On Apr 15, 2014, at 11:59 AM, David Vanderson <david.vander...@gmail.com> wrote:
> Sorry for the delay. I hacked together something that lets you drag points > around on a plot (attached). > > Is there a way to access area's plot->dc? For this example I wanted to ask > if the mouse was within 2 pixels of any point. > > When dragging the point around on the plot, it looks like I'm seeing multiple > repaints queueing up. It's especially bad on Linux where I can move the > mouse a bunch and then watch all the repaints happen over the next few > seconds. I'm trying to figure out if this can be improved. > > Question for GUI experts: Is there a reason why multiple repaint requests in > the queue should not be coalesced into a single paint? I had this problem recently, and it turned out that the problem was that I was calling “printf” as part of the handling of the redraw request. Removing this allowed coalescing to occur. Probably unrelated, but maybe worth a try. John Clements > > Thanks, > Dave > > On 04/01/2014 05:41 PM, Neil Toronto wrote: >> On 04/01/2014 02:17 PM, David Vanderson wrote: >>> Plot is fantastic - thanks so much! >>> >>> Is there a way to hook into the interactive features of plot so, for >>> instance, the user could click to add data or drag data points around? >>> >>> I'm using plot/dc to draw onto a canvas, and I'd be more than happy just >>> to be able to ask a plot to translate a pixel position to the >>> corresponding axes' positions. I know that plot does this for the >>> zooming feature, but is there a way for external code to do it? >> >> There's not an easy way right now. >> >> If you don't mind copying code, you can take some from `plot/dc' here: >> >> pkgs/plot-pkgs/plot-lib/plot/private/no-gui/plot2d.rkt >> >> The main thing you need is access to the `area' object, which has a public >> `dc->plot' method that translates device context coordinates into plot >> coordinates. I'm sorry it's not easier. :/ >> >> It will be someday, I promise! I've lately decided that "2D and 3D games >> that use Plot to render scenes" will be two of my main test cases. Games are >> the most interactive uses I can think of, and they need to be fast, so that >> should cover pretty much everyone's interactivity needs. >> >> Neil ⊥ >> >> > > <graph_ui.rkt>____________________ > Racket Users list: > http://lists.racket-lang.org/users ____________________ Racket Users list: http://lists.racket-lang.org/users
