#!/usr/bin/env python

import gdal
import gdalconst
import sys
import Numeric
import os.path
import osr
import colorsys
import Image
import glob
import string
import os
import pickle

def mask_min(output_band, mask, x, y):
	(size_y, size_x) = Numeric.shape(mask)
	print size_x, size_y
	current = output_band.ReadAsArray(x, y, size_x, size_y)

	output_band.WriteArray(Numeric.minimum(current, mask), x, y)

test_image = gdal.GetDriverByName('GTiff').Create(
	'test.tif',
	200, 200,
	1, gdal.GDT_Byte,
	[ 'TILED=YES' ]
)
test_band = test_image.GetRasterBand(1)

# test_band.SetNoDataValue(255) # Does not work.

blank_lines = Numeric.ones((200, 200)) * 255
test_band.WriteArray(blank_lines,0,0)

mask = Numeric.fromfunction(lambda y, x: y, (100, 200))
mask_min(test_band, mask, 0, 0)

mask = Numeric.fromfunction(lambda y, x: x, (200, 100))
mask_min(test_band, mask, 0, 0)

test_image = None

os.system('convert test.tif test.png')
#	src_data = src_band.ReadAsArray(
#		horizontal_skip_min, iY,
#		src_ds.RasterXSize - horizontal_skip_min, 1
#	)