plots.py

import torch
import torch.nn.functional as F
import cv2
from PIL import Image
import numpy as np


class Colors:
    def __init__(self):
        # hexs = matplotlib.colors.TABLEAU_COLORS.values()
        hexs = (
            "00FF00",  # aorta class 0
            "FF3838",
            "FF701F",
            "FFB21D",
            "CFD231",
            "48F90A",
            "92CC17",
            "3DDB86",
            "1A9334",
            "00D4BB",
            "2C99A8",
            "00C2FF",
            "344593",
            "6473FF",
            "0018EC",
            "8438FF",
            "520085",
            "CB38FF",
            "FF95C8",
            "FF37C7",
        )
        self.palette = [self.hex2rgb(f"#{c}") for c in hexs]
        self.n = len(self.palette)

    def __call__(self, i, bgr=False):
        c = self.palette[int(i) % self.n]
        return (c[2], c[1], c[0]) if bgr else c

    @staticmethod
    def hex2rgb(h):  # rgb order (PIL)
        return tuple(int(h[1 + i : 1 + i + 2], 16) for i in (0, 2, 4))


colors = Colors()  # create instance for 'from utils.plots import colors'


def is_ascii(s=""):
    # Is string composed of all ASCII (no UTF) characters? (note str().isascii() introduced in python 3.7)
    s = str(s)  # convert list, tuple, None, etc. to str
    return len(s.encode().decode("ascii", "ignore")) == len(s)


def clip_boxes(boxes, shape):
    # Clip boxes (xyxy) to image shape (height, width)
    if isinstance(boxes, torch.Tensor):  # faster individually
        boxes[:, 0].clamp_(0, shape[1])  # x1
        boxes[:, 1].clamp_(0, shape[0])  # y1
        boxes[:, 2].clamp_(0, shape[1])  # x2
        boxes[:, 3].clamp_(0, shape[0])  # y2
    else:  # np.array (faster grouped)
        boxes[:, [0, 2]] = boxes[:, [0, 2]].clip(0, shape[1])  # x1, x2
        boxes[:, [1, 3]] = boxes[:, [1, 3]].clip(0, shape[0])  # y1, y2


def scale_boxes(img1_shape, boxes, img0_shape, ratio_pad=None):
    # Rescale boxes (xyxy) from img1_shape to img0_shape
    if ratio_pad is None:  # calculate from img0_shape
        gain = min(
            img1_shape[0] / img0_shape[0], img1_shape[1] / img0_shape[1]
        )  # gain  = old / new
        pad = (img1_shape[1] - img0_shape[1] * gain) / 2, (
            img1_shape[0] - img0_shape[0] * gain
        ) / 2  # wh padding
    else:
        gain = ratio_pad[0][0]
        pad = ratio_pad[1]

    boxes[:, [0, 2]] -= pad[0]  # x padding
    boxes[:, [1, 3]] -= pad[1]  # y padding
    boxes[:, :4] /= gain
    clip_boxes(boxes, img0_shape)
    return boxes


def crop_mask(masks, boxes):
    """
    "Crop" predicted masks by zeroing out everything not in the predicted bbox.
    Vectorized by Chong (thanks Chong).
    Args:
        - masks should be a size [h, w, n] tensor of masks
        - boxes should be a size [n, 4] tensor of bbox coords in relative point form
    """

    n, h, w = masks.shape
    x1, y1, x2, y2 = torch.chunk(boxes[:, :, None], 4, 1)  # x1 shape(1,1,n)
    r = torch.arange(w, device=masks.device, dtype=x1.dtype)[
        None, None, :
    ]  # rows shape(1,w,1)
    c = torch.arange(h, device=masks.device, dtype=x1.dtype)[
        None, :, None
    ]  # cols shape(h,1,1)

    return masks * ((r >= x1) * (r < x2) * (c >= y1) * (c < y2))


def process_mask(protos, masks_in, bboxes, shape, upsample=False):
    """
    Crop before upsample.
    proto_out: [mask_dim, mask_h, mask_w]
    out_masks: [n, mask_dim], n is number of masks after nms
    bboxes: [n, 4], n is number of masks after nms
    shape:input_image_size, (h, w)
    return: h, w, n
    """

