Sofiaml Boo

Sofiaml Boo

1603953181

How to Create simple HTML Canvas animations with Fabric.js

In the “Introduction to Canvas” lesson, we learned about the Canvas Web API and how to draw basic shapes. In that lesson, we also saw how to animate those shapes on the canvas and how surreal it can be to achieve the simplest animations. The Canvas API is not at fault, this is how animations work.

Animation, in a nutshell, is a sequence of frames played quickly so that our eyes perceive smooth motion. This is how traditional film projectors work. It flashes each film 24 frames a second on the screen and due to  persistence of vision, it looks like a natural motion to us.

A “frame” in a general sense is a state of an object at a particular moment in time. Each frame contains a slightly different state of the object such as its position, shape, or characteristics. If we have sufficient enough frames, we can display it on the screen one after the other after enough to create a smooth animation. So what we basically need to do is to change the state of the object, clear the screen (old state), and paint the current state.

In the previous article, we learned how to setup Fabric.js and render basic shapes on the canvas. We are going to follow the same setup so you should take a look at this article before continuing with this.

In this lesson, we are going to only play with rectangles to keep things simple and to the point. Therefore, let’s draw a basic rectangle on the canvas.

#gaming #graphics #canvas #web-development #html

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Buddha Community

How to Create simple HTML Canvas animations with Fabric.js

NBB: Ad-hoc CLJS Scripting on Node.js

Nbb

Not babashka. Node.js babashka!?

Ad-hoc CLJS scripting on Node.js.

Status

Experimental. Please report issues here.

Goals and features

Nbb's main goal is to make it easy to get started with ad hoc CLJS scripting on Node.js.

Additional goals and features are:

  • Fast startup without relying on a custom version of Node.js.
  • Small artifact (current size is around 1.2MB).
  • First class macros.
  • Support building small TUI apps using Reagent.
  • Complement babashka with libraries from the Node.js ecosystem.

Requirements

Nbb requires Node.js v12 or newer.

How does this tool work?

CLJS code is evaluated through SCI, the same interpreter that powers babashka. Because SCI works with advanced compilation, the bundle size, especially when combined with other dependencies, is smaller than what you get with self-hosted CLJS. That makes startup faster. The trade-off is that execution is less performant and that only a subset of CLJS is available (e.g. no deftype, yet).

Usage

Install nbb from NPM:

$ npm install nbb -g

Omit -g for a local install.

Try out an expression:

$ nbb -e '(+ 1 2 3)'
6

And then install some other NPM libraries to use in the script. E.g.:

$ npm install csv-parse shelljs zx

Create a script which uses the NPM libraries:

(ns script
  (:require ["csv-parse/lib/sync$default" :as csv-parse]
            ["fs" :as fs]
            ["path" :as path]
            ["shelljs$default" :as sh]
            ["term-size$default" :as term-size]
            ["zx$default" :as zx]
            ["zx$fs" :as zxfs]
            [nbb.core :refer [*file*]]))

(prn (path/resolve "."))

(prn (term-size))

(println (count (str (fs/readFileSync *file*))))

(prn (sh/ls "."))

(prn (csv-parse "foo,bar"))

(prn (zxfs/existsSync *file*))

(zx/$ #js ["ls"])

Call the script:

$ nbb script.cljs
"/private/tmp/test-script"
#js {:columns 216, :rows 47}
510
#js ["node_modules" "package-lock.json" "package.json" "script.cljs"]
#js [#js ["foo" "bar"]]
true
$ ls
node_modules
package-lock.json
package.json
script.cljs

Macros

Nbb has first class support for macros: you can define them right inside your .cljs file, like you are used to from JVM Clojure. Consider the plet macro to make working with promises more palatable:

(defmacro plet
  [bindings & body]
  (let [binding-pairs (reverse (partition 2 bindings))
        body (cons 'do body)]
    (reduce (fn [body [sym expr]]
              (let [expr (list '.resolve 'js/Promise expr)]
                (list '.then expr (list 'clojure.core/fn (vector sym)
                                        body))))
            body
            binding-pairs)))

Using this macro we can look async code more like sync code. Consider this puppeteer example:

(-> (.launch puppeteer)
      (.then (fn [browser]
               (-> (.newPage browser)
                   (.then (fn [page]
                            (-> (.goto page "https://clojure.org")
                                (.then #(.screenshot page #js{:path "screenshot.png"}))
                                (.catch #(js/console.log %))
                                (.then #(.close browser)))))))))

Using plet this becomes:

(plet [browser (.launch puppeteer)
       page (.newPage browser)
       _ (.goto page "https://clojure.org")
       _ (-> (.screenshot page #js{:path "screenshot.png"})
             (.catch #(js/console.log %)))]
      (.close browser))

See the puppeteer example for the full code.

