我是一个javascript函数，用于将图像从剪贴板复制粘贴到HTML画布，还有一个功能让用户在粘贴在画布上的图像上绘制（突出显示）。但是，绘图工具功能似乎会覆盖复制粘贴功能，因为它是匿名的。我需要帮助才能使这两个功能运行起来。
这是我从剪贴板复制的功能。
function CLIPBOARD_CLASS(canvas_id, autoresize) {
alert("BLAH");
var _self = this;
var canvas = document.getElementById(canvas_id);
var ctx = document.getElementById(canvas_id).getContext("2d");
var ctrl_pressed = false;
var reading_dom = false;
var text_top = 15;
var pasteCatcher;
var paste_mode;
//handlers
document.addEventListener('keydown', function (e) {
_self.on_keyboard_action(e);
}, false); //firefox fix
document.addEventListener('keyup', function (e) {
_self.on_keyboardup_action(e);
}, false); //firefox fix
document.addEventListener('paste', function (e) {
_self.paste_auto(e);
}, false); //official paste handler
//constructor - prepare
this.init = function () {
//if using auto
if (window.Clipboard)
return true;
pasteCatcher = document.createElement("div");
pasteCatcher.setAttribute("id", "paste_ff");
pasteCatcher.setAttribute("contenteditable", "");
pasteCatcher.style.cssText = 'opacity:0;position:fixed;top:0px;left:0px;';
pasteCatcher.style.marginLeft = "-20px";
pasteCatcher.style.width = "10px";
document.body.appendChild(pasteCatcher);
document.getElementById('paste_ff').addEventListener('DOMSubtreeModified', function () {
if (paste_mode == 'auto' || ctrl_pressed == false)
return true;
//if paste handle failed - capture pasted object manually
if (pasteCatcher.children.length == 1) {
if (pasteCatcher.firstElementChild.src != undefined) {
//image
_self.paste_createImage(pasteCatcher.firstElementChild.src);
}
}
//register cleanup after some time.
setTimeout(function () {
pasteCatcher.innerHTML = '';
}, 20);
}, false);
}();
//default paste action
this.paste_auto = function (e) {
paste_mode = '';
pasteCatcher.innerHTML = '';
var plain_text_used = false;
if (e.clipboardData) {
var items = e.clipboardData.items;
if (items) {
paste_mode = 'auto';
//access data directly
for (var i = 0; i < items.length; i++) {
if (items[i].type.indexOf("image") !== -1) {
//image
var blob = items[i].getAsFile();
var URLObj = window.URL || window.webkitURL;
var source = URLObj.createObjectURL(blob);
this.paste_createImage(source);
}
}
e.preventDefault();
}
else {
//wait for DOMSubtreeModified event
//https://bugzilla.mozilla.org/show_bug.cgi?id=891247
}
}
};
//on keyboard press -
this.on_keyboard_action = function (event) {
k = event.keyCode;
//ctrl
if (k == 17 || event.metaKey || event.ctrlKey) {
if (ctrl_pressed == false)
ctrl_pressed = true;
}
//c
if (k == 86) {
if (document.activeElement != undefined && document.activeElement.type == 'text') {
//let user paste into some input
return false;
}
if (ctrl_pressed == true && !window.Clipboard)
pasteCatcher.focus();
}
};
//on kaybord release
this.on_keyboardup_action = function (event) {
k = event.keyCode;
//ctrl
if (k == 17 || event.metaKey || event.ctrlKey || event.key == 'Meta')
ctrl_pressed = false;
};
//draw image
this.paste_createImage = function (source) {
var pastedImage = new Image();
pastedImage.onload = function () {
if (autoresize == true) {
//resize canvas
canvas.width = pastedImage.width;
canvas.height = pastedImage.height;
}
else {
//clear canvas
ctx.clearRect(0, 0, canvas.width, canvas.height);
}
ctx.drawImage(pastedImage, 0, 0);
};
pastedImage.src = source;
};
}
这是我的绘图工具功能
if (window.addEventListener) {
window.addEventListener('load', function () {
var canvas, context, canvaso, contexto;
// The active tool instance.
var tool;
var tool_default = 'line';
function init() {
// Find the canvas element.
canvaso = document.getElementById('my_canvas_1');
if (!canvaso) {
alert('Error: I cannot find the canvas element!');
return;
}
if (!canvaso.getContext) {
alert('Error: no canvas.getContext!');
return;
}
// Get the 2D canvas context.
