On 2009-10-25 15:11-0500 Hezekiah M. Carty wrote: > On Sun, Oct 25, 2009 at 12:34 PM, Alan W. Irwin > <ir...@beluga.phys.uvic.ca> wrote: >> Hi Hazen: >> >> If you look at the results from ext-cairo-test, the current background is >> white. I followed up that issue, and our default cmap0 file is being read >> correctly which includes a black background. However, that black PLplot >> background is currently being ignored (and I presume we are getting a >> default white background from the cairo libraries instead) because there is >> no handling of background colour for the extcairo device in cairo.c. >> >> Would you be willing to add background colour handling to extcairo like you >> do for all other cairo devices? > > It is my understanding that automatically clearing the page to the > background color is intentionally left out of the extcairo device > intentionally so that the provided context is preserved. This way a > user can provide, for example, an image they want to plot over and it > will be preserved. > > I use this feature of the driver quite often, so I would prefer that > the extcairo functionality remain as-is, at least in the default case.
There are two issues here. (1) Should we allow specifying a possibly transparent background colour for extcairo similar to every other device driver? (2) If the answer to (1) is yes, should that default background be transparent? I would argue pretty strongly for (1) simply because most/all of our devices have background colour setting capability, and I assume some extcairo users will want this as well (e.g., for our ext-cairo-test case). I think the answer to (2) should depend on what the majority of users are doing with extcairo. I don't have a clue about that usage, but if you think the majority will be using background images instead of solid backgrounds, then I would be willing to go along with making the background transparent by default for the extcairo case simply as a matter of convenience for that majority use case. 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); PLplot scientific plotting software package (plplot.org); 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 __________________________ ------------------------------------------------------------------------------ Come build with us! The BlackBerry(R) 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/devconference _______________________________________________ Plplot-devel mailing list Plplot-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/plplot-devel
