re-implement expanded view widgets

cwidgets/expanded/hist.go

@@ -0,0 +1,60 @@
+package expanded
+
+type IntHist struct {
+	Val    int   // most current data point
+	Data   []int // historical data points
+	Labels []string
+}
+
+func NewIntHist(max int) *IntHist {
+	return &IntHist{
+		Data:   make([]int, max),
+		Labels: make([]string, max),
+	}
+}
+
+func (h *IntHist) Append(val int) {
+	if len(h.Data) == cap(h.Data) {
+		h.Data = append(h.Data[:0], h.Data[1:]...)
+	}
+	h.Val = val
+	h.Data = append(h.Data, val)
+}
+
+type DiffHist struct {
+	*IntHist
+	lastVal int
+}
+
+func NewDiffHist(max int) *DiffHist {
+	return &DiffHist{NewIntHist(max), -1}
+}
+
+func (h *DiffHist) Append(val int) {
+	if h.lastVal >= 0 { // skip append if this is the initial update
+		diff := val - h.lastVal
+		h.IntHist.Append(diff)
+	}
+	h.lastVal = val
+}
+
+type FloatHist struct {
+	Val    float64   // most current data point
+	Data   []float64 // historical data points
+	Labels []string
+}
+
+func NewFloatHist(max int) FloatHist {
+	return FloatHist{
+		Data:   make([]float64, max),
+		Labels: make([]string, max),
+	}
+}
+
+func (h FloatHist) Append(val float64) {
+	if len(h.Data) == cap(h.Data) {
+		h.Data = append(h.Data[:0], h.Data[1:]...)
+	}
+	h.Val = val
+	h.Data = append(h.Data, val)
+}