@khanhkhanh1991/wasm-hpcc

v0.3.11-custom.40

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a year ago

hpcc-js - WASM Libraries

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khanhkhanh1991

@hpcc-js/wasm

This repository contains a collection of useful c++ libraries compiled to WASM for (re)use in Web Browsers and JavaScript Libraries.

Installation

The simplest way to include this project is via NPM:

npm install --save @hpcc-js/wasm

@hpcc-js/wasm includes the following files in its dist folder:

index.js / index.min.js files: Exposes all the available APIs for all WASM files.
WASM Files:
- graphvizlib.wasm
- expatlib.wasm
- ...more to follow...

Important: WASM files are dynamically loaded at runtime (this is a browser / emscripten requirement), which has a few implications for the consumer:

Pros:

While this package has potentially many large WASM files, only the ones being used will ever be downloaded from your CDN / Web Server.

Cons:

Most browsers don't support fetch and loading pages via file:// URN, so for testing / development work you will need to run a test web server.
Bundlers (RollupJS / WebPack) will ignore the WASM files, so you will need to manually ensure they are present in your final distribution (typically they are placed in the same folder as the bundled JS)

API Reference

Common

Utility functions relating to @hpcc-js/wasm as a package

# wasmFolder([url]) · <>

If url is specified, sets the default location for all WASM files. If url is not specified it returns the current url (defaults to undefined).

# __hpcc_wasmFolder · <>

Global variable for setting default WASM location, this is an alternative to wasmFolder

GraphViz (`graphvizlib.wasm`)

GraphViz WASM library, see graphviz.org for c++ details. While this package is similar to Viz.js, it employs a completely different build methodology taken from GraphControl.

The GraphViz library comes in two flavours

An exported graphviz namespace, where each API function is asynchrounous and returns a Promise<string>.
A graphvizSync asynchrounous function which returns a Promise<GraphvizSync> which is a mirror instance of graphviz, where each API function is synchrounous and returns a string.

Hello World

<!DOCTYPE html>
<html>

<head>
    <meta charset="UTF-8">
    <title>GraphViz WASM</title>
    <script src="https://unpkg.com/@hpcc-js/wasm/dist/index.min.js"></script>
    <script>
        var hpccWasm = window["@hpcc-js/wasm"];
    </script>
</head>

<body>
    <div id="placeholder"></div>
    <div id="placeholder2"></div>
    <script>
        const dot = `
            digraph G {
                node [shape=rect];

                subgraph cluster_0 {
                    style=filled;
                    color=lightgrey;
                    node [style=filled,color=white];
                    a0 -> a1 -> a2 -> a3;
                    label = "Hello";
                }

                subgraph cluster_1 {
                    node [style=filled];
                    b0 -> b1 -> b2 -> b3;
                    label = "World";
                    color=blue
                }

                start -> a0;
                start -> b0;
                a1 -> b3;
                b2 -> a3;
                a3 -> a0;
                a3 -> end;
                b3 -> end;

                start [shape=Mdiamond];
                end [shape=Msquare];
            }
        `;

        // Asynchronous call to layout
        hpccWasm.graphviz.layout(dot, "svg", "dot").then(svg => {
            const div = document.getElementById("placeholder");
            div.innerHTML = svg;
        });

        hpccWasm.graphvizSync().then(graphviz => {
            const div = document.getElementById("placeholder2");
            // Synchronous call to layout
            div.innerHTML = graphviz.layout(dot, "svg", "dot");
        });
    </script>

</body>

</html>

GraphViz API

# layout(dotSource[, outputFormat][, layoutEngine][, ext]) · <>

Performs layout for the supplied dotSource, see The DOT Language for specification.

outputFormat supports the following options:

dot
dot_json
json
svg (default)
xdot_json

See Output Formats for more information.

layoutEngine supports the following options:

circo
dot (default)
fdp
neato
osage
patchwork
twopi

See Layout manual pages for more information.

ext optional "extra params":

images: An optional array of

{
    path: string;   //  The path for the image.
    width: string;  //  Width of Image
    height: string; //  Height of Image
}

files: An optional array of

{
    path: string;   //  The path for the file.
    data: string;   //  The data for the file.
}

For example passing a web hosted Image to GraphViz:

hpccWasm.graphviz.layout('digraph { a[image="https://.../image.png"]; }', "svg", "dot", { 
    images: [{ 
        path: "https://.../image.png", 
        width: "272px", 
        height: "92px" 
    }] 
}).then(svg => {
    document.getElementById("placeholder").innerHTML = svg;
}).catch(err => console.error(err.message));

# circo(dotSource[, outputFormat][, ext]) · <>

Convenience function that performs circo layout, is equivalent to layout(dotSource, outputFormat, "circo");.

