Add an auto-measure toggle with a cable length range, and console keys through the harness

ui.go

@@ -70,7 +70,7 @@ const (
 	cellGapX = 3
 	rowHMin  = 46
 
-	btnW         = 220
+	btnW         = 190
 	btnH         = 72
 	btnRadius    = 10
 	btnBorder    = 2
@@ -124,6 +124,9 @@ type display struct {
 	holdFrac  float64
 	fired     bool
 
+	autoBtn  rect
+	autoDown bool
+
 	version     string
 	versionSpot rect
 	showVersion bool
@@ -186,6 +189,7 @@ func (d *display) layout(w, h int) error {
 	d.headerH = headerTop + ringD + 24
 	colHdrH := d.small.lineH + 18
 	d.resetBtn = rect{w - uiMargin - btnW, h - uiMargin - btnH, btnW, btnH}
+	d.autoBtn = rect{d.resetBtn.x - uiColGap - btnW, d.resetBtn.y, btnW, btnH}
 
 	// Rows stretch to spend the whole band between the column headers and the
 	// footer, cells riding along at their design proportion of the row.
@@ -229,33 +233,26 @@ func (d *display) holdReset(x, y int, down bool, now time.Time) bool {
 	return true
 }
 
-// Accent rather than the status colours because it is something to press, not
-// something being reported.
-func (d *display) drawResetButton() {
-	r := d.resetBtn
-	d.fb.roundRect(r.x, r.y, r.w, r.h, btnRadius, uiAccent)
+func (d *display) fillButton(r rect, frac float64, label string, frame, ink rgb) {
+	d.fb.roundRect(r.x, r.y, r.w, r.h, btnRadius, frame)
 	d.fb.roundRect(r.x+btnBorder, r.y+btnBorder, r.w-2*btnBorder, r.h-2*btnBorder,
 		btnRadius-btnBorder, uiBg)
 
 	split := r.x + btnBorder
-	if d.holdFrac > 0 {
-		w := int(float64(r.w-2*btnBorder) * math.Min(d.holdFrac, 1))
+	if frac > 0 {
+		w := int(float64(r.w-2*btnBorder) * math.Min(frac, 1))
 		d.fb.roundRect(r.x+btnBorder, r.y+btnBorder, w, r.h-2*btnBorder,
-			btnRadius-btnBorder, uiAccent)
+			btnRadius-btnBorder, frame)
 		split += w
 	}
 
-	label, base := "RESET", uiAccent
-	if d.showVersion {
-		label, base = d.version, uiMuted
-	}
 	lx := r.x + (r.w-len(label)*d.textB.cellW)/2
 	ly := r.y + (r.h-d.textB.lineH)/2 - d.textB.capTop
 	// The label straddles the fill, so each glyph takes the colour that reads
 	// against whatever is behind it.
 	for i, c := range label {
 		gx := lx + i*d.textB.cellW
-		col := base
+		col := ink
 		if gx+d.textB.cellW/2 < split {
 			col = uiBg
 		}
@@ -263,6 +260,32 @@ func (d *display) drawResetButton() {
 	}
 }
 
+// Accent rather than the status colours because it is something to press, not
+// something being reported.
+func (d *display) drawResetButton() {
+	label, ink := "RESET", uiAccent
+	if d.showVersion {
+		label, ink = d.version, uiMuted
+	}
+	d.fillButton(d.resetBtn, d.holdFrac, label, uiAccent, ink)
+}
+
+// Muted until switched on; the fill is the time already spent toward the next
+// automatic measure.
+func (d *display) drawAutoButton(on bool, frac float64) {
+	c := uiMuted
+	if on {
+		c = uiAccent
+	}
+	d.fillButton(d.autoBtn, frac, "AUTO", c, c)
+}
+
+func (d *display) tapAuto(x, y int, down bool) bool {
+	was := d.autoDown
+	d.autoDown = down
+	return down && !was && d.autoBtn.contains(x, y)
+}
+
 // go run never stamps VCS info, so dev builds have no revision to show.
 func buildVersion() string {
 	info, ok := debug.ReadBuildInfo()
@@ -574,7 +597,7 @@ func (d *display) drawFooter(v view, elapsed time.Duration) {
 }
 
 func (d *display) render(v view, elapsed time.Duration, phy phyDisplay,
-	measuring bool, hv histView, target float64) error {
+	measuring bool, hv histView, target float64, autoOn bool, autoFrac float64) error {
 	fb := d.fb
 	fb.fill(uiBg)
 
@@ -583,6 +606,7 @@ func (d *display) render(v view, elapsed time.Duration, phy phyDisplay,
 	d.drawColHeaders()
 	d.drawRows(v, phy, measuring, hv, target)
 	d.drawFooter(v, elapsed)
+	d.drawAutoButton(autoOn, autoFrac)
 	d.drawResetButton()
 	return fb.flush()
 }