Interactive text fields with Fabric.js

Question

I've been playing with Fabric.js a lot in the last few weeks, but regarding text fields I've only found it possible to set the text on creation.

Is there any possible way to make an interactive text field, or do I have to find a workaround to achieve that? (With interactive text field I mean an area of the canvas I can click on and write directly into it.)

Answer 1

The latest version of fabric.js includes a class IText which incorporates the interaction for editing and selection of text dynamically. try the code below with the latest version of fabric.js

canvas.add(new fabric.IText('Tap and Type', { 
  fontFamily: 'arial black',
  left: 100, 
  top: 100 ,
}));

Answer 2

I recently built a mind mapping tool using fabric.js and I encountered the same problem.

To achieve what you have described (changing the text on and after creation of textual elements in the canvas), I used jquery to detect the keydown event. Assuming you have selected the desired textual element in the fabric canvas the following snippet will change the text.

$(document).keydown(function(e){
    var keyPressed = String.fromCharCode(e.which);
    var text = canvas.getActiveObject();
    if (text)
    {
        var newText = '';
        var stillTyping = true;
        if (e.which == 27) //esc
        {
            if (!text.originalText) return; //if there is no original text, there is nothing to undo
            newText = text.originalText;
            stillTyping = false;
        }
        //if the user wants to make a correction
        else
        {
            //Store the original text before beginning to type
            if (!text.originalText)
            {
                text.originalText = text.text;
            }
            //if the user wants to remove all text, or the element entirely
            if (e.which == 46) //delete
            {
                activeObject.element.remove(true);
                return;
            }
            else if (e.which == 16) { //shift
                newText = text.text;
            }
            else if (e.which == 8) //backspace
            {
                e.preventDefault();
                newText = text.text.substr(0, text.text.length - 1);
            }
            else if (e.which == 13) //enter
            {
                //canvas clear selection
                canvas.discardActiveObject();
                canvas.renderAll();
                canvasBeforeSelectionCleared({ memo: { target: text} });

                newText = text.text;
                stillTyping = false;
            }
            //if the user is typing alphanumeric characters
            else if (
                (e.which > 64 && e.which < 91) || //A-Z
                (e.which > 47 && e.which < 58) || //0-9
                (e.which == 32) || //Space
                (keyPressed.match(/[!&()"'?-]/)) //Accepted special characters
            )
            {
                if (text.text == text.originalText) text.text = '';
                if (keyPressed.match(/[A-Z]/) && !e.shiftKey)
                    keyPressed = keyPressed.toLowerCase();
                newText = text.text + keyPressed;
            }
        }
        text.set({ text: newText }); //Change the text
        canvas.renderAll(); //Update the canvas

        if (!stillTyping)
        {
            this.text.originalText = null;
        }
    }
});

Using this technique, I can select a text element in the fabric canvas, begin typing and the text is replaced. You could change it so it didn't erase the text each time you select the element.

There are some compromises with this method. For example you cannot select text as if it were in a regular HTML input text element and there is no blinking cursor, therefore the "virtual" cursor is always at the end of the text.

If you really wanted to you could draw a blinking cursor at the end of the text.

Answer 3

I guess its too late, but this might be of help to others.

There is a demo on fabricjs to do the exact same thing.

Answer 4

    text.set({ text: newText }); //Change the text
    canvas.renderAll(); //Update the canvas

That was what I was looking for :) Thanks alot!