Sharp-apng NPM

sharp-apng

APNG(animated PNG) encoder and decoder for sharp base on upng-js.

Install

npm install sharp-apng

Usage

const sharp = require("sharp");
const apng = require("sharp-apng");

(async () => {
  // APNG to GIF
  const image = await apng.sharpFromApng("./animated.png");
  image.toFile("./output/apng2gif.gif");

  // APNG to frames
  const frames = apng.framesFromApng("./animated.png");
  frames.forEach((frame, index) => {
    frame.toFile(`./output/apng-${("000" + index).substr(-4)}.png`);
  });

  // GIF to APNG
  apng.sharpToApng(
    sharp("./animated.gif", { animated: true }),
    "./output/gif2apng.png"
  );

  // frames to APNG
  apng.framesToApng(
    [
      sharp("./frames/0000.png"),
      sharp("./frames/0001.png"),
      sharp("./frames/0002.png"),
    ],
    "./output/animated.png"
  );
})();

API

`apng.framesFromApng(input, resolveWithObject?)`

Create instances of sharp from APNG frames.

input (String | Buffer) - A String containing the filesystem path to an APNG image file, or a Buffer containing APNG image data.
resolveWithObject Boolean (optional) - Return an ImageData containing frames (an array of instances of sharp) property and decoding info instead of only an array of instances of sharp. Default by false.

Returns Sharp[] | ImageData - Return an array of instance of sharp, or an ImageData containing frames (an array of instances of sharp) property and decoding info.

`apng.sharpFromApng(input, options?, resolveWithObject?)`

Create an instance of animated sharp from an APNG image.

input (String | Buffer) - A String containing the filesystem path to an APNG image file, or a Buffer containing APNG image data.
options DecoderOptions - Options for encode animated GIF and create sharp instance.
resolveWithObject Boolean (optional) - Return an ImageData containing image (an instance of sharp) property and decoding info instead of only an instance of sharp. Default by false.

Returns Promise<Sharp | ImageData> - Resolve with an instance of animated sharp, or an ImageData containing image (an instances of sharp) property and decoding info.

`DecoderOptions`

Options for encode animated GIF and create sharp instance.

sharpOptions Number (optional) - Sharp constructor options.
delay (Number | Number[]) (optional) - Delay(s) between animation frames (in milliseconds).
repeat Number (optional) - Number of animation iterations, use 0 for infinite animation. Default by 0.
transparent Boolean (optional) - Enable 1-bit transparency for the GIF. Default by false.
maxColors Number (optional) - Quantize the total number of colors down to a reduced palette no greater than maxColors. Default by 256.
format ("rgb565" | "rgb444" | "rgba4444") (optional) - Color format. Default by rgb565.
- rgb565 means 5 bits red, 6 bits green, 5 bits blue (better quality, slower)
- rgb444 is 4 bits per channel (lower quality, faster)
- rgba4444 is the same as above but with alpha support
gifEncoderOptions Object (optional) - gifenc GIFEncoder() options.
gifEncoderQuantizeOptions Object (optional) - gifenc quantize() options.
gifEncoderFrameOptions Object (optional) - gifenc gif.writeFrame() options.

`ImageData`

Contains the following decoding info:

width Number - The width of the image, in pixels.
height Number - The height of the image, in pixels.
depth Number - Number of bits per channel.
ctype Number - Color type of the file (Truecolor, Grayscale, Palette ...).
pages Number - Number of frames contained within the image.
delay Number[] - Delay in ms between each frame.
frames Sharp[] (apng.framesFromApng() only) - Instances of sharp from APNG frames.
image Sharp (apng.sharpFromApng() only) - Animated sharp instance.

`apng.framesToApng(images, fileOut, options?)`

Write an APNG file from sharps.

images Sharp[] - An array of instances of sharp.
fileOut String - The path to write the image data to.
options EncoderOptions (optional) - Options for resize frames and encoding APNG.

Returns Promise<Object> - Resolve with an Object containing size, width, height properties.

`apng.sharpToApng(image, fileOut, options?)`

Write an APNG file from an animated sharp.

image Sharp - An instance of animated sharp.
fileOut String - The path to write the image data to.
options EncoderOptions (optional) - Options for resize frames and encoding APNG.

Returns Promise<Object> - Resolve with an Object containing size, width, height properties.

EncoderOptions

Options for resize frames and encode APNG.

width Number (optional) - Width, in pixels, of the APNG to output. If omitted, will use resizeTo option.
height Number (optional) - Height, in pixels, of the APNG to output. If omitted, will use resizeTo option.
cnum Number (optional) - Number of colors in the result; 0: all colors (lossless PNG)
delay (Number | Number[]) (optional) - Delay(s) between animation frames (in milliseconds, only when 2 or more frames)
resizeTo ("largest" | "smallest") (optional) - Resize all frame to the largest frame or smallest frame size. Default by largest.
resizeType ("zoom" | "crop") (optional) - zoom use sharp.resize(), crop use sharp.extend() and sharp.extract().
resizeOptions sharp.ResizeOptions (optional) - Options for sharp.resize().
extendBackground sharp.Color (optional) - Background option for sharp.extend(). Default by { r: 0, g: 0, b: 0, alpha: 0 }.