js刮一刮/橡皮擦 插件jquery.eraser.js使用方法
引入jquery和jquery.eraser.js
https://github.com/boblemarin/jQuery.eraser
JS部分：
$(window).load(function () { //这个适用手机端，等图片加载完再显示，因为有可能会出现第一次加载图片没有加载完就不会出现canvas
$('#redux').eraser( {
size: 50, //设置橡皮擦大小
completeRatio: .6, //设置擦除面积比例
completeFunction: showResetButton //大于擦除面积比例触发函数
});
function showResetButton(){
$(".main_box .show,.main_box .mask").fadeIn(300);
$(".show").css("display","flex");
}
$(".main_box .mask,.main_box .show .close,.main_box .show .btn,.show").click(function(){
// $(".main_box .show,.main_box .mask").fadeOut(300);
// $(".show").css("display","none");
window.location.reload();
})
})
HTML部分
<img id="redux" src="images/mask-img.png" />
/*
* jQuery.eraser v0.4.2
* makes any image or canvas erasable by the user, using touch or mouse input
* https://github.com/boblemarin/jQuery.eraser
*
* Usage:
*
* $('#myImage').eraser(); // simple way
*
* $(#canvas').eraser( {
* size: 20, // define brush size (default value is 40)
* completeRatio: .65, // allows to call function when a erased ratio is reached (between 0 and 1, default is .7 )
* completeFunction: myFunction // callback function when complete ratio is reached
* } );
*
* $('#image').eraser( 'clear' ); // erases all canvas content
*
* $('#image').eraser( 'reset' ); // revert back to original content
*
* $('#image').eraser( 'size', 80 ); // change the eraser size
*
*
* https://github.com/boblemarin/jQuery.eraser
* http://minimal.be/lab/jQuery.eraser/
*
* Copyright (c) 2010 boblemarin emeric@minimal.be http://www.minimal.be
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following
* conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
(function( $ ){
var methods = {
init : function( options ) {
return this.each(function(){
var $this = $(this),
data = $this.data('eraser');
if ( !data ) {
var width = $this.width(),
height = $this.height(),
pos = $this.offset(),
$canvas = $("<canvas/>"),
canvas = $canvas.get(0),
size = ( options && options.size )?options.size:40,
completeRatio = ( options && options.completeRatio )?options.completeRatio:.7,
completeFunction = ( options && options.completeFunction )?options.completeFunction:null,
parts = [],
colParts = Math.floor( width / size ),
numParts = colParts * Math.floor( height / size ),
n = numParts,
ctx = canvas.getContext("2d");
// replace target with canvas
$this.after( $canvas );
canvas.id = this.id;
canvas.className = this.className;
canvas.width = width;
canvas.height = height;
ctx.drawImage( this, 0, 0 ,width ,height );
$this.remove();
// prepare context for drawing operations
ctx.globalCompositeOperation = "destination-out";
ctx.strokeStyle = 'rgba(255,0,0,255)';
ctx.lineWidth = size;
ctx.lineCap = "round";
// bind events
$canvas.bind('mousedown.eraser', methods.mouseDown);
$canvas.bind('touchstart.eraser', methods.touchStart);
$canvas.bind('touchmove.eraser', methods.touchMove);
$canvas.bind('touchend.eraser', methods.touchEnd);
// reset parts
while( n-- ) parts.push(1);
// store values
data = {
posX:pos.left,
posY:pos.top,
touchDown: false,
touchID:-999,
touchX: 0,
touchY: 0,
ptouchX: 0,
ptouchY: 0,
canvas: $canvas,
ctx: ctx,
w:width,
h:height,
source: this,
size: size,
parts: parts,
colParts: colParts,
numParts: numParts,
ratio: 0,
complete: false,
completeRatio: completeRatio,
completeFunction: completeFunction
};
$canvas.data('eraser', data);
// listen for resize event to update offset values
$(window).resize( function() {
var pos = $canvas.offset();
data.posX = pos.left;
data.posY = pos.top;
});
}
});
},
touchStart: function( event ) {
var $this = $(this),
data = $this.data('eraser');
if ( !data.touchDown ) {
