Package Exports

pixel-scale-epx
pixel-scale-epx/index.js

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (pixel-scale-epx) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

pixel-scale-epx

EPX / Scale2x / AdvMAME2x pixel art scaling algorithm (Eric's Pixel Expansion)

Can also do fast [faux] anti-aliasing by applying EPX then downsampling back to the orignal size.

Also includes the 3x version, aka Scale3x / AdvMAME3x.

Scale pixel art 2x, 3x, 4x, 6x, 8x.

var upscale = require('pixel-scale-epx');
var pixelsData = [r,g,b,a,  r,g,b,a, ... ]; //rgba array 0...255
var width = 256, height = 256; //dimensions of original img
var use8BitColors = false; //if true, ignore lower 8 bits of color channels 
var D2x = upscale.upscaleRgba2x(pixelsData,width,height,use8BitColors); //2x bigger
var D3x = upscale.upscaleRgba3x(pixelsData,width,height,use8BitColors); //3x bigger
var D4x = upscale.upscaleRgba4x(pixelsData,width,height,use8BitColors); //4x bigger [applies 2x op twice]
var D6x = upscale.upscaleRgba6x(pixelsData,width,height,use8BitColors); //6x bigger [applies 2x op then 3x op]
var D8x = upscale.upscaleRgba8x(pixelsData,width,height,use8BitColors); //8x bigger [applies 2x op thrice]

//expand 2x + anti-alias -- eg, expand 4x then downsample 2x -- result is 2x bigger than input 
var D2xAA = upscale.expandAndAntiAliasRgba2x(pixelsData,width,height,use8BitColors);

//if you want ONLY anti-alias without any size change:
var DAA1x = upscale.antiAliasRgba2x_inPlace(pixelsData,width,height,use8BitColors); //works IN PLACE -- size of image not affected

//^in-place anti aliasing via applying EPX 2x then downscaling 2x after

//4x anti aliasing also available, but results look virtually identical
var DAA4x = upscale.antiAliasRgba4x_inPlace(pixelsData,width,height,use8BitColors); //works IN PLACE -- size of image not affected

//can also do "blocky" / naive nearest-neighbor upscale
var blocky2x = upscale.upscaleRgba2x_blocky(pixelsData,width,height);
var blocky4x = upscale.upscaleRgba4x_blocky(pixelsData,width,height);
var blocky8x = upscale.upscaleRgba8x_blocky(pixelsData,width,height);

//format of output is same as input [r,g,b,a ...]

original

^ pixel art enlarged 4x with nearest neighbors

^ pixel art enlarged 4x with EPX

aa2x

^ anti-aliasing via EPX - epx2x + 2x scale down [resulting image scaled 4x to show pixels]

Installation

npm i pixel-scale-epx

Example - upscale a PNG file

In this example we load a PNG file, scale it up 8x (internally we apply EPX algorithm 3 times), then save the result.

var fs = require("fs")
var png = require('fast-png');
var readimage = require("readimage")

var upscale = require('pixel-scale-epx');
var filedata = fs.readFileSync("./test-epx.png");

readimage(filedata, function (err, image) {
    var w = image.width;
    var h = image.height;
    var d = image.frames[0].data;

    var d8x = upscale.upscaleRgba8x(d,w,h)

    var fileData8x = png.encode({width: w*8, height: h*8, data: d8x});
    fs.writeFileSync(`./test_out_8x.png`, fileData8x);
});

enlarged 8x

pixel-scale-epx

Package Exports

Readme

pixel-scale-epx

Installation

Example - upscale a PNG file

See Also