lines not aliased anymore after bitmap rotation

[killerwhale65]

Hello,

I notice that vertical and horizontal lines in a bitmap, are not aliased anymore when i rotate the bitmap a little bit. Is that normal? How can i prevent this?

thanks!

Matt

[Soquili]

Hello Matt,

Can you post an example?

Post the non-rotated and then a screen grab of the rotated bitmap.

[killerwhale65]

hello,

please look here.

regards,

Matt

[Soquili]

I think it is more related to how computer screens are made rather than the program.

Look at the first attachment (click the thumbnail to see a larger version).

Notice the jaggies on the rotated screen grab of the Blend Tool's Position profile dialog.

The second attachment is zoomed in, notice that jaggies are less pronounced.

Pixels on a computer screen are rectangular rather than circular or square, this creates a longer vertical offset than horizontal. Lines in a bitmap (matrix of pixels) exhibit this when rotated.

[killerwhale65]

i agree, but look here: http://southcreative.com.au/images/p...lainsource.jpg

This looks much nicer then my rotated screenshot, not?

[Soquili]

Look at how Photoshop does it, and that is a dedicated bitmap editor program.

The link you provided was most likely created in a vector application and not using bitmaps to create the rotated letterhead pages.

[Soquili]

The attached is an example of rotated vector objects rather than a bitmap.

[killerwhale65]

ok, indeed it will work better with vector source files.

Thanks!

Matt

[salaam]

You can have the original set as a high resolution eg 300 dpi and then rotate it and save it at a lower dpi. If the image is for your computer rather than print, then 96dpi or 76dpi is OK.

[gwpriester]

Actually 72 or 75, Salaam, and that is Mac screen resolution.