svg到canvas转换完成后如何立即发布? [英] How to post immediately after svg to canvas conversion is done?
问题描述
在将html元素中的所有svg转换为canvas之后,我尝试使用html2canvas进行发布,但是该帖子会在svg到画布的转换完成之前立即执行.我曾尝试使用延期和承诺,但仍然遇到同样的问题.
I am attempting post with html2canvas after converting all the svgs in a html element to canvas, but the post executes immediately before the svg to canvas conversion finishes, since it takes a few seconds. I have tried using deferred and promises, but I am still having the same issue.
// https://github.com/niklasvh/html2canvas/issues/95#issuecomment-45114424
// First render all SVGs to canvases
targetElem = $('#dashboard');
var elements = targetElem.find('svg').map(function() {
var svg = $(this);
var canvas = $('<canvas></canvas>');
svg.replaceWith(canvas);
// Get the raw SVG string and curate it
var content = svg.wrap('<p></p>').parent().html();
content = content.replace(/xlink:title='hide\/show'/g, '');
content = encodeURIComponent(content);
svg.unwrap();
// Create an image from the svg
var image = new Image();
image.src = 'data:image/svg+xml,' + content;
image.onload = function() {
canvas[0].width = image.width;
canvas[0].height = image.height;
// Render the image to the canvas
var context = canvas[0].getContext('2d');
context.drawImage(image, 0, 0);
};
return {
svg: svg,
canvas: canvas
};
}); // end of targetElem.find('svg').map(function() {...});
已编辑:这是我一直试图实现的创建两个顺序运行的操作的延迟和承诺.
EDITED: Here is the deferred and promise I have been attempting to implement to create two operations that run in sequential order.
$(document).ready(function() {
$( '#save_dashboard' ).click(function() {
// Create a deferred object
var dfd = $.Deferred();
// https://github.com/niklasvh/html2canvas/issues/95#issuecomment-45114424
// First render all SVGs to canvases
targetElem = $('#dashboard');
var elements = targetElem.find('svg').map(function() {
var svg = $(this);
var canvas = $('<canvas></canvas>');
svg.replaceWith(canvas);
// Get the raw SVG string and curate it
var content = svg.wrap('<p></p>').parent().html();
content = content.replace(/xlink:title='hide\/show'/g, '');
content = encodeURIComponent(content);
svg.unwrap();
// Create an image from the svg
var image = new Image();
image.src = 'data:image/svg+xml,' + content;
image.onload = function() {
canvas[0].width = image.width;
canvas[0].height = image.height;
// Render the image to the canvas
var context = canvas[0].getContext('2d');
context.drawImage(image, 0, 0);
};
dfd.resolve();
return dfd.promise();
};
}); // end of targetElem.find('svg').map(function() {...});
dfd.resolve();
$.when(dfd).done(function(){
console.log('dfd done');
// http://www.kubilayerdogan.net/html2canvas-take-screenshot-of-web-page-and-save-it-to-server-javascript-and-php/
$('#dashboard').html2canvas({
onrendered: function (canvas) {
//Set hidden field's value to image data (base-64 string)
var dashboardPng = canvas.toDataURL('image/png');
console.log('dashboardPng: ' + dashboardPng);
$.ajax({
url:'save_dashboard_image.php',
data:{dashboardPngData: dashboardPng},
type:'POST',
dataType:'json',
success: function(){
console.log('success');
}
,
error: function(xhr, status, error){
console.log('The requested page was: ' + document.URL +
'. The error number returned was: ' + xhr.status +
'. The error message was: ' + error);
}
});
}
});
}); // end of $.when(dfd).done(...)
}); // end of save_dashboard click function
}); // end of document ready
推荐答案
已更新
注意,未经测试.调整了click
事件,以将多个canvas
,promise对象返回给.then()
Note, Untested. Adjusted click
event to return multiple canvas
, promise objects , to .then()
如果正确解释问题,请尝试
If interpret question correctly, try
$(document).ready(function() {
$( '#save_dashboard' ).click(function() {
// Create a deferred object
// dfd = new $.Deferred();
// https://github.com/niklasvh/html2canvas/issues/95#issuecomment-45114424
// First render all SVGs to canvases
targetElem = $('#dashboard');
var promises = $.when.apply(targetElem, $.map(targetElem.find('svg')
, function(el, index) {
return new $.Deferred(function(dfd) {
var svg = $(el);
var canvas = $('<canvas></canvas>');
svg.replaceWith(canvas);
// Get the raw SVG string and curate it
var content = svg.wrap('<p></p>').parent().html();
content = content.replace(/xlink:title='hide\/show'/g, '');
content = encodeURIComponent(content);
svg.unwrap();
// Create an image from the svg
var image = new Image();
image.onload = function() {
canvas[0].width = image.width;
canvas[0].height = image.height;
// Render the image to the canvas
var context = canvas[0].getContext('2d');
dfd.resolve(context.drawImage(image, 0, 0));
};
image.src = 'data:image/svg+xml,' + content;
}).promise();
})
); // end of targetElem.find('svg').map(function() {...});
promises.then(function(_canvas) {
console.log('dfd done', _canvas, arguments);
// http://www.kubilayerdogan.net/html2canvas-take-screenshot-of-web-page-and-save-it-to-server-javascript-and-php/
$('#dashboard').html2canvas({
onrendered: function (canvas) {
//Set hidden field's value to image data (base-64 string)
var dashboardPng = canvas.toDataURL('image/png');
console.log('dashboardPng: ' + dashboardPng);
$.ajax({
url:'save_dashboard_image.php',
data:{dashboardPngData: dashboardPng},
type:'POST',
dataType:'json',
success: function(){
console.log('success');
}
,
error: function(xhr, status, error){
console.log('The requested page was: ' + document.URL +
'. The error number returned was: ' + xhr.status +
'. The error message was: ' + error);
}
});
}
});
}); // end of $.when(dfd).done(...)
}); // end of save_dashboard click function
}); // end of document
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