    c, mh, mw = protos.shape  # CHW
    ih, iw = shape
    masks = (masks_in @ protos.float().view(c, -1)).sigmoid().view(-1, mh, mw)  # CHW

    downsampled_bboxes = bboxes.clone()
    downsampled_bboxes[:, 0] *= mw / iw
    downsampled_bboxes[:, 2] *= mw / iw
    downsampled_bboxes[:, 3] *= mh / ih
    downsampled_bboxes[:, 1] *= mh / ih

    masks = crop_mask(masks, downsampled_bboxes)  # CHW
    if upsample:
        masks = F.interpolate(masks[None], shape, mode="bilinear", align_corners=False)[
            0
        ]  # CHW
    return masks.gt_(0.5)


def scale_image(im1_shape, masks, im0_shape, ratio_pad=None):
    """
    img1_shape: model input shape, [h, w]
    img0_shape: origin pic shape, [h, w, 3]
    masks: [h, w, num]
    """
    # Rescale coordinates (xyxy) from im1_shape to im0_shape
    if ratio_pad is None:  # calculate from im0_shape
        gain = min(
            im1_shape[0] / im0_shape[0], im1_shape[1] / im0_shape[1]
        )  # gain  = old / new
        pad = (im1_shape[1] - im0_shape[1] * gain) / 2, (
            im1_shape[0] - im0_shape[0] * gain
        ) / 2  # wh padding
    else:
        pad = ratio_pad[1]
    top, left = int(pad[1]), int(pad[0])  # y, x
    bottom, right = int(im1_shape[0] - pad[1]), int(im1_shape[1] - pad[0])

    if len(masks.shape) < 2:
        raise ValueError(
            f'"len of masks shape" should be 2 or 3, but got {len(masks.shape)}'
        )
    masks = masks[top:bottom, left:right]
    # masks = masks.permute(2, 0, 1).contiguous()
    # masks = F.interpolate(masks[None], im0_shape[:2], mode='bilinear', align_corners=False)[0]
    # masks = masks.permute(1, 2, 0).contiguous()
    masks = cv2.resize(masks, (im0_shape[1], im0_shape[0]))

    if len(masks.shape) == 2:
        masks = masks[:, :, None]
    return masks


class Annotator:
    # YOLOv5 Annotator for train/val mosaics and jpgs and detect/hub inference annotations
    def __init__(
        self,
        im,
        line_width=None,
        font_size=None,
        font="Arial.ttf",
        pil=False,
        example="abc",
    ):
        assert (
            im.data.contiguous
        ), "Image not contiguous. Apply np.ascontiguousarray(im) to Annotator() input images."
        non_ascii = not is_ascii(
            example
        )  # non-latin labels, i.e. asian, arabic, cyrillic
        self.pil = pil or non_ascii
        if self.pil:  # use PIL
            self.im = im if isinstance(im, Image.Image) else Image.fromarray(im)
            self.draw = ImageDraw.Draw(self.im)
            self.font = check_pil_font(
                font="Arial.Unicode.ttf" if non_ascii else font,
                size=font_size or max(round(sum(self.im.size) / 2 * 0.035), 12),
            )
        else:  # use cv2
            self.im = im
        self.lw = line_width or max(round(sum(im.shape) / 2 * 0.003), 2)  # line width