Since v0.0.36, nbb includes promesa which is a library to deal with promises. The above plet macro is similar to promesa.core/let.

Startup time

$ time nbb -e '(+ 1 2 3)'
6
nbb -e '(+ 1 2 3)'   0.17s  user 0.02s system 109% cpu 0.168 total

The baseline startup time for a script is about 170ms seconds on my laptop. When invoked via npx this adds another 300ms or so, so for faster startup, either use a globally installed nbb or use $(npm bin)/nbb script.cljs to bypass npx.

Dependencies

NPM dependencies

Nbb does not depend on any NPM dependencies. All NPM libraries loaded by a script are resolved relative to that script. When using the Reagent module, React is resolved in the same way as any other NPM library.

Classpath

To load .cljs files from local paths or dependencies, you can use the --classpath argument. The current dir is added to the classpath automatically. So if there is a file foo/bar.cljs relative to your current dir, then you can load it via (:require [foo.bar :as fb]). Note that nbb uses the same naming conventions for namespaces and directories as other Clojure tools: foo-bar in the namespace name becomes foo_bar in the directory name.

To load dependencies from the Clojure ecosystem, you can use the Clojure CLI or babashka to download them and produce a classpath:

$ classpath="$(clojure -A:nbb -Spath -Sdeps '{:aliases {:nbb {:replace-deps {com.github.seancorfield/honeysql {:git/tag "v2.0.0-rc5" :git/sha "01c3a55"}}}}}')"

and then feed it to the --classpath argument:

$ nbb --classpath "$classpath" -e "(require '[honey.sql :as sql]) (sql/format {:select :foo :from :bar :where [:= :baz 2]})"
["SELECT foo FROM bar WHERE baz = ?" 2]

Currently nbb only reads from directories, not jar files, so you are encouraged to use git libs. Support for .jar files will be added later.

Current file

The name of the file that is currently being executed is available via nbb.core/*file* or on the metadata of vars:

(ns foo
  (:require [nbb.core :refer [*file*]]))

(prn *file*) ;; "/private/tmp/foo.cljs"

(defn f [])
(prn (:file (meta #'f))) ;; "/private/tmp/foo.cljs"

Reagent

Nbb includes reagent.core which will be lazily loaded when required. You can use this together with ink to create a TUI application:

$ npm install ink

ink-demo.cljs:

(ns ink-demo
  (:require ["ink" :refer [render Text]]
            [reagent.core :as r]))

(defonce state (r/atom 0))

(doseq [n (range 1 11)]
  (js/setTimeout #(swap! state inc) (* n 500)))

(defn hello []
  [:> Text {:color "green"} "Hello, world! " @state])

(render (r/as-element [hello]))

Promesa

Working with callbacks and promises can become tedious. Since nbb v0.0.36 the promesa.core namespace is included with the let and do! macros. An example:

(ns prom
  (:require [promesa.core :as p]))

(defn sleep [ms]
  (js/Promise.
   (fn [resolve _]
     (js/setTimeout resolve ms))))

(defn do-stuff
  []
  (p/do!
   (println "Doing stuff which takes a while")
   (sleep 1000)
   1))

(p/let [a (do-stuff)
        b (inc a)
        c (do-stuff)
        d (+ b c)]
  (prn d))
$ nbb prom.cljs
Doing stuff which takes a while
Doing stuff which takes a while
3

Also see API docs.

Js-interop

Since nbb v0.0.75 applied-science/js-interop is available:

(ns example
  (:require [applied-science.js-interop :as j]))

(def o (j/lit {:a 1 :b 2 :c {:d 1}}))

(prn (j/select-keys o [:a :b])) ;; #js {:a 1, :b 2}
(prn (j/get-in o [:c :d])) ;; 1

Most of this library is supported in nbb, except the following:

  • destructuring using :syms
  • property access using .-x notation. In nbb, you must use keywords.

See the example of what is currently supported.

Examples

See the examples directory for small examples.

Also check out these projects built with nbb:

API

See API documentation.

Migrating to shadow-cljs

See this gist on how to convert an nbb script or project to shadow-cljs.

Build

Prequisites:

  • babashka >= 0.4.0
  • Clojure CLI >= 1.10.3.933
  • Node.js 16.5.0 (lower version may work, but this is the one I used to build)

To build:

  • Clone and cd into this repo
  • bb release

Run bb tasks for more project-related tasks.

Download Details:
Author: borkdude
Download Link: Download The Source Code
Official Website: https://github.com/borkdude/nbb 
License: EPL-1.0

#node #javascript

Sofiaml Boo

Sofiaml Boo

1603953181

How to Create simple HTML Canvas animations with Fabric.js

In the “Introduction to Canvas” lesson, we learned about the Canvas Web API and how to draw basic shapes. In that lesson, we also saw how to animate those shapes on the canvas and how surreal it can be to achieve the simplest animations. The Canvas API is not at fault, this is how animations work.

