Visualize simulated BWE as a piecewise constant function.
To facilitate this change, I replaced the graph style with one style
config for lines/interpolation and one style config for points.
The output functions were updated to make use of the new styles.
Bug: None
Change-Id: I42404a8ce274d6e433bcdd6aee4b15b640e78b40
Reviewed-on: https://webrtc-review.googlesource.com/22000
Reviewed-by: Niels Moller <nisse@webrtc.org>
Commit-Queue: Björn Terelius <terelius@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20645}diff --git a/rtc_tools/event_log_visualizer/analyzer.cc b/rtc_tools/event_log_visualizer/analyzer.cc
index c9750c8..c351b78 100644
--- a/rtc_tools/event_log_visualizer/analyzer.cc
+++ b/rtc_tools/event_log_visualizer/analyzer.cc
@@ -651,7 +651,7 @@
continue;
}
- TimeSeries time_series(GetStreamName(stream_id), BAR_GRAPH);
+ TimeSeries time_series(GetStreamName(stream_id), LineStyle::kBar);
ProcessPoints<LoggedRtpPacket>(
[](const LoggedRtpPacket& packet) -> rtc::Optional<float> {
return rtc::Optional<float>(packet.total_length);
@@ -686,7 +686,7 @@
}
std::string label = label_prefix + " " + GetStreamName(stream_id);
- TimeSeries time_series(label, LINE_STEP_GRAPH);
+ TimeSeries time_series(label, LineStyle::kStep);
for (size_t i = 0; i < packet_stream.size(); i++) {
float x = static_cast<float>(packet_stream[i].timestamp - begin_time_) /
1000000;
@@ -743,7 +743,7 @@
// Set labels and put in graph.
for (auto& kv : time_series) {
kv.second.label = SsrcToString(kv.first);
- kv.second.style = BAR_GRAPH;
+ kv.second.line_style = LineStyle::kBar;
plot->AppendTimeSeries(std::move(kv.second));
}
@@ -776,7 +776,7 @@
for (auto& series : time_series) {
series.second.label = GetStreamName(series.first);
- series.second.style = LINE_GRAPH;
+ series.second.line_style = LineStyle::kLine;
plot->AppendTimeSeries(std::move(series.second));
}
@@ -797,7 +797,7 @@
continue;
}
- TimeSeries time_series(GetStreamName(stream_id), BAR_GRAPH);
+ TimeSeries time_series(GetStreamName(stream_id), LineStyle::kBar);
ProcessPairs<LoggedRtpPacket, float>(
[](const LoggedRtpPacket& old_packet,
const LoggedRtpPacket& new_packet) {
@@ -827,7 +827,8 @@
continue;
}
- TimeSeries time_series(GetStreamName(stream_id), LINE_DOT_GRAPH);
+ TimeSeries time_series(GetStreamName(stream_id), LineStyle::kLine,
+ PointStyle::kHighlight);
const uint64_t kWindowUs = 1000000;
const uint64_t kStep = 1000000;
SequenceNumberUnwrapper unwrapper_;
@@ -886,14 +887,14 @@
}
TimeSeries capture_time_data(GetStreamName(stream_id) + " capture-time",
- BAR_GRAPH);
+ LineStyle::kBar);
ProcessPairs<LoggedRtpPacket, double>(NetworkDelayDiff_CaptureTime,
packet_stream, begin_time_,
&capture_time_data);
plot->AppendTimeSeries(std::move(capture_time_data));
TimeSeries send_time_data(GetStreamName(stream_id) + " abs-send-time",
- BAR_GRAPH);
+ LineStyle::kBar);
ProcessPairs<LoggedRtpPacket, double>(NetworkDelayDiff_AbsSendTime,
packet_stream, begin_time_,
&send_time_data);
@@ -919,14 +920,14 @@
}
TimeSeries capture_time_data(GetStreamName(stream_id) + " capture-time",
- LINE_GRAPH);
+ LineStyle::kLine);
AccumulatePairs<LoggedRtpPacket, double>(NetworkDelayDiff_CaptureTime,
packet_stream, begin_time_,
&capture_time_data);
plot->AppendTimeSeries(std::move(capture_time_data));
TimeSeries send_time_data(GetStreamName(stream_id) + " abs-send-time",
- LINE_GRAPH);
+ LineStyle::kLine);
AccumulatePairs<LoggedRtpPacket, double>(NetworkDelayDiff_AbsSendTime,
packet_stream, begin_time_,
&send_time_data);
@@ -941,7 +942,8 @@
// Plot the fraction of packets lost (as perceived by the loss-based BWE).
