Modo python API: Create a custom preview render and write its image to disk as png in sRGB color space

CustomPreviewRender.py

import lx
import modo

ImgSrv = lx.service.Image()
colorService = lx.service.ColorMapping()
TosRGB = lx.object.ColorMapping(colorService.MakeColorMapping("nuke-default:sRGB", 0))

width = 1000
height = 800

# Create preview and render
Preview = lx.service.Preview().CreatePreview()
Preview.SetRes(width, height)
Preview.SetRenderTime(15.0)

Preview.IsComplete()

# Get the preview buffer
previewImage = Preview.GetBuffer()
w, h = previewImage.Size()
ch = previewImage.Components()

# create a new storage object for our pixels
Pixel = lx.object.storage()
Pixel.setType('f')
Pixel.setSize(w * h * ch)

# Create a new image for export
exportImage = ImgSrv.Create(w, h, lx.symbol.iIMP_RGBAFP, 0)
imWrite = lx.object.ImageWrite(exportImage)

for ih in range(h):
	for iw in range(w):
		previewImage.GetPixel(iw, ih, lx.symbol.iIMP_RGBAFP, Pixel)
		iR = Pixel[0]
		iG = Pixel[1]
		iB = Pixel[2]
		# convert to sRGB
		R, G, B = TosRGB.FromLinear((iR, iG, iB), 3)
		# set the RGBA pixels
		Pixel.set((R, G, B, Pixel[3]))
		imWrite.SetPixel(iw, ih, lx.symbol.iIMP_RGBAFP, Pixel)	

# Write image to disk
ImgSrv.Save(imWrite, '/tmp/test1.png', 'PNG', 0)