Add y-axis tick labels.

This is intended to by used for visualizing catagorical data, i.e. mapping
numerical enum values to string labels.

Bug: webrtc:10623
Change-Id: Ic9c3da9a3874f479c07412f394a774ae90fd3d7e
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/145408
Reviewed-by: Sebastian Jansson <srte@webrtc.org>
Commit-Queue: Björn Terelius <terelius@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#28656}

rtc_tools/event_log_visualizer/plot_base.cc

@@ -66,6 +66,11 @@ void Plot::SetSuggestedYAxis(float min_value,
   SetYAxis(min_value, max_value, label, bottom_margin, top_margin);
 }
 
+void Plot::SetYAxisTickLabels(
+    const std::vector<std::pair<float, std::string>>& labels) {
+  yaxis_tick_labels_ = labels;
+}
+
 void Plot::SetTitle(const std::string& title) {
   title_ = title;
 }

rtc_tools/event_log_visualizer/plot_base.h

@@ -137,6 +137,9 @@ class Plot {
                          float bottom_margin = 0,
                          float top_margin = 0);
 
+  void SetYAxisTickLabels(
+      const std::vector<std::pair<float, std::string>>& labels);
+
   // Sets the title of the plot.
   void SetTitle(const std::string& title);
 
@@ -162,6 +165,7 @@ class Plot {
   float yaxis_min_;
   float yaxis_max_;
   std::string yaxis_label_;
+  std::vector<std::pair<float, std::string>> yaxis_tick_labels_;
   std::string title_;
   std::string id_;
   std::vector<TimeSeries> series_list_;

rtc_tools/event_log_visualizer/plot_protobuf.cc

@@ -60,6 +60,12 @@ void ProtobufPlot::ExportProtobuf(webrtc::analytics::Chart* chart) {
   chart->set_yaxis_label(yaxis_label_);
   chart->set_title(title_);
   chart->set_id(id_);
+
+  for (const auto& kv : yaxis_tick_labels_) {
+    webrtc::analytics::TickLabel* tick = chart->add_yaxis_tick_labels();
+    tick->set_value(kv.first);
+    tick->set_label(kv.second);
+  }
 }
 
 ProtobufPlotCollection::ProtobufPlotCollection() {}

rtc_tools/event_log_visualizer/plot_python.cc

@@ -150,6 +150,17 @@ void PythonPlot::Draw() {
   printf("plt.xlabel(\'%s\')\n", xaxis_label_.c_str());
   printf("plt.ylabel(\'%s\')\n", yaxis_label_.c_str());
   printf("plt.title(\'%s\')\n", title_.c_str());
+  printf("fig = plt.gcf()\n");
+  printf("fig.canvas.set_window_title(\'%s\')\n", id_.c_str());
+  if (!yaxis_tick_labels_.empty()) {
+    printf("yaxis_tick_labels = [");
+    for (const auto& kv : yaxis_tick_labels_) {
+      printf("(%f,\"%s\"),", kv.first, kv.second.c_str());
+    }
+    printf("]\n");
+    printf("yaxis_tick_labels = list(zip(*yaxis_tick_labels))\n");
+    printf("plt.yticks(*yaxis_tick_labels)\n");
+  }
   if (!series_list_.empty() || !interval_list_.empty()) {
     printf("handles, labels = plt.gca().get_legend_handles_labels()\n");
     printf("for lp in legend_patches:\n");

rtc_tools/event_log_visualizer/proto/chart.proto

@@ -13,6 +13,11 @@ message DataSet {
   bool highlight_points = 5;
 }
 
+message TickLabel {
+  float value = 1;
+  string label = 2;
+}
+
 message Chart {
   repeated DataSet data_sets = 1;
   float xaxis_min = 2;
@@ -23,6 +28,7 @@ message Chart {
   string yaxis_label = 7;
   string title = 8;
   string id = 9;
+  repeated TickLabel yaxis_tick_labels = 10;
 }
 
 message ChartCollection {