On Sun, Oct 04, 2009 at 10:53:38AM +0200, Frank van Maarseveen wrote: > > > The y axis is the right choice for our purposes, because for many > > subjects without text or suchlike, a photo can be flipped on that axis > > for pure compositional preference. However for almost any subject aside > > from closeups of textures, a vertical flip would be considered "upside > > down" as well as "mirrored" by the viewer. > > You mean that we actually need an "upside-down" button, i.e. rotate 180 > degree button instead of a vertical flip button?
No. I'm just explaining why it's natural that we've chosen the y-axis as the one we primarily flip around, and why the vertical flip button should result in a 180 degree rotation being reported after use. > There is always more than one way to get the same result with rotation > and flipping (actually, one flip button and a rotation control can do > it all). Currently, the vertical flip button does not vertically flip > at all. Instead, it rotates and flips horizontally which happens to have > visually the same effect but with a different rotation control afterwards. Exactly. And this is what we want, because it means that although you can arrive at the same visual result with many different combinations of the tools, each result is always represented in the same way: boolean (horizontal) flip and float rotation in the -180 < a <= 180 range. The alternative is to allow a boolean state for both horizontal and vertical flip - the combined effect of which is identical to a 180 degree rotation - and hence two different ways to reach any given visual result. We don't display or store 365 degree rotations: we normalise them to 5 degree ones, because the visual result is the same. We normalise the result of flip operations for the same reason. The choice of which flip axis we normalise to is arbitrary, but the choice of the y-axis is more natural for photography. > This is a choice but what the vertical flip button now does is not > reflected by its icon image. Yes it is. The effect on the image is a vertical flip. The icon is the same, rotated 90 degrees, as the horizontal flip. > And I still don't see why it is useful to present the user with a > rotation control at 180 degrees after a vertical flip. Because: (a) the image looks "upside down". (b) this is consistent with what they get when they arrive at the same image by performing a 180 degree rotation and a horizontal flip. Martin ------------------------------------------------------------------------------ Come build with us! The BlackBerry® Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9-12, 2009. Register now! http://p.sf.net/sfu/devconf _______________________________________________ ufraw-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/ufraw-devel
