isoblend

PDF Blend modes as defined by the Adobe® Supplement to the ISO 32000/-1

Optimised RGBA blend functions performing blend operations based on the PDF / Adobe® Photoshop® blend modes. The functions are designed to work with the pixel format of an ImageData object, where pixel values are stored as

[R, G, B, A, R, G, B, A, R, G, B, A, ... ]

Each blend function takes src, dst and out array, where

• src is the image on top
• dst is the image underneath
• out is the array in which to write the result of the operation

The following RGBA blend modes are supported

• Normal isoblend/normal
• Compatible isoblend/compatible
• Multiply isoblend/multiply
• Screen isoblend/screen
• Overlay isoblend/overlay
• Darken isoblend/darken
• Lighten isoblend/lighten
• ColorDodge* isoblend/dodge
• ColorBurn* isoblend/burn
• HardLight isoblend/hardlight
• SoftLight isoblend/softlight
• Difference isoblend/difference
• Exclusion isoblend/exclusion

*Based on extension level 5

Adobe® Supplement to the ISO 32000 Base Version: 1.7 Extension Level: 3

Adobe® Supplement to ISO 32000-1 Base Version: 1.7 Extension Level: 5

Example

var isoblend = require("isoblend")

var src = [0.1, 0.5, 0.7, 0.9, 0.1, 0.5, 0.7, 0.9]  // 2 pixels [RGBARGBA]
var dst = [0.5, 0.4, 0.3, 0.4, 0.9, 0.2, 0.5, 0.8]  // 2 pixels to blend over

var out = []

iso.normal(src, dst, out)

// out contains the result after blending src on top of dst using normal blend

Installation

npm install isoblend

Contributors

• Matt-Esch

MIT Licenced