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#!/usr/bin/env python2
# 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 3 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, see <https://www.gnu.org/licenses/>.
# 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 = gimp.tile_width()
self.tile_height = gimp.tile_height()
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 is 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 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_rgb and not drawable.is_grey:
return
gimp.tile_cache_ntiles(2 * (1 + self.width / gimp.tile_width()))
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(-cy) + 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(int(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",
"_Whirl and Pinch...",
"RGB*, GRAY*",
[
(PF_IMAGE, "image", "Input image", None),
(PF_DRAWABLE, "drawable", "Input drawable", None),
(PF_SLIDER, "whirl", "Whirl angle", 90, (-360, 360, 1)),
(PF_FLOAT, "pinch", "Pinch amount", 0),
(PF_FLOAT, "radius", "radius", 1)
],
[],
whirl_pinch, menu="<Image>/Filters/Distorts")
main()
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