有关如何使用FileSaver.js保存svg画布的详细示例？
我按照https://github.com/eligrey/FileSaver.js上的画布示例 但是我在line83上看到“未定义不是函数”，这是一个空行。
请参阅我的示例代码...
<!doctype html>
<meta charset="utf-8">
<link rel="stylesheet" href="dagre_example.css">
<script src="http://d3js.org/d3.v3.min.js" charset="utf-8"></script>
<script src="./dagre-d3.js"></script>
<script src="./Blob.js"></script>
<script src="./canvas-toBlob.js"></script>
<script src="./FileSaver.js"></script>
<h1>Dagre D3 Demo: Sentence Tokenization</h1>
<svg id="svg-canvas" width=960 height=600></svg>
<script id="js">
// Create the input graph
var g = new dagreD3.graphlib.Graph()
.setGraph({})
.setDefaultEdgeLabel(function() { return {}; });
// Here we"re setting nodeclass, which is used by our custom drawNodes function
// below.
g.setNode(0, { label: "TOP", class: "type-TOP" });
g.setNode(1, { label: "S", class: "type-S" });
g.setNode(2, { label: "NP", class: "type-NP" });
g.setNode(3, { label: "DT", class: "type-DT" });
g.setNode(4, { label: "This", class: "type-TK" });
g.setNode(5, { label: "VP", class: "type-VP" });
g.setNode(6, { label: "VBZ", class: "type-VBZ" });
g.setNode(7, { label: "is", class: "type-TK" });
g.setNode(8, { label: "NP", class: "type-NP" });
g.setNode(9, { label: "DT", class: "type-DT" });
g.setNode(10, { label: "an", class: "type-TK" });
g.setNode(11, { label: "NN", class: "type-NN" });
g.setNode(12, { label: "example", class: "type-TK" });
g.setNode(13, { label: ".", class: "type-." });
g.setNode(14, { label: "sentence", class: "type-TK" });
g.nodes().forEach(function(v) {
var node = g.node(v);
// Round the corners of the nodes
node.rx = node.ry = 5;
});
// Set up edges, no special attributes.
g.setEdge(3, 4);
g.setEdge(2, 3);
g.setEdge(1, 2);
g.setEdge(6, 7);
g.setEdge(5, 6);
g.setEdge(9, 10);
g.setEdge(8, 9);
g.setEdge(11,12);
g.setEdge(8, 11);
g.setEdge(5, 8);
g.setEdge(1, 5);
g.setEdge(13,14);
g.setEdge(1, 13);
g.setEdge(0, 1)
// Create the renderer
var render = new dagreD3.render();
// Set up an SVG group so that we can translate the final graph.
var svg = d3.select("svg"),
svgGroup = svg.append("g");
// Run the renderer. This is what draws the final graph.
render(d3.select("svg g"), g);
// Center the graph
var xCenterOffset = (svg.attr("width") - g.graph().width) / 2;
svgGroup.attr("transform", "translate(" + xCenterOffset + ", 20)");
svg.attr("height", g.graph().height + 40);
// Convert to image
var canvas = document.getElementById("svg-canvas"), ctx = canvas.getContext("2d");
// draw to canvas...
canvas.toBlob(function(blob) {
saveAs(blob, "prettyimage.png");
});
</script>
答案 0 :(得分：5)
以下是使用FileSaver进行本地保存的工作示例：
var canvas=document.getElementById("canvas");
var ctx=canvas.getContext("2d");
var img=new Image()
img.onload=function(){
ctx.fillStyle="red";
ctx.drawImage(img,0,0);
ctx.fillRect(100,100,50,30);
}
img.crossOrigin="anonymous";
img.src="https://dl.dropboxusercontent.com/u/139992952/stackoverflow/ship.png";
$("#save").click(function(){
canvas.toBlob(function(blob){ saveAs(blob,"temp4.png"); });
});
//////////////////////////////////////
// FileSaver scripts
//////////////////////////////////////
/* FileSaver.js
* A saveAs() FileSaver implementation.
