Example of converting OpenImageIO ColorData float32 rgb pixel values into stdlib image; Encode to JPEG

openimageigo_issue1.go

/*
Example of taking an OpenColorIO ColorData and converting
it into a stdlib Image. Then encoding to jpeg format.

Ref: https://github.com/justinfx/opencolorigo/issues/1

Author: Justin Israel ([email protected])
*/
package main

import (
	"bufio"
	"image"
	"image/jpeg"
	"os"
)

const maxRgb = 255.999

// ColorData is a slice of float32 color values
// representing rgbrgbrgb...
type ColorData []float32

// FloatToInt converts a float color component value
// into an 8bit value (0-255)
func FloatToInt(f float32) uint8 {
	return uint8(f * maxRgb)
}

// ColorDataToImage converts ColorData float pixels
// into an *image.RGBA
func ColorDataToImage(pixels ColorData, w, h int) *image.RGBA {
	// Properly sized blank image
	img := image.NewRGBA(image.Rect(0, 0, w, h))

	j := 0
	comp := 1 // which color component we are on

	// Set each R,G,B,A component of the image
	for i := range img.Pix {
		// Handle Alpha
		if comp == 4 {
			img.Pix[i] = 255
			comp = 1
			continue
		}

		// Handle color convert
		img.Pix[i] = FloatToInt(pixels[j])

		j += 1
		comp += 1
	}

	return img
}

// Make some random ColorData pixel data in format of:
// rgbrgbrgb...
func createImageData(w, h int) ColorData {
	imageData := make(ColorData, w*h*3)
	for i := range imageData {
		imageData[i] = 0.5
	}
	return imageData
}

func main() {
	w := 512
	h := 512

	// Some random ColorData for a given image size
	imageData := createImageData(w, h)

	// Convert ColorData to *image.RGBA
	img := ColorDataToImage(imageData, w, h)

	// Encode to jpeg
	out, _ := os.Create("out.jpg")
	err := jpeg.Encode(bufio.NewWriter(out), img, nil)
	if err != nil {
		panic(err.Error())
	}
}

haha, My code just add thego func to this, mayBe it is faster,I will tip my code if it works