#!/usr/local/bin/python3.7
# ******************************************************************************
#  $Id: rgb2pct.py 8e263710cb425c4a8b76b1f363b98be41ea0a983 2018-04-30 19:40:20 +1000 Ben Elliston $
#
#  Name:     rgb2pct
#  Project:  GDAL Python Interface
#  Purpose:  Application for converting an RGB image to a pseudocolored image.
#  Author:   Frank Warmerdam, warmerdam@pobox.com
#
# ******************************************************************************
#  Copyright (c) 2001, Frank Warmerdam
#
#  Permission is hereby granted, free of charge, to any person obtaining a
#  copy of this software and associated documentation files (the "Software"),
#  to deal in the Software without restriction, including without limitation
#  the rights to use, copy, modify, merge, publish, distribute, sublicense,
#  and/or sell copies of the Software, and to permit persons to whom the
#  Software is furnished to do so, subject to the following conditions:
#
#  The above copyright notice and this permission notice shall be included
#  in all copies or substantial portions of the Software.
#
#  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
#  OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
#  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
#  THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
#  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
#  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
#  DEALINGS IN THE SOFTWARE.
# ******************************************************************************

import os.path
import sys

from osgeo import gdal


def Usage():
    print('Usage: rgb2pct.py [-n colors | -pct palette_file] [-of format] source_file dest_file')
    sys.exit(1)


def DoesDriverHandleExtension(drv, ext):
    exts = drv.GetMetadataItem(gdal.DMD_EXTENSIONS)
    return exts is not None and exts.lower().find(ext.lower()) >= 0


def GetExtension(filename):
    ext = os.path.splitext(filename)[1]
    if ext.startswith('.'):
        ext = ext[1:]
    return ext


def GetOutputDriversFor(filename):
    drv_list = []
    ext = GetExtension(filename)
    for i in range(gdal.GetDriverCount()):
        drv = gdal.GetDriver(i)
        if (drv.GetMetadataItem(gdal.DCAP_CREATE) is not None or
            drv.GetMetadataItem(gdal.DCAP_CREATECOPY) is not None) and \
           drv.GetMetadataItem(gdal.DCAP_RASTER) is not None:
            if ext and DoesDriverHandleExtension(drv, ext):
                drv_list.append(drv.ShortName)
            else:
                prefix = drv.GetMetadataItem(gdal.DMD_CONNECTION_PREFIX)
                if prefix is not None and filename.lower().startswith(prefix.lower()):
                    drv_list.append(drv.ShortName)

    # GMT is registered before netCDF for opening reasons, but we want
    # netCDF to be used by default for output.
    if ext.lower() == 'nc' and not drv_list and \
       drv_list[0].upper() == 'GMT' and drv_list[1].upper() == 'NETCDF':
        drv_list = ['NETCDF', 'GMT']

    return drv_list


def GetOutputDriverFor(filename):
    drv_list = GetOutputDriversFor(filename)
    if not drv_list:
        ext = GetExtension(filename)
        if not ext:
            return 'GTiff'
        else:
            raise Exception("Cannot guess driver for %s" % filename)
    elif len(drv_list) > 1:
        print("Several drivers matching %s extension. Using %s" % (ext, drv_list[0]))
    return drv_list[0]

# =============================================================================
#      Mainline
# =============================================================================


color_count = 256
frmt = None
src_filename = None
dst_filename = None
pct_filename = None

gdal.AllRegister()
argv = gdal.GeneralCmdLineProcessor(sys.argv)
if argv is None:
    sys.exit(0)

# Parse command line arguments.
i = 1
while i < len(argv):
    arg = argv[i]

    if arg == '-of' or arg == '-f':
        i = i + 1
        frmt = argv[i]

    elif arg == '-n':
        i = i + 1
        color_count = int(argv[i])

    elif arg == '-pct':
        i = i + 1
        pct_filename = argv[i]

    elif src_filename is None:
        src_filename = argv[i]

    elif dst_filename is None:
        dst_filename = argv[i]

    else:
        Usage()

    i = i + 1

if dst_filename is None:
    Usage()

# Open source file

src_ds = gdal.Open(src_filename)
if src_ds is None:
    print('Unable to open %s' % src_filename)
    sys.exit(1)

if src_ds.RasterCount < 3:
    print('%s has %d band(s), need 3 for inputs red, green and blue.'
          % (src_filename, src_ds.RasterCount))
    sys.exit(1)

# Ensure we recognise the driver.

if frmt is None:
    frmt = GetOutputDriverFor(dst_filename)

dst_driver = gdal.GetDriverByName(frmt)
if dst_driver is None:
    print('"%s" driver not registered.' % frmt)
    sys.exit(1)

# Generate palette

ct = gdal.ColorTable()
if pct_filename is None:
    err = gdal.ComputeMedianCutPCT(src_ds.GetRasterBand(1),
                                   src_ds.GetRasterBand(2),
                                   src_ds.GetRasterBand(3),
                                   color_count, ct,
                                   callback=gdal.TermProgress_nocb)
else:
    pct_ds = gdal.Open(pct_filename)
    ct = pct_ds.GetRasterBand(1).GetRasterColorTable().Clone()

# Create the working file.  We have to use TIFF since there are few formats
# that allow setting the color table after creation.

if format == 'GTiff':
    tif_filename = dst_filename
else:
    import tempfile
    tif_filedesc, tif_filename = tempfile.mkstemp(suffix='.tif')

gtiff_driver = gdal.GetDriverByName('GTiff')

tif_ds = gtiff_driver.Create(tif_filename,
                             src_ds.RasterXSize, src_ds.RasterYSize, 1)

tif_ds.GetRasterBand(1).SetRasterColorTable(ct)

# ----------------------------------------------------------------------------
# We should copy projection information and so forth at this point.

tif_ds.SetProjection(src_ds.GetProjection())
tif_ds.SetGeoTransform(src_ds.GetGeoTransform())
if src_ds.GetGCPCount() > 0:
    tif_ds.SetGCPs(src_ds.GetGCPs(), src_ds.GetGCPProjection())

# ----------------------------------------------------------------------------
# Actually transfer and dither the data.

err = gdal.DitherRGB2PCT(src_ds.GetRasterBand(1),
                         src_ds.GetRasterBand(2),
                         src_ds.GetRasterBand(3),
                         tif_ds.GetRasterBand(1),
                         ct,
                         callback=gdal.TermProgress_nocb)

tif_ds = None

if tif_filename != dst_filename:
    tif_ds = gdal.Open(tif_filename)
    dst_driver.CreateCopy(dst_filename, tif_ds)
    tif_ds = None

    os.close(tif_filedesc)
    gtiff_driver.Delete(tif_filename)
