Introduced a Screen (sub) module and divided app into multiple screens.

common/app/screen_main.c

@@ -0,0 +1,72 @@
+#include "screen_main.h"
+#include "screen_guitest.h"
+#include "screen_pixytest.h"
+#include "button.h"
+#include "tft.h"
+
+BUTTON_STRUCT b_guitest;
+BUTTON_STRUCT b_pixytest;
+
+
+static void b_guitest_cb(void* button) {
+	gui_screen_navigate(get_screen_guitest());
+}
+
+static void b_pixytest_cb(void* button) {
+	gui_screen_navigate(get_screen_pixytest());
+}
+
+
+static void enter(void* screen) {
+	tft_clear(WHITE);
+
+	//button to reach guitest
+	b_guitest.base.x1=25; //Start X of Button
+        b_guitest.base.y1=45; //Start Y of Button
+        b_guitest.base.x2=AUTO; //b_guitest.base.x1+160; //Auto Calculate X2 with String Width
+        b_guitest.base.y2=AUTO; //Auto Calculate Y2 with String Height
+        b_guitest.txtcolor=WHITE; //Set foreground color
+        b_guitest.bgcolor=HEX(0xDE1010); //Set background color (Don't take 255 or 0 on at least one channel, to make shadows possible)
+        b_guitest.font=0; //Select Font
+        b_guitest.text="Gui/Tft Test"; //Set Text (For formatted strings take sprintf)
+        b_guitest.callback=b_guitest_cb; //Call b_guitest_cb as Callback
+        gui_button_add(&b_guitest); //Register Button (and run the callback from now on)
+
+	//button to reach pixy test
+        b_pixytest.base.x1=200; //Start X of Button
+        b_pixytest.base.y1=45; //Start Y of Button
+        b_pixytest.base.x2=AUTO; //b_pixytest.base.x1+160; //Auto Calculate X2 with String Width
+        b_pixytest.base.y2=AUTO; //Auto Calculate Y2 with String Height
+        b_pixytest.txtcolor=BLUE; //Set foreground color
+        b_pixytest.bgcolor=HEX(0x10DE10); //Set background color (Don't take 255 or 0 on at least one channel, to make shadows possible)
+        b_pixytest.font=0; //Select Font
+        b_pixytest.text="Pixy Test"; //Set Text (For formatted strings take sprintf)
+        b_pixytest.callback=b_pixytest_cb; //Call b_pixytest_cb as Callback
+        gui_button_add(&b_pixytest); //Register Button (and run the callback from now on)
+
+
+
+}
+
+static void leave(void* screen) {
+	gui_button_remove(&b_guitest);
+	gui_button_remove(&b_pixytest);
+}
+
+static void update(void* screen) {
+	//gui_button_redraw(&b_guitest); //only needed if button is overdrawn by others
+}
+
+
+static SCREEN_STRUCT screen = {
+	enter,
+	leave,
+	update
+};
+
+
+SCREEN_STRUCT* get_screen_main() {
+	return &screen;
+}
+
+