Retrieve the image (via copy and paste) directly from the web browser

Question

Retrieve the image (via copy and paste) directly from the web browser

When it comes to copying images in a browser like chrome, there are two methods available: copying the image itself and copying the address of the image.

If I copy the image address and paste it using my Paste Image button, I can successfully retrieve the base64 version of the image. However, simply copying the image does not yield the same result. Is there a way to extract the image by using the image copier, as demonstrated in the examples?

See Demo

Code:

  clickPaste() {
    let self = this;
    (navigator as any).clipboard.readText().then(clipboard => self.clip = clipboard);
console.log(self.clip) // copied image address ---> base64
  }

Example of Copying Image Address - Functional https://i.sstatic.net/ECi2V.png

https://i.sstatic.net/lAjUs.png

Example of Copying Image - Not Functional

https://i.sstatic.net/tM8DM.png

https://i.sstatic.net/ETTz2.png

While I understand that copying an image and copying its address are distinct actions, I am struggling to figure out how to acquire the image (either as a blob or base64) when opting for the image copy method.

javascript angular typescript clipboard clipboarddata

Answer 1

Answer №1

To retrieve the content, you can utilize the paste event within the ClipboardEvent's .clipboardData DataTransfer.

If the content is in a file format, it will be stored within the .files FileList:

document.onpaste = (evt) => {
  const dT = evt.clipboardData || window.clipboardData;
  const file = dT.files[ 0 ];
  console.log( file );
};

img{ height: 100vh; }

<div contenteditable>You can paste the image here</div>
<figure>
  <figcaption>Copy this image</figcaption>
  <img src="https://upload.wikimedia.org/wikipedia/commons/4/47/PNG_transparency_demonstration_1.png">
</figure>

If you wish to access the content outside of the event, you'll need to use the async Clipboard API.
This API still lacks widespread support (currently only supported by Blink), however, here's how you can read an image file using this API.

First, request or verify the "clipboard-read" Permission.
If permission is granted, proceed with reading the clipboard content using navigator.clipboard.read(). This will return a DataTransferItemsList (technically an Array), where you'll need to identify and access the specific type based on its .type.

document.getElementById('btn').onclick = async (evt) => {
  const auth = await navigator.permissions.query( { name: "clipboard-read" } );
  if( auth.state !== 'denied' ) {
    const item_list = await navigator.clipboard.read();
    let image_type; // define image type
    const item = item_list.find( item => 
      item.types.some( type => { 
        if( type.startsWith( 'image/' ) ) {
          image_type = type;
          return true;
        }
      } )
    );
    const file = item && await item.getType( image_type );
    console.log( file );
  }
};

img{ height: 100vh; }

<button id="btn">read clipboard content</button>
<figure>
  <figcaption>Copy this image</figcaption>
  <img src="https://upload.wikimedia.org/wikipedia/commons/4/47/PNG_transparency_demonstration_1.png">
</figure>

Answer 2

To retrieve the content, you can utilize the paste event within the ClipboardEvent's .clipboardData DataTransfer.

If the content is in a file format, it will be stored within the .files FileList:

document.onpaste = (evt) => {
  const dT = evt.clipboardData || window.clipboardData;
  const file = dT.files[ 0 ];
  console.log( file );
};

img{ height: 100vh; }

<div contenteditable>You can paste the image here</div>
<figure>
  <figcaption>Copy this image</figcaption>
  <img src="https://upload.wikimedia.org/wikipedia/commons/4/47/PNG_transparency_demonstration_1.png">
</figure>

If you wish to access the content outside of the event, you'll need to use the async Clipboard API.
This API still lacks widespread support (currently only supported by Blink), however, here's how you can read an image file using this API.

First, request or verify the "clipboard-read" Permission.
If permission is granted, proceed with reading the clipboard content using navigator.clipboard.read(). This will return a DataTransferItemsList (technically an Array), where you'll need to identify and access the specific type based on its .type.

document.getElementById('btn').onclick = async (evt) => {
  const auth = await navigator.permissions.query( { name: "clipboard-read" } );
  if( auth.state !== 'denied' ) {
    const item_list = await navigator.clipboard.read();
    let image_type; // define image type
    const item = item_list.find( item => 
      item.types.some( type => { 
        if( type.startsWith( 'image/' ) ) {
          image_type = type;
          return true;
        }
      } )
    );
    const file = item && await item.getType( image_type );
    console.log( file );
  }
};

img{ height: 100vh; }

<button id="btn">read clipboard content</button>
<figure>
  <figcaption>Copy this image</figcaption>
  <img src="https://upload.wikimedia.org/wikipedia/commons/4/47/PNG_transparency_demonstration_1.png">
</figure>