Animation, in a nutshell, is a sequence of frames played quickly so that our eyes perceive smooth motion. This is how traditional film projectors work. It flashes each film 24 frames a second on the screen and due to  persistence of vision, it looks like a natural motion to us.

A “frame” in a general sense is a state of an object at a particular moment in time. Each frame contains a slightly different state of the object such as its position, shape, or characteristics. If we have sufficient enough frames, we can display it on the screen one after the other after enough to create a smooth animation. So what we basically need to do is to change the state of the object, clear the screen (old state), and paint the current state.

In the previous article, we learned how to setup Fabric.js and render basic shapes on the canvas. We are going to follow the same setup so you should take a look at this article before continuing with this.

In this lesson, we are going to only play with rectangles to keep things simple and to the point. Therefore, let’s draw a basic rectangle on the canvas.

#gaming #graphics #canvas #web-development #html

Ava Watson

Ava Watson

1595318322

Know Everything About HTML With HTML Experts

HTML stands for a hypertext markup language. For the designs to be displayed in web browser HTML is the markup language. Technologies like Cascading style sheets (CSS) and scripting languages such as JavaScript assist HTML. With the help of HTML websites and the web, designs are created. Html has a wide range of academic applications. HTML has a series of elements. HTML helps to display web content. Its elements tell the web how to display the contents.

The document component of HTML is known as an HTML element. HTML element helps in displaying the web pages. An HTML document is a mixture of text nodes and HTML elements.

Basics of HTML are-

The simple fundamental components oh HTML is

  1. Head- the setup information for the program and web pages is carried in the head
  2. Body- the actual substance that is to be shown on the web page is carried in the body
  3. HTML- information starts and ends with and labels.
  4. Comments- come up in between

Html versions timeline

  1. HTML was created in 1990. Html is a program that is updated regularly. the timeline for the HTML versions is
  2. HTML 2- November, 1995
  3. HTML 3- January, 1997
  4. HTML 4- December, 1997; April, 1998; December, 1999; May, 2000
  5. HTML 5- October, 2014; November, 2016; December, 2017

HTML draft version timelines are

  1. October 1991
  2. June 1992
  3. November 1992
  4. June 1993
  5. November 1993
  6. November 1994
  7. April 1995
  8. January 2008
  9. HTML 5-
    2011, last call
    2012 candidate recommendation
    2014 proposed recommendation and recommendation

HTML helps in creating web pages. In web pages, there are texts, pictures, colouring schemes, tables, and a variety of other things. HTML allows all these on a web page.
There are a lot of attributes in HTML. It may get difficult to memorize these attributes. HTML is a tricky concept. Sometimes it gets difficult to find a single mistake that doesn’t let the web page function properly.

Many minor things are to be kept in mind in HTML. To complete an HTML assignment, it is always advisable to seek help from online experts. These experts are well trained and acknowledged with the subject. They provide quality content within the prescribed deadline. With several positive reviews, the online expert help for HTML assignment is highly recommended.

#html assignment help #html assignment writing help #online html assignment writing help #html assignment help service online #what is html #about html

Alisha  Larkin

Alisha Larkin

1617789060

HTML Tutorial For Beginners

The prospect of learning HTML can seem confusing at first: where to begin, what to learn, the best ways to learn — it can be difficult to get started. In this article, we’ll explore the best ways for learning HTML to assist you on your programming journey.

What is HTML?

Hypertext Markup Language (HTML) is the standard markup language for documents meant to be displayed in a web browser. Along with Cascading Style Sheets (CSS) and JavaScript, HTML completes the trio of essential tools used in creating modern web documents.

HTML provides the structure of a webpage, from the header and footer sections to paragraphs of text, videos, and images. CSS allows you to set the visual properties of different HTML elements, like changing colors, setting the order of blocks on the screen, and defining which elements to display. JavaScript automates changes to HTML and CSS, for example, making the font larger in a paragraph when a user clicks a button on the page.

#html #html-css #html-fundamentals #learning-html #html-css-basics #html-templates

ashika eliza

1625652623

HTML - A Complete Guide to Master the Top Programming Language

In this era of technology, anything digital holds a prime significance in our day-to-day life. Hence, developers have submerged themselves to create a major impact using programming languages.According to Statista, HTML/CSS holds the second position (the first being Javascript), in the list of most widely-used programming languages globally (2020).Interested to learn this language? Then head on to this tutorial and get to know all about HTML! Plus we have added numerous examples such that you can learn better! So happy learning!
html for beginners

#html #html-for-beginners #html-tutorials #introduction-to-html #learn-html #tutorials-html