void EventLogAnalyzer::CreateFractionLossGraph(Plot* plot) {
- TimeSeries time_series("Fraction lost", LINE_DOT_GRAPH);
+ TimeSeries time_series("Fraction lost", LineStyle::kLine,
+ PointStyle::kHighlight);
for (auto& bwe_update : bwe_loss_updates_) {
float x = static_cast<float>(bwe_update.timestamp - begin_time_) / 1000000;
float y = static_cast<float>(bwe_update.fraction_loss) / 255 * 100;
@@ -988,7 +990,7 @@
size_t bytes_in_window = 0;
// Calculate a moving average of the bitrate and store in a TimeSeries.
- TimeSeries bitrate_series("Bitrate", LINE_GRAPH);
+ TimeSeries bitrate_series("Bitrate", LineStyle::kLine);
for (uint64_t time = begin_time_; time < end_time_ + step_; time += step_) {
while (window_index_end < packets.size() &&
packets[window_index_end].timestamp < time) {
@@ -1011,7 +1013,7 @@
// Overlay the send-side bandwidth estimate over the outgoing bitrate.
if (desired_direction == kOutgoingPacket) {
- TimeSeries loss_series("Loss-based estimate", LINE_STEP_GRAPH);
+ TimeSeries loss_series("Loss-based estimate", LineStyle::kStep);
for (auto& loss_update : bwe_loss_updates_) {
float x =
static_cast<float>(loss_update.timestamp - begin_time_) / 1000000;
@@ -1019,7 +1021,7 @@
loss_series.points.emplace_back(x, y);
}
- TimeSeries delay_series("Delay-based estimate", LINE_STEP_GRAPH);
+ TimeSeries delay_series("Delay-based estimate", LineStyle::kStep);
IntervalSeries overusing_series("Overusing", "#ff8e82",
IntervalSeries::kHorizontal);
IntervalSeries underusing_series("Underusing", "#5092fc",
@@ -1062,14 +1064,16 @@
RTC_CHECK(last_series);
last_series->intervals.emplace_back(last_detector_switch, end_time_);
- TimeSeries created_series("Probe cluster created.", DOT_GRAPH);
+ TimeSeries created_series("Probe cluster created.", LineStyle::kNone,
+ PointStyle::kHighlight);
for (auto& cluster : bwe_probe_cluster_created_events_) {
float x = static_cast<float>(cluster.timestamp - begin_time_) / 1000000;
float y = static_cast<float>(cluster.bitrate_bps) / 1000;
created_series.points.emplace_back(x, y);
}
- TimeSeries result_series("Probing results.", DOT_GRAPH);
+ TimeSeries result_series("Probing results.", LineStyle::kNone,
+ PointStyle::kHighlight);
for (auto& result : bwe_probe_result_events_) {
if (result.bitrate_bps) {
float x = static_cast<float>(result.timestamp - begin_time_) / 1000000;
@@ -1094,7 +1098,7 @@
// and outgoing REMB over incoming bitrate.
