fabric.js VS GoJS, a JavaScript Library for HTML Diagrams

This AI-powered Story Card Maker is built as a SvelteKit application with Typescript. Using Flowbite Svelte component library, the whole application was laid out. The layout for the Story Card (emulating the size of a postcard - 4" x 3") is created as an HTML Canvas using Fabric.js.

Fabric.js is a powerful and simple Javascript HTML5 canvas library. It provides an interactive object model on top of the canvas element. Fabric also has SVG-to-canvas (and canvas-to-SVG) parser.

Based on this, I found that some of the libraries are dead and no longer have any support. Only two libraries are still alive and have significant amount of stars on GitHub and downloads on NPM. They are Fabric.js and Konva.js.

I'm actually in the process of building something similar. It's a React app and I'm using the FabricJs library

I've played with this tech in early 2010s - they are using HTML5 Canvas tech + something like Fabric.js(http://fabricjs.com/) that controls Canvas objects.

this library might help you: http://fabricjs.com/

I did some research and the most promising result was using Fabric.js (http://fabricjs.com/) to put images on products. I may not be experienced enough in JS to understand the full capabilities of this library, but it looks like most of their stuff works on flat surfaces. I am trying to replicate the properly wrapped/textured affect that is achieved in the blanket below.

set up a canvas drawing & rendering framework, for example http://fabricjs.com/

body{ display:flex; flex-direction:column; align-items:center; }

Learning Fabric

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Next, we initiate a Canvas instance in our script tag:

Syntax

new fabric.Canvas(element: HTMLElement|String, options: Object)

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This allows Fabric.js to create this class instance so that we can use the provided methods of Fabric.js:

const canvas = new fabric.Canvas("canvas", {})

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Now, we’ll go ahead and give our canvas different properties, such as width, height, and background color:

const canvas = new fabric.Canvas("canvas", {
 width:500,
 height:500,
 backgroundColor:green
})

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Output

Creating a Rectangle with Fabric.js

Now that we’ve initialized a canvas and given it various properties, we’re going to create a rectangle using the Fabric.js object fabric.Rect:

Syntax

new fabric.Rect({object})

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Here the object houses the rectangle properties:

const canvas = new fabric.Canvas("canvas", {
 width:500,
 height:500,
 backgroundColor:green
});

const rectangle = new fabric.Rect({
 width:200,
 height:200,
 /* fill is used to define the background color*/
    fill:'red'
})
/*the add method is used to add objects to the canvas element */
canvas.add(rectangle)
/*the renderAll method used to render the canvas*/
canvas.renderAll();

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The add() method is used to add objects to the Canvas element. In this case, it adds the rectangle we created to the canvas:

Output

Creating a Circle

In the same way, we’ll create a circle. This time, we’ll use fabric.Circle:

const canvas = new fabric.Canvas("canvas", {
 width:500,
 height:500,
 backgroundColor:"lightgray"
});

const circle = new fabric.Circle({
 radius:60,
 fill:"blue"
})
canvas.add(circle);
canvas.renderALl();

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Output

With the above steps, we created a rectangle and a circle using Fabric.js. Note how interactive the objects are! Next, we’ll discuss images in Fabric.js.

Images with Fabric

The Fabric.Image is a Fabric.js object used to render images on a canvas. With Fabric.js, we can interact with the image. Images can be added to our canvas in two ways:

• Fabric.Image
• Fabric.Image.fromURL

Using the Fabric.Image constructor requires us to create an image element in our HTML and then insert it into the constructor:

Syntax

fabric.Image(image_element)

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HTML

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JS

const image_element = document.querySelector('#image');
const image = new fabric.Image(image_element)
canvas.add(image);
canvas.renderAll();

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However, Fabric.Image.fromURL requires only the image URL (the URL can be retrieved from a website or your local folder), and is simpler than the former:

fabric.Image.fromURL(URL, function());

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After passing the URL, the callback function after the image is loaded. The first default parameter of the callback function is the fabric.Image object. Now, we can modify the image properties and then add it to the canvas:

const canvas = new fabric.Canvas("canvas", {
 width:500,
 height:500,
 backgroundColor:"White"
});

fabric.Image.fromURL('my_image.png',(img) => {
 // the scaleToHeight property is use to set the image height
    img.scaleToHeight(250)
 // scaleToWidth is use to set the image width
    img.scaleToWidth(250)
    canvas.add(img)  
})
canvas.renderAll()

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Output

Editing Images with Fabric.js

Now that we know how to insert an image into a canvas, we’ll look at other image objects like image filters.

