@nativescript-community/ui-canvas

Implement Canvas into your NativeScript apps.

Table of Contents

• Installation
  • Usage
• Plain NativeScript
  • XML
• NativeScript + Angular
• NativeScript + Vue
• NativeScript + Svelte
• Draw Method
  • Examples:
• Demos and Development
  • Repo Setup
  • Build
  • Demos
• Contributing
  • Update repo
  • Update readme
  • Update doc
  • Publish
  • modifying submodules
• Questions

Installation

Run the following command from the root of your project:

ns plugin add @nativescript-community/ui-canvas

Usage

The nativescript Canvas is based on the Android Canvas class. The android API is actually a direct subclass with some Additions

Plain NativeScript

IMPORTANT: Make sure you include xmlns:cv="@nativescript-community/ui-canvas" on the Page element

XML

<Page xmlns:cv="@nativescript-community/ui-canvas">
    <StackLayout horizontalAlignment="center">
        <cv:CanvasView width="100" height="100" draw="draw"/>
   </StackLayout>
</Page>

NativeScript + Angular

import { registerElement } from 'nativescript-angular/element-registry';
import { CanvasView } from '@nativescript-community/ui-canvas';
registerElement('CanvasView', () => CanvasView);

<CanvasView width="100" height="100" (draw)="draw($event)></CanvasView>

NativeScript + Vue

import Vue from 'nativescript-vue';
import CanvasPlugin from '@nativescript-community/ui-canvas/vue';

Vue.use(CanvasPlugin);

<CanvasView  width="100" height="100" @draw="draw"/>

NativeScript + Svelte

// app/app.ts
import { registerNativeViewElement } from 'svelte-native/dom';
registerNativeViewElement('canvasView', () => require('@nativescript-community/ui-canvas').CanvasView);

<!-- app/components/Foo.svelte -->
<stackLayout>
    <canvasView width="300" height="300" on:draw={draw} />
</stackLayout>

Draw Method

import type { Canvas } from '@nativescript-community/ui-canvas';
import { Paint, createRect } from '@nativescript-community/ui-canvas';
import { Color } from '@nativescript/core';

function draw(event: { canvas: Canvas }) {
    const canvas = event.canvas;
    const paint = new Paint();
    paint.setColor(new Color('black'));
    paint.strokeWidth = 10;
    canvas.drawRect(createRect(0, 0, 200, 100), paint);
}

Examples:

• Simple
  • A basic example
• Image
  • An example drawing an image
• Shapes
  • An example drawing shapes using template
• Animation
  • An example of animating a shape
• Complex
  • An example of animating a shape

Demos and Development

Repo Setup

The repo uses submodules. If you did not clone with --recursive then you need to call

git submodule update --init

The package manager used to install and link dependencies must be pnpm or yarn. npm wont work.

To develop and test: if you use yarn then run yarn if you use pnpm then run pnpm i

Interactive Menu:

To start the interactive menu, run npm start (or yarn start or pnpm start). This will list all of the commonly used scripts.

Build

npm run build.all

WARNING: it seems yarn build.all wont always work (not finding binaries in node_modules/.bin) which is why the doc explicitly uses npm run

Demos

npm run demo.[ng|react|svelte|vue].[ios|android]

npm run demo.svelte.ios # Example

Demo setup is a bit special in the sense that if you want to modify/add demos you dont work directly in demo-[ng|react|svelte|vue] Instead you work in demo-snippets/[ng|react|svelte|vue] You can start from the install.ts of each flavor to see how to register new demos

Contributing

Update repo

You can update the repo files quite easily

First update the submodules

npm run update

Then commit the changes Then update common files

npm run sync

Then you can run yarn|pnpm, commit changed files if any

Update readme

npm run readme

Update doc

npm run doc

Publish

The publishing is completely handled by lerna (you can add -- --bump major to force a major release) Simply run

npm run publish

modifying submodules

The repo uses https:// for submodules which means you won't be able to push directly into the submodules. One easy solution is t modify ~/.gitconfig and add

[url "ssh://[e-mail]/"]
	pushInsteadOf = https://github.com/

Questions

If you have any questions/issues/comments please feel free to create an issue or start a conversation in the NativeScript Community Discord.