Answer 3

Answer №2

Take a look at this practical example from an informative tutorial: To start, set up an event listener for "paste":

window.addEventListener("paste", function(e){

    // Manage the event
    retrieveImageFromClipboardAsBase64(e, function(imageDataBase64){
        // If an image is detected, display it in a new browser window :)
        if(imageDataBase64){
            // data:image/png;base64,iVBORw0KGgoAAAAN......
            window.open(imageDataBase64);
        }
    });
}, false);

This handy function allows you to extract the image as base64:

**
 * This handler retrieves images from the clipboard as a base64 string and returns them through a callback.
 * 
 * @param pasteEvent 
 * @param callback 
 */
function retrieveImageFromClipboardAsBase64(pasteEvent, callback, imageFormat){
    if(pasteEvent.clipboardData == false){
        if(typeof(callback) == "function"){
            callback(undefined);
        }
    };

    // Get elements from the clipboard
    var items = pasteEvent.clipboardData.items;

    if(items == undefined){
        if(typeof(callback) == "function"){
            callback(undefined);
        }
    };
    // Iterate through the elements
    for (var i = 0; i < items.length; i++) {
        // Skip content that is not an image
        if (items[i].type.indexOf("image") == -1) continue;
        // Extract image from clipboard as blob
        var blob = items[i].getAsFile();

        // Create a virtual canvas and obtain context
        var mycanvas = document.createElement("canvas");
        var ctx = mycanvas.getContext('2d');

        // Create an image element
        var img = new Image();

        // Render the img on the canvas upon loading the image
        img.onload = function(){
            // Adjust canvas dimensions to match the image's dimensions
            mycanvas.width = this.width;
            mycanvas.height = this.height;

            // Draw the image on the canvas
            ctx.drawImage(img, 0, 0);

            // Trigger the callback with the base64 URI of the image
            if(typeof(callback) == "function"){
                callback(mycanvas.toDataURL(
                    (imageFormat || "image/png")
                ));
            }
        };

        // Ensure crossbrowser support for URL
        var URLObj = window.URL || window.webkitURL;

        // Generate a URL representing the original Blob object
        img.src = URLObj.createObjectURL(blob);
    }
}

Answer 4

Take a look at this practical example from an informative tutorial: To start, set up an event listener for "paste":

window.addEventListener("paste", function(e){

    // Manage the event
    retrieveImageFromClipboardAsBase64(e, function(imageDataBase64){
        // If an image is detected, display it in a new browser window :)
        if(imageDataBase64){
            // data:image/png;base64,iVBORw0KGgoAAAAN......
            window.open(imageDataBase64);
        }
    });
}, false);

This handy function allows you to extract the image as base64:

**
 * This handler retrieves images from the clipboard as a base64 string and returns them through a callback.
 * 
 * @param pasteEvent 
 * @param callback 
 */
function retrieveImageFromClipboardAsBase64(pasteEvent, callback, imageFormat){
    if(pasteEvent.clipboardData == false){
        if(typeof(callback) == "function"){
            callback(undefined);
        }
    };

    // Get elements from the clipboard
    var items = pasteEvent.clipboardData.items;

    if(items == undefined){
        if(typeof(callback) == "function"){
            callback(undefined);
        }
    };
    // Iterate through the elements
    for (var i = 0; i < items.length; i++) {
        // Skip content that is not an image
        if (items[i].type.indexOf("image") == -1) continue;
        // Extract image from clipboard as blob
        var blob = items[i].getAsFile();

        // Create a virtual canvas and obtain context
        var mycanvas = document.createElement("canvas");
        var ctx = mycanvas.getContext('2d');

        // Create an image element
        var img = new Image();

        // Render the img on the canvas upon loading the image
        img.onload = function(){
            // Adjust canvas dimensions to match the image's dimensions
            mycanvas.width = this.width;
            mycanvas.height = this.height;

            // Draw the image on the canvas
            ctx.drawImage(img, 0, 0);

            // Trigger the callback with the base64 URI of the image
            if(typeof(callback) == "function"){
                callback(mycanvas.toDataURL(
                    (imageFormat || "image/png")
                ));
            }
        };

        // Ensure crossbrowser support for URL
        var URLObj = window.URL || window.webkitURL;

        // Generate a URL representing the original Blob object
        img.src = URLObj.createObjectURL(blob);
    }
}

Retrieve the image (via copy and paste) directly from the web browser

Answer №1

Answer №2

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