plots.py

# Ultralytics 🚀 AGPL-3.0 License - https://ultralytics.com/license

import contextlib
import math
from pathlib import Path

import cv2
import matplotlib.pyplot as plt
import numpy as np
import pandas as pd
import torch

from .. import threaded
from ..general import xywh2xyxy
from ..plots import Annotator, colors


@threaded
def plot_images_and_masks(images, targets, masks, paths=None, fname="images.jpg", names=None):
    """Plots a grid of images with annotations and masks, optionally resizing and saving the result."""
    if isinstance(images, torch.Tensor):
        images = images.cpu().float().numpy()
    if isinstance(targets, torch.Tensor):
        targets = targets.cpu().numpy()
    if isinstance(masks, torch.Tensor):
        masks = masks.cpu().numpy().astype(int)

    max_size = 1920  # max image size
    max_subplots = 16  # max image subplots, i.e. 4x4
    bs, _, h, w = images.shape  # batch size, _, height, width
    bs = min(bs, max_subplots)  # limit plot images
    ns = np.ceil(bs**0.5)  # number of subplots (square)
    if np.max(images[0]) <= 1:
        images *= 255  # de-normalise (optional)

    # Build Image
    mosaic = np.full((int(ns * h), int(ns * w), 3), 255, dtype=np.uint8)  # init
    for i, im in enumerate(images):
        if i == max_subplots:  # if last batch has fewer images than we expect
            break
        x, y = int(w * (i // ns)), int(h * (i % ns))  # block origin
        im = im.transpose(1, 2, 0)
        mosaic[y : y + h, x : x + w, :] = im

    # Resize (optional)
    scale = max_size / ns / max(h, w)
    if scale < 1:
        h = math.ceil(scale * h)
        w = math.ceil(scale * w)
        mosaic = cv2.resize(mosaic, tuple(int(x * ns) for x in (w, h)))

    # Annotate
    fs = int((h + w) * ns * 0.01)  # font size
    annotator = Annotator(mosaic, line_width=round(fs / 10), font_size=fs, pil=True, example=names)
    for i in range(i + 1):
        x, y = int(w * (i // ns)), int(h * (i % ns))  # block origin
        annotator.rectangle([x, y, x + w, y + h], None, (255, 255, 255), width=2)  # borders
        if paths:
            annotator.text([x + 5, y + 5], text=Path(paths[i]).name[:40], txt_color=(220, 220, 220))  # filenames
        if len(targets) > 0:
            idx = targets[:, 0] == i
            ti = targets[idx]  # image targets

            boxes = xywh2xyxy(ti[:, 2:6]).T
            classes = ti[:, 1].astype("int")
            labels = ti.shape[1] == 6  # labels if no conf column
            conf = None if labels else ti[:, 6]  # check for confidence presence (label vs pred)

            if boxes.shape[1]:
                if boxes.max() <= 1.01:  # if normalized with tolerance 0.01
                    boxes[[0, 2]] *= w  # scale to pixels
                    boxes[[1, 3]] *= h
                elif scale < 1:  # absolute coords need scale if image scales
                    boxes *= scale
            boxes[[0, 2]] += x
            boxes[[1, 3]] += y
            for j, box in enumerate(boxes.T.tolist()):
                cls = classes[j]
                color = colors(cls)
                cls = names[cls] if names else cls
                if labels or conf[j] > 0.25:  # 0.25 conf thresh
                    label = f"{cls}" if labels else f"{cls} {conf[j]:.1f}"
                    annotator.box_label(box, label, color=color)

            # Plot masks
            if len(masks):
                if masks.max() > 1.0:  # mean that masks are overlap
                    image_masks = masks[[i]]  # (1, 640, 640)
                    nl = len(ti)
                    index = np.arange(nl).reshape(nl, 1, 1) + 1
                    image_masks = np.repeat(image_masks, nl, axis=0)
                    image_masks = np.where(image_masks == index, 1.0, 0.0)
                else:
                    image_masks = masks[idx]

                im = np.asarray(annotator.im).copy()
                for j, box in enumerate(boxes.T.tolist()):
                    if labels or conf[j] > 0.25:  # 0.25 conf thresh
                        color = colors(classes[j])
                        mh, mw = image_masks[j].shape
                        if mh != h or mw != w:
                            mask = image_masks[j].astype(np.uint8)
                            mask = cv2.resize(mask, (w, h))
                            mask = mask.astype(bool)
                        else:
                            mask = image_masks[j].astype(bool)
                        with contextlib.suppress(Exception):
                            im[y : y + h, x : x + w, :][mask] = (
                                im[y : y + h, x : x + w, :][mask] * 0.4 + np.array(color) * 0.6
                            )
                annotator.fromarray(im)
    annotator.im.save(fname)  # save


def plot_results_with_masks(file="path/to/results.csv", dir="", best=True):
    """Plots training results from CSV, highlighting best/last metrics; supports custom file paths and directory
    saving.
    """
    save_dir = Path(file).parent if file else Path(dir)
    fig, ax = plt.subplots(2, 8, figsize=(18, 6), tight_layout=True)
    ax = ax.ravel()
    files = list(save_dir.glob("results*.csv"))
    assert len(files), f"No results.csv files found in {save_dir.resolve()}, nothing to plot."
    for f in files:
        try:
            data = pd.read_csv(f)
            index = np.argmax(
                0.9 * data.values[:, 8] + 0.1 * data.values[:, 7] + 0.9 * data.values[:, 12] + 0.1 * data.values[:, 11]
            )
            s = [x.strip() for x in data.columns]
            x = data.values[:, 0]
            for i, j in enumerate([1, 2, 3, 4, 5, 6, 9, 10, 13, 14, 15, 16, 7, 8, 11, 12]):
                y = data.values[:, j]
                # y[y == 0] = np.nan  # don't show zero values
                ax[i].plot(x, y, marker=".", label=f.stem, linewidth=2, markersize=2)
                if best:
                    # best
                    ax[i].scatter(index, y[index], color="r", label=f"best:{index}", marker="*", linewidth=3)
                    ax[i].set_title(s[j] + f"\n{round(y[index], 5)}")
                else:
                    # last
                    ax[i].scatter(x[-1], y[-1], color="r", label="last", marker="*", linewidth=3)
                    ax[i].set_title(s[j] + f"\n{round(y[-1], 5)}")
                # if j in [8, 9, 10]:  # share train and val loss y axes
                #     ax[i].get_shared_y_axes().join(ax[i], ax[i - 5])
        except Exception as e:
            print(f"Warning: Plotting error for {f}: {e}")
    ax[1].legend()
    fig.savefig(save_dir / "results.png", dpi=200)
    plt.close()