当页面加载时，我试图在画布中重新创建签名。我已经设法捕获签名，并将其存储在MySQL数据库中使用PHP。它被存储为json数据。现在的问题是:我有一个页面与画布元素，我可以检索json数据从数据库页面加载使用php之前，但我不知道如何将此数据传递到画布元素。希望有个解决办法，因为我花了太多时间搞砸了。谢谢你！
json数据:"[
{
'"lx'":87,
'"ly'":6,
'"mx'":87,
'"my'":5
},
{
'"lx'":88,
'"ly'":5,
'"mx'":87,
'"my'":6
},
{
'"lx'":89,
'"ly'":6,
'"mx'":88,
'"my'":5
},
{
'"lx'":89,
'"ly'":7,
'"mx'":89,
'"my'":6
},
{
'"lx'":90,
'"ly'":7,
'"mx'":89,
'"my'":7
},
{
'"lx'":90,
'"ly'":8,
'"mx'":90,
'"my'":7
},
{
'"lx'":90,
'"ly'":10,
'"mx'":90,
'"my'":8
},
{
'"lx'":91,
'"ly'":11,
'"mx'":90,
'"my'":10
},
{
'"lx'":92,
'"ly'":11,
'"mx'":91,
'"my'":11
},
{
'"lx'":92,
'"ly'":12,
'"mx'":92,
'"my'":11
},
{
'"lx'":93,
'"ly'":12,
'"mx'":92,
'"my'":12
},
{
'"lx'":93,
'"ly'":13,
'"mx'":93,
'"my'":12
},
{
'"lx'":95,
'"ly'":15,
'"mx'":93,
'"my'":13
},
{
'"lx'":96,
'"ly'":16,
'"mx'":95,
'"my'":15
},
{
'"lx'":97,
'"ly'":16,
'"mx'":96,
'"my'":16
},
{
'"lx'":97,
'"ly'":17,
'"mx'":97,
'"my'":16
},
{
'"lx'":98,
'"ly'":18,
'"mx'":97,
'"my'":17
},
{
'"lx'":99,
'"ly'":18,
'"mx'":98,
'"my'":18
},
{
'"lx'":99,
'"ly'":19,
'"mx'":99,
'"my'":18
},
{
'"lx'":99,
'"ly'":20,
'"mx'":99,
'"my'":19
},
{
'"lx'":102,
'"ly'":5,
'"mx'":102,
'"my'":4
},
{
'"lx'":101,
'"ly'":5,
'"mx'":102,
'"my'":5
},
{
'"lx'":101,
'"ly'":6,
'"mx'":101,
'"my'":5
},
{
'"lx'":100,
'"ly'":7,
'"mx'":101,
'"my'":6
},
{
'"lx'":100,
'"ly'":8,
'"mx'":100,
'"my'":7
},
{
'"lx'":99,
'"ly'":8,
'"mx'":100,
'"my'":8
},
{
'"lx'":99,
'"ly'":9,
'"mx'":99,
'"my'":8
},
{
'"lx'":98,
'"ly'":9,
'"mx'":99,
'"my'":9
},
{
'"lx'":98,
'"ly'":10,
'"mx'":98,
'"my'":9
},
{
'"lx'":97,
'"ly'":11,
'"mx'":98,
'"my'":10
},
{
'"lx'":96,
'"ly'":12,
'"mx'":97,
'"my'":11
},
{
'"lx'":95,
'"ly'":12,
'"mx'":96,
'"my'":12
},
{
'"lx'":94,
'"ly'":12,
'"mx'":95,
'"my'":12
},
{
'"lx'":93,
'"ly'":12,
'"mx'":94,
'"my'":12
},
{
'"lx'":91,
'"ly'":13,
'"mx'":93,
'"my'":12
},
{
'"lx'":89,
'"ly'":14,
'"mx'":91,
'"my'":13
},
{
'"lx'":89,
'"ly'":15,
'"mx'":89,
'"my'":14
},
{
'"lx'":88,
'"ly'":15,
'"mx'":89,
'"my'":15
},
{
'"lx'":87,
'"ly'":16,
'"mx'":88,
'"my'":15
},
{
'"lx'":86,
'"ly'":17,
'"mx'":87,
'"my'":16
},
{
'"lx'":86,
'"ly'":18,
'"mx'":86,
'"my'":17
},
{
'"lx'":85,
'"ly'":18,
'"mx'":86,
'"my'":18
},
{
'"lx'":85,
'"ly'":19,
'"mx'":85,
'"my'":18
},
{
'"lx'":85,
'"ly'":20,
'"mx'":85,
'"my'":19
},
{
'"lx'":84,
'"ly'":20,
'"mx'":85,
'"my'":20
}
]"
你有两个选择:
在生成页面时回显到一个javascript变量中:
echo "<script>var sig = ".$jsonsig.";</script>";
或者在用AJAX调用
加载页面后检索它(jQuery在你的页面脚本，需要一个PHP脚本返回JSON代码)
$.getJSON("getmysig.php",function(data) {
// create canvas here
});