PacketDirection remb_direction =
desired_direction == kOutgoingPacket ? kIncomingPacket : kOutgoingPacket;
- TimeSeries remb_series("Remb", LINE_STEP_GRAPH);
+ TimeSeries remb_series("Remb", LineStyle::kStep);
std::multimap<uint64_t, const LoggedRtcpPacket*> remb_packets;
for (const auto& kv : rtcp_packets_) {
if (kv.first.GetDirection() == remb_direction) {
@@ -1138,7 +1142,7 @@
continue;
}
- TimeSeries time_series(GetStreamName(stream_id), LINE_GRAPH);
+ TimeSeries time_series(GetStreamName(stream_id), LineStyle::kLine);
MovingAverage<LoggedRtpPacket, double>(
[](const LoggedRtpPacket& packet) {
return rtc::Optional<double>(packet.total_length * 8.0 / 1000.0);
@@ -1186,10 +1190,12 @@
static const uint32_t kDefaultStartBitrateBps = 300000;
cc.SetBweBitrates(0, kDefaultStartBitrateBps, -1);
- TimeSeries time_series("Delay-based estimate", LINE_DOT_GRAPH);
- TimeSeries acked_time_series("Acked bitrate", LINE_DOT_GRAPH);
- TimeSeries acked_estimate_time_series("Acked bitrate estimate",
- LINE_DOT_GRAPH);
+ TimeSeries time_series("Delay-based estimate", LineStyle::kStep,
+ PointStyle::kHighlight);
+ TimeSeries acked_time_series("Acked bitrate", LineStyle::kLine,
+ PointStyle::kHighlight);
+ TimeSeries acked_estimate_time_series(
+ "Acked bitrate estimate", LineStyle::kLine, PointStyle::kHighlight);
auto rtp_iterator = outgoing_rtp.begin();
auto rtcp_iterator = incoming_rtcp.begin();
@@ -1337,8 +1343,9 @@
// static const uint32_t kDefaultStartBitrateBps = 300000;
// rscc.SetBweBitrates(0, kDefaultStartBitrateBps, -1);
- TimeSeries time_series("Receive side estimate", LINE_DOT_GRAPH);
- TimeSeries acked_time_series("Received bitrate", LINE_GRAPH);
+ TimeSeries time_series("Receive side estimate", LineStyle::kLine,
+ PointStyle::kHighlight);
+ TimeSeries acked_time_series("Received bitrate", LineStyle::kLine);
RateStatistics acked_bitrate(250, 8000);
int64_t last_update_us = 0;
@@ -1397,8 +1404,10 @@
SimulatedClock clock(0);
TransportFeedbackAdapter feedback_adapter(&clock);
- TimeSeries late_feedback_series("Late feedback results.", DOT_GRAPH);
- TimeSeries time_series("Network Delay Change", LINE_DOT_GRAPH);
+ TimeSeries late_feedback_series("Late feedback results.", LineStyle::kNone,
+ PointStyle::kHighlight);
+ TimeSeries time_series("Network Delay Change", LineStyle::kLine,
+ PointStyle::kHighlight);
int64_t estimated_base_delay_ms = std::numeric_limits<int64_t>::max();
auto rtp_iterator = outgoing_rtp.begin();
@@ -1530,7 +1539,7 @@
TimeSeries pacer_delay_series(
GetStreamName(stream_id) + "(" +
std::to_string(*estimated_frequency / 1000) + " kHz)",
- LINE_DOT_GRAPH);
+ LineStyle::kLine, PointStyle::kHighlight);
SeqNumUnwrapper<uint32_t> timestamp_unwrapper;
uint64_t first_capture_timestamp =
timestamp_unwrapper.Unwrap(packets.front().header.timestamp);
@@ -1562,7 +1571,7 @@
{
TimeSeries timestamp_data(GetStreamName(stream_id) + " capture-time",
- LINE_DOT_GRAPH);
+ LineStyle::kLine, PointStyle::kHighlight);
for (LoggedRtpPacket packet : rtp_packets) {
float x = static_cast<float>(packet.timestamp - begin_time_) / 1000000;
float y = packet.header.timestamp;
@@ -1576,7 +1585,8 @@
if (kv != rtcp_packets_.end()) {
const auto& packets = kv->second;
TimeSeries timestamp_data(
- GetStreamName(stream_id) + " rtcp capture-time", LINE_DOT_GRAPH);
+ GetStreamName(stream_id) + " rtcp capture-time", LineStyle::kLine,
+ PointStyle::kHighlight);
for (const LoggedRtcpPacket& rtcp : packets) {
if (rtcp.type != kRtcpSr)
continue;
@@ -1597,7 +1607,8 @@
}
void EventLogAnalyzer::CreateAudioEncoderTargetBitrateGraph(Plot* plot) {
- TimeSeries time_series("Audio encoder target bitrate", LINE_DOT_GRAPH);