* 2014-08-29
*
* By Eli Grey, http://eligrey.com
* License: X11/MIT
* See https://github.com/eligrey/FileSaver.js/blob/master/LICENSE.md
*/
/*global self */
/*jslint bitwise: true, indent: 4, laxbreak: true, laxcomma: true, smarttabs: true, plusplus: true */
/*! @source http://purl.eligrey.com/github/FileSaver.js/blob/master/FileSaver.js */
var saveAs = saveAs
// IE 10+ (native saveAs)
|| (typeof navigator !== "undefined" &&
navigator.msSaveOrOpenBlob && navigator.msSaveOrOpenBlob.bind(navigator))
// Everyone else
|| (function(view) {
"use strict";
// IE <10 is explicitly unsupported
if (typeof navigator !== "undefined" &&
/MSIE [1-9]\./.test(navigator.userAgent)) {
return;
}
var
doc = view.document
// only get URL when necessary in case Blob.js hasn't overridden it yet
, get_URL = function() {
return view.URL || view.webkitURL || view;
}
, save_link = doc.createElementNS("http://www.w3.org/1999/xhtml", "a")
, can_use_save_link = "download" in save_link
, click = function(node) {
var event = doc.createEvent("MouseEvents");
event.initMouseEvent(
"click", true, false, view, 0, 0, 0, 0, 0
, false, false, false, false, 0, null
);
node.dispatchEvent(event);
}
, webkit_req_fs = view.webkitRequestFileSystem
, req_fs = view.requestFileSystem || webkit_req_fs || view.mozRequestFileSystem
, throw_outside = function(ex) {
(view.setImmediate || view.setTimeout)(function() {
throw ex;
}, 0);
}
, force_saveable_type = "application/octet-stream"
, fs_min_size = 0
// See https://code.google.com/p/chromium/issues/detail?id=375297#c7 for
// the reasoning behind the timeout and revocation flow
, arbitrary_revoke_timeout = 10
, revoke = function(file) {
var revoker = function() {
if (typeof file === "string") { // file is an object URL
get_URL().revokeObjectURL(file);
} else { // file is a File
file.remove();
}
};
if (view.chrome) {
revoker();
} else {
setTimeout(revoker, arbitrary_revoke_timeout);
}
}
, dispatch = function(filesaver, event_types, event) {
event_types = [].concat(event_types);
var i = event_types.length;
while (i--) {
var listener = filesaver["on" + event_types[i]];
if (typeof listener === "function") {
try {
listener.call(filesaver, event || filesaver);
} catch (ex) {
throw_outside(ex);
}
}
}
}
, FileSaver = function(blob, name) {
// First try a.download, then web filesystem, then object URLs
var
filesaver = this
, type = blob.type
, blob_changed = false
, object_url
, target_view
, dispatch_all = function() {
dispatch(filesaver, "writestart progress write writeend".split(" "));
}
// on any filesys errors revert to saving with object URLs
, fs_error = function() {
// don't create more object URLs than needed
if (blob_changed || !object_url) {
object_url = get_URL().createObjectURL(blob);
}
if (target_view) {
target_view.location.href = object_url;
} else {
var new_tab = view.open(object_url, "_blank");
if (new_tab == undefined && typeof safari !== "undefined") {
//Apple do not allow window.open, see http://bit.ly/1kZffRI
view.location.href = object_url
}
}
filesaver.readyState = filesaver.DONE;
dispatch_all();
revoke(object_url);
}
, abortable = function(func) {
return function() {
if (filesaver.readyState !== filesaver.DONE) {
return func.apply(this, arguments);
}
};
}
, create_if_not_found = {create: true, exclusive: false}
, slice
;
filesaver.readyState = filesaver.INIT;
if (!name) {
name = "download";
}
if (can_use_save_link) {
object_url = get_URL().createObjectURL(blob);
save_link.href = object_url;
save_link.download = name;
click(save_link);
filesaver.readyState = filesaver.DONE;
dispatch_all();
revoke(object_url);
return;
}
// Object and web filesystem URLs have a problem saving in Google Chrome when
// viewed in a tab, so I force save with application/octet-stream
// http://code.google.com/p/chromium/issues/detail?id=91158
// Update: Google errantly closed 91158, I submitted it again:
// https://code.google.com/p/chromium/issues/detail?id=389642
if (view.chrome && type && type !== force_saveable_type) {
slice = blob.slice || blob.webkitSlice;
blob = slice.call(blob, 0, blob.size, force_saveable_type);
blob_changed = true;
}
// Since I can't be sure that the guessed media type will trigger a download
// in WebKit, I append .download to the filename.
// https://bugs.webkit.org/show_bug.cgi?id=65440
if (webkit_req_fs && name !== "download") {
name += ".download";
}
if (type === force_saveable_type || webkit_req_fs) {
target_view = view;
}
if (!req_fs) {
fs_error();
return;
}
fs_min_size += blob.size;
req_fs(view.TEMPORARY, fs_min_size, abortable(function(fs) {
fs.root.getDirectory("saved", create_if_not_found, abortable(function(dir) {
var save = function() {
dir.getFile(name, create_if_not_found, abortable(function(file) {
file.createWriter(abortable(function(writer) {
writer.onwriteend = function(event) {
target_view.location.href = file.toURL();
filesaver.readyState = filesaver.DONE;
dispatch(filesaver, "writeend", event);
revoke(file);
};
writer.onerror = function() {
var error = writer.error;
if (error.code !== error.ABORT_ERR) {
fs_error();
}
};
"writestart progress write abort".split(" ").forEach(function(event) {
writer["on" + event] = filesaver["on" + event];
});
writer.write(blob);
filesaver.abort = function() {
writer.abort();
filesaver.readyState = filesaver.DONE;
};
filesaver.readyState = filesaver.WRITING;
}), fs_error);
}), fs_error);
};
dir.getFile(name, {create: false}, abortable(function(file) {
// delete file if it already exists
file.remove();
save();
}), abortable(function(ex) {
if (ex.code === ex.NOT_FOUND_ERR) {
save();
} else {
fs_error();
}
}));
}), fs_error);
}), fs_error);
}
, FS_proto = FileSaver.prototype
, saveAs = function(blob, name) {
return new FileSaver(blob, name);
}
;
FS_proto.abort = function() {
var filesaver = this;
filesaver.readyState = filesaver.DONE;
dispatch(filesaver, "abort");
};
FS_proto.readyState = FS_proto.INIT = 0;
FS_proto.WRITING = 1;
FS_proto.DONE = 2;
FS_proto.error =
FS_proto.onwritestart =
FS_proto.onprogress =
FS_proto.onwrite =
FS_proto.onabort =
FS_proto.onerror =
FS_proto.onwriteend =
null;
return saveAs;
}(
typeof self !== "undefined" && self
|| typeof window !== "undefined" && window
|| this.content
));
// `self` is undefined in Firefox for Android content script context
// while `this` is nsIContentFrameMessageManager
// with an attribute `content` that corresponds to the window
if (typeof module !== "undefined" && module !== null) {
module.exports = saveAs;
} else if ((typeof define !== "undefined" && define !== null) && (define.amd != null)) {
define([], function() {
return saveAs;
});
}
/* canvas-toBlob.js
* A canvas.toBlob() implementation.
