better precision for small negative numbers

- also fix BADPREC(bad precision) issue when 0 is max in series.
guptarohit · Jun 30, 2018 · b8c6bd8 · b8c6bd8
1 parent b8f636e
commit b8c6bd8
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Showing 2 changed files with 23 additions and 1 deletion.
diff --git a/asciigraph.go b/asciigraph.go
@@ -54,7 +54,7 @@ func Plot(series []float64, options ...Option) string {
 	}
 
 	precision := 2
-	logMaximum := math.Log10(math.Abs(maximum)) //to find number of zeros after decimal
+	logMaximum := math.Log10(math.Max(math.Abs(maximum), math.Abs(minimum))) //to find number of zeros after decimal
 
 	if logMaximum < 0 {
 		// negative log

diff --git a/asciigraph_test.go b/asciigraph_test.go
@@ -129,6 +129,28 @@ func TestPlot(t *testing.T) {
      -1.70    ┤        ││                 ││                 ││         
      -3.00    ┤        ╰╯                 ╰╯                 ╰╯         
                  I'm a doctor, not an engineer.`},
+		{
+			[]float64{-5, -2, -3, -4, 0, -5, -6, -7, -8, 0, -9, -3, -5, -2, -9, -3, -1},
+			nil,
+			`  0.00 ┤   ╭╮   ╭╮       
+ -1.00 ┤   ││   ││     ╭ 
+ -2.00 ┤╭╮ ││   ││  ╭╮ │ 
+ -3.00 ┤│╰╮││   ││╭╮││╭╯ 
+ -4.00 ┤│ ╰╯│   │││││││  
+ -5.00 ┼╯   ╰╮  │││╰╯││  
+ -6.00 ┤     ╰╮ │││  ││  
+ -7.00 ┤      ╰╮│││  ││  
+ -8.00 ┤       ╰╯││  ││  
+ -9.00 ┼         ╰╯  ╰╯  `},
+		{
+			[]float64{-0.000018527, -0.021, -.00123, .00000021312, -.0434321234, -.032413241234, .0000234234},
+			[]Option{Height(5),Width(45)},
+			`  0.000 ┼─╮           ╭────────╮                    ╭ 
+ -0.008 ┤ ╰──╮     ╭──╯        ╰─╮                ╭─╯ 
+ -0.017 ┤    ╰─────╯             ╰╮             ╭─╯   
+ -0.025 ┤                         ╰─╮         ╭─╯     
+ -0.034 ┤                           ╰╮   ╭────╯       
+ -0.042 ┼                            ╰───╯            `},
 	}
 
 	for i := range cases {