On Thu, Mar 13, 2008 at 10:54 AM, Doug Hunt <[EMAIL PROTECTED]> wrote: > Hi Hezekiah: I'm not sure what 'truecolor' is, but the 'mem' and > 'memcairo' drivers (which I'm fiddling with right now) are designed to > allow one to make a plot on an image background.
By "truecolor," I meant a photograph or similar image (MODIS visible wavelength images in my case) plotted in the same colors perceived by a human eye. The currently available plimage* functions plot colors based on the magnitude or intensity of values. The mem and memcairo drivers were my first thought for this. However, I think it would be useful to have an RGBA image plotting function included in PLplot for the following reasons: - It would be simpler to, for example, use the same coordinate transformations in each portion of a plot. This would include consistent pixel -> plot coordinate mapping and 3D orientation of images for 3D plots. - Images could be used as layers other than the background, without needing to do post-processing of the PLplot output - The available PLplot output devices are available for "free." - I may be wrong about this, but I think it would make the process of using such images easier for users of PLplot in languages other than C. > You pass in an RGB array as the background, and make normal PLplot > function calls. The lines, points, labels, etc generated by PLplot > overlay the image, which is passed back to the user as an RGB array. > Then you need to write the RGB array to some image format using external > software. > > Currently the decorations are opaque, but I'm looking into allowing > semi-transparent overlays on the input image (using the cairo alpha > channel support in memcairo) right now. Is there documentation available for the this use of the memcairo driver? If I am unable to implement a function to do what I want then this would still do a lot of what I need. Thank you for the response! Hez > Regards, > > Doug > On Wed, 12 Mar 2008, Hezekiah M. Carty wrote: > > > Are there currently plans to add either of truecolor image support > > (photo as a plot background for example) or 3D oriented plimagefr > > support? If not, and there is an interest in including such functions > > in plplot, I would like to tackle those after getting the plimagefr > > coordinate transformation support finalized. > > > > For the truecolor image support, my thought is to have a function > > along the lines of: > > void plimagergba( > > PLFLT** r, PLFLT** g, PLFLT** b, PLFLT** a, > > PLINT xdim, PLINT ydim, > > PLFLT xmin, PLFLT xmax, PLFLT ymin, PLFLT ymax, > > void (*pltr) (PLFLT, PLFLT, PLFLT *, PLFLT *, PLPointer), PLPointer > pltr_data) > > with function arguments being used similarly to how plimage works. > > With the r,g,b,a values separate, any image loading routines could be > > handles on the user's end or at least abstracted on top of this. > > > > Is there a function like plfill (and/or plfill3) which can take a RGBA > > color to plot? The plimage* functions use plfill internally. Or is > > there a better, more plplot-like way to go about this? > > > > Thanks, > > Hez -- Hezekiah M. Carty Graduate Research Assistant University of Maryland Department of Atmospheric and Oceanic Science ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Plplot-devel mailing list Plplot-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/plplot-devel