+ TimeSeries time_series("Audio encoder target bitrate", LineStyle::kLine,
+ PointStyle::kHighlight);
ProcessPoints<AudioNetworkAdaptationEvent>(
[](const AudioNetworkAdaptationEvent& ana_event) -> rtc::Optional<float> {
if (ana_event.config.bitrate_bps)
@@ -1613,7 +1624,8 @@
}
void EventLogAnalyzer::CreateAudioEncoderFrameLengthGraph(Plot* plot) {
- TimeSeries time_series("Audio encoder frame length", LINE_DOT_GRAPH);
+ TimeSeries time_series("Audio encoder frame length", LineStyle::kLine,
+ PointStyle::kHighlight);
ProcessPoints<AudioNetworkAdaptationEvent>(
[](const AudioNetworkAdaptationEvent& ana_event) {
if (ana_event.config.frame_length_ms)
@@ -1630,7 +1642,7 @@
void EventLogAnalyzer::CreateAudioEncoderPacketLossGraph(Plot* plot) {
TimeSeries time_series("Audio encoder uplink packet loss fraction",
- LINE_DOT_GRAPH);
+ LineStyle::kLine, PointStyle::kHighlight);
ProcessPoints<AudioNetworkAdaptationEvent>(
[](const AudioNetworkAdaptationEvent& ana_event) {
if (ana_event.config.uplink_packet_loss_fraction)
@@ -1647,7 +1659,8 @@
}
void EventLogAnalyzer::CreateAudioEncoderEnableFecGraph(Plot* plot) {
- TimeSeries time_series("Audio encoder FEC", LINE_DOT_GRAPH);
+ TimeSeries time_series("Audio encoder FEC", LineStyle::kLine,
+ PointStyle::kHighlight);
ProcessPoints<AudioNetworkAdaptationEvent>(
[](const AudioNetworkAdaptationEvent& ana_event) {
if (ana_event.config.enable_fec)
@@ -1663,7 +1676,8 @@
}
void EventLogAnalyzer::CreateAudioEncoderEnableDtxGraph(Plot* plot) {
- TimeSeries time_series("Audio encoder DTX", LINE_DOT_GRAPH);
+ TimeSeries time_series("Audio encoder DTX", LineStyle::kLine,
+ PointStyle::kHighlight);
ProcessPoints<AudioNetworkAdaptationEvent>(
[](const AudioNetworkAdaptationEvent& ana_event) {
if (ana_event.config.enable_dtx)
@@ -1679,7 +1693,8 @@
}
void EventLogAnalyzer::CreateAudioEncoderNumChannelsGraph(Plot* plot) {
- TimeSeries time_series("Audio encoder number of channels", LINE_DOT_GRAPH);
+ TimeSeries time_series("Audio encoder number of channels", LineStyle::kLine,
+ PointStyle::kHighlight);
ProcessPoints<AudioNetworkAdaptationEvent>(
[](const AudioNetworkAdaptationEvent& ana_event) {
if (ana_event.config.num_channels)
@@ -1914,19 +1929,20 @@
RTC_DCHECK_EQ(time_series_relative_packet_arrival.size(), 1);
for (auto& series : time_series_relative_packet_arrival) {
series.second.label = "Relative packet arrival delay";
- series.second.style = LINE_GRAPH;
+ series.second.line_style = LineStyle::kLine;
plot->AppendTimeSeries(std::move(series.second));
}
RTC_DCHECK_EQ(time_series_play_time.size(), 1);
for (auto& series : time_series_play_time) {
series.second.label = "Playout delay";
- series.second.style = LINE_GRAPH;
+ series.second.line_style = LineStyle::kLine;
plot->AppendTimeSeries(std::move(series.second));
}
RTC_DCHECK_EQ(time_series_target_time.size(), 1);
for (auto& series : time_series_target_time) {
series.second.label = "Target delay";
- series.second.style = LINE_DOT_GRAPH;
+ series.second.line_style = LineStyle::kLine;
+ series.second.point_style = PointStyle::kHighlight;
plot->AppendTimeSeries(std::move(series.second));
}
diff --git a/rtc_tools/event_log_visualizer/plot_base.h b/rtc_tools/event_log_visualizer/plot_base.h
index 318d425..700ffbf 100644
--- a/rtc_tools/event_log_visualizer/plot_base.h
+++ b/rtc_tools/event_log_visualizer/plot_base.h
@@ -18,12 +18,16 @@
namespace webrtc {
namespace plotting {
-enum PlotStyle {
- LINE_GRAPH,
- LINE_DOT_GRAPH,
- BAR_GRAPH,
- LINE_STEP_GRAPH,
- DOT_GRAPH
+enum class LineStyle {
+ kNone, // No line connecting the points. Used to create scatter plots.
