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