I got it working! The plot demo application has a slideshow feature that updated the plot in place without flickering. Here's the working code:
NB. ------------------------------------------------- NB. animated sine plot in J NB. by michal wallace (http://tangentstorm.com/) NB. free for use under the MIT license NB. ------------------------------------------------- load'plot' coinsert each 'jgl2'; 'jzplot' pc =: 'w0' NB. name of parent control (window) pn =: 'animated plot' NB. parent name (window title) cc =: 'g0' NB. name of child control (isidraw canvas) wh =: 720 200 NB. width and height of the window n =: 0x NB. tick counter s =: 0$0 NB. series to plot update =: verb define NB. build a series for a sine wave s =: 1 o. (n =: n + 1) + 0.1 * i: 100 ) render =: verb define NB. put pd commands here pd 'frame 1; axes 1 1; labels 0 0;' pd 'color red' pd s ) NB. ------------------------------------------------- NB. everything below here is pretty much boilerplate NB. ------------------------------------------------ trap_z_ =: verb define NB. halt timer to avoid infinite modal error msg death loop wd 'timer 0' smoutput LF,(13!:12''),'timer stopped.' [ wd 'timer 0' ) signal_jzplot_=:13!:8&12 [ trap 3 : 0'' NB. create the window if it doesn't exist if. -. wdisparent pc do. wd 'pc ',pc,' closeok; pn "',pn,'";' wd 'minwh ',(":wh),'; cc ',cc,' isidraw flush;' wd 'pshow; pcenter;' end. ) to_pc =: verb define NB. choose where to draw pd commands wd 'psel ', PForm_jzplot_=: pc PFormhwnd_jzplot_ =: wd 'qhwndp' PIdhwnd_jzplot_ =: wd 'qhwndc ', PId_jzplot_=: cc glclear'' pd 'reset ',pc ) paint =: verb define NB. repaint current window on demand glpaint @ ppaint'' ) step =: verb define NB. animation engine, with error trap try. paint render to_pc [ update'' catch. trap'' end. ) sys_timer_z_ =: step_base_ wd 'timer 100' NB. set to 0 to stop the timer On Sat, Aug 10, 2019 at 2:52 PM Michal Wallace <michal.wall...@gmail.com> wrote: > Hey all, > > > I'm experimenting with animation in J for a new video... > > > I'm use the wd timer to make an animated plot, and it mostly works, but > the window itself disappears and reappears on every frame, causing an > unwatchable flicker effect. > > > How can I keep the plot window from flickering, or pipe the output to an > isidraw in my own window? > > > Here's a simple sine wave example to demonstrate the problem. (Running in > j807 / jqtide) > > > > NB. warning: put this code in the j editor before running, or > > NB. you may wind up having to kill your j session... > > > load'plot' > > > step =: 0x > > sys_timer_z_ =: 3 : 0 > > n =. step_base_ =: step_base_ + 1 > > NB. plot wants to focus on the window, and if you don't use > > NB. wd to refocus on the editor, your session will become unusable. > > wd 'sm focus edit' [ plot 1 o. 8 %~ n + i:32 > > ) > > > wd'timer 50' NB. change this to 0 to stop the timer > > > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
