instance-labeler/app/canvas.tsx

'use client';
import { useState, useRef, useEffect } from 'react';
import axios from 'axios';
import useImage from 'use-image';
import Konva from 'konva';
import { Stage, Image, Layer } from 'react-konva';
import { BASE_URL } from './constants';
import Dropdown from './dropdown';


interface RGB {
  r: number;
  g: number;
  b: number;
}

interface Box {
  x: number;
  y: number;
  width: number;
  height: number;
}

const maskFilter = (imageData: ImageData, color: RGB) => {
  const nPixels = imageData.data.length;
  for (let i = 0; i < nPixels; i += 4) {
    const r = imageData.data[i];
    const g = imageData.data[i + 1];
    const b = imageData.data[i + 2];

    if (r === 0 && g === 0 && b === 0) {
      imageData.data[i + 3] = 0;
    } else {
      imageData.data[i] = color.r;
      imageData.data[i + 1] = color.g;
      imageData.data[i + 2] = color.b;
      imageData.data[i + 3] = 128;
    }
  }
};

export default function Canvas({ imageUrl, imageName }: { imageUrl: string, imageName: string }) {
  const [image] = useImage(imageUrl, 'anonymous');
  const stageRef = useRef<Konva.Stage>(null);
  const layerRef = useRef<Konva.Layer>(null);
  const groupRef = useRef<Konva.Group[]>([]);

  const pointsRef = useRef<Array<[number, number]>>([]);
  const labelsRef = useRef<Array<number>>([]);

  const instanceColorsRef = useRef<string[]>([]);
  const [classList, setClassList] = useState<string[]>([]);
  const classOptionsRef = useRef<string[]>([]);
  const classSelectionRef = useRef<string>('');

  const [useLatest, setUseLatest] = useState<boolean>(false);
  const selectedInstanceRef = useRef<number>(-1);

  const [selectedInstanceStyle, setSelectedInstanceStyle] = useState<boolean>(false);

  const clearLayers = () => {
    groupRef.current.forEach((group) => {
      group.destroy();
    });
    groupRef.current = [];
    layerRef.current?.draw();
    pointsRef.current = [];
    labelsRef.current = [];
    instanceColorsRef.current = [Konva.Util.getRandomColor()];
    setClassList(_ => ([]));
  }

  useEffect(() => {
    clearLayers();
  }, [imageUrl]);

  const showMask = (data: string, group: Konva.Group) => {
    const layer = layerRef.current;
    if (!layer) return;

    const color = Konva.Util.getRGB(
      instanceColorsRef.current[instanceColorsRef.current.length - 1]
    );

    const width = image?.width;
    const height = image?.height;

    const maskObj = new window.Image();
    maskObj.onload = () => {
      const image = new Konva.Image({
        x: 0,
        y: 0,
        image: maskObj,
        width: width,
        height: height,
      });
      image.filters([(imageData: ImageData) => maskFilter(imageData, color)]);
      image.cache();

      group.add(image);

      if (groupRef.current.length === 0)
        groupRef.current.push(group);

      layer.add(group);
      layer.draw()
    };
    maskObj.src = `data:image/png;base64,${data}`;
    setUseLatest(true);
  }

  const showBox = (box: Box, group: Konva.Group) => {
    const layer = layerRef.current;
    if (!layer) return;

    const color = Konva.Util.getRGB(
      instanceColorsRef.current[instanceColorsRef.current.length - 1]
    );

    const width = image?.width;
    const height = image?.height;

    function rgbToHex(r, g, b) {
      return '#' + (1 << 24 | r << 16 | g << 8 | b).toString(16).slice(1);
    }

    const rect = new Konva.Rect({
      x: box.x,
      y: box.y,
      width: box.width,
      height: box.height,
      stroke: rgbToHex(color.r, color.g, color.b),
      storkeWidth: 2,
    });

    if (groupRef.current.length === 0)
      groupRef.current.push(group);
    group.add(rect);
    layer.add(group);
    layer.draw();
    setUseLatest(true);
  }

  const handleStageClick = async (e: Konva.KonvaEventObject<MouseEvent>) => {
    const stage = stageRef.current;
    const layer = layerRef.current;
    if (!stage || !layer) return;

    const pos = e.target.getStage()?.getPointerPosition();
    if (!pos) return;

    let labels = labelsRef.current;
    if (e.evt.button === 2) {
      labels = [...labels, 0];
    } else {
      labels = [...labels, 1];
    }
    labelsRef.current = labels;

    // re-draw last layer so we don't overlap masks on clicks
    if (groupRef.current.length > 0) {
      groupRef.current[groupRef.current.length - 1].destroy();
    } else {
      groupRef.current.push(new Konva.Group());
    }

    layer.draw();

    let points = pointsRef.current;
    points = [...points, [pos.x, pos.y]];
    pointsRef.current = points;

    const res = await axios.post(
      `${BASE_URL}/v1/get_label_preds/${imageName}`,
      {
        points: points,
        labels: labels,
      }
    );
    showMask(res.data.masks[0], groupRef.current[groupRef.current.length - 1]);
  }

  const pinInstance = async () => {
    const layer = layerRef.current;
    if (!layer) return;

    const groupList = groupRef.current;
    // if (groupList.length === 0) return;

    if (classSelectionRef.current === '') {
      alert('Please select a class');
    } else {
      groupList.push(new Konva.Group());
      pointsRef.current = [];
      labelsRef.current = [];
      instanceColorsRef.current.push(Konva.Util.getRandomColor());
      setClassList(prev => ([...prev, classSelectionRef.current]))
      setUseLatest(false);
    }
  }

  const deleteSelectedInstance = () => {
    const layer = layerRef.current;
    if (!layer) return;
    if (selectedInstanceRef.current === -1) return;

