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Improved comments in implementation of button, checkbox, numupdown, tft, touch and screen modules/submodules.

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t-moe
2015-05-17 14:23:12 +02:00
parent e46314b760
commit 2d463366c1
9 changed files with 441 additions and 396 deletions
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67
common/gui/screen.c
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@@ -1,32 +1,40 @@
#include "screen.h"
/* The idea is as follows:
* We only call screen callbacks from the gui_screen_update() method, which is called from the applications main loop.
* Instructions to switch the screen will be delayed until the gui_screen_update() method is called again.
* This makes it safe to change the screen from an touch interrupt (e.g. button callback)
*/
static SCREEN_STRUCT* screen_list = NULL;
static SCREEN_STRUCT* screen_current = NULL;
static volatile SCREEN_STRUCT* screen_goto = NULL;
static SCREEN_STRUCT* screen_list = NULL; //Head of the linked list which stores the screen history.
static SCREEN_STRUCT* screen_current = NULL; //Pointer to the current screen (= tail of the list)
static volatile SCREEN_STRUCT* screen_goto = NULL; //Screen we should navigate to once we enter the gui_screen_update() method again
SCREEN_STRUCT* gui_screen_get_current() {
return screen_current;
}
void gui_screen_update() {
if(screen_goto!=NULL) { //we received the task to switch the screen
SCREEN_STRUCT* go = (SCREEN_STRUCT*) screen_goto; //Backup volatile variable
screen_goto=NULL;
if(go->next!=NULL) { //we're going back
if(go->next!=screen_current) return; //list corrupted?
screen_current->on_leave(screen_current);
go->next=NULL;
} else { //we're going forward
screen_goto=NULL; //reset the "goto instruction", since we're processing it now
if(go->next!=NULL) { //The screen is not the last in the list, so we're going back
if(go->next!=screen_current) { //this condition should always be false
return; //list corrupted?
}
screen_current->on_leave(screen_current); //let the current screen free/unregister it's resources
go->next=NULL; //remove the current screen from the list
} else { //we're going forward (to a new screen)
if(screen_current!=NULL) { //this is not the first screen
screen_current->on_leave(screen_current);
screen_current->next = go;
} else { //first screen ever seen
screen_list=go;
}
screen_current->on_leave(screen_current); //let the current screen free/unregister it's resources
screen_current->next = go; //append the new screen to the end of the list
} else { //first screen ever seen
screen_list=go; //set the new screen as list-head
}
}
go->on_enter(go);
screen_current =go;
go->on_enter(go); //let the new screen allocate/register it's resources
screen_current = go; //the new screen is now the current screen. Transition done
}
if(screen_current!=NULL) { //A screen has been set
@@ -37,16 +45,18 @@ void gui_screen_update() {
bool gui_screen_navigate(SCREEN_STRUCT* screen) {
if(screen==NULL) return false;
screen->next = NULL;
screen_goto=screen; //send message to main loop, to switch the screen
if(screen==NULL) { //invalid argument passed
return false;
}
screen->next = NULL; //this will become the new tail of the list, so the next pointer must be NULL
screen_goto=screen; //"send message" to main loop, to switch the screen
return true;
}
bool gui_screen_back() {
if(screen_list==NULL) return false;
if(screen_list==NULL) { //the list head is emtpy, nothing to go back to
return false;
}
SCREEN_STRUCT* current = screen_list;
SCREEN_STRUCT* last = NULL;
//Find second last element in list
@@ -54,15 +64,8 @@ bool gui_screen_back() {
last = current;
current = current->next;
}
if(last==NULL) return false; //There's only a single screen.
if(current!=screen_current) return false; //List corrupted?
screen_goto=last; //send message to main loop, to switch the screen
if(last==NULL) return false; //There's only a single screen, there's no going back here
if(current!=screen_current) return false; //The last entry in the list is not the current screen. List corrupted?
screen_goto=last; //"send message" to main loop, to switch the screen
return true;
}