Image Filters

Fabric.js provides us with built-in filters:

• BaseFilter
• Brightness
• convolute
• GradientTransparency
• Grayscale
• Invert
• Mask
• Noise
• Pixelate
• RemoveWhite
• Sepia
• Sepia2
• Tint

Every instance of fabric.Image has the "filters" property, which is a simple array of filters. We can use the array method to perform any required operation, including removing filters (pop, slice, shift), adding filters (push, unshift, slice), and even combining multiple filters. When we call applyFilters, any filter in the “filters” array will be applied one by one. Let’s use some of these filters:

Syntax

new fabric.Image.filters
// after that you can add any filter of your choice
// Example 
new fabric.Image.filters.Grayscale()

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fabric.Image.fromURL('my_image.png', (image) => {
      image.scaleToHeight(300)
       image.ScaleToWidth(300)

 // Creating filter
 const filter = new fabric.Image.filters.Grayscale()

 //push the filter instance to filters
        image.filter.push(filter)

 // apply filter
         image.applyFilters()

 //add image into canvas (it also re-render the canvas)
         canvas.add(image)
},{crossOrigin: 'anonymous'});
canvas.renderAll();

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Output

Above, we used the Grayscale filter; we can also apply other filters. All we have to do is simply change the filter, as shown in this example:

fabric.Image.fromURL('my_image.png', (image) => {
      image.scaleToHeight(300)
       image.ScaleToWidth(300)

 // creating filter
 const filter = new fabric.Image.filters.Sepia()

 //add filter
        image.filter.push(filter)

 // apply filter
         image.applyFilters()

 //add image into canvas (it also re-render the canvas)
         canvas.add(image)
},{crossOrigin: 'anonymous'});
canvas.renderAll();

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Output

Image Blending

Blending is mixing two or more images to create a new image. Fabric.js gives us this ability. Here, we’re going to use the image blending filter for our image:

Syntax

new fabric.Image.filters.BlendImage({
 // the image that we want to blend
          image:imageA,
 // blend mode (in this case we are using the 'add' mode)
          mode:'add',

 alpha:0.5
      });

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fabric.Image.fromURL('my_image.png', (imageA) => {
    imageA.scaleToWidth(350)
    imageA.scaleToHeight(350)
    canvas.add(imageA)

 // Blending filter
    filter = new fabric.Image.filters.BlendImage({
 image:imageA,
 mode:'add',
 alpha:0.5
      });

 //Add the second image  
     fabric.Image.fromURL('my_image2.png',(imageB) => {
           imageB.scaleToHeight(100),
            imageB.scaleToWidth(100),
            canvas.add(imageB)
       }, {crossOrigin:''});

     imageA.filters.push(filter);
     imageA.applyFilters(canvas.renderAll.bind(canvas));
},{crossOrigin:''})

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Output

Image Clipping

A very popular effect used today is image clipping, or rather image cropping, which is done to remove parts of an image that we don’t want. With Fabric.js, we can achieve this by using the clipPath method.

First, we have to create our own clipPath using any Fabric.js object. Then, we’ll assign it to the clipPath property of the object we want to clip. Here, we’ll use a circle object:

const clipPath = new fabric.Circle({
 radius:150,
 top:200,
 left:250,
 // The originY and originX helps to center the image and the clipPath
    originY:"center",
 originX:"center"
})

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After that, we add it to the image that we want to clip using the filter method:

new fabric.Image.fromURL('my_image.png',(img) => {
  img.scaleToHeight(300)
  img.scaleToWidth(300)
 // positioning the image
  img.scale(o.5).set({top:50,left:100})
 // Clip Path
  clipPath = new fabric.Circle({
 radius:150,
 top:200,
 left:250,
 originY:"center",
 originX:"center"
    })
  canvas.add(img)
  canvas.clipPath = clipPath;
  });
canvas.renderAll();

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Output

Image Blurring

Like other image filters, the blur filter accepts objects because they can be adjusted. A practical example is changing the brightness of an image. You can apply other image filters without any additional configurations (like grayscale, invert, or sepia). Other image filters like brightness, pixelate, tint, and noise all operate in this way, too. However, the difference is that their values are not the same. The brightness filter's actual brightness level ranges from-1 (full black) to 1 (full white). The noise filter's value is between 0 and 1000. For the blur filter, the value ranges from 0 to 10.

Syntax

new fabric.Image.filters.Blur(object)

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fabric.Image.fromURL('my_image.png', (image) => {
      image.scaleToHeight(300)
       image.ScaleToWidth(300)

 // Creating the blur filter
 const filter = new fabric.Image.filters.Blur({
 blur:0.6
       })

 //push the filter instance to filters
        image.filter.push(filter)
         image.applyFilters()
         canvas.add(image)
},{crossOrigin: 'anonymous'});
canvas.renderAll();

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Output

Conclusion

In conclusion, Fabric.js gives us an awesome experience when working with Canvas. It also provides a lot of features, some of which we covered in this article. For full details on some of the Fabric.js objects, you can review its documentation here.

