perf: add more visible gridline for y=0 in the dashboard graphs
Change-Id: I3ae9eabf2c526584c978df01a63d260425acc491
Reviewed-on: https://go-review.googlesource.com/c/build/+/412378
Reviewed-by: Michael Pratt <mpratt@google.com>
diff --git a/third_party/bandchart/bandchart.js b/third_party/bandchart/bandchart.js
index d9f5450..5369555 100644
--- a/third_party/bandchart/bandchart.js
+++ b/third_party/bandchart/bandchart.js
@@ -150,6 +150,19 @@
.attr("width", xRange[1] - xRange[0])
.attr("height", (-yDomain[0]/(yDomain[1]-yDomain[0]))*(height-marginTop-marginBottom));
+ // Add a harder gridline for Y=0 to make it stand out.
+
+ const line0 = d3.line()
+ .defined(i => D[i])
+ .x(i => xScale(X[i]))
+ .y(i => yScale(0))
+
+ svg.append("path")
+ .attr("fill", "none")
+ .attr("stroke", "#999999")
+ .attr("stroke-width", 2)
+ .attr("d", line0(I))
+
// Create CI area.
const area = d3.area()
