demos/resize-image.html

<!--
  speedy-vision.js
  GPU-accelerated Computer Vision for JavaScript
  Copyright 2020-2024 Alexandre Martins <alemartf(at)gmail.com>

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at
  
      http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

  resize-image.html
  Resize an image
-->
<!doctype html>
<html>
    <head>
        <meta charset="utf-8">
        <meta name="description" content="speedy-vision.js: GPU-accelerated Computer Vision for JavaScript">
        <meta name="author" content="Alexandre Martins">
        <title>Resize an image</title>
        <link href="demo-base.css" rel="stylesheet">
        <script src="demo-base.js"></script>
        <script src="../dist/speedy-vision.js"></script>
    </head>
    <body>
        <h1>Resize an image</h1>
        <form autocomplete="off">
            <div>
                <label for="scale-x">Width</label>
                <input type="range" min="0.1" max="5.0" value="1.0" step="0.1" id="scale-x">
                <span id="scale-x-percentage">100%</span>
                <span>&nbsp;&nbsp;&nbsp;</span>
            </div>
            <div>
                <label for="scale-y">Height</label>
                <input type="range" min="0.1" max="5.0" value="1.0" step="0.1" id="scale-y">
                <span id="scale-y-percentage">100%</span>
                <span>&nbsp;&nbsp;&nbsp;</span>
            </div>
            <div>
                <label for="keep-aspect-ratio">Keep aspect ratio</label>
                <input type="checkbox" id="keep-aspect-ratio" checked>
            </div>
            <div>
                <select id="interpolation-method">
                    <option value="bilinear" selected>Bilinear interpolation</option>
                    <option value="nearest">Nearest neighbors</option>
                </select>
            </div>
        </form>
        <div>
            <canvas id="canvas-demo"></canvas>
        </div>
        <img id="image" src="../assets/speedy-wall.jpg" title="Image by Bride of Frankenstein (CC-BY)" hidden>
        <script>
window.onload = async function()
{
    // form controls
    const scaleX = document.getElementById('scale-x');
    const scaleY = document.getElementById('scale-y');
    const scaleXPercentage = document.getElementById('scale-x-percentage');
    const scaleYPercentage = document.getElementById('scale-y-percentage');
    const keepAspectRatio = document.getElementById('keep-aspect-ratio');
    const interpolationMethod = document.getElementById('interpolation-method');
    const format = x => (x >= 100 ? x : (x >= 10 ? '0' + x : '00' + x)) + '%';

    scaleX.oninput = () => {
        scaleXPercentage.innerText = format(Math.round(scaleX.value * 100));
        if(keepAspectRatio.checked) {
            scaleY.value = scaleX.value;
            scaleYPercentage.innerText = format(Math.round(scaleY.value * 100));
        }
        render();
    };

    scaleY.oninput = () => {
        scaleYPercentage.innerText = format(Math.round(scaleY.value * 100));
        if(keepAspectRatio.checked) {
            scaleX.value = scaleY.value;
            scaleXPercentage.innerText = format(Math.round(scaleX.value * 100));
        }
        render();
    };

    keepAspectRatio.onchange = () => {
        if(keepAspectRatio.checked) {
            scaleY.value = scaleX.value;
            scaleYPercentage.innerText = format(Math.round(scaleY.value * 100));
        }
        render();
    }

    interpolationMethod.onchange = render;

    /*

    This is the pipeline:

    Image ---> Resize ---> Image
    Source                 Sink

    */

    // load an image
    const img = document.getElementById('image');
    const media = await Speedy.load(img);

    // create the pipeline
    const pipeline = Speedy.Pipeline();
    const source = Speedy.Image.Source();
    const sink = Speedy.Image.Sink();
    const resize = Speedy.Transform.Resize();

    source.media = media;
    resize.size = Speedy.Size(0,0);

    source.output().connectTo(resize.input());
    resize.output().connectTo(sink.input());

    pipeline.init(source, sink, resize);

    // display the result
    const canvas = setupCanvas('canvas-demo', media.width, media.height, img.title);
    async function render()
    {
        resize.scale = Speedy.Vector2(scaleX.value, scaleY.value);
        resize.method = interpolationMethod.value;

        const { image } = await pipeline.run();

        canvas.width = image.width;
        canvas.height = image.height;

        renderMedia(image, canvas);
    }
    render();
}
        </script>
        <section id="speedy-vision">
            <span>Powered by <a href="https://github.com/alemart/speedy-vision" target="_blank">speedy-vision.js</a></span>
            <a href="https://github.com/sponsors/alemart" target="_blank" class="button">
                <img alt="GitHub Sponsors" src="https://img.shields.io/github/sponsors/alemart?style=for-the-badge&logo=github&label=Sponsor&labelColor=royalblue&color=gold">
            </a>
        </section>
    </body>
</html>