1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
|
package dashboard
import "math"
var sparkChars = []rune("▁▂▃▄▅▆▇█")
func renderSparkline(data []float64, width int) string {
if len(data) == 0 || width <= 0 {
return ""
}
samples := sampleForWidth(data, width)
min, max := minMax(samples)
if min == max {
return repeatRune('▄', len(samples))
}
out := make([]rune, len(samples))
scale := float64(len(sparkChars) - 1)
denom := max - min
for i, value := range samples {
idx := int(math.Round((value - min) / denom * scale))
if idx < 0 {
idx = 0
}
if idx >= len(sparkChars) {
idx = len(sparkChars) - 1
}
out[i] = sparkChars[idx]
}
return string(out)
}
func sampleForWidth(data []float64, width int) []float64 {
if width >= len(data) {
return append([]float64(nil), data...)
}
if width == 1 {
return []float64{data[len(data)-1]}
}
last := len(data) - 1
samples := make([]float64, width)
for i := 0; i < width; i++ {
idx := int(math.Round(float64(i) * float64(last) / float64(width-1)))
samples[i] = data[idx]
}
return samples
}
func minMax(values []float64) (float64, float64) {
min := values[0]
max := values[0]
for _, v := range values[1:] {
if v < min {
min = v
}
if v > max {
max = v
}
}
return min, max
}
func repeatRune(r rune, count int) string {
if count <= 0 {
return ""
}
out := make([]rune, count)
for i := range out {
out[i] = r
}
return string(out)
}
|
