How to hyperlink download file canvas

How to hyperlink download file canvas

how to hyperlink download file canvas

Use Google apps for your content, link it in your course site, and update with one click! Navigate to Canvas. Modules: Download file from drive and update it. In order to practice inserting a link to internal course content, start by creating a new assignment and naming it "Assignment 2." Then complete the following steps. Open New Rich Content Editor. Open the New Rich Content Editor when using one of the. how to hyperlink download file canvas

How to hyperlink download file canvas - consider

HTMLCanvasElement.toBlob()

The method creates a object representing the image contained in the canvas; this file may be cached on the disk or stored in memory at the discretion of the user agent. If is not specified, the image type is . The created image is in a resolution of 96dpi.

The third argument is used when creating images using lossy compression (such as ) to specify the quality of the output.

Syntax

.toBlob(, , );

Parameters

A callback function with the resulting object as a single argument.
Optional
A indicating the image format. The default type is .
Optional
A between and indicating image quality if the requested type is or . If this argument is anything else, the default values 0.92 and 0.80 are used for image/jpeg and image/webp respectively. Other arguments are ignored.

Return value

None.

Exceptions

The canvas's bitmap is not origin clean; at least some of its contents come from secure

Examples

Getting a file representing the canvas

Once you have drawn content into a canvas, you can convert it into a file of any supported image format. The code snippet below, for example, takes the image in the element whose ID is "canvas", obtains a copy of it as a PNG image, then appends a new element to the document, whose source image is the one created using the canvas.

var canvas = document.getElementById('canvas'); canvas.toBlob(function(blob) { var newImg = document.createElement('img'), url = URL.createObjectURL(blob); newImg.onload = function() { // no longer need to read the blob so it's revoked URL.revokeObjectURL(url); }; newImg.src = url; document.body.appendChild(newImg); });

Note that here we're creating a PNG image; if you add a second parameter to the call, you can specify the image type. For example, to get the image in JPEG format:

canvas.toBlob(function(blob){...}, 'image/jpeg', 0.95); // JPEG at 95% quality

A way to convert a canvas to an ico (Mozilla only)

This uses to convert the canvas to ico. Windows XP doesn't support converting from PNG to ico, so it uses bmp instead. A download link is created by setting the download attribute. The value of the download attribute is the name it will use as the file name.

var canvas = document.getElementById('canvas'); var d = canvas.width; ctx = canvas.getContext('2d'); ctx.beginPath(); ctx.moveTo(d / 2, 0); ctx.lineTo(d, d); ctx.lineTo(0, d); ctx.closePath(); ctx.fillStyle = 'yellow'; ctx.fill(); function blobCallback(iconName) { return function(b) { var a = document.createElement('a'); a.textContent = 'Download'; document.body.appendChild(a); a.style.display = 'block'; a.download = iconName + '.ico'; a.href = window.URL.createObjectURL(b); } } canvas.toBlob(blobCallback('passThisString'), 'image/vnd.microsoft.icon', '-moz-parse-options:format=bmp;bpp=32');

Save toBlob to disk with OS.File (chrome/add-on context only)

This technique saves it to the desktop and is only useful in Firefox chrome context or add-on code, as OS APIs are not present on web sites.

var canvas = document.getElementById('canvas'); var d = canvas.width; ctx = canvas.getContext('2d'); ctx.beginPath(); ctx.moveTo(d / 2, 0); ctx.lineTo(d, d); ctx.lineTo(0, d); ctx.closePath(); ctx.fillStyle = 'yellow'; ctx.fill(); function blobCallback(iconName) { return function(b) { var r = new FileReader(); r.onloadend = function () { // r.result contains the ArrayBuffer. Cu.import('resource://gre/modules/osfile.jsm'); var writePath = OS.Path.join(OS.Constants.Path.desktopDir, iconName + '.ico'); var promise = OS.File.writeAtomic(writePath, new Uint8Array(r.result), {tmpPath:writePath + '.tmp'}); promise.then( function() { console.log('successfully wrote file'); }, function() { console.log('failure writing file') } ); }; r.readAsArrayBuffer(b); } } canvas.toBlob(blobCallback('passThisString'), 'image/vnd.microsoft.icon', '-moz-parse-options:format=bmp;bpp=32');

Specifications

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
ChromeFull support 50EdgeFull support 79
Full support 79
No support12 — 79
Prefixed Implemented with the vendor prefix: ms
FirefoxFull support 19IEFull support 10
Full support 10
Prefixed Implemented with the vendor prefix: ms
OperaFull support 37SafariFull support 11WebView AndroidFull support 50Chrome AndroidFull support 50Firefox AndroidFull support 4Opera AndroidFull support 37Safari iOSFull support 11Samsung Internet AndroidFull support 5.0
Image quality parameterChromeFull support 50EdgeFull support 79FirefoxFull support 25IENo support NoOperaFull support YesSafariNo support NoWebView AndroidFull support 50Chrome AndroidNo support NoFirefox AndroidFull support 25Opera AndroidNo support NoSafari iOSNo support NoSamsung Internet AndroidNo support No

Legend

Full support
Full support
No support
No support
Requires a vendor prefix or different name for use.
Requires a vendor prefix or different name for use.

See also

Источник: [https://torrent-igruha.org/3551-portal.html]

How to hyperlink download file canvas

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