Lossy rotation in jpegs?


#1

so if i am using the windows xp built in picture and fax viewer, and rotating my images, is that a lossy function?? or is it just doing some math on it and all the bits are still there…

im suspicious for some reason.


#2

I’m 99% sure that it is a lossy fuction, because in the setup of the photo gallery “Gallery”, it recommends you download some program so that you can do lossless rotations and transformations.


#3

Like the much maligned Paintshop Pro…


#4

well i definitely have other programs to rotate my stuff with, i just like it when its all built in and stuff.

my camera doesnt seem to pick up on when i’ve rotated it 90, apparently there is some sort of inertial sensor or something that can determine when its oriented sideways, and its supposed to rotate them on camera, but it only works 1 in 10 times.

chanks dudes.


#5

I just looked it up… the program that Gallery uses to do lossless rotations is jpegtran.

What kind of camera do you have? My Kodak camera has the orientation sensor, and it’s worked perfectly every time.


#6

canon


#7

My Canon has that feature too, and it works fine. Not a big deal with a Mac, though, since rotation and stuff is just handled by Quartz, so it’s all lossless.


#8

What’s Quartz?


#9

The OS X display layer.

apple.com/macosx/features/quartzextreme/

Makes for really easy graphics programming.


#10