On Wed, Nov 19, 2008 at 5:02 PM, Christopher Barker <[EMAIL PROTECTED]> wrote:
>> In fact, one thing I want to do is to apply my own spatial >> transformation (which I would calculate based on some points in the >> image) to the coordinates of the canvas. I don't need to do image >> calibration (I mean to change the image itself), I understand this is >> not the type of application fc was designed for > > I'm not entirely sure what you mean, but I think it should be able to > accomidate that. It is simple: for an image shown in the screen I just want to click on an image point (pixel) and get the coordinates of that in meters, using a given transformation I obtained before in a calibration procedure (where I digitize points in an image I know the coordinates in the real space), What I meant is that I don't need to apply this transformation to the image to produce its transformed bitmap (but if I can do that would be nice). Later, I want to be able to open two images (two different panels?) from different perspectives of an object and find the 3d coordinates of that point after I digitize the same point in the two images). These are 2d or 3d camera (or image) calibration. But I don't care about the image itself; I just want the calibrated position of certain points. I also could have a non-linear transformation. If it is still not clear, don't worry, fc can/will do that! > > > (also because my images are bitmaps not svgs). > > true -- but one can think of (and work with) bitmaps as scalable > graphics, too-a whole lot of rectangles! ANd I need to be able to work > with bitmaps too, so I hope we can get some of this to work out. > I hope I can help you in some way. >> What I need is just the calibration (transformation) of the coordinates. >> So, in this scenario it would be great something like >> evt.coords.Global for the position at the global (screen) coordinate >> system; > > OK _- i don't see "global" as meaning "screen". I see these: > > "Global" or "World" -- the natural coordinates of your data > -- in the case of images, I guess that would be pixels of the image, > unless you are putting that image in another context. > > "Transformed" -- coordinates after the main transformation is applied. > The transformation is arbitrary, and can be non linear, but the > transformed coordinates should be transformable into rectilinear coords > (pixels) via an affine transform. In general, they will be rectilinear > as well. > > "Local" -- coordinates local to a given object -- I think these are an > affine transform from "Transformed" coords. This would be the transform > applied to only that object. > > > "Pixel" or "Screen" -- the actual pixel coords when drawn on the screen. > -- this is the final result when you start with world coords, and apply > all the transformations. > > "Paper" -- coordinates if the iamge was printed -- this would relate to > pixel coords by a resolution parameter -- PPI or whatever. This would > allow folks to specify thinks like line widths and fotn sizes in points > (or inches, or mm, or ...) and also specify a scale, which would map > transformed coordinates to paper coords. The resolution would determine > sizes of things in screen coords. > > > Does this work with how FC2 is now constructed? I think it has > everything but the "paper" coords concept. > > -Chris > I agree with this definition and it will very useful if fcx exposes that to the user. Marcos Duarte http://lob.iv.fapesp.br/ University of Sao Paulo, Brazil _______________________________________________ FloatCanvas mailing list [email protected] http://mail.mithis.com/cgi-bin/mailman/listinfo/floatcanvas
