Re: Exporting image files #HowTo #dxf


Robert Heller
 

At Mon, 20 Jan 2020 12:53:05 +0000 main@xtrackcad.groups.io wrote:


it worked again! I've no idea why a 2.5 MB JPG can be so much better
than a 26.5 MB BMP.
BMP is a very old very simple file format that's a good 30 years old and
often not compressed at all. GIF would probably come out smaller still as
JPG is designed to compressed photographs with some fuzzing allowed while
GIF is designed to compress sharp bitmaps.
JPEG is lossy compression -- it is meant for "natrual" images (eg photos),
since it compresses by deliberatly throwing data away. This is data that the
human mind re-creates based on inate knowledge of natural scenes. GIF is an
8-bit/pixel format, using color lookup tables and is fine when the number of
colors <= 256. For computer generated images with more than 256 colors, PNG is
probably the best format.


Alan



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