xcfreader

Parses files generated by Gimp (.xcf)

xcfreader can

• Parse a gimp file.
• Provide image width and height information.
• Provide layer information including width, height, x offset in the main image, y offset from the main image.
• Render each layer using an image generator
• Flatten the file using an image generator

xcfreader only supports

• rgb and rgba file formats.
• raster images

xcfreader todo

• support text layers.
• support indexed images
• support grayscale images
• support paths
• perform proper layer flattening. (Currently the pixel is over written by the layer)

Installation

Install this module with the following command:

npm install xcfreader

Add the module to your package.json dependencies:

npm install --save xcfreader

Add the module to your package.json dev-dependencies

npm install --save-dev xcfreader

Usage

Require the module

import XCFReader from 'xcfreader';

Read a file

    XCFReader.parseFile('./myimage.xcf, function(err, xcfReader){
        if (err) throw err;

        // Get width and height
        console.log(xcfReader.width);
        console.log(xcfReader.height);

        // Get the number of layers
        console.log(xcfReader.layers.length);

        // Get the width and height of the top layer
        console.log(xcfreader.layers[0].width);
        console.log(xcfreader.layers[0].height);

        // Flattern an image
        var xcf = new XCFImage() // should call your Image class.
        xcf.fill({red:0, green:0, blue: 0, alpha: 255}); // You need to set up the image with the default background for the image.

        // Layer[0] is the top most layer whilst layer[layer.length-1] is the lowest level
        // So we need to apply from the end of the layer array. 
        var numLayers = xcfreader.layers.length;
        for(var loop = numLayers -1; loop >=0; loop -=1){
            xcfreader.layers[loop].makeImage(xcf,true); // Put the current layer on to the image.
        }

        xcf.save('myImage.png');
    });

Saving an Image If you want to save either the layer images or the whole image you need to provide a class instance that implements the folling interface

  XCFImageInterface {

      //set a pixel at a given position.
      // @param x the x co-ordinate to set (Can be outside of the image);
      // @param y the y co-ordinate to set (Can be outside of the image);
      // @param colour { red:<0-255> , green:<0-255> , blue: <0-255>, alpha: <o-255>} // alpha is only include if the layer includes transparancy informatin 
      setAt(int: x, int: y, obj: colour);

      // get the pixel at a given position ( Not currently used, but will in the future to perform flattening)
      // @param x the x co-ordinate to set (Can be outside of the image);
      // @param y the y co-ordinate to set (Can be outside of the image);
      // @return colour { red:<0-255> , green:<0-255> , blue: <0-255>, alpha: <o-255>} // alpha is only include if the layer includes transparancy informatin 
      obj: colour getAt(int: x, int: y);
  }

Class XCFParser

Static methods

parseImage(string: filename, function: callback)

filename the file to parse

callback function(Error:err , GimpParser: xcfReader) called when the parsing has completed.

Methods

createImage(XCFImage image)

image instance of a class derived from the above interface.

Returns the image with all visible layers flattened. If image if null then an XCFImage is created of the correct width and height

Properties

**width**The width of the image

**height**The height of the image

**layers**An array of GimpLayer objects

Class GimpLayer

Methods

makeImage(XCFImage: image , boolean: useOffset)

image instance of a class derived from the above interface.

useOffset (defaults to false) wether to use the layer offset.

Returns:

| image | useOffset | layer is visible|Action | |------------|--------------|-----------------|--------------| | null | true / false | false | returns null | | null | true | true | returns a XCFImage the width and height of the main image, with the layer rendered in the correct location| | null | false | true | returns a XCFImage the width and height of the layer| | XCFImage | true / false | false | returns the passed XCFImage unaltered| | XCFImage | true | true | returns the passed XCFImage with the layer rendered in the correct location| | XCFImage | false | true | returns the passed XCFImage with the layer rendered in the top left corner|

Properties

**name**The name of the layer

**width**The width of the layer

**height**The height of the layer

**x**The x offset of the layer on the base image

**y**The y offset of the layer on the base image

Class XCFImage

The XCFImage wraps round a pngjs-image object. See the docs of pngjs-image for details

The XCFImage overwrites setAt(x,y,color) and getAt(x,y,colour) to provide functionality describe above