Files
discoverpixy/common/gui/screen.c

59 lines
1.0 KiB
C

#include "screen.h"
static SCREEN_STRUCT* screen_list = NULL;
static SCREEN_STRUCT* screen_current = NULL;
SCREEN_STRUCT* gui_screen_get_current() {
return screen_current;
}
void gui_screen_update() {
if(screen_current!=NULL) {
screen_current->on_update(screen_current);
}
}
bool gui_screen_navigate(SCREEN_STRUCT* screen) {
if(screen==NULL) return false;
screen->next = NULL;
if(screen_current!=NULL) {
screen_current->on_leave(screen_current);
screen_current->next = screen;
} else {
screen_list=screen;
}
screen->on_enter(screen);
screen_current = screen;
return true;
}
bool gui_screen_back() {
if(screen_list==NULL) return false;
SCREEN_STRUCT* current = screen_list;
SCREEN_STRUCT* last = NULL;
while(current->next != NULL) {
last = current;
current = current->next;
}
if(last==NULL) return false; //There's only a single screen.
if(current!=screen_current) return false; //List corrupted?
current->on_leave(current);
last->next=NULL;
last->on_enter(last);
screen_current=last;
return true;
}