/linechart_test.go

@@ -960,53 +960,6 @@ func TestLineChartDraws(t *testing.T) {
 				return ft
 			},
 		},
-		{
-			desc:   "more values than capacity, X rescales with NaN values ignored",
-			canvas: image.Rect(0, 0, 11, 10),
-			writes: func(lc *LineChart) error {
-				return lc.Series("first", []float64{0, 1, 2, 3, 4, 5, 6, 7, math.NaN(), math.NaN(), math.NaN(), math.NaN(), 12, 13, 14, 15, 16, 17, 18, 19})
-			},
-			wantCapacity: 12,
-			want: func(size image.Point) *faketerm.Terminal {
-				ft := faketerm.MustNew(size)
-				c := testcanvas.MustNew(ft.Area())
-
-				// Y and X axis.
-				lines := []draw.HVLine{
-					{Start: image.Point{4, 0}, End: image.Point{4, 8}},
-					{Start: image.Point{4, 8}, End: image.Point{10, 8}},
-				}
-				testdraw.MustHVLines(c, lines)
-
-				// Value labels.
-				testdraw.MustText(c, "0", image.Point{3, 7})
-				testdraw.MustText(c, "9.92", image.Point{0, 3})
-				testdraw.MustText(c, "0", image.Point{5, 9})
-				testdraw.MustText(c, "14", image.Point{9, 9})
-
-				// Braille line.
-				graphAr := image.Rect(5, 0, 11, 8)
-				bc := testbraille.MustNew(graphAr)
-				testdraw.MustBrailleLine(bc, image.Point{0, 31}, image.Point{1, 29})
-				testdraw.MustBrailleLine(bc, image.Point{1, 29}, image.Point{1, 28})
-				testdraw.MustBrailleLine(bc, image.Point{1, 28}, image.Point{2, 26})
-				testdraw.MustBrailleLine(bc, image.Point{2, 26}, image.Point{2, 25})
-				testdraw.MustBrailleLine(bc, image.Point{2, 25}, image.Point{3, 23})
-				testdraw.MustBrailleLine(bc, image.Point{3, 23}, image.Point{3, 21})
-				testdraw.MustBrailleLine(bc, image.Point{3, 21}, image.Point{4, 20})
-				testdraw.MustBrailleLine(bc, image.Point{7, 12}, image.Point{8, 10})
-				testdraw.MustBrailleLine(bc, image.Point{8, 10}, image.Point{8, 8})
-				testdraw.MustBrailleLine(bc, image.Point{8, 8}, image.Point{9, 7})
-				testdraw.MustBrailleLine(bc, image.Point{9, 7}, image.Point{9, 5})
-				testdraw.MustBrailleLine(bc, image.Point{9, 5}, image.Point{10, 4})
-				testdraw.MustBrailleLine(bc, image.Point{10, 4}, image.Point{10, 2})
-				testdraw.MustBrailleLine(bc, image.Point{10, 2}, image.Point{11, 0})
-				testbraille.MustCopyTo(bc, c)
-
-				testcanvas.MustApply(c, ft)
-				return ft
-			},
-		},
 		{
 			desc: "more values than capacity, X unscaled",
 			opts: []Option{
@@ -1570,6 +1523,119 @@ func TestLineChartDraws(t *testing.T) {
 				testdraw.MustBrailleLine(bc, image.Point{0, 31}, image.Point{26, 0})
 				testbraille.MustCopyTo(bc, c)
 
+				testcanvas.MustApply(c, ft)
+				return ft
+			},
+		},
+		{
+			desc:   "all NaN values",
+			canvas: image.Rect(0, 0, 20, 10),
+			writes: func(lc *LineChart) error {
+				return lc.Series("first", []float64{math.NaN(), math.NaN(), math.NaN(), math.NaN(), math.NaN()})
+			},
+			wantCapacity: 36,
+			want: func(size image.Point) *faketerm.Terminal {
+				ft := faketerm.MustNew(size)
+				c := testcanvas.MustNew(ft.Area())
+
+				// Y and X axis.
+				lines := []draw.HVLine{
+					{Start: image.Point{1, 0}, End: image.Point{1, 8}},
+					{Start: image.Point{1, 8}, End: image.Point{19, 8}},
+				}
+				testdraw.MustHVLines(c, lines)
+
+				// Value labels.
