Function:ds2protect
From S2PLOT
ds2protect
Protect dynamic geometry.
Prototype
void ds2protect(void);
Description
Protect the dynamic geometry, in order reduce the amount of geometry to call each refresh cycle. Typically use this by setting ds2protect() at the end of your standard dynamic callback, then call ds2unprotect() if key presses / events processed by other callbacks will result in a changed geometry state. Use with caution ... incorrect use can result in TMC: total memory consumption.
See Also
| ds2unprotect | Unprotect the dynamic geometry. |
| ds2isprotected | Query state of dynamic geometry protection. |
Code Example
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <time.h>
#include "s2plot.h"
void ncb(int *N)
{
int pstate = ds2isprotected(); /* What is current protection state? */
if ((*N == 1) && (pstate == 0)) { /* Key 1 was pressed */
ds2protect(); /* Protect dynamic geometry */
}
if ((*N == 2) && (pstate == 1)) { /* Key 2 was pressed */
ds2unprotect(); /* Unprotect dynamic geometry */
}
}
void cb(double *t, int *kc)
{
static XYZ orbit; /* Position of point to draw */
static float tt = 0; /* Current position in orbit */
orbit.x = cos(tt); /* Update point position */
orbit.y = sin(tt);
tt += 0.05;
COLOUR ocol = { 1, 1, 0 }; /* Point colour = yellow*/
ns2vthpoint(orbit, ocol, 3); /* Draw the point */
}
int main(int argc, char *argv[])
{
srand48((long)time(NULL)); /* Seed random numbers */
s2opend("/?", argc, argv); /* Prompt for display type */
s2swin(-1.,1., -1.,1., -1.,1.); /* Set the window coordinates */
s2box("BCDET",0,0,"BCDET",0,0,"BCDET",0,0); /* Draw coordinate box */
cs2scb(cb); /* Install dynamic geometry callback */
cs2sncb(ncb); /* Install number key press callback */
char string[32]; /* Write instruction label */
sprintf(string,"Press 1 to protect, press 2 to unprotect");
s2lab("","","",string);
s2show(1); /* Open the s2plot window */
return 1;
}
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