Javascript <;帆布>;Firefox Mobile、华为Mediapad 10、Android 4.1.2上的图形损坏
我在android版firefox和html5画布上遇到了一个奇怪的问题 我有一张允许客户签名的表格。该表单将在say chrome(屏幕截图1)上完美运行,但在用户尝试登录android版Firefox时会出现混乱 签名板的JS代码来自 js代码如下所示:Javascript <;帆布>;Firefox Mobile、华为Mediapad 10、Android 4.1.2上的图形损坏,javascript,android,firefox,html5-canvas,Javascript,Android,Firefox,Html5 Canvas,我在android版firefox和html5画布上遇到了一个奇怪的问题 我有一张允许客户签名的表格。该表单将在say chrome(屏幕截图1)上完美运行,但在用户尝试登录android版Firefox时会出现混乱 签名板的JS代码来自 js代码如下所示: // JavaScript Document function signatureCapture() { //Actual Code starts here var parent=document.getElement
// JavaScript Document
function signatureCapture() {
//Actual Code starts here
var parent=document.getElementById("canvas");
parent.childNodes[0].nodeValue = "";
var canvasArea=document.createElement("canvas");
canvasArea.setAttribute("id", "newSignature");
parent.appendChild(canvasArea);
var canvas = document.getElementById("newSignature");
var context = canvas.getContext("2d");
if (!context) {
throw new Error("Failed to get canvas' 2d context");
}
screenwidth = screen.width;
//if (screenwidth < 480){
// canvas.width = screenwidth - 8 ;
// canvas.height = (screenwidth * 0.63) ;
//}
//else {
canvas.width = 460 ;
canvas.height = 300 ;
//}
context.fillStyle = "#fff";
context.strokeStyle = "#444";
context.lineWidth = 1.2;
context.lineCap = "round";
context.fillRect(0, 0, canvas.width, canvas.height);
context.fillStyle = "#3a87ad";
context.strokeStyle = "#3a87ad";
context.lineWidth = 1;
context.moveTo((canvas.width*0.042),(canvas.height * 0.7));
context.lineTo((canvas.width*0.958),(canvas.height * 0.7));
context.stroke();
context.fillStyle = "#fff";
context.strokeStyle = "#444";
var disableSave = true;
var pixels = [];
var cpixels = [];
var xyLast = {};
var xyAddLast = {};
var calculate = false;
//functions
{
function remove_event_listeners() {
canvas.removeEventListener('mousemove', on_mousemove, false);
canvas.removeEventListener('mouseup', on_mouseup, false);
canvas.removeEventListener('touchmove', on_mousemove, false);
canvas.removeEventListener('touchend', on_mouseup, false);
document.body.removeEventListener('mouseup', on_mouseup, false);
document.body.removeEventListener('touchend', on_mouseup, false);
}
function get_board_coords(e) {
var x, y;
if (e.changedTouches && e.changedTouches[0]) {
var offsety = canvas.offsetTop || 0;
var offsetx = canvas.offsetLeft || 0;
x = e.changedTouches[0].pageX - offsetx;
y = e.changedTouches[0].pageY - offsety;
} else if (e.layerX || 0 == e.layerX) {
x = e.layerX;
y = e.layerY;
} else if (e.offsetX || 0 == e.offsetX) {
x = e.offsetX;
y = e.offsetY;
}
return {
x : x,
y : y
};
};
function on_mousedown(e) {
e.preventDefault();
e.stopPropagation();
canvas.addEventListener('mousemove', on_mousemove, false);
canvas.addEventListener('mouseup', on_mouseup, false);
canvas.addEventListener('touchmove', on_mousemove, false);
canvas.addEventListener('touchend', on_mouseup, false);
document.body.addEventListener('mouseup', on_mouseup, false);
document.body.addEventListener('touchend', on_mouseup, false);