    // always 1 extra group for the next instance
    if (groupRef.current.length <= 1) return;

    groupRef.current[selectedInstanceRef.current].destroy();
    groupRef.current.splice(selectedInstanceRef.current, 1);
    setClassList([
      ...classList.slice(0, selectedInstanceRef.current),
      ...classList.slice(selectedInstanceRef.current + 1)
    ]);
    instanceColorsRef.current.splice(selectedInstanceRef.current, 1);
    layer.draw()
    // reset selectedInstanceRef?
    selectedInstanceRef.current = -1;
  }

  const submitLabels = async () => {
    const groupList = groupRef.current;
    if (groupList.length === 0) return;

    const masks = [];
    const length = useLatest ? groupList.length : groupList.length - 1;
    for (let i = 0; i < length; i++) {
      const labelData = groupList[i].toDataURL({ x: 0, y: 0, width: image?.width, height: image?.height });
      masks.push(labelData);
    }

    const res = await axios.put(`${BASE_URL}/v1/label_image/${imageName}`,
      {
        masks: masks,
        labels: classList,
      }
    );

    pointsRef.current = [];
    labelsRef.current = [];
    clearLayers();
  }

  const getLabels = async () => {
    clearLayers();
    try {
      const res = await axios.get(`${BASE_URL}/v1/get_labels/${imageName}`);
      classOptionsRef.current = [...new Set(res.data.labels)];
      // add an initial group to start with
      groupRef.current.push(new Konva.Group());
      for (let i = 0; i < res.data.masks.length; i++) {
        showMask(res.data.masks[i], groupRef.current[groupRef.current.length - 1]);
        classSelectionRef.current = res.data.labels[i];
        pinInstance();
      }
    } catch (err) {
      console.log(err);
    }
  }

  const predLabels = async () => {
    const length = useLatest ? groupRef.current.length : groupRef.current.length - 1;
    if (groupRef.current.length === 0) {
      alert('Please pin an instance');
      return
    }
    const mask = groupRef.current[length - 1].toDataURL({ x: 0, y: 0, width: image?.width, height: image?.height });

    clearLayers();
    try {
      const res = await axios.post(`${BASE_URL}/v1/get_multi_label_preds/${imageName}`, {
        mask: mask,
        label: classList[length - 1],
      });
      groupRef.current.push(new Konva.Group());
      for (let i = 0; i < res.data.masks.length; i++) {
        showMask(res.data.masks[i], groupRef.current[groupRef.current.length - 1]);
        classSelectionRef.current = res.data.labels[i];
        pinInstance();
      }
    } catch (err) {
      console.log(err);
    }
  }

  const getBboxes = async () => {
    clearLayers();
    try {
      const res = await axios.get(`${BASE_URL}/v1/get_labels/${imageName}`);
      classOptionsRef.current = [...new Set(res.data.labels)];
      groupRef.current.push(new Konva.Group());
      for (let i = 0; i < res.data.bboxes.length; i++) {
        showBox(res.data.bboxes[i], groupRef.current[groupRef.current.length - 1]);
        classSelectionRef.current = res.data.labels[i];
        pinInstance();
      }
    } catch (err) {
      console.log(err);
    }
  }

  return (
    <div className="flex flex-row columns-2 gap-20">
      <div className="">
        <h1>Instance Class List</h1>
        <ul>
          {classList.map((item, index) => (
            <li key={index}>
              <div
                // style={{ background: instanceColorsRef.current[index], border: '2px solid red'}}
                style={{ 
                  background: instanceColorsRef.current[index], 
                  border: selectedInstanceRef.current === index && selectedInstanceStyle ? '2px solid red' : 'none'
                }}
                onClick={() => {
                  selectedInstanceRef.current = index;
                  setSelectedInstanceStyle(prev => !prev)
                }}
              >{item}</div>
            </li>
          ))}
        </ul>
        <br />
        <Dropdown
          options={classOptionsRef}
          selectedOption={classSelectionRef}
        />
      </div>
      <div className="">
        <Stage
          width={image?.width}
          height={image?.height}
          ref={stageRef}
          onClick={handleStageClick}
          onContextMenu={(e) => e.evt.preventDefault()}
        >
          <Layer ref={layerRef}>
            <Image image={image} alt="image" />
          </Layer>
        </Stage>
        <br />
        <button className="bg-blue-500 hover:bg-blue-700 text-white font-bold py-2 px-2"
          onClick={clearLayers}>Clear All</button>&nbsp;

        <button className="bg-blue-500 hover:bg-blue-700 text-white font-bold py-2 px-2"
          onClick={getBboxes}>Load BBoxes</button>&nbsp;
        <button className="bg-blue-500 hover:bg-blue-700 text-white font-bold py-2 px-2"
          onClick={getLabels}>Load Masks</button>&nbsp;

        <button className="bg-blue-500 hover:bg-blue-700 text-white font-bold py-2 px-2"
          onClick={deleteSelectedInstance}>Delete Selected Instance</button>&nbsp;
        <button className="bg-blue-500 hover:bg-blue-700 text-white font-bold py-2 px-2"
          onClick={pinInstance}>Pin Instance</button>&nbsp;
        <button className="bg-blue-500 hover:bg-blue-700 text-white font-bold py-2 px-2"
          onClick={submitLabels}>Save All</button>&nbsp;
        <button className="bg-blue-500 hover:bg-blue-700 text-white font-bold py-2 px-2"
          onClick={predLabels}>Auto Label</button>
      </div>
    </div>
  );
};