#!/usr/bin/env python

#   Gimp-Python - allows the writing of Gimp plugins in Python.
#   Copyright (C) 1997  James Henstridge <james@daa.com.au>
#
#    This program is free software; you can redistribute it and/or modify
#   it under the terms of the GNU General Public License as published by
#   the Free Software Foundation; either version 2 of the License, or
#   (at your option) any later version.
#
#   This program is distributed in the hope that it will be useful,
#   but WITHOUT ANY WARRANTY; without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#   GNU General Public License for more details.
#
#   You should have received a copy of the GNU General Public License
#   along with this program; if not, write to the Free Software
#   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

# Algorithms stolen from the whirl and pinch plugin distributed with Gimp,
# by Federico Mena Quintero and Scott Goehring
#
# This version does the same thing, except there is no preview, and it is
# written in python and is slower.

import math, struct
from gimpfu import *

class pixel_fetcher:
	def __init__(self, drawable):
		self.col = -1
		self.row = -1
		self.img_width = drawable.width
		self.img_height = drawable.height
		self.img_bpp = drawable.bpp
		self.img_has_alpha = drawable.has_alpha
		self.tile_width = 64
		self.tile_height = 64
		self.bg_colour = '\0\0\0\0'
		self.bounds = drawable.mask_bounds
		self.drawable = drawable
		self.tile = None
	def set_bg_colour(self, r, g, b, a):
		self.bg_colour = struct.pack('bbb', r,g,b)
		if self.img_has_alpha:
			self.bg_colour = self.bg_colour + chr(a)
	def get_pixel(self, x, y):
		sel_x1, sel_y1, sel_x2, sel_y2 = self.bounds
		if x < sel_x1 or x >= sel_x2 or y < sel_y1 or y >= sel_y2:
			return self.bg_colour
		col = x / self.tile_width
		coloff = x % self.tile_width
		row = y / self.tile_height
		rowoff = y % self.tile_height

		if col != self.col or row != self.row or self.tile == None:
			self.tile = self.drawable.get_tile(FALSE, row, col)
			self.col = col
			self.row = row
		return self.tile[coloff, rowoff]

class Dummy:
	pass

def python_whirl_pinch(image, drawable, whirl, pinch, radius):
	self = Dummy()
	self.width = drawable.width
	self.height = drawable.height
	self.bpp = drawable.bpp
	self.has_alpha = drawable.has_alpha
	self.bounds = drawable.mask_bounds
	self.sel_x1, self.sel_y1, self.sel_x2, self.sel_y2 = \
		     drawable.mask_bounds
	self.sel_w = self.sel_x2 - self.sel_x1
	self.sel_h = self.sel_y2 - self.sel_y1
	self.cen_x = (self.sel_x1 + self.sel_x2 - 1) / 2.0
	self.cen_y = (self.sel_y1 + self.sel_y2 - 1) / 2.0
	xhsiz = (self.sel_w - 1) / 2.0
	yhsiz = (self.sel_h - 1) / 2.0

	if xhsiz < yhsiz:
		self.scale_x = yhsiz / xhsiz
		self.scale_y = 1.0
	elif xhsiz > yhsiz:
		self.scale_x = 1.0
		self.scale_y = xhsiz / yhsiz
	else:
		self.scale_x = 1.0
		self.scale_y = 1.0

	self.radius = max(xhsiz, yhsiz);

	if not drawable.is_colour and not drawable.is_grey:
		return

	gimp.tile_cache_ntiles(2 * (self.width + 63) / 64)

