Titik mula dan akhir imej

Question

Saya cuba menetapkan titik mula dan akhir imej. Jadi saya mempunyai kanvas dan imej saya, apabila saya meletakkan imej itu ke dalam kanvas, saya mahu ia menyala sedikit bulatan merah apabila saya menuding di atas titik mula/tamat, yang bermaksud saya boleh mencipta dengan imej lain menyambung. Contohnya: 1) Seret imej. 2) Letakkan imej ke dalam kanvas. 3) Tuding tetikus ke titik permulaan/titik tamat, dan titik merah kecil akan menyala. Seperti yang anda lihat, titik merah hanya muncul pada tuding. Soalan lain, tetapi sejuk jika anda menyelesaikan yang pertama, imej tidak mengikut gril (persegi). Ini adalah contoh contressistor untuk html/js

P粉214089349 · Answer

Anda boleh menjejaki x dan y imej dalam tatasusunan dan mengulangi tatasusunan untuk memeriksa sama ada penuding tetikus berada agak jauh dari mana-mana objek, jika ya maka lukis bulatan dan dalam imej jauh sambungannya adalah jika anda bercadang untuk menambah lebih daripada 2 imej yang dipaparkan (tidak tahu tentang imej yang dihoskan secara tempatan) dan titik mula dan tamat adalah berbeza, kemudian pada titik tengah kedua-dua belah anda perlu menggunakan tetapan semasa berdasarkan nilai perubahan imej, anda boleh hardcodenya, berikut ialah pelaksanaan saya:

const resistor = document.getElementById('component_circuit_resistor');
const condensator = document.getElementById('component_circuit_condensator');
const tranistor = document.getElementById('component_circuit_tranistor');
const alimentator = document.getElementById('component_circuit_alimentator');
const circuit = document.getElementById('components_circuit');
const back_button = document.getElementById('back-button');
const clear_button = document.getElementById('clear-button');
const draggable = document.querySelectorAll('.draggable');
const container = document.querySelectorAll('.container');
const canvas = document.getElementById('canvas');
const foward_button = document.getElementById('foward-button');
let images = [];

/** EDIT START */
const draggableImages = document.querySelectorAll('img[draggable]');

for (let i = 0; i < draggableImages.length; i++)
  draggableImages[i].ondragstart = (ev) => {
    ev.dataTransfer.setData('text/plain', i.toString());
  };

canvas.ondragover = (ev) => ev.preventDefault(); // IMPORTANT

const orderStack = [];
const deletedOrderStack = [];

const drawnImageData = [];
const deletedImageData = [];
canvas.ondrop = (ev) => {
    
    const index = parseInt(ev.dataTransfer.getData('text/plain'));
    const img = draggableImages[index];
    const x = ev.clientX - canvas.offsetLeft - img.width / 2;
    const y = ev.clientY - canvas.offsetTop - img.height / 2;
    const squareSize = 10; // adjust this to match the size of your squares


    const maxSize = 75; // maximum size of the image
    const aspectRatio = img.width / img.height;
    let width = maxSize;
    let height = maxSize / aspectRatio;
    if (height > maxSize) {
      height = maxSize;
      width = height * aspectRatio;
    }
    const snappedX = Math.round(x / squareSize) * squareSize;
    const snappedY = Math.round(y / squareSize) * squareSize;
    ctx.drawImage(img, snappedX, snappedY, width, height);
    images.push({ img, x: snappedX, y: snappedY, width, height });
    // Add the image and its position to the images array

  };
  

  
 
clear_button.disabled = true;
clear_button.style.cursor = 'not-allowed';
foward_button.disabled = true;
foward_button.style.cursor = 'not-allowed';
back_button.disabled = true;
back_button.style.cursor = 'not-allowed';
/** EDIT END */

canvas.width = 1900;

canvas.height = 1000;
canvas.style.backgroundColor = 'white';
circuit.appendChild(canvas);
canvas.style.borderRadius = '10px';
canvas.style.marginLeft = 'auto';
canvas.style.marginRight = 'auto';
canvas.style.display = 'block';
const ctx = canvas.getContext('2d');

//const circles = [];
const lines = [];
const lines_c = [];
var deletedLines = [];

function drawSquares() {
  const squareSize = 10;
  const numColumns = Math.floor(canvas.width / squareSize);
  const numRows = Math.floor(canvas.height / squareSize);

  ctx.fillStyle = "#FAF9F9";
  ctx.strokeStyle = "#F4F1F0";
  ctx.lineWidth = 1;

  for (let i = 0; i < numColumns; i++) {
    for (let j = 0; j < numRows; j++) {
      const x = i * squareSize;
      const y = j * squareSize;

      if (i % 10 === 0 && j % 10 === 0) {
        ctx.lineWidth = 2.6;
        ctx.fillStyle = "#F1ECEB";
        ctx.strokeStyle = "#E6E0DE"; // set the stroke color to a darker shade
        ctx.strokeRect(x, y, squareSize * 10, squareSize * 10);
        ctx.fillStyle = "#F4F1F0";
        ctx.strokeStyle = "#F4F1F0"; // reset the stroke color
        ctx.lineWidth = 1;
      } else {
        ctx.strokeRect(x, y, squareSize, squareSize);
      }
    }
  }
}

drawSquares();

// Add a mousemove event to the canvas to show the red dot
  const redDotRadius = 5; // The radius of the red dots
  const hoverDistance = 10; // The distance from a point at which to show the dot

canvas.onmousemove = (ev) => {
    const mouseX = ev.clientX - canvas.offsetLeft;
    const mouseY = ev.clientY - canvas.offsetTop;
    
    // Clear the canvas and redraw everything
    ctx.clearRect(0, 0, canvas.width, canvas.height);
    drawSquares();
    for (let i = 0; i < images.length; i++) {
      let image = images[i];
      ctx.drawImage(image.img, image.x, image.y, image.width, image.height);
    }
    
    // Check if the mouse is near a starting or ending point
    for (let i = 0; i < images.length; i++) {
      let image = images[i];
      let startX = image.x+5;
      let startY = image.y + image.height/2;
      let endX = image.x + image.width -5;
      let endY = image.y + image.height/2;
      
      if (Math.abs(mouseX - startX) < hoverDistance && Math.abs(mouseY - startY) < hoverDistance) {
        // Near the starting point, draw a red dot
        ctx.beginPath();
        ctx.arc(startX, startY, redDotRadius, 0, 2 * Math.PI, false);
        ctx.fillStyle = 'red';
        ctx.fill();
      } else if (Math.abs(mouseX - endX) < hoverDistance && Math.abs(mouseY - endY) < hoverDistance) {
        // Near the ending point, draw a red dot
        ctx.beginPath();
        ctx.arc(endX, endY, redDotRadius, 0, 2 * Math.PI, false);
        ctx.fillStyle = 'red';
        ctx.fill();
      }
    }
  };

Saya tidak menukar html