img onclick函数立即进入被调用函数

Question

当我单击下面的img并继续进行processToolClick函数时，将执行2个eventListener事件，而不是等待继续之前的mouseup或mousedown事件发生。我已经尝试使用匿名函数和.bind来阻止对processToolClick函数的访问。如何停止onclick并等待mousup或mousedown事件？

 <img src="graphicPaneResources/linetool.png"  alt="Line Tool" onClick = "processToolClick(this, event)";>

function processToolClick(elem, evt)  {
let tmpToolName = elem.src;
tmpToolName = tmpToolName.substring(tmpToolName.lastIndexOf("/")+1);
tmpToolName = tmpToolName.substring(0, tmpToolName.indexOf("."));
switch(tmpToolName)  {
    case "linetool":
        console.log("OK "+tmpToolName+"  "+evt)     
        toolSelection = "linetool";
        canvas.addEventListener("onmousedown", lineDrawer.startLine(evt));
        canvas.addEventListener("onmouseup", lineDrawer.endLine(evt));
        lineDrawer.processLine(evt);
    break;
    default:
}