Re: TIF Rotation
In article <13k8qshogc8lv6a@xxxxxxxxxxxxxxxxxx>,
Brian <my@xxxxxxxxxxxxxxxxx> wrote:
Just about to post about the image mode, but I could never understand
why the color of the pixel makes a difference in rotation?
Because you can not rotate a pixel. When Photoshop rotates an image, it
starts from the source image, then maps the source image onto a new
image that is rotated from the original. If oyu have an image that is
black in the original, the result of this mapping could very well be 50%
gray.
In a bitmap, you can not have a pixel be 50% gray. If you rotate a
bitmap by an arbitrary amount, the result is often hideously aliased
(stairstepped) and distorted, because Photoshop can not create pixels of
intermediate value. To see what I mean, take a bitmap, convert it to
grayscale, rotate it an arbitrary amount, then convert it back to bitmap
using the 50% threshold option. Notice how bad it looks?
--
Photography, kink, polyamory, shareware, and more: all at
http://www.xeromag.com/franklin.html
.
Relevant Pages
- Re: Grainy Rotate
... rather than go through each pixel in the original bitmap and ... the rotated bitmap and identify what the pixel should be (by finding the ... nearest pixel in the original bitmap). ... >how to rotate an image with better quality. ...
(microsoft.public.dotnet.framework.compactframework) - Re: In Picasa2, Is Rotating A Vertical JPEG Image Lossy Or Lossless?
... Picasa2 maintains the original image with all its pixels, and edited pix can have the editing undone. ... I can not see the reason why any programmer would want or need to change the values stored in the memory representing a pixel location when the image is rotated 90 Deg. because the pixel is moving relative its neighbor. ... In a different image software,, when clicking on to rotate an image there is an on-screen warning that carrying out the rotation will permanently deteriorate the image. ...
(rec.photo.digital) - Re: Rotate a pixmap
... algorithm to rotate a X11 Pixmap. ... i am on the right pass and i am searching for ideas ... For each pixel in the destination: ...
(comp.windows.x) - Re: Rotate 90, 270
... For the 90 and 270 degree rotations which the OP says are the only ones he wants to perform then you don't have to actually calculate the new coordinates for every pixel since you already know them. ... On tests I've just performed using a 1450 x 1000 pixel bitmap on the machine I am using at the moment it is possible to rotate it by 90 degrees in about 70 milliseconds by iterating through every pixel whereas on the same machine it takes PlgBlt about 125 milliseconds to rotate the same bitmap by the same 90 degrees. ...
(microsoft.public.vb.general.discussion) - Re: Landscape Bitmap Rotation
... For the text you could use CreateFontIndirect and rotate the text with the lf.lfEscapement member of the LOGFONT, select it to your DC and use DrawText. ... I'm looking for any info regarding fast bitmap rotation or any method ... Currently I'm drawing all my data into a memory bitmap, ... pixel by pixel, which is quite a lengthy process. ...
(microsoft.public.pocketpc.developer) |
|