+ kLine, // Straight line between consecutive points.
+ kStep, // Horizontal line until the next value. Used for state changes.
+ kBar // Vertical bars from the x-axis to the point.
+};
+
+enum class PointStyle {
+ kNone, // Don't draw the points.
+ kHighlight // Draw circles or dots to highlight the points.
};
struct TimeSeriesPoint {
@@ -33,23 +37,31 @@
};
struct TimeSeries {
- TimeSeries() = default;
- TimeSeries(const char* label, PlotStyle style) : label(label), style(style) {}
- TimeSeries(const std::string& label, PlotStyle style)
- : label(label), style(style) {}
+ TimeSeries() = default; // TODO(terelius): Remove the default constructor.
+ TimeSeries(const char* label,
+ LineStyle line_style,
+ PointStyle point_style = PointStyle::kNone)
+ : label(label), line_style(line_style), point_style(point_style) {}
+ TimeSeries(const std::string& label,
+ LineStyle line_style,
+ PointStyle point_style = PointStyle::kNone)
+ : label(label), line_style(line_style), point_style(point_style) {}
TimeSeries(TimeSeries&& other)
: label(std::move(other.label)),
- style(other.style),
+ line_style(other.line_style),
+ point_style(other.point_style),
points(std::move(other.points)) {}
TimeSeries& operator=(TimeSeries&& other) {
label = std::move(other.label);
- style = other.style;
+ line_style = other.line_style;
+ point_style = other.point_style;
points = std::move(other.points);
return *this;
}
std::string label;
- PlotStyle style;
+ LineStyle line_style = LineStyle::kLine;
+ PointStyle point_style = PointStyle::kNone;
std::vector<TimeSeriesPoint> points;
};
diff --git a/rtc_tools/event_log_visualizer/plot_protobuf.cc b/rtc_tools/event_log_visualizer/plot_protobuf.cc
index 1316f63..e5e0a8b 100644
--- a/rtc_tools/event_log_visualizer/plot_protobuf.cc
+++ b/rtc_tools/event_log_visualizer/plot_protobuf.cc
@@ -31,22 +31,21 @@
data_set->add_y_values(point.y);
}
- if (series_list_[i].style == BAR_GRAPH) {
+ if (series_list_[i].line_style == LineStyle::kBar) {
data_set->set_style(webrtc::analytics::ChartStyle::BAR_CHART);
- } else if (series_list_[i].style == LINE_GRAPH) {
+ } else if (series_list_[i].line_style == LineStyle::kLine) {
data_set->set_style(webrtc::analytics::ChartStyle::LINE_CHART);
- } else if (series_list_[i].style == LINE_DOT_GRAPH) {
- data_set->set_style(webrtc::analytics::ChartStyle::LINE_CHART);
- data_set->set_highlight_points(true);
- } else if (series_list_[i].style == LINE_STEP_GRAPH) {
+ } else if (series_list_[i].line_style == LineStyle::kStep) {
data_set->set_style(webrtc::analytics::ChartStyle::LINE_STEP_CHART);
- } else if (series_list_[i].style == DOT_GRAPH) {
+ } else if (series_list_[i].line_style == LineStyle::kNone) {
data_set->set_style(webrtc::analytics::ChartStyle::SCATTER_CHART);
- data_set->set_highlight_points(true);
} else {
data_set->set_style(webrtc::analytics::ChartStyle::UNDEFINED);
}
+ if (series_list_[i].point_style == PointStyle::kHighlight)
+ data_set->set_highlight_points(true);
+
data_set->set_label(series_list_[i].label);
}
diff --git a/rtc_tools/event_log_visualizer/plot_python.cc b/rtc_tools/event_log_visualizer/plot_python.cc
index f8643ca..58fad10 100644
--- a/rtc_tools/event_log_visualizer/plot_python.cc
+++ b/rtc_tools/event_log_visualizer/plot_python.cc
@@ -32,7 +32,7 @@
printf(
"hls_colors = [(i*1.0/color_count, 0.25+i*0.5/color_count, 0.8) for i "
"in range(color_count)]\n");
- printf("rgb_colors = [colorsys.hls_to_rgb(*hls) for hls in hls_colors]\n");
+ printf("colors = [colorsys.hls_to_rgb(*hls) for hls in hls_colors]\n");
for (size_t i = 0; i < series_list_.size(); i++) {
printf("\n# === Series: %s ===\n", series_list_[i].label.c_str());
@@ -52,37 +52,49 @@
printf(", %G", series_list_[i].points[j].y);
printf("]\n");
- if (series_list_[i].style == BAR_GRAPH) {
+ if (series_list_[i].line_style == LineStyle::kBar) {
// There is a plt.bar function that draws bar plots,
// but it is *way* too slow to be useful.
