Question

我尝试创建一个'瓷砖压模'应用程序，允许您从顶部选择一个瓷砖，然后将该瓷砖“标记”到下面的画布区域。您基本上可以将其视为HTML5游戏的地图编辑器。

除了选择和标记外，一切正常：http://www.exeneva.com/html5/tileStamper

JS错误控制台说我的事件监听器不正确，但我100％确定它们是有效的：

// Event listeners
theCanvas.addEventListener("mousemove", onMouseMove, false);   
theCanvas.addEventListener("click", onMouseClick, false);

这是我的鼠标移动和鼠标点击处理代码：

function onMouseMove(e) {
  // Accounts for the canvas not being at the top left of screen
  mouseX = e.clientX - theCanvas.offsetLeft;
  mouseY = e.clientY - theCanvas.offsetTop;
}

function onMouseClick(e) {
  console.log("click: " + mouseX + "," + mouseY);
  if (mouseY < 128) {
    // Find tile to highlight
    var totalRows = 7; // 8 total rows, but relative zero means we use 7
    var col = Math.floor(mouseX / tileLength);
    var row = Math.floor(mouseY / tileLength);
    var tileId = (row * totalRows) + (col + row);
    highlightTile(tileId, col * tileLength, row * tileLength);
  } else {
    // stamp the selected tile
    var col = Math.floor(mouseX / tileLength);
    var row = Math.floor(mouseY / tileLength);
    context.putImageData(imageData, col * tileLength, row * tileLength);
  }
}

以下是拼贴代码：

function highlightTile(tileId, x, y) {
  // redraw tilesheet and highlight selected tile
  context.fillStyle = "#aaaaaa";
  context.fillRect(0, 0, 256, 128);
  drawTileSheet();

  imageData = context.getImageData(x, y, 32, 32);
  // set alpha to 128
  for (j = 3; j < imageData.data.length; j += 4) {
    imageData.data[j] = 128;
  }

  // draw red line around selected tile
  var startX = Math.floor(tileId % 8) * 32;
  var startY = Math.floor(tileId / 8) * 32;
  context.strokeStyle = "red";
  context.strokeRect(startX, startY, 32, 32);
}

有人可以帮我弄清楚为什么这不起作用吗？

Answer 1

根据这条线：

var theCanvas = $("#canvasOne");

theCanvas是jquery包装器，而不是纯DOM元素。因此它没有addEventListener方法。你可以尝试这样：

theCanvas[0].addEventListener("mousemove", onMouseMove, false);   
theCanvas[0].addEventListener("click", onMouseClick, false);

Answer 2

请改为：

theCanvas.click(onMouseClick);
theCanvas.mousemove(onMouseMove);

根据工程师的回答，你正在使用jQuery。

PS：你还在为坦克项目工作吗？好的。

我的瓷砖压模不起作用

2 个答案: