def dither_1():
drv = gdal.GetDriverByName('GTiff')
src_ds = gdal.Open('../gdrivers/data/rgbsmall.tif')
r_band = src_ds.GetRasterBand(1)
g_band = src_ds.GetRasterBand(2)
b_band = src_ds.GetRasterBand(3)
dst_ds = drv.Create('tmp/rgbsmall.tif', src_ds.RasterXSize,
src_ds.RasterYSize, 1, gdal.GDT_Byte)
dst_band = dst_ds.GetRasterBand(1)
ct = gdal.ColorTable()
nColors = 8
gdal.ComputeMedianCutPCT(r_band, g_band, b_band, nColors, ct)
dst_band.SetRasterColorTable(ct)
gdal.DitherRGB2PCT(r_band, g_band, b_band, dst_band, ct)
cs_expected = 8803
cs = dst_band.Checksum()
dst_band = None
dst_ds = None
if ct.GetCount() != nColors:
gdaltest.post_reason('color table size wrong')
return 'fail'
ref_ct = [(36, 48, 32, 255), (92, 120, 20, 255), (88, 96, 20, 255),
(92, 132, 56, 255), (0, 0, 0, 255), (96, 152, 24, 255),
(60, 112, 32, 255), (164, 164, 108, 255)]
for i in range(nColors):
ct_data = ct.GetColorEntry(i)
ref_data = ref_ct[i]
for j in range(4):
if ct_data[j] != ref_data[j]:
gdaltest.post_reason('color table mismatch')
for k in range(nColors):
print(ct.GetColorEntry(k))
print(ref_ct[k])
return 'fail'
if cs == cs_expected \
or gdal.GetConfigOption( 'CPL_DEBUG', 'OFF' ) != 'ON':
drv.Delete('tmp/rgbsmall.tif')
if cs != cs_expected:
print('Got: ', cs)
gdaltest.post_reason('got wrong checksum')
return 'fail'
else:
return 'success'
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')
if format is None:
format = GetOutputDriverFor(dst_filename)
dst_driver = gdal.GetDriverByName(format)
if dst_driver is None:
print('"%s" driver not registered.' % format)
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,
callback_data = 'Generate PCT' )
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')
def doit(pct_filename=None,
src_filename=None,
dst_filename=None,
color_count=256,
frmt=None):
# Open source file
src_ds = gdal.Open(src_filename)
if src_ds is None:
print('Unable to open %s' % src_filename)
return None, 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))
return None, 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)
return None, 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)
if tif_filename == dst_filename:
dst_ds = tif_ds
else:
dst_ds = dst_driver.CreateCopy(dst_filename, tif_ds)
tif_ds = None
gtiff_driver.Delete(tif_filename)
os.close(tif_filedesc)
return dst_ds, err
def rgb2pct(self, src_filename, dst_filename, driver, color_count=256):
"""Convert a 24bit RGB image to 8bit paletted.
From GDAL: https://gdal.org/programs/rgb2pct.html.
Compute an optimal pseudo-color table for a given RGB image using a median cut algorithm on a downsampled RGB histogram. Then it converts the image into a pseudo-colored image using the color table. This conversion utilizes Floyd-Steinberg dithering (error diffusion) to maximize output image visual quality.
Arguments:
src_filename (str): The input RGB file path.
dst_filename (str): The output path of the pseudo-colored file that will be created.
driver (str): The driver to open the input RGB file.
Keyword Arguments:
color_count (number): The number of colors in the generated color table. Must be between 2 and 256. (default: {256})
"""
src_ds = gdal.Open(src_filename)
ct = gdal.ColorTable()
err = gdal.ComputeMedianCutPCT(src_ds.GetRasterBand(1),
src_ds.GetRasterBand(2),
src_ds.GetRasterBand(3),
color_count, ct,
callback=gdal.TermProgress_nocb)
# Create the working file. We have to use TIFF since there are few formats
# that allow setting the color table after creation.
if driver.ShortName == '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)
driver.CreateCopy(dst_filename, tif_ds)
tif_ds = None
os.close(tif_filedesc)
gtiff_driver.Delete(tif_filename)
def rgb2pct(src_filename: PathLikeOrStr,
pct_filename: Optional[PathLikeOrStr] = None,
dst_filename: Optional[PathLikeOrStr] = None,
color_count: int = 256,
driver_name: Optional[str] = None):
# Open source file
src_ds = open_ds(src_filename)
if src_ds is None:
raise Exception(f'Unable to open {src_filename}')
if src_ds.RasterCount < 3:
raise Exception(
f'{src_filename} has {src_ds.RasterCount} band(s), need 3 for inputs red, green and blue.'
)
# Ensure we recognise the driver.
if not driver_name:
driver_name = GetOutputDriverFor(dst_filename)
dst_driver = gdal.GetDriverByName(driver_name)
if dst_driver is None:
raise Exception(f'"{driver_name}" driver not registered.')
# Generate palette
if pct_filename is None:
ct = gdal.ColorTable()
err = gdal.ComputeMedianCutPCT(src_ds.GetRasterBand(1),
src_ds.GetRasterBand(2),
src_ds.GetRasterBand(3),
color_count,
ct,
callback=gdal.TermProgress_nocb)
else:
ct = get_color_table(pct_filename)
# Create the working file. We have to use TIFF since there are few formats
# that allow setting the color table after creation.
if driver_name.lower() == '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)
if err != gdal.CE_None:
raise Exception('DitherRGB2PCT failed')
if tif_filename == dst_filename:
dst_ds = tif_ds
else:
dst_ds = dst_driver.CreateCopy(dst_filename or '', tif_ds)
tif_ds = None
os.close(tif_filedesc)
gtiff_driver.Delete(tif_filename)
return dst_ds
def main(argv):
color_count = 256
frmt = None
src_filename = None
dst_filename = None
pct_filename = None
gdal.AllRegister()
argv = gdal.GeneralCmdLineProcessor(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)
return err