var t = event.originalEvent.changedTouches[0],
tx = t.pageX - data.posX,
ty = t.pageY - data.posY;
methods.evaluatePoint( data, tx, ty );
data.touchDown = true;
data.touchID = t.identifier;
data.touchX = tx;
data.touchY = ty;
event.preventDefault();
}
},
touchMove: function( event ) {
var $this = $(this),
data = $this.data('eraser');
if ( data.touchDown ) {
var ta = event.originalEvent.changedTouches,
n = ta.length;
while( n-- )
if ( ta[n].identifier == data.touchID ) {
var tx = ta[n].pageX - data.posX,
ty = ta[n].pageY - data.posY;
methods.evaluatePoint( data, tx, ty );
data.ctx.beginPath();
data.ctx.moveTo( data.touchX, data.touchY );
data.touchX = tx;
data.touchY = ty;
data.ctx.lineTo( data.touchX, data.touchY );
data.ctx.stroke();
event.preventDefault();
break;
}
}
},
touchEnd: function( event ) {
var $this = $(this),
data = $this.data('eraser');
if ( data.touchDown ) {
var ta = event.originalEvent.changedTouches,
n = ta.length;
while( n-- )
if ( ta[n].identifier == data.touchID ) {
data.touchDown = false;
event.preventDefault();
break;
}
}
},
evaluatePoint: function( data, tx, ty ) {
var p = Math.floor(tx/data.size) + Math.floor( ty / data.size ) * data.colParts;
if ( p >= 0 && p < data.numParts ) {
data.ratio += data.parts[p];
data.parts[p] = 0;
if ( !data.complete) {
if ( data.ratio/data.numParts >= data.completeRatio ) {
data.complete = true;
if ( data.completeFunction != null ) data.completeFunction();
}
}
}
},
mouseDown: function( event ) {
var $this = $(this),
data = $this.data('eraser'),
tx = event.pageX - data.posX,
ty = event.pageY - data.posY;
methods.evaluatePoint( data, tx, ty );
data.touchDown = true;
data.touchX = tx;
data.touchY = ty;
data.ctx.beginPath();
data.ctx.moveTo( data.touchX-1, data.touchY );
data.ctx.lineTo( data.touchX, data.touchY );
data.ctx.stroke();
$this.bind('mousemove.eraser', methods.mouseMove);
$(document).bind('mouseup.eraser', data, methods.mouseUp);
event.preventDefault();
},
mouseMove: function( event ) {
var $this = $(this),
data = $this.data('eraser'),
tx = event.pageX - data.posX,
ty = event.pageY - data.posY;
methods.evaluatePoint( data, tx, ty );
data.ctx.beginPath();
data.ctx.moveTo( data.touchX, data.touchY );
data.touchX = tx;
data.touchY = ty;
data.ctx.lineTo( data.touchX, data.touchY );
data.ctx.stroke();
event.preventDefault();
},
mouseUp: function( event ) {
var data = event.data,
$this = data.canvas;
data.touchDown = false;
$this.unbind('mousemove.eraser');
$(document).unbind('mouseup.eraser');
event.preventDefault();
},
clear: function() {
var $this = $(this),
data = $this.data('eraser');
if ( data )
{
data.ctx.clearRect( 0, 0, data.w, data.h );
var n = data.numParts;
while( n-- ) data.parts[n] = 0;
data.ratio = data.numParts;
data.complete = true;
if ( data.completeFunction != null ) data.completeFunction();
}
},
size: function(value) {
var $this = $(this),
data = $this.data('eraser');
if ( data && value )
{
data.size = value;
data.ctx.lineWidth = value;
}
},
reset: function() {
var $this = $(this),
data = $this.data('eraser');
if ( data )
{
data.ctx.globalCompositeOperation = "source-over";
data.ctx.drawImage( data.source, 0, 0 );
data.ctx.globalCompositeOperation = "destination-out";
var n = data.numParts;
while( n-- ) data.parts[n] = 1;
data.ratio = 0;
data.complete = false;
}
}
};
$.fn.eraser = function( method ) {
if ( methods[method] ) {
return methods[method].apply( this, Array.prototype.slice.call( arguments, 1 ));
} else if ( typeof method === 'object' || ! method ) {
return methods.init.apply( this, arguments );
} else {
$.error( 'Method ' + method + ' does not yet exist on jQuery.eraser' );
}
};
})( jQuery );
