io_import_images_as_planes.py

                    material = mat
        if not material:
            material = bpy.data.materials.new(name=name_compat)

        material.use_nodes = True
        if self.use_transparency:
            material.blend_method = 'BLEND'
        node_tree = material.node_tree
        out_node = clean_node_tree(node_tree)

        tex_image = self.create_cycles_texnode(context, node_tree, img_spec)

        if self.shader == 'PRINCIPLED':
            core_shader = node_tree.nodes.new('ShaderNodeBsdfPrincipled')
        elif self.shader == 'SHADELESS':
            core_shader = get_shadeless_node(node_tree)
        else:  # Emission Shading
            core_shader = node_tree.nodes.new('ShaderNodeEmission')
            core_shader.inputs['Strength'].default_value = self.emit_strength

        # Connect color from texture
        node_tree.links.new(core_shader.inputs[0], tex_image.outputs['Color'])

        if self.use_transparency:
            if self.shader == 'PRINCIPLED':
                node_tree.links.new(core_shader.inputs['Alpha'], tex_image.outputs['Alpha'])
            else:
                bsdf_transparent = node_tree.nodes.new('ShaderNodeBsdfTransparent')

                mix_shader = node_tree.nodes.new('ShaderNodeMixShader')
                node_tree.links.new(mix_shader.inputs['Fac'], tex_image.outputs['Alpha'])
                node_tree.links.new(mix_shader.inputs[1], bsdf_transparent.outputs['BSDF'])
                node_tree.links.new(mix_shader.inputs[2], core_shader.outputs[0])
                core_shader = mix_shader

        node_tree.links.new(out_node.inputs['Surface'], core_shader.outputs[0])

        auto_align_nodes(node_tree)
        return material

    # -------------------------------------------------------------------------
    # Geometry Creation
    def create_image_plane(self, context, name, img_spec):

        width, height = self.compute_plane_size(context, img_spec)

        # Create new mesh
        bpy.ops.mesh.primitive_plane_add('INVOKE_REGION_WIN')
        plane = context.active_object
        # Why does mesh.primitive_plane_add leave the object in edit mode???
        if plane.mode != 'OBJECT':
            bpy.ops.object.mode_set(mode='OBJECT')
        plane.dimensions = width, height, 0.0
        plane.data.name = plane.name = name
        bpy.ops.object.transform_apply(location=False, rotation=False, scale=True)

        # If sizing for camera, also insert into the camera's field of view
        if self.size_mode == 'CAMERA':
            offset_axis = self.axis_id_to_vector[self.offset_axis]
            translate_axis = [0 if offset_axis[i] else 1 for i in (0, 1)]
            center_in_camera(context.scene, context.scene.camera, plane, translate_axis)

        self.align_plane(context, plane)

        return plane

    def compute_plane_size(self, context, img_spec):
        """Given the image size in pixels and location, determine size of plane"""
        px, py = img_spec.size

        # can't load data
        if px == 0 or py == 0:
            px = py = 1

        if self.size_mode == 'ABSOLUTE':
            y = self.height
            x = px / py * y

        elif self.size_mode == 'CAMERA':
            x, y = compute_camera_size(
                context, context.scene.cursor.location,
                self.fill_mode, px / py
            )

        elif self.size_mode == 'DPI':
            fact = 1 / self.factor / context.scene.unit_settings.scale_length * 0.0254
            x = px * fact
            y = py * fact

        else:  # elif self.size_mode == 'DPBU'
            fact = 1 / self.factor
            x = px * fact
            y = py * fact

        return x, y

    def align_plane(self, context, plane):
        """Pick an axis and align the plane to it"""
        if 'CAM' in self.align_axis:
            # Camera-aligned
            camera = context.scene.camera
            if (camera):
                # Find the axis that best corresponds to the camera's view direction
                axis = camera.matrix_world @ \
                    Vector((0, 0, 1)) - camera.matrix_world.col[3].xyz
                # pick the axis with the greatest magnitude
                mag = max(map(abs, axis))
                # And use that axis & direction
                axis = Vector([
                    n / mag if abs(n) == mag else 0.0
                    for n in axis
                ])
            else:
                # No camera? Just face Z axis
                axis = Vector((0, 0, 1))
                self.align_axis = 'Z+'
        else:
            # Axis-aligned
            axis = self.axis_id_to_vector[self.align_axis]

        # rotate accordingly for x/y axiis
        if not axis.z:
            plane.rotation_euler.x = pi / 2

            if axis.y > 0:
                plane.rotation_euler.z = pi
            elif axis.y < 0:
                plane.rotation_euler.z = 0
            elif axis.x > 0:
                plane.rotation_euler.z = pi / 2
            elif axis.x < 0:
                plane.rotation_euler.z = -pi / 2

        # or flip 180 degrees for negative z
        elif axis.z < 0:
            plane.rotation_euler.y = pi

        if self.align_axis == 'CAM':
            constraint = plane.constraints.new('COPY_ROTATION')
            constraint.target = camera
            constraint.use_x = constraint.use_y = constraint.use_z = True
            if not self.align_track:
                bpy.ops.object.visual_transform_apply()
                plane.constraints.clear()

        if self.align_axis == 'CAM_AX' and self.align_track:
            constraint = plane.constraints.new('LOCKED_TRACK')
            constraint.target = camera
            constraint.track_axis = 'TRACK_Z'
            constraint.lock_axis = 'LOCK_Y'


# -----------------------------------------------------------------------------
# Register

def import_images_button(self, context):
    self.layout.operator(IMPORT_IMAGE_OT_to_plane.bl_idname, text="Images as Planes", icon='TEXTURE')


classes = (
    IMPORT_IMAGE_OT_to_plane,
)


def register():
    for cls in classes:
        bpy.utils.register_class(cls)

    bpy.types.TOPBAR_MT_file_import.append(import_images_button)
    bpy.types.VIEW3D_MT_image_add.append(import_images_button)

    bpy.app.handlers.load_post.append(register_driver)
    register_driver()


def unregister():
    bpy.types.TOPBAR_MT_file_import.remove(import_images_button)
    bpy.types.VIEW3D_MT_image_add.remove(import_images_button)

    # This will only exist if drivers are active
    if check_drivers in bpy.app.handlers.depsgraph_update_post:
        bpy.app.handlers.depsgraph_update_post.remove(check_drivers)

    bpy.app.handlers.load_post.remove(register_driver)
    del bpy.app.driver_namespace['import_image__find_plane_corner']

    for cls in classes:
        bpy.utils.unregister_class(cls)


if __name__ == "__main__":
    # Run simple doc tests
    import doctest
    doctest.testmod()

    unregister()
    register()