bpy - how to select an image running blender in -background mode so an operator can use it?

Question

I need to invert an image running blender from the command line using the -background flag. To archive it I need to make the image active and later apply the invert operator.

I managed to select and invert the image with Blender running the UI, with the following code:

# Select the active image
m = bpy.context.area.type
bpy.context.area.type = "IMAGE_EDITOR"
bpy.context.area.spaces.active.image = myImageToInvert

# Operate over the selected image
bpy.ops.image.invert(invert_r=True, invert_g=True, invert_b=True)

But this code does not run when Blender is called from the command line with the -background flag, because the UI is not loaded so bpy.context.area is null.

How can I select the image (myImageToInvert) in the background so bpy.ops.image.invert() can operate over my image?

Thank you

Answer 1

(Edit) Deleted 1. Solution

2. Solution This code inverts, the color of a picture. Maybe a bit slower than the Operator but not by much.

It's use bpy.data so you have to input the name of the picture to get it.

import bpy

def invert(image, invert_r = True, invert_g = True, invert_b = True, invert_a = True):
    pixels = list(image.pixels)
    if invert_r: 
        for i in range(0, len(pixels), 4): # R
            pixels[i] = 1 - pixels[i]
    if invert_g:
        for i in range(1, len(pixels), 4): # G
            pixels[i] = 1 - pixels[i]
    if invert_b:
        for i in range(2, len(pixels), 4): # B
            pixels[i] = 1 - pixels[i]
    if invert_a:
        for i in range(3, len(pixels), 4): # A
            pixels[i] = 1 - pixels[i]
    image.pixels = pixels
            
#Example           
image = bpy.data.images['Untitled']     
invert(image, invert_a = False)

You could also use this code to input a sequence of images (exchange this with the code after #Example).

images = ['Untitled', 'Untitled.001']
for image in images:
    invert(image, invert_a = False)

Answer 2

win = bpy.context.window_manager.windows[0]
area = win.screen.areas[0]
area.type = "IMAGE_EDITOR"
override = bpy.context.copy()
override['window'] = win
override['screen'] = win.screen
override['area'] = win.screen.areas[0]
override['area'].spaces.active.image = bpy.data.images['Untitled']

bpy.ops.image.invert(override, invert_r=True, invert_g=True, invert_b=True)

I have this as another solution, but Blender always crash with an exception_access_violation if the operator get called. If somebody has a solution for this it would probably work.