contexto = canvaso.getContext('2d');
if (!contexto) {
alert('Error: failed to getContext!');
return;
}
// Add the temporary canvas.
var container = canvaso.parentNode;
canvas = document.createElement('canvas');
if (!canvas) {
alert('Error: I cannot create a new canvas element!');
return;
}
canvas.id = 'imageTemp';
canvas.width = canvaso.width;
canvas.height = canvaso.height;
container.appendChild(canvas);
context = canvas.getContext('2d');
// Get the tool select input.
var tool_select = document.getElementById('dtool');
if (!tool_select) {
alert('Error: failed to get the dtool element!');
return;
}
tool_select.addEventListener('change', ev_tool_change, false);
// Activate the default tool.
if (tools[tool_default]) {
tool = new tools[tool_default]();
tool_select.value = tool_default;
}
// Attach the mousedown, mousemove and mouseup event listeners.
canvas.addEventListener('mousedown', ev_canvas, false);
canvas.addEventListener('mousemove', ev_canvas, false);
canvas.addEventListener('mouseup', ev_canvas, false);
}
// The general-purpose event handler. This function just determines the mouse
// position relative to the canvas element.
function ev_canvas(ev) {
if (ev.layerX || ev.layerX == 0) { // Firefox
ev._x = ev.layerX;
ev._y = ev.layerY;
} else if (ev.offsetX || ev.offsetX == 0) { // Opera
ev._x = ev.offsetX;
ev._y = ev.offsetY;
}
// Call the event handler of the tool.
var func = tool[ev.type];
if (func) {
func(ev);
}
}
// The event handler for any changes made to the tool selector.
function ev_tool_change(ev) {
if (tools[this.value]) {
tool = new tools[this.value]();
}
}
// This function draws the #imageTemp canvas on top of #my_cavas_1, after which
// #imageTemp is cleared. This function is called each time when the user
// completes a drawing operation.
function img_update() {
contexto.drawImage(canvas, 0, 0);
context.clearRect(0, 0, canvas.width, canvas.height);
}
// This object holds the implementation of each drawing tool.
var tools = {};
// The drawing pencil.
tools.pencil = function () {
var tool = this;
this.started = false;
// This is called when you start holding down the mouse button.
// This starts the pencil drawing.
this.mousedown = function (ev) {
context.beginPath();
context.moveTo(ev._x, ev._y);
tool.started = true;
};
// This function is called every time you move the mouse. Obviously, it only
// draws if the tool.started state is set to true (when you are holding down
// the mouse button).
this.mousemove = function (ev) {
if (tool.started) {
context.lineTo(ev._x, ev._y);
context.stroke();
}
};
// This is called when you release the mouse button.
this.mouseup = function (ev) {
if (tool.started) {
tool.mousemove(ev);
tool.started = false;
img_update();
}
};
};
// The rectangle tool.
tools.rect = function () {
var tool = this;
this.started = false;
this.mousedown = function (ev) {
tool.started = true;
tool.x0 = ev._x;
tool.y0 = ev._y;
};
this.mousemove = function (ev) {
if (!tool.started) {
return;
}
var x = Math.min(ev._x, tool.x0),
y = Math.min(ev._y, tool.y0),
w = Math.abs(ev._x - tool.x0),
h = Math.abs(ev._y - tool.y0);
context.clearRect(0, 0, canvas.width, canvas.height);
if (!w || !h) {
return;
}
context.strokeRect(x, y, w, h);
};
this.mouseup = function (ev) {
if (tool.started) {
tool.mousemove(ev);
tool.started = false;
img_update();
}
};
};
// The line tool.
tools.line = function () {
var tool = this;
this.started = false;
this.mousedown = function (ev) {
tool.started = true;
tool.x0 = ev._x;
tool.y0 = ev._y;
};
this.mousemove = function (ev) {
if (!tool.started) {
return;
}
context.clearRect(0, 0, canvas.width, canvas.height);
context.beginPath();
context.moveTo(tool.x0, tool.y0);
context.lineTo(ev._x, ev._y);
context.stroke();
context.closePath();
};
this.mouseup = function (ev) {
if (tool.started) {
tool.mousemove(ev);
tool.started = false;
img_update();
}
};
};
init();
}, false);
}
这是我的HTML CANVAS TAG
<canvas id="my_canvas_1" width="300" height="300" onclick="CLIPBOARD_CLASS('my_canvas_1',true);"></canvas>