	whirl = whirl * math.pi / 180
	dest_rgn = drawable.get_pixel_rgn(self.sel_x1, self.sel_y1,
					  self.sel_w, self.sel_h, TRUE, TRUE)
	pft = pixel_fetcher(drawable)
	pfb = pixel_fetcher(drawable)
	bg_colour = gimp.get_background()
	pft.set_bg_colour(bg_colour[0], bg_colour[1], bg_colour[2], 0)
	pfb.set_bg_colour(bg_colour[0], bg_colour[1], bg_colour[2], 0)
	progress = 0
	max_progress = self.sel_w * self.sel_h
	gimp.progress_init("Whirling and pinching...")
	self.radius2 = self.radius * self.radius * radius
	pixel = ['', '', '', '']
	values = [0,0,0,0]
	for row in range(self.sel_y1, (self.sel_y1+self.sel_y2)/2+1):
		top_p = ''
		bot_p = ''
		for col in range(self.sel_x1, self.sel_x2):
			q, cx, cy = calc_undistorted_coords(self, col,
						row, whirl, pinch, radius)
			if q:
				if cx >= 0: ix = int(cx)
				else:       ix = -(int(-cx) + 1)
				if cy >= 0: iy = int(cy)
				else:       iy = -(int(-cx) + 1)
				pixel[0] = pft.get_pixel(ix, iy)
				pixel[1] = pft.get_pixel(ix+1, iy)
				pixel[2] = pft.get_pixel(ix, iy+1)
				pixel[3] = pft.get_pixel(ix+1, iy+1)
				for i in range(self.bpp):
					values[0] = ord(pixel[0][i])
					values[1] = ord(pixel[1][i])
					values[2] = ord(pixel[2][i])
					values[3] = ord(pixel[3][i])
					top_p = top_p + bilinear(cx,cy, values)
				cx = self.cen_x + (self.cen_x - cx)
				cy = self.cen_y + (self.cen_y - cy)
				if cx >= 0: ix = int(cx)
				else:       ix = -(int(-cx) + 1)
				if cy >= 0: iy = int(cy)
				else:       iy = -(int(-cy) + 1)
				pixel[0] = pfb.get_pixel(ix, iy)
				pixel[1] = pfb.get_pixel(ix+1, iy)
				pixel[2] = pfb.get_pixel(ix, iy+1)
				pixel[3] = pfb.get_pixel(ix+1, iy+1)
				tmp = ''
				for i in range(self.bpp):
					values[0] = ord(pixel[0][i])
					values[1] = ord(pixel[1][i])
					values[2] = ord(pixel[2][i])
					values[3] = ord(pixel[3][i])
					tmp = tmp + bilinear(cx,cy, values)
				bot_p = tmp + bot_p
			else:
				top_p = top_p + pft.get_pixel(col, row)
				bot_p = pfb.get_pixel((self.sel_x2 - 1) -
					(col - self.sel_x1), (self.sel_y2-1) -
					(row - self.sel_y1)) + bot_p
		dest_rgn[self.sel_x1:self.sel_x2, row] = top_p
		dest_rgn[self.sel_x1:self.sel_x2, (self.sel_y2 - 1)
			 - (row - self.sel_y1)] = bot_p
		progress = progress + self.sel_w * 2
		gimp.progress_update(float(progress) / max_progress)
	drawable.flush()
	drawable.merge_shadow(TRUE)
	drawable.update(self.sel_x1,self.sel_y1,self.sel_w,self.sel_h)

def calc_undistorted_coords(self, wx, wy, whirl, pinch, radius):
	dx = (wx - self.cen_x) * self.scale_x
	dy = (wy - self.cen_y) * self.scale_y
	d = dx * dx + dy * dy
	inside = d < self.radius2

	if inside:
		dist = math.sqrt(d / radius) / self.radius
		if (d == 0.0):
			factor = 1.0
		else:
			factor = math.pow(math.sin(math.pi / 2 * dist),
					  -pinch)
		dx = dx * factor
		dy = dy * factor
		factor = 1 - dist
		ang = whirl * factor * factor
		sina = math.sin(ang)
		cosa = math.cos(ang)
		x = (cosa * dx - sina * dy) / self.scale_x + self.cen_x
		y = (sina * dx + cosa * dy) / self.scale_y + self.cen_y
	else:
		x = wx
		y = wy
	return inside, float(x), float(y)
	
def bilinear(x, y, values):
	x = x % 1.0
	y = y % 1.0
	m0 = values[0] + x * (values[1] - values[0])
	m1 = values[2] + x * (values[3] - values[2])
	return chr(m0 + y * (m1 - m0))


register(
	"python_fu_whirl_pinch",
	"Distorts an image by whirling and pinching",
	"Distorts an image by whirling and pinching",
	"James Henstridge (translated from C plugin)",
	"James Henstridge",
	"1997-1999",
	"<Image>/Filter/Distorts/Whirl and Pinch",
	"RGB*, GRAY*",
	[
		(PF_SLIDER, "whirl", "Whirl angle", 90, (-360, 360, 1)),
		(PF_FLOAT, "pinch", "Pinch amount", 0),
		(PF_FLOAT, "radius", "radius", 1)
	],
	[],
	python_whirl_pinch)
				
main()

