Hi All I am doing quite a bit of speculating here, as I neither use GDL, nor have I been involved in writing the gcc driver. However based on my wxWidgets driver writing experience and the fact that I have used that driver to overplot on images I think I can make a good stab at guessing the problem.
Based on Gregs description it seems like his background images are being covered by plplot calls. I would guess that GDL draws an image on a device context or Window then initialises plplot passing in the device context/window to draw on. This used to be fine, but now the image gets covered. It seems likely that it is covered by the plclear() call. In most drivers that call just draws a rectangle of the background colour over the subpage. There are a few reasons why that might now be failing 1) The image is drawn after plinit has been called. When using the plot "fresh" this will work, but if the buffer is being used(e.g. using plreplot) then there is no point at which the calling program can access the canvas between all the plots so the newly added plclear calls will draw over the original image. 2) The image was always drawn before plinit was called and the plplot background colour was set to transparent, but the gcc behaviour of a clear command has changed. One notable bug I introduced when working on wxWidgets was caused because alpha is on a 0-1 scale, but rgb are on 0-255 scales so the alpha needs converting. As it happens there is potentially a gap in the API that is exposed here. FIrst is that it would be good to be able to draw a rgb raster image on a plplot - the current plimage function can't really do that. Second for the interactive (and maybe even the noninteractive) drivers. It might be interesting to add a callback function, basically this puts a flag in the buffer to call a provided callback which the user could use to render something to the canvas or provide progress information for a plot that takes a long time to render. Or maybe this could be a callback that could be called after every n render operations again to provide progress information. This also exposes a gap in our testing. I know the wxWidgets driver can be given a canvas to draw on - in this way it actas rather like a noninteractive driver. It seems like the gcc driver can be used in the same way. We currently don't have any explicit tests of this usage - although it is how I use plplot day-to-day so the wxWidgets driver is pretty well tested in that respect. Anyway Greg, is it possible to confirm firstly what the background colour used by plplot is, and second where in the plplot calls the image is drawn. Phil On 1 February 2016 at 08:19, Alan W. Irwin <ir...@beluga.phys.uvic.ca> wrote: > On 2016-01-31 19:34-0800 Greg Jung wrote: > >> Hi Alan, >> >> I don't program in plplot directly and so I'm pretty sure I'd be going >> through a month >> of debugging my own "example" before it would purport to show a plplot >> bug. > > > Hi Greg: > > I sympathize with your lack of PLplot knowledge because we have the > reverse issue here; we have very little knowledge of GDL. So my > feeling is it is time to consult someone who is familiar with both GDL > and PLplot. I presume that would be the guy who originally > implemented the GDL plot commands in terms of calls to the PLplot API > or someone who is continuing to maintain that GDL plotting code. If > someone with that sort of expertise was willing to help you out, they > should be able to very quickly implement the requested test programme > by translating the group of GDL plot commands that do not work for you > into the corresponding PLplot API calls. > > > Alan > __________________________ > Alan W. Irwin > > Astronomical research affiliation with Department of Physics and Astronomy, > University of Victoria (astrowww.phys.uvic.ca). > > Programming affiliations with the FreeEOS equation-of-state > implementation for stellar interiors (freeeos.sf.net); the Time > Ephemerides project (timeephem.sf.net); PLplot scientific plotting > software package (plplot.sf.net); the libLASi project > (unifont.org/lasi); the Loads of Linux Links project (loll.sf.net); > and the Linux Brochure Project (lbproject.sf.net). > __________________________ > > Linux-powered Science > __________________________ ------------------------------------------------------------------------------ Site24x7 APM Insight: Get Deep Visibility into Application Performance APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month Monitor end-to-end web transactions and take corrective actions now Troubleshoot faster and improve end-user experience. Signup Now! http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140 _______________________________________________ Plplot-devel mailing list Plplot-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/plplot-devel