printf(
"plt.vlines(x%zu, map(lambda t: min(t,0), y%zu), map(lambda t: "
- "max(t,0), y%zu), color=rgb_colors[%zu], "
+ "max(t,0), y%zu), color=colors[%zu], "
"label=\'%s\')\n",
i, i, i, i, series_list_[i].label.c_str());
- } else if (series_list_[i].style == LINE_GRAPH) {
- printf("plt.plot(x%zu, y%zu, color=rgb_colors[%zu], label=\'%s\')\n", i,
- i, i, series_list_[i].label.c_str());
- } else if (series_list_[i].style == LINE_DOT_GRAPH) {
- printf(
- "plt.plot(x%zu, y%zu, color=rgb_colors[%zu], label=\'%s\', "
- "marker='.')\n",
- i, i, i, series_list_[i].label.c_str());
- } else if (series_list_[i].style == LINE_STEP_GRAPH) {
+ if (series_list_[i].point_style == PointStyle::kHighlight) {
+ printf(
+ "plt.plot(x%zu, y%zu, color=colors[%zu], "
+ "marker='.', ls=' ')\n",
+ i, i, i);
+ }
+ } else if (series_list_[i].line_style == LineStyle::kLine) {
+ if (series_list_[i].point_style == PointStyle::kHighlight) {
+ printf(
+ "plt.plot(x%zu, y%zu, color=colors[%zu], label=\'%s\', "
+ "marker='.')\n",
+ i, i, i, series_list_[i].label.c_str());
+ } else {
+ printf("plt.plot(x%zu, y%zu, color=colors[%zu], label=\'%s\')\n", i,
+ i, i, series_list_[i].label.c_str());
+ }
+ } else if (series_list_[i].line_style == LineStyle::kStep) {
// Draw lines from (x[0],y[0]) to (x[1],y[0]) to (x[1],y[1]) and so on
// to illustrate the "steps". This can be expressed by duplicating all
// elements except the first in x and the last in y.
- printf("x%zu = [v for dup in x%zu for v in [dup, dup]]\n", i, i);
- printf("y%zu = [v for dup in y%zu for v in [dup, dup]]\n", i, i);
+ printf("xd%zu = [dup for v in x%zu for dup in [v, v]]\n", i, i);
+ printf("yd%zu = [dup for v in y%zu for dup in [v, v]]\n", i, i);
printf(
- "plt.plot(x%zu[1:], y%zu[:-1], color=rgb_colors[%zu], "
- "path_effects=[pe.Stroke(linewidth=2, foreground='black'), "
- "pe.Normal()], "
+ "plt.plot(xd%zu[1:], yd%zu[:-1], color=colors[%zu], "
"label=\'%s\')\n",
i, i, i, series_list_[i].label.c_str());
- } else if (series_list_[i].style == DOT_GRAPH) {
+ if (series_list_[i].point_style == PointStyle::kHighlight) {
+ printf(
+ "plt.plot(x%zu, y%zu, color=colors[%zu], "
+ "marker='.', ls=' ')\n",
+ i, i, i);
+ }
+ } else if (series_list_[i].line_style == LineStyle::kNone) {
printf(
- "plt.plot(x%zu, y%zu, color=rgb_colors[%zu], label=\'%s\', "
+ "plt.plot(x%zu, y%zu, color=colors[%zu], label=\'%s\', "
"marker='o', ls=' ')\n",
i, i, i, series_list_[i].label.c_str());
} else {
@@ -93,7 +105,7 @@
// IntervalSeries
printf("interval_colors = ['#ff8e82','#5092fc','#c4ffc4']\n");
RTC_CHECK_LE(interval_list_.size(), 3);
- // To get the intervals to show up in the legend we have to created patches
+ // To get the intervals to show up in the legend we have to create patches
// for them.
printf("legend_patches = []\n");
for (size_t i = 0; i < interval_list_.size(); i++) {