+				testdraw.MustText(c, "0", image.Point{0, 7})
+				testdraw.MustText(c, "0", image.Point{2, 9})
+				testdraw.MustText(c, "1", image.Point{6, 9})
+				testdraw.MustText(c, "2", image.Point{10, 9})
+				testdraw.MustText(c, "3", image.Point{14, 9})
+				testdraw.MustText(c, "4", image.Point{18, 9})
+
+				testcanvas.MustApply(c, ft)
+				return ft
+			},
+		},
+		{
+			desc:   "first and last NaN values",
+			canvas: image.Rect(0, 0, 28, 10),
+			writes: func(lc *LineChart) error {
+				return lc.Series("first", []float64{math.NaN(), math.NaN(), 100, 150, math.NaN()})
+			},
+			wantCapacity: 44,
+			want: func(size image.Point) *faketerm.Terminal {
+				ft := faketerm.MustNew(size)
+				c := testcanvas.MustNew(ft.Area())
+
+				// Y and X axis.
+				lines := []draw.HVLine{
+					{Start: image.Point{5, 0}, End: image.Point{5, 8}},
+					{Start: image.Point{5, 8}, End: image.Point{27, 8}},
+				}
+				testdraw.MustHVLines(c, lines)
+
+				// Value labels.
+				testdraw.MustText(c, "0", image.Point{4, 7})
+				testdraw.MustText(c, "77.44", image.Point{0, 3})
+				testdraw.MustText(c, "0", image.Point{6, 9})
+				testdraw.MustText(c, "1", image.Point{11, 9})
+				testdraw.MustText(c, "2", image.Point{16, 9})
+				testdraw.MustText(c, "3", image.Point{22, 9})
+				testdraw.MustText(c, "4", image.Point{27, 9})
+
+				graphAr := image.Rect(6, 0, 25, 8)
+				bc := testbraille.MustNew(graphAr)
+				testdraw.MustBrailleLine(bc, image.Point{21, 10}, image.Point{32, 0})
+				testbraille.MustCopyTo(bc, c)
+
+				testcanvas.MustApply(c, ft)
+				return ft
+			},
+		},
+		{
+			desc:   "more values than capacity, X rescales with NaN values ignored",
+			canvas: image.Rect(0, 0, 11, 10),
+			writes: func(lc *LineChart) error {
+				return lc.Series("first", []float64{0, 1, 2, 3, 4, 5, 6, 7, math.NaN(), math.NaN(), math.NaN(), math.NaN(), 12, 13, 14, 15, 16, 17, 18, 19})
+			},
+			wantCapacity: 12,
+			want: func(size image.Point) *faketerm.Terminal {
+				ft := faketerm.MustNew(size)
+				c := testcanvas.MustNew(ft.Area())
+
+				// Y and X axis.
+				lines := []draw.HVLine{
+					{Start: image.Point{4, 0}, End: image.Point{4, 8}},
+					{Start: image.Point{4, 8}, End: image.Point{10, 8}},
+				}
+				testdraw.MustHVLines(c, lines)
+
+				// Value labels.
+				testdraw.MustText(c, "0", image.Point{3, 7})
+				testdraw.MustText(c, "9.92", image.Point{0, 3})
+				testdraw.MustText(c, "0", image.Point{5, 9})
+				testdraw.MustText(c, "14", image.Point{9, 9})
+
+				// Braille line.
+				graphAr := image.Rect(5, 0, 11, 8)
+				bc := testbraille.MustNew(graphAr)
+				testdraw.MustBrailleLine(bc, image.Point{0, 31}, image.Point{1, 29})
+				testdraw.MustBrailleLine(bc, image.Point{1, 29}, image.Point{1, 28})
+				testdraw.MustBrailleLine(bc, image.Point{1, 28}, image.Point{2, 26})
+				testdraw.MustBrailleLine(bc, image.Point{2, 26}, image.Point{2, 25})
+				testdraw.MustBrailleLine(bc, image.Point{2, 25}, image.Point{3, 23})
+				testdraw.MustBrailleLine(bc, image.Point{3, 23}, image.Point{3, 21})
+				testdraw.MustBrailleLine(bc, image.Point{3, 21}, image.Point{4, 20})
+				testdraw.MustBrailleLine(bc, image.Point{7, 12}, image.Point{8, 10})
+				testdraw.MustBrailleLine(bc, image.Point{8, 10}, image.Point{8, 8})
+				testdraw.MustBrailleLine(bc, image.Point{8, 8}, image.Point{9, 7})
+				testdraw.MustBrailleLine(bc, image.Point{9, 7}, image.Point{9, 5})
+				testdraw.MustBrailleLine(bc, image.Point{9, 5}, image.Point{10, 4})
+				testdraw.MustBrailleLine(bc, image.Point{10, 4}, image.Point{10, 2})
+				testdraw.MustBrailleLine(bc, image.Point{10, 2}, image.Point{11, 0})
+				testbraille.MustCopyTo(bc, c)
+
 				testcanvas.MustApply(c, ft)
 				return ft
 			},