* 2013-12-27
*
* By Eli Grey, http://eligrey.com and Devin Samarin, https://github.com/eboyjr
* License: X11/MIT
* See https://github.com/eligrey/canvas-toBlob.js/blob/master/LICENSE.md
*/
/*global self */
/*jslint bitwise: true, regexp: true, confusion: true, es5: true, vars: true, white: true,
plusplus: true */
/*! @source http://purl.eligrey.com/github/canvas-toBlob.js/blob/master/canvas-toBlob.js */
(function(view) {
"use strict";
var
Uint8Array = view.Uint8Array
, HTMLCanvasElement = view.HTMLCanvasElement
, canvas_proto = HTMLCanvasElement && HTMLCanvasElement.prototype
, is_base64_regex = /\s*;\s*base64\s*(?:;|$)/i
, to_data_url = "toDataURL"
, base64_ranks
, decode_base64 = function(base64) {
var
len = base64.length
, buffer = new Uint8Array(len / 4 * 3 | 0)
, i = 0
, outptr = 0
, last = [0, 0]
, state = 0
, save = 0
, rank
, code
, undef
;
while (len--) {
code = base64.charCodeAt(i++);
rank = base64_ranks[code-43];
if (rank !== 255 && rank !== undef) {
last[1] = last[0];
last[0] = code;
save = (save << 6) | rank;
state++;
if (state === 4) {
buffer[outptr++] = save >>> 16;
if (last[1] !== 61 /* padding character */) {
buffer[outptr++] = save >>> 8;
}
if (last[0] !== 61 /* padding character */) {
buffer[outptr++] = save;
}
state = 0;
}
}
}
// 2/3 chance there's going to be some null bytes at the end, but that
// doesn't really matter with most image formats.
// If it somehow matters for you, truncate the buffer up outptr.
return buffer;
}
;
if (Uint8Array) {
base64_ranks = new Uint8Array([
62, -1, -1, -1, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1
, -1, -1, 0, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25
, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35
, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51
]);
}
if (HTMLCanvasElement && !canvas_proto.toBlob) {
canvas_proto.toBlob = function(callback, type /*, ...args*/) {
if (!type) {
type = "image/png";
} if (this.mozGetAsFile) {
callback(this.mozGetAsFile("canvas", type));
return;
} if (this.msToBlob && /^\s*image\/png\s*(?:$|;)/i.test(type)) {
callback(this.msToBlob());
return;
}
var
args = Array.prototype.slice.call(arguments, 1)
, dataURI = this[to_data_url].apply(this, args)
, header_end = dataURI.indexOf(",")
, data = dataURI.substring(header_end + 1)
, is_base64 = is_base64_regex.test(dataURI.substring(0, header_end))
, blob
;
if (Blob.fake) {
// no reason to decode a data: URI that's just going to become a data URI again
blob = new Blob
if (is_base64) {
blob.encoding = "base64";
} else {
blob.encoding = "URI";
}
blob.data = data;
blob.size = data.length;
} else if (Uint8Array) {
if (is_base64) {
blob = new Blob([decode_base64(data)], {type: type});
} else {
blob = new Blob([decodeURIComponent(data)], {type: type});
}
}
callback(blob);
};
if (canvas_proto.toDataURLHD) {
canvas_proto.toBlobHD = function() {
to_data_url = "toDataURLHD";
var blob = this.toBlob();
to_data_url = "toDataURL";
return blob;
}
} else {
canvas_proto.toBlobHD = canvas_proto.toBlob;
}
}
}(typeof self !== "undefined" && self || typeof window !== "undefined" && window || this.content || this));body{ background-color: ivory; }
canvas{border:1px solid red;}<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<button id="save">Save</button><br>
<canvas id="canvas" width=300 height=300></canvas>