spd_ui_draw_object method: makeSpec Purpose: helper routine for draw object. It helps construct the image for spectrograms very quickly. Inputs: x: the 1-d x scaling values for the z components(x-axis) y: the 1-d y scaling values for the z components z: the 2-d z array of values for the image pixx: the desired resolution of the output on the x-axis pixy: the desired resolution of the output on the y-axis xrange: x range of the desired output in data space yrange: y range of the desired output in data space Output: refz: The gridded z-axis array refx: The x-values associated with the z-values refy: The y-values associated with the z-values Notes: 1. This uses an alpha channel to make all NaNs transparent. 2. PixX and PixY are not totally necessary because object graphics can stretch an image quite well, but selecting the resolution of the screen with them prevents any inadvertent errors from showing up during interpolation. It might actually be better to render the image at twice the screen resolution to prevent aliasing errors. 3. May-2013: Code modified to create a spectrogram over the panel's range (xrange/yrange) rather than over the data's range. The pixx/pixy variables should now contain the number of pixels across the panel instead of those required to represent the entire dataset. $LastChangedBy: jimm $ $LastChangedDate: 2014-02-11 10:54:32 -0800 (Tue, 11 Feb 2014) $ $LastChangedRevision: 14326 $ $URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/spdsoft/trunk/spedas/gui/display/draw_object/spd_ui_draw_object__makespec.pro $