empty = false;
var xy = get_board_coords(e);
context.beginPath();
pixels.push('moveStart');
context.moveTo(xy.x, xy.y);
pixels.push(xy.x, xy.y);
xyLast = xy;
};
function on_mousemove(e, finish) {
e.preventDefault();
e.stopPropagation();
var xy = get_board_coords(e);
var xyAdd = {
x : (xyLast.x + xy.x) / 2,
y : (xyLast.y + xy.y) / 2
};
if (calculate) {
var xLast = (xyAddLast.x + xyLast.x + xyAdd.x) / 3;
var yLast = (xyAddLast.y + xyLast.y + xyAdd.y) / 3;
pixels.push(xLast, yLast);
} else {
calculate = true;
}
context.quadraticCurveTo(xyLast.x, xyLast.y, xyAdd.x, xyAdd.y);
pixels.push(xyAdd.x, xyAdd.y);
context.stroke();
context.beginPath();
context.moveTo(xyAdd.x, xyAdd.y);
xyAddLast = xyAdd;
xyLast = xy;
};
function on_mouseup(e) {
remove_event_listeners();
disableSave = false;
context.stroke();
pixels.push('e');
calculate = false;
};
}//end
canvas.addEventListener('mousedown', on_mousedown, false);
canvas.addEventListener('touchstart', on_mousedown, false);
}
function signatureSave() {
var canvas = document.getElementById("newSignature");
// save canvas image as data url (png format by default)
var dataURL = canvas.toDataURL("image/png");
document.getElementById("saveSignature").src = dataURL;
};
function signaturePost() {
var canvas = document.getElementById("newSignature");
// save canvas image as data url (png format by default)
document.getElementById('postSignature').value = canvas.toDataURL('image/png');
document.forms["submit_signature"].submit()
}
/*
Reload page instead of this function:
function signatureClear() {
var parent=document.getElementById("canvas");
var child=document.getElementById("newSignature");
parent.removeChild(child);
signatureCapture();
}
*/
// http://stackoverflow.com/questions/11385471/save-canvas-image-post-the-data-string-to-php
function signatureSend() {
var canvas = document.getElementById("newSignature");
var dataURL = canvas.toDataURL("image/png");
document.getElementById("saveSignature").src = dataURL;
var sendemail = document.getElementById('sendemail').value;
var replyemail = document.getElementById('replyemail').value;
var form = document.createElement("form");
form.setAttribute("action","upload_file.php");
form.setAttribute("enctype","multipart/form-data");
form.setAttribute("method","POST");
form.setAttribute("target","_self");
form.innerHTML = '<input type="text" name="image" value="'+dataURL+'"/>'+'<input type="email" name="email" value="'+sendemail+'"/>'+'<input type="email" name="replyemail" value="'+replyemail+'"/>';
form.submit();
}
//JavaScript文档
函数signatureCapture(){
//实际代码从这里开始
var parent=document.getElementById(“画布”);
parent.childNodes[0].nodeValue=“”;
var canvasArea=document.createElement(“canvas”);
canvasArea.setAttribute(“id”,“newSignature”);
父母、子女(拉票区);
var canvas=document.getElementById(“新闻签名”);
var context=canvas.getContext(“2d”);
如果(!上下文){
抛出新错误(“未能获取画布的2d上下文”);
}
屏幕宽度=屏幕宽度;
//如果(屏幕宽度<480){
//canvas.width=屏幕宽度-8;
//canvas.height=(屏幕宽度*0.63);
//}
//否则{
画布宽度=460;
帆布高度=300;
//}
context.fillStyle=“#fff”;
