Reference for ultralytics/solutions/analytics.py

def process_data(self, im0, frame_number):
    """
    Process the image data, run object tracking.

    Args:
        im0 (ndarray): Input image for processing.
        frame_number (int): Video frame # for plotting the data.
    """
    self.extract_tracks(im0)  # Extract tracks

    if self.type == "line":
        for box in self.boxes:
            self.total_counts += 1
        im0 = self.update_graph(frame_number=frame_number)
        self.total_counts = 0
    elif self.type == "pie" or self.type == "bar" or self.type == "area":
        self.clswise_count = {}
        for box, cls in zip(self.boxes, self.clss):
            if self.names[int(cls)] in self.clswise_count:
                self.clswise_count[self.names[int(cls)]] += 1
            else:
                self.clswise_count[self.names[int(cls)]] = 1
        im0 = self.update_graph(frame_number=frame_number, count_dict=self.clswise_count, plot=self.type)
    else:
        raise ModuleNotFoundError(f"{self.type} chart is not supported ❌")
    return im0

def update_graph(self, frame_number, count_dict=None, plot="line"):
    """
    Update the graph (line or area) with new data for single or multiple classes.

    Args:
        frame_number (int): The current frame number.
        count_dict (dict, optional): Dictionary with class names as keys and counts as values for multiple classes.
                                      If None, updates a single line graph.
        plot (str): Type of the plot i.e. line, bar or area.
    """
    if count_dict is None:
        # Single line update
        x_data = np.append(self.line.get_xdata(), float(frame_number))
        y_data = np.append(self.line.get_ydata(), float(self.total_counts))

        if len(x_data) > self.max_points:
            x_data, y_data = x_data[-self.max_points :], y_data[-self.max_points :]

        self.line.set_data(x_data, y_data)
        self.line.set_label("Counts")
        self.line.set_color("#7b0068")  # Pink color
        self.line.set_marker("*")
        self.line.set_markersize(self.line_width * 5)
    else:
        labels = list(count_dict.keys())
        counts = list(count_dict.values())
        if plot == "area":
            color_cycle = cycle(["#DD00BA", "#042AFF", "#FF4447", "#7D24FF", "#BD00FF"])
            # Multiple lines or area update
            x_data = self.ax.lines[0].get_xdata() if self.ax.lines else np.array([])
            y_data_dict = {key: np.array([]) for key in count_dict.keys()}
            if self.ax.lines:
                for line, key in zip(self.ax.lines, count_dict.keys()):
                    y_data_dict[key] = line.get_ydata()

            x_data = np.append(x_data, float(frame_number))
            max_length = len(x_data)
            for key in count_dict.keys():
                y_data_dict[key] = np.append(y_data_dict[key], float(count_dict[key]))
                if len(y_data_dict[key]) < max_length:
                    y_data_dict[key] = np.pad(y_data_dict[key], (0, max_length - len(y_data_dict[key])), "constant")
            if len(x_data) > self.max_points:
                x_data = x_data[1:]
                for key in count_dict.keys():
                    y_data_dict[key] = y_data_dict[key][1:]

            self.ax.clear()
            for key, y_data in y_data_dict.items():
                color = next(color_cycle)
                self.ax.fill_between(x_data, y_data, color=color, alpha=0.7)
                self.ax.plot(
                    x_data,
                    y_data,
                    color=color,
                    linewidth=self.line_width,
                    marker="o",
                    markersize=self.line_width * 5,
                    label=f"{key} Data Points",
                )
        if plot == "bar":
            self.ax.clear()  # clear bar data
            for label in labels:  # Map labels to colors
                if label not in self.color_mapping:
                    self.color_mapping[label] = next(self.color_cycle)
            colors = [self.color_mapping[label] for label in labels]
            bars = self.ax.bar(labels, counts, color=colors)
            for bar, count in zip(bars, counts):
                self.ax.text(
                    bar.get_x() + bar.get_width() / 2,
                    bar.get_height(),
                    str(count),
                    ha="center",
                    va="bottom",
                    color=self.fg_color,
                )
            # Create the legend using labels from the bars
            for bar, label in zip(bars, labels):
                bar.set_label(label)  # Assign label to each bar
            self.ax.legend(loc="upper left", fontsize=13, facecolor=self.fg_color, edgecolor=self.fg_color)
        if plot == "pie":
            total = sum(counts)
            percentages = [size / total * 100 for size in counts]
            start_angle = 90
            self.ax.clear()

            # Create pie chart and create legend labels with percentages
            wedges, autotexts = self.ax.pie(
                counts, labels=labels, startangle=start_angle, textprops={"color": self.fg_color}, autopct=None
            )
            legend_labels = [f"{label} ({percentage:.1f}%)" for label, percentage in zip(labels, percentages)]

            # Assign the legend using the wedges and manually created labels
            self.ax.legend(wedges, legend_labels, title="Classes", loc="center left", bbox_to_anchor=(1, 0, 0.5, 1))
            self.fig.subplots_adjust(left=0.1, right=0.75)  # Adjust layout to fit the legend

    # Common plot settings
    self.ax.set_facecolor("#f0f0f0")  # Set to light gray or any other color you like
    self.ax.set_title(self.title, color=self.fg_color, fontsize=self.fontsize)
    self.ax.set_xlabel(self.x_label, color=self.fg_color, fontsize=self.fontsize - 3)
    self.ax.set_ylabel(self.y_label, color=self.fg_color, fontsize=self.fontsize - 3)

    # Add and format legend
    legend = self.ax.legend(loc="upper left", fontsize=13, facecolor=self.bg_color, edgecolor=self.bg_color)
    for text in legend.get_texts():
        text.set_color(self.fg_color)

    # Redraw graph, update view, capture, and display the updated plot
    self.ax.relim()
    self.ax.autoscale_view()
    self.canvas.draw()
    im0 = np.array(self.canvas.renderer.buffer_rgba())
    im0 = cv2.cvtColor(im0[:, :, :3], cv2.COLOR_RGBA2BGR)
    self.display_output(im0)

    return im0  # Return the image