Have spent six figures yearly on ads, mostly for reach for the developer-focused diagram library GoJS (https://gojs.net)

> Each experiment will need ~$500 and 2 weeks

I would add a zero if you want serious data. I would also double the timescale. $5,000 over 4 weeks

I second the uselessness of Google Display, it might look like conversions numbers are good but they are 100% too good to be true. As soon as you look into them you find the sources are things like "ad from HappyFunBabyTime Android app". You have to ruthlessly prune daily for months to get anything real, and even then I'm skeptical of value. For a developer tool with very strict conversion metrics!

But I disagree on Google Search:

> Good for conversion, bad for awareness.

Before we were popular it was excellent for awareness. Post popularity its much more arguable.

Creating the Halogen components would be simple enough if one takes inspiration from gojs-react. The issue is that there are no PureScript bindings for the GoJS types themselves, but GoJS does provide .ts.d declarations, which means I could use purescript-read-dts, but that library's maturity/usability seems somewhat ambiguous, according to an author's post from 3 years ago.

used goJS in one project and konva in another

I built GoJS, which is one of the most popular commercial JS diagramming libraries: https://gojs.net

I built carefulwords, a very fast thesaurus and quote site for inspiration, used by... tens of people a day. Eg: https://carefulwords.com/gift https://carefulwords.com/solitude

I mostly made it for myself, me and my wife use it all the time. I am slowly editing down the thesaurus to managable size.

I built a 12x16 "Goose Palace" barn out of local pine timbers, which taught me timber framing, and taught my tiny baby who turned 2 years old while doing it that this is just the kind of thing that people normally do, build barns in their driveway. Some context: https://simonsarris.substack.com/p/the-goose-palace

Some photos of building it with the baby: https://twitter.com/simonsarris/status/1584169368203956225

I designed my house, and have been writing extensively about that. Maybe this is the most impactful, since photos of it are all over Pinterest and other sites, now. The first post on that: https://simonsarris.substack.com/p/designing-a-new-old-home-...

I am not sure what is most impactful. Maybe ultimately it is building my family.

I made a pull request for GoJS (https://gojs.net)

I have been building this canvas-based graphing library since 2011, and it contains a good number of features around customization and interactivity that are not found in other libraries. It is commercial for non-academic use however.

in one project we use konva, in another we used gojs. Any of them or some other library needs some training and introduce own limitations but it still way way way better than handing all the coordinates, calculations, routing etc on your own.

I am really surprised by this guy's opinion. I make GoJS (https://gojs.net/), a diagramming library written in TypeScript. The project began in 2011 and we converted it to TS in 2018. It's been a huge plus. The sole downside was the initial time it took during conversion, but even in doing so we caught bugs with incorrect input types, documentation mistakes, etc.

On our end, it enforces type safety better than the Google Closure Compiler. There has scarcely been a problem with type complexity that was not ultimately our fault. Just a couple minor things that TS amended later. For that matter the TS experience has only gotten better, generally.

On our users end, we can now give them a .d.ts file that's much richer and easier for us to produce to aid their autocompletion. And we can use that .d.ts file to ensure that all the methods we intended to expose/minify are getting exposed. The advantages with the .d.ts and documentation make it feel almost essential to me for library developers to consider TS.

TypeScript has only made debugging easier, much easier since it catches errors at time of typing unlike the closure compiler. The sole exception is that debugging is a bit slower since I have to transpile instead of just refreshing the browser. But I have tsc set to compile a relatively unminified version of the JS. But if the slowness gets to me, I can just edit the JS output until I solve the issue, and then carry those edits over to the TS. This has never felt like a problem, though maybe his library is significantly more complicated.

Feel free to ask me anything if you have questions about library design + TS.

GoJS might work for you: https://gojs.net

Although the focus of the library is interactivity and not setting up sequences of animation, but that is possible too.

My livelihood has been primarily building a Canvas diagramming library since 2010 (https://gojs.net), if anyone has any questions about 2D Canvas use in the real-world I'd be happy to answer them.

roundRect is great. Though you don't need 4 arcTo in order to make a rounded rect, you can use bezier instead (we do). Their example is also 1% amusing because they set the `fillStyle` but then call `stroke` (and not `fill`). I'll have to do some performance comparisons, since that's the operative thing for my use case (and any library author).

text modifiers are very welcome. It's crazy how annoying measuring still is, especially if you want thinks to look perfectly consistent across browsers. Though the chrome dominance is making things easier in one way, I guess.

context.reset is kinda funny. Most high-performance canvas apps will never want to use it. For that matter you want to set all properties as little as possible, especially setting things like context.font, which are slow even if you're setting it to the same value. (Or it was, I haven't tested that in several years).

I'm sure most users know this by now, but generally for performance the fewer calls you make to the canvas and the context, the beter. This is even true of transforms: It's faster to make your own Matrix class, do all your own matrix translation, rotation, multiplication, etc, and then make a single call to `context.setTransform`, than it is to call the other context methods.

I have some problem with gojs(https://gojs.net/),