context.strokeStyle=“#444”;
context.lineWidth=1.2;
context.lineCap=“round”;
context.fillRect(0,0,canvas.width,canvas.height);
context.fillStyle=“#3a87ad”;
context.strokeStyle=“#3a87ad”;
context.lineWidth=1;
context.moveTo((canvas.width*0.042),(canvas.height*0.7));
context.lineTo((canvas.width*0.958),(canvas.height*0.7));
stroke();
context.fillStyle=“#fff”;
context.strokeStyle=“#444”;
var disableSave=true;
var像素=[];
var-cpixels=[];
var xyLast={};
var xyAddLast={};
var计算=假;
//功能
{
函数remove_event_listeners(){
canvas.removeEventListener('mousemove',on_mousemove,false);
canvas.removeEventListener('mouseup',on_mouseup,false);
canvas.removeEventListener('touchmove',在鼠标移动上,false);
canvas.removeEventListener('touchend',在鼠标上,false);
document.body.removeEventListener('mouseup',on_mouseup,false);
document.body.removeEventListener('touchend',在鼠标上,假);
}
功能获取板协调(e){
变量x,y;
if(e.changedTouches&&e.changedTouches[0]){
var offsety=canvas.offsetTop | | 0;
var offsetx=canvas.offsetLeft | | 0;
x=e.changedTouches[0].pageX-offsetx;
y=e.changedTouches[0].pageY-offsety;
}else if(e.layerX | | 0==e.layerX){
x=e.rx;
y=e.分层;
}else if(e.offsetX | | 0==e.offsetX){
x=e.offsetX;
y=e.offsetY;
}
返回{
x:x,
y:y
};
};
鼠标向下(e)时的函数{
e、 预防默认值();
e、 停止传播();
canvas.addEventListener('mousemove',on_mousemove,false);
canvas.addEventListener('mouseup',on_mouseup,false);
canvas.addEventListener('touchmove',在鼠标移动上,false);
canvas.addEventListener('touchend',在鼠标上,false);
document.body.addEventListener('mouseup',on_mouseup,false);
document.body.addEventListener('touchend',在鼠标上,假);
空=假;
var xy=获取板坐标(e);
context.beginPath();
push('moveStart');
context.moveTo(xy.x,xy.y);
像素推送(xy.x,xy.y);
xyLast=xy;
};
_mousemove上的函数(e,finish){
e、 预防默认值();
e、 停止传播();
var xy=获取板坐标(e);
变量xyAdd={
x:(xyLast.x+xy.x)/2,
y:(xyLast.y+xy.y)/2
};
如果(计算){
var xLast=(xyAddLast.x+xyLast.x+xyAdd.x)/3;
变量yLast=(xyAddLast.y+xyadst.y+xyAdd.y)/3;
像素推送(xLast,yLast);
}否则{
计算=真;
}
context.quadraticCurveTo(xyLast.x,xyLast.y,xyAdd.x,xyAdd.y);
像素推送(xyAdd.x,xyAdd.y);
stroke();
context.beginPath();
moveTo(xyAdd.x,xyAdd.y);
xyAddLast=xyAdd;
xyLast=xy;
};
鼠标上的函数(e){
删除事件侦听器();
disableSave=false;
stroke();
像素。推('e');
计算=假;
};
}//结束
canvas.addEventListener('mousedown',on_mousedown,false);
canvas.addEventListener(“touchstart”,鼠标向下,假);
}
函数signatureSave(){
var canvas=document.getElementById(“新闻签名”);
//将画布图像另存为数据url(默认为png格式)
var dataURL=canvas.toDataURL(“image/png”);
document.getElementById(“saveSignature”).src=dataURL;
};
函数signaturePost(){
var canvas=document.getElementById(“新闻签名”);
//将画布图像另存为数据url(默认为png格式)
document.getElementById('postSignature')。value=canvas.toDataURL('image/png');
文件。表格[“提交\签名”]。提交()
}
/*
重新加载页面而不是此功能:
函数SignatureLear(){
var parent=document.getElementById(“画布”);
var child=document.getElementById(“新闻签名”);
父母。removeChild(子女);
signatureCapture();
}
*/
// http://stackoverflow.com/questions/11385471/save-canvas-image-post-the-data-string-to-php
函数signatureSend(){
var canvas=document.getElementById(“新闻签名”);
var dataURL=canvas.toDataURL(“image/png”);
做