Limit TIFF strip size when saving with libtiff

This commit is contained in:
Miloš Komarčević 2021-05-27 15:40:04 +02:00 committed by Andrew Murray
parent 20bd9e9261
commit 7752fb5131

View File

@ -1558,12 +1558,18 @@ def _save(im, fp, filename):
ifd[COLORMAP] = tuple(v * 256 for v in lut)
# data orientation
stride = len(bits) * ((im.size[0] * bits[0] + 7) // 8)
ifd[ROWSPERSTRIP] = im.size[1]
rows_per_strip = im.size[1]
strip_byte_counts = stride * im.size[1]
# aim for 64 KB strips when using libtiff writer
while libtiff and strip_byte_counts > 2 ** 16 and rows_per_strip > 1:
rows_per_strip = (rows_per_strip + 1) // 2
strip_byte_counts = stride * rows_per_strip
strips_per_image = (im.size[1] + rows_per_strip - 1) // rows_per_strip
ifd[ROWSPERSTRIP] = rows_per_strip
if strip_byte_counts >= 2 ** 16:
ifd.tagtype[STRIPBYTECOUNTS] = TiffTags.LONG
ifd[STRIPBYTECOUNTS] = strip_byte_counts
ifd[STRIPOFFSETS] = 0 # this is adjusted by IFD writer
ifd[STRIPBYTECOUNTS] = (strip_byte_counts,) * (strips_per_image - 1) + (stride * im.size[1] - strip_byte_counts * (strips_per_image - 1),)
ifd[STRIPOFFSETS] = tuple(range(0, strip_byte_counts * strips_per_image, strip_byte_counts)) # this is adjusted by IFD writer
# no compression by default:
ifd[COMPRESSION] = COMPRESSION_INFO_REV.get(compression, 1)