Graphic Context with Groups

This is a example of how switch graphic context with group widgets.

#include <xstep.h>

struct xtree *group1,*group2;

void draw(struct xtree *t) {

        if(!animate) return;

        XSetForeground(display,t->gc,rand()%256);
        XFillRectangle(display,t->win,t->gc,
                t->aw/2+rand()%t->aw-rand()%t->aw,
                t->ah/2+rand()%t->ah-rand()%t->ah,
                rand()%t->aw/4,rand()%t->ah/4);

        downbox(0,0,t->aw,t->ah,invisible,t);
}

void group1f(struct xtree *t) { XRaiseWindow(display,group1->win); }
void group2f(struct xtree *t) { XRaiseWindow(display,group2->win); }

void xmain(int n,char *p[]) {

        window_create(0,0,400,180,"group_gc");
        animate=1;

        group1=group_begin(8,8,-8,-(24+16),getcolor(0,-1,0));

                group1->broadcast=draw;
        group_end();

        group2=group_begin(8,8,-8,-(24+16),getcolor(-1,0,0));

                group2->broadcast=draw;
        group_end();

        button_create(-(8+80*2),-8,72,24,"group 1",group1f);
        button_create(-(8+80*1),-8,72,24,"group 2",group2f);
        button_create(-(8+80*0),-8,72,24,"close",window_close);
}