    def box_label(
        self, box, label="", color=(128, 128, 128), txt_color=(255, 255, 255)
    ):
        # Add one xyxy box to image with label
        if self.pil or not is_ascii(label):
            self.draw.rectangle(box, width=self.lw, outline=color)  # box
            if label:
                w, h = self.font.getsize(label)  # text width, height
                outside = box[1] - h >= 0  # label fits outside box
                self.draw.rectangle(
                    (
                        box[0],
                        box[1] - h if outside else box[1],
                        box[0] + w + 1,
                        box[1] + 1 if outside else box[1] + h + 1,
                    ),
                    fill=color,
                )
                # self.draw.text((box[0], box[1]), label, fill=txt_color, font=self.font, anchor='ls')  # for PIL>8.0
                self.draw.text(
                    (box[0], box[1] - h if outside else box[1]),
                    label,
                    fill=txt_color,
                    font=self.font,
                )
        else:  # cv2
            p1, p2 = (int(box[0]), int(box[1])), (int(box[2]), int(box[3]))
            cv2.rectangle(
                self.im, p1, p2, color, thickness=self.lw, lineType=cv2.LINE_AA
            )
            if label:
                tf = max(self.lw - 1, 1)  # font thickness
                w, h = cv2.getTextSize(label, 0, fontScale=self.lw / 3, thickness=tf)[
                    0
                ]  # text width, height
                outside = p1[1] - h >= 3
                p2 = p1[0] + w, p1[1] - h - 3 if outside else p1[1] + h + 3
                cv2.rectangle(self.im, p1, p2, color, -1, cv2.LINE_AA)  # filled
                cv2.putText(
                    self.im,
                    label,
                    (p1[0], p1[1] - 2 if outside else p1[1] + h + 2),
                    0,
                    self.lw / 3,
                    txt_color,
                    thickness=tf,
                    lineType=cv2.LINE_AA,
                )

    def masks(self, masks, colors, im_gpu, alpha=0.5, retina_masks=False):
        """Plot masks at once.
        Args:
            masks (tensor): predicted masks on cuda, shape: [n, h, w]
            colors (List[List[Int]]): colors for predicted masks, [[r, g, b] * n]
            im_gpu (tensor): img is in cuda, shape: [3, h, w], range: [0, 1]
            alpha (float): mask transparency: 0.0 fully transparent, 1.0 opaque
        """
        im_gpu = torch.from_numpy(im_gpu)  # not sure why we need this fix?
        # print(im_gpu)
        if self.pil:
            # convert to numpy first
            self.im = np.asarray(self.im).copy()
        if len(masks) == 0:
            self.im[:] = im_gpu.permute(1, 2, 0).contiguous().cpu().numpy() * 255
        colors = torch.tensor(colors, device=im_gpu.device, dtype=torch.float32) / 255.0
        colors = colors[:, None, None]  # shape(n,1,1,3)
        masks = masks.unsqueeze(3)  # shape(n,h,w,1)
        masks_color = masks * (colors * alpha)  # shape(n,h,w,3)

        inv_alph_masks = (1 - masks * alpha).cumprod(0)  # shape(n,h,w,1)
        mcs = (masks_color * inv_alph_masks).sum(
            0
        ) * 2  # mask color summand shape(n,h,w,3)

        im_gpu = im_gpu.flip(dims=[0])  # flip channel
        im_gpu = im_gpu.permute(1, 2, 0).contiguous()  # shape(h,w,3)
        im_gpu = im_gpu * inv_alph_masks[-1] + mcs
        im_mask = (im_gpu * 255).byte().cpu().numpy()
        self.im[:] = (
            im_mask
            if retina_masks
            else scale_image(im_gpu.shape, im_mask, self.im.shape)
        )
        if self.pil:
            # convert im back to PIL and update draw
            self.fromarray(self.im)

    def rectangle(self, xy, fill=None, outline=None, width=1):
        # Add rectangle to image (PIL-only)
        self.draw.rectangle(xy, fill, outline, width)

    def text(self, xy, text, txt_color=(255, 255, 255), anchor="top"):
        # Add text to image (PIL-only)
        if anchor == "bottom":  # start y from font bottom
            w, h = self.font.getsize(text)  # text width, height
            xy[1] += 1 - h
        self.draw.text(xy, text, fill=txt_color, font=self.font)

    def fromarray(self, im):
        # Update self.im from a numpy array
        self.im = im if isinstance(im, Image.Image) else Image.fromarray(im)
        self.draw = ImageDraw.Draw(self.im)

    def result(self):
        # Return annotated image as array
        return np.asarray(self.im)