#!/usr/bin/env python


from gimpfu import *

def py_luminance_extract(img, draw):
        pdb.gimp_image_undo_group_start(img)

        name = pdb.gimp_drawable_get_name(draw)

        newlayer = pdb.gimp_layer_copy(draw, 0)
        pdb.gimp_image_add_layer(img, newlayer, -1)

        pdb.gimp_desaturate_full(newlayer, 1)
        
        newlayer2 = pdb.gimp_layer_copy(newlayer, 1)
        pdb.gimp_image_add_layer(img, newlayer2, -1)

        pdb.gimp_layer_set_mode(newlayer, GRAIN_EXTRACT_MODE)
        ndraw = pdb.gimp_image_merge_down(img, newlayer, 0)
        pdb.gimp_layer_set_mode(newlayer2, GRAIN_MERGE_MODE)        

        pdb.gimp_drawable_set_name(ndraw, name + " Chroma")
        pdb.gimp_drawable_set_name(newlayer2, name + " Luminance")
        
        pdb.gimp_image_undo_group_end(img)

register(
        "luminance_extract",
        "Extract luminance from a layer",
        "Extracts the luminance from a layer",
        "dd",
        "2011",
        "2011",
        "<Image>/Filters/Luminance/_Extract...", 
        "RGB*",
        [],
        [],
        py_luminance_extract)


def py_luminance_remove(img, draw):
        pdb.gimp_image_undo_group_start(img)       

        newlayer = pdb.gimp_layer_copy(draw, 0)
        pdb.gimp_image_add_layer(img, newlayer, -1)

        pdb.gimp_desaturate_full(newlayer, 1)
        
        pdb.gimp_layer_set_mode(newlayer, GRAIN_EXTRACT_MODE)
        pdb.gimp_image_merge_down(img, newlayer, 0)       

        pdb.gimp_image_undo_group_end(img)

register(
        "luminance_remove",
        "Remove luminance from a layer",
        "Removes the luminance from a layer",
        "dd",
        "2011",
        "2011",
        "<Image>/Filters/Luminance/_Remove...", 
        "RGB*",
        [],
        [],
        py_luminance_remove)


def py_luminance_hsadjust(img, draw, hue, sat):

        name = pdb.gimp_drawable_get_name(draw)
        
        pdb.gimp_image_undo_group_start(img)       

        pos = pdb.gimp_image_get_layer_position(img, draw)

        pdb.python_fu_luminance_extract(img, draw)

        llayer = img.layers[pos]
        clayer = img.layers[pos+1]

        pdb.gimp_hue_saturation(clayer, 0, hue, 0, sat)
        pdb.python_fu_luminance_remove(img, clayer)

        ndraw = pdb.gimp_image_merge_down(img, llayer, 0)
        pdb.gimp_drawable_set_name(ndraw, name)
        
        pdb.gimp_image_undo_group_end(img)

register(
        "luminance_hsadjust",
        "Adjust hue/saturation while preserving luminance",
        "Adjusts hue/saturation while preserving luminance",
        "dd",
        "2011",
        "2011",
        "<Image>/Filters/Luminance/_Hue-Saturation...",
        "RGB*",
        [
                (PF_SLIDER, "hue", "Hue", 0, (-180, 180, 1)),
                (PF_SLIDER, "sat", "Saturation", 0, (-100, 100, 1))
        ],
        [],
        py_luminance_hsadjust)


main()