# dot(dotSource[, outputFormat][, ext]) · <>

Convenience function that performs dot layout, is equivalent to layout(dotSource, outputFormat, "dot");.

# fdp(dotSource[, outputFormat][, ext]) · <>

Convenience function that performs circo layout, is equivalent to layout(dotSource, outputFormat, "fdp");.

# neato(dotSource[, outputFormat][, ext]) · <>

Convenience function that performs neato layout, is equivalent to layout(dotSource, outputFormat, "neato");.

# osage(dotSource[, outputFormat][, ext]) · <>

Convenience function that performs osage layout, is equivalent to layout(dotSource, outputFormat, "osage");.

# patchwork(dotSource[, outputFormat][, ext]) · <>

Convenience function that performs patchwork layout, is equivalent to layout(dotSource, outputFormat, "patchwork");.

# twopi(dotSource[, outputFormat][, ext]) · <>

Convenience function that performs twopi layout, is equivalent to layout(dotSource, outputFormat, "twopi");.

Expat (`expatlib.wasm`)

Expat WASM library, provides a simplified wrapper around the Expat XML Parser library, see libexpat.github.io for c++ details.

Hello World

<!DOCTYPE html>
<html>

<head>
    <meta charset="UTF-8">
    <title>GraphViz WASM</title>
    <script src="https://unpkg.com/@hpcc-js/wasm/dist/index.min.js"></script>
    <script>
        var hpccWasm = window["@hpcc-js/wasm"];
    </script>
</head>

<body>
    <script>
        const xml = `
            <root>
                <child xxx="yyy">content</child>
            </root>
        `;

        var callback = {
            startElement(tag, attrs) { console.log("start", tag, attrs); },
            endElement(tag) { console.log("end", tag); },
            characterData(content) { console.log("characterData", content); }
        };
        hpccWasm.parse(xml, callback);
    </script>

</body>

</html>

Expat API

# parse(xml, callback) · <>

xml: XML String.
callback: Callback Object with the following methods:
- startElement(tag: string, attrs: {[key: string]: string]): void;
- endElement(tag: string): void;
- characterData(content: string): void;

Parses the XML with suitable callbacks.

Note: characterData may get called several times for a single tag element.

Building @hpcc-js/wasm

Building is supported on both Linux (tested with Ubuntu 18.04) and Windows with WSL enabled (Ubuntu-18.04). Building in other environments should work, but may be missing certain prerequisites.

These are then known required OS dependencies:

sudo apt-get install -y curl
sudo curl --silent --location https://deb.nodesource.com/setup_12.x | sudo bash -
sudo apt-get install -y nodejs
sudo apt-get install -y build-essential

sudo apt-get install -y git cmake wget
sudo apt-get install -y gcc-multilib g++-multilib pkg-config autoconf bison libtool flex zlib1g-dev 
sudo apt-get install -y python2.7 python-pip

Build steps:

git clone https://github.com/hpcc-systems/hpcc-js-wasm.git
cd hpcc-js-wasm
npm ci
npm run install-build-deps
npm run build

Note: The install-build-deps downloads the following dependencies:

This has been made a manual step as the downloads are quite large and the auto-configuration can be time consuming.

Clean dependencies:

It is worth noting that npm run clean will only clean any artifacts associated with the build, but won't clean clean any of the third party dependencies. To remove those for a "full clean", run:

npm run clean-build-deps

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@hpcc-js/wasm

Installation

Contents

API Reference

Common

GraphViz (graphvizlib.wasm)

Hello World

GraphViz API

Expat (expatlib.wasm)

Hello World

Expat API

Building @hpcc-js/wasm

Build steps:

Clean dependencies:

GraphViz (`graphvizlib.wasm`)

Expat (`expatlib.wasm`)