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    png-img
    TypeScript icon, indicating that this package has built-in type declarations

    5.0.0 • Public • Published

    png-img

    Build Status

    Lite self-contained png image processing library for macOS and Linux.

    Requirements

    Linux

    • Depends on GCC 4.6+

    macOs

    Windows

    Installation

    npm install png-img
    

    API

    new PngImg(buffer)

    Create PngImg object from passed buffer with image.

    Arguments:

    • buf - Buffer with image file content.
    const fs = require('fs');
    const {PngImg} = require('png-img');
    
    const buf = fs.readFileSync('path/to/img.png');
    const img = new PngImg(buf);

    size()

    Get image size as an object.

    console.log(img.size());

    for 32x32 image will print out:

    { width: 32, height: 32 }
    

    get(x, y)

    Get pixel color and alpha.

    Returns object:

    • r: red channel (0 to 255)
    • g: green channel (0 to 255)
    • b: blue channel (0 to 255)
    • a: alpha (0 to 255). 0 - transparent
    console.log(img.get(0, 0));

    will print pixel and color for pixel (0, 0):

    {
      r: 100,
      g: 150,
      b: 200,
      a: 255
    }

    fill(offsetX, offsetY, widht, height, color)

    Fill region with passed color. Modifies current image.

    Arguments:

    • offsetX - horizontal offset from the left side of the image
    • offsetY - vertical offset from the top side of the image
    • width - region width
    • height - region height
    • color - color as {r,g,b,a} object or as a '#XXXXXX' string

    Returns: current image object

    Throws if region is not inside the current image

    img
      .fill(0, 0, 16, 16, '#00ffFF') // fill with cyan
      .fill(16, 16, 16, 16, {r: 0, g: 255, b: 255, a: 127}); // fill with half-transparent cyan

    set(x, y, color)

    Same as fill(x, y, 1, 1, color)

    crop(offsetX, offsetY, widht, height)

    Crop image. Modifies current image.

    Arguments:

    • offsetX - horizontal offset from the left side of the image
    • offsetY - vertical offset from the top side of the image
    • width - new width
    • height - new height

    Returns: current image object

    Throws if new image is not inside the current image.

    img
        .crop(0, 0, 16, 16)
        .crop(8, 8, 8, 8);

    setSize(width, height)

    Sets new image size. Modifies current image.

    Arguments:

    • width - new width
    • height - new height

    Returns: current image object

    If new size is less or equal than current size, than crop will be performed.

    Note: this method doesn't strech current image, it just sets new size. If new dimension is less than previous than image will be cut. If new dimension is greater than previous than image will be extended with black area.

    var size = img.size();
    img
      .setSize(size.width/2, size.height*2);

    insert(img, offsetX, offsetY)

    Inserts image into specified place.

    Arguments:

    • img - image to insert. Should be a PngImg object
    • offsetX - horizontal offset from the left side of the image
    • offsetY - vertical offset from the top side of the image

    Join to images (pretend that they have same witdh):

    var otherImg = new PngImg(/*...*/)
    img
     .setSize(img.size().width, img.size().height + otherImg.size().height)
     .insert(otherImg, 0, img.size().height);

    rotateRight()

    Rotates image 90 degrees clockwise

    rotateLeft()

    Rotates image 90 degress counterclockwise

    save(file)

    Save image to file. Asynchronous operation.

    Arguments:

    • file - path to file to save image

    Overwrites existing file.

    await img.save('path/to/file.png');

    Build

    npm run build
    

    This will build native node extension and place it to the compiled directory

    Release

    1. Up version in package json, create tag, and push it to repo. Note: Do not publish the package.
    $ npm version <patch|minor|major>
    $ git push && git push --tags
    
    1. Go to tags page and create release from pushed tag.
    2. Wait for the release workflow to finish. See the actions page to find the workflow.

    Vagrant

    Use Vagrant to build and test on Linux and Windows from macOS.

    Tested with Vagrant 1.7 and VirtualBox 4.3.

    1. Install Vagrant and VirtualBox.
    2. Create Windows vagrant box (see howto)
    3. Run vagrant up --provider virtualbox
    4. Specify OS env variable to run and test on specific platform:
    • npm run build, npm test - current platform
    • OS=linux npm test - Ubuntu 14.04
    • OS=linux-old npm test - Ubuntu 12.04
    • OS=win npm test - Windows
    • OS=all npm test - all

    Keywords

    none

    Install

    npm i png-img

    DownloadsWeekly Downloads

    3,477

    Version

    5.0.0

    License

    MIT

    Unpacked Size

    1.91 MB

    Total Files

    78

    Last publish

    Collaborators

    • sevinf
    • mcheshkov
    • j0tunn
    • xrsd
    • oldskytree
    • y-infra