tur-png

PNG image read and write for Turmeric via libpng. Decode an existing PNG into a pixel buffer, manipulate per-pixel RGBA, and write the result back out.

Overview

tur-png is a cmake-dep spice that wraps libpng. It exposes png-read / png-write for whole-file I/O, plus an img accessor module that gives you width, height, channel count, bit depth, and per-pixel R/G/B/A read/write.

It is intentionally minimal -- exactly enough to do generative-art-style work or post-process the output of tur-plutovg. For drawing primitives use tur-plutovg; tur-png is the I/O layer.

Install

:spices {
  "png" {:url    "https://github.com/rjungemann/turmeric-spices"
         :ref    "png-v0.1.0"
         :subdir "spices/png"}
}

(import png/reader :refer [png-read img-free])
(import png/info   :refer [img-width img-height pixel-r])

(let [r (png-read "input.png")]
  (when (ok? r)
    (let [img (ok-val r)]
      (println (img-width img) (img-height img))
      (println (pixel-r img 0 0))
      (img-free img))))

#lang sweet-exp
import png/reader :refer [png-read img-free]
import png/info   :refer [img-width img-height pixel-r]

let [r png-read("input.png")]
  when ok?(r)
    let [img ok-val(r)]
      println(img-width(img) img-height(img))
      println $ pixel-r img 0 0
      img-free(img)

See also

• API reference
• Source: https://github.com/rjungemann/turmeric-spices/tree/main/spices/png