#!/usr/bin/env python
# -*- coding: utf-8 -*-

from gimpfu import * 
import ctypes

def napln(image, drawable):

    # Merging operation
    pdb.gimp_image_undo_group_start(image)
    
    # Image size recognition and layer creation       
    sirka = drawable.width
    vyska = drawable.height

    vrstva1 = pdb.gimp_layer_new_from_drawable(drawable, image)
       
    # Edge detection using Sobel operator       
    pdb.plug_in_edge(image, drawable, 1, 0, 0)
    
    # Converting to gryscale according to the value parameter
    monochrome = TRUE
    rr_gain = 0.299
    rg_gain = 0.299
    rb_gain = 0.299
    gr_gain = 0.587
    gg_gain = 0.587
    gb_gain = 0.587 
    br_gain = 0.114
    bg_gain = 0.114
    bb_gain = 0.114
    
    pdb.plug_in_colors_channel_mixer(image, drawable, monochrome, rr_gain, rg_gain, rb_gain, gr_gain, gg_gain, gb_gain, br_gain, bg_gain, bb_gain)

    # Converting to monochrome    
    pdb.gimp_image_convert_grayscale(image)

    # Bit depth recognition
    hloubka = drawable.bpp
    if pdb.gimp_drawable_has_alpha(drawable):
        hloubka = (256 ** (hloubka / 2)) - 1
    else:
        hloubka = (256 ** hloubka) - 1
    
    rozliseni = ((int(pdb.gimp_image_get_resolution(image)[0]) + int(pdb.gimp_image_get_resolution(image)[0])) / 2)  
    
    # Average pixel value recognition    
    histogram = pdb.gimp_drawable_histogram(drawable, 0, 0, 1)
    jdh = histogram[0] / hloubka
    jdh = jdh * 100

    # Visualization of the map load distribution
    # pdb.gimp_drawable_invert(drawable, True)
    # pdb.gimp_drawable_brightness_contrast(drawable, -0.5, 0.5)
        
    sirka = int(sirka / 10)
    vyska = int(vyska / 10)
    if sirka > vyska:
      pdb.plug_in_pixelize2(image, drawable, vyska, vyska)
    else:
      pdb.plug_in_pixelize2(image, drawable, sirka, sirka)   
    
    pdb.gimp_image_convert_rgb(image)      
    vrstva2 = pdb.gimp_layer_new_from_drawable(drawable, image)
    
    pdb.gimp_layer_set_opacity(vrstva2, 85)
    pdb.gimp_image_insert_layer(image, vrstva1, None, -1)
    pdb.gimp_image_insert_layer(image, vrstva2, None, -1)    
    
    # Value notification
    hlaska = ""
    if rozliseni != 100:
      hlaska = " Warning: Image resolution is "  + str(rozliseni) + " DPI while 100 DPI is recommended\n\n"  
    hlaska = hlaska + " Map load value: " + str(round(jdh, 1)) + " %"
    ctypes.windll.user32.MessageBoxW(0, unicode(hlaska, "utf-8"), u"MEASUREMENT RESULTS", 0x40)
    
    # Finishing operations
    pdb.gimp_image_undo_group_end(image)
    
register(
    "MAPLOAD_1-1",
    "Experimental tool for graphic map load measurement based on edge detection",
    "Experimental tool for graphic map load measurement based on edge detection using Sobel operator, developed at the Department of Geoinformatics, Palacký University Olomouc within the research project Graphic map load evaluation using metrics based od raster format (resolution 100 DPI prefered)",
    "Radek Barvíř", "CC BY-SA", "v 1.1, build 201125, 2020",
    "GMLMT 1.1 (map load)",
    "RGB*", 
    [
        (PF_IMAGE, "image", "takes current image", None),
        (PF_DRAWABLE, "drawable", "Input layer", None)
    ],
    [],
    napln, menu="<Image>/Filters/Edge-Detect")

main()