Hi Hazen > > Having said that, things are as they are because this is the behaviour > > of the current cairo-based devices. Admittedly a pre-existing drawable > > is different from one created by plplot but even so, consistency can > > sometimes be a good thing. The other thing to bear in mind is that > > "clearing to the background colour" will be the usual operational mode I > > would imagine, so an argument could be raised that the "don't clear" > > behaviour should be an opt-in option - possibly set using a new escape > > function or perhaps via a new "flags" option to the PLXcairoDrawableInfo > > structure. If we went with the latter though, PLXcairoDrawableInfo > > really needs to be made available to applications. Currently there's > > only 2 members - the display and the drawable - and it's not too hard > > for users to hack up their own structure to pass in. However, once we > > go beyond this PLXcairoDrawableInfo really must be publically available > > so users can't get it wrong. > > I'd propose making "clearing to the background color" a driver option > so that we can use it with xcairo, memcairo and extcairo.
Yep, that would work nicely. > I think that we should make our decision about the clearing default > consistent across these 3 driver options, but I don't have much > preference about whether or not clearing is the default. > > Doug, any thoughts about having clearing be the default? My own personal view is that clearing should be the default with an option to not clear being available. This is because in most cases one will be drawing a plain plot for data display purposes without needing pre-prepared backgrounds to be preserved. For those cases where a background (or any other previously prepared content) needs to be preserved the option is there to cope with it. I also suspect that newcomers to plplot may well expect the drawable/cairo-context to be cleared by the implicit "beginning of page" operation which happens before the first plot At the end of the day though I could live with either decision so long as it's clearly documented. Regards jonathan ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Register now and save $200. Hurry, offer ends at 11:59 p.m., Monday, April 7! Use priority code J8TLD2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone _______________________________________________ Plplot-devel mailing list Plplot-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/plplot-devel
