Weather forecast page, 16 elements per page, attribute paths, examples from the display

- Home Assistant attributes can be paths into lists (forecast.1.condition).
- Date elements can show a day ahead (day offset 0-7).
- Pages hold 16 elements (page format 6; the old formats are frozen at 8).
  Pages are reset in place (clearPage), not through a 4 KB temporary.
- Verwachting page: today (icon, temperature, max/min) and the next 2
  days with 7 x 7 icons (weer7 <condition>), from a template sensor
  (docs/home-assistant.md).
- examples/home-pages.json is exported from the display with all pages
  and their icons, private entity id parts replaced by placeholders
  (tools/export_examples.py replaces tools/make_example_pages.py).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/esp32/logic/builtin_pages.cpp

@@ -26,7 +26,7 @@ const char *builtinPageName(const char *name)
 
 static void clockPage(DynamicPage &page)
 {
-	page = DynamicPage();
+	clearPage(page);
 	page.slot_count = 2;
 	page.slots[0].start = 0;
 	strcpy(page.slots[0].bitmap, "Pikachu");

src/esp32/logic/page.cpp

@@ -127,7 +127,7 @@ static bool strncasecmpAscii(const char *a, const char *b, size_t n)
 static bool validAttribute(const char *attribute)
 {
 	for (const char *c = attribute; *c; c++)
-		if (!isalnum((unsigned char)*c) && *c != '_')
+		if (!isalnum((unsigned char)*c) && *c != '_' && *c != '.') // dots: a path, e.g. forecast.1.condition
 			return false;
 	return true;
 }
@@ -196,6 +196,8 @@ const char *validatePage(const DynamicPage &page)
 			return "The list of texts can only contain plain characters, up to 63";
 		if (e.format >= formatCount(e))
 			return "Unknown format";
+		if (e.day_offset < 0 || e.day_offset > DAY_OFFSET_MAX)
+			return "Date: 0-7 days after today";
 		if (!isfinite(e.factor) || e.factor == 0)
 			return "The multiplier must be a number other than 0";
 		if (e.scroll_width > 2 * BITMAP_WIDTH ||
@@ -368,8 +370,37 @@ static int language(const PageElement &e)
 	return e.language < Language::Count ? (int)e.language : 0;
 }
 
-static void formatDate(const PageElement &e, const LocalTime &t, char *out, size_t size)
+static int daysInMonth(int year, int month)
 {
+	static const int DAYS[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
+	bool leap = (year % 4 == 0 && year % 100 != 0) || year % 400 == 0;
+	return month == 2 && leap ? 29 : DAYS[(month - 1 + 12) % 12];
+}
+
+LocalTime addDays(const LocalTime &time, int days)
+{
+	LocalTime t = time;
+	if (t.month < 1 || t.month > 12)
+		return t;
+	for (int i = 0; i < days; i++)
+	{
+		t.weekday = (t.weekday + 1) % 7;
+		if (++t.day > daysInMonth(t.year, t.month))
+		{
+			t.day = 1;
+			if (++t.month > 12)
+			{
+				t.month = 1;
+				t.year++;
+			}
+		}
+	}
+	return t;
+}
+
+static void formatDate(const PageElement &e, const LocalTime &today, char *out, size_t size)
+{
+	LocalTime t = addDays(today, e.day_offset);
 	int lang = language(e);
 	int wd = t.weekday >= 0 && t.weekday < 7 ? t.weekday : 0;
 	int mo = t.month >= 1 && t.month <= 12 ? t.month - 1 : 0;

src/esp32/logic/page.h

@@ -1,5 +1,6 @@
 #pragma once
 
+#include <new>
 #include <stddef.h>
 #include <stdint.h>
 
@@ -16,7 +17,7 @@
 
 const int PAGE_NAME_SIZE = BITMAP_NAME_MAX + 1;
 const int PAGE_SLOTS = 8;
-const int PAGE_ELEMENTS = 8;
+const int PAGE_ELEMENTS = 16;
 const int ELEMENT_TEXT_SIZE = 33;
 const int ELEMENT_SUFFIX_SIZE = 17;
 const int ELEMENT_ENTITY_SIZE = 65;
@@ -78,6 +79,8 @@ const uint8_t DATE_NUMERIC_YEAR = 4;      // 15-10-2026
 const uint8_t DATE_WEEKDAY = 5;           // donderdag / Thursday
 const uint8_t DATE_WEEKDAY_SHORT = 6;     // do / Thu
 const uint8_t DATE_FORMAT_COUNT = 7;
+// Date elements can show a later day (a forecast's weekday)
+const int8_t DAY_OFFSET_MAX = 7;
 
 // Countdown formats
 const uint8_t COUNTDOWN_SMART = 0;        // 12 dagen, 5 uur, 34 min, then 0:45
@@ -171,6 +174,8 @@ struct PageElement
 	uint8_t bar_height = 3;
 	float bar_max = 100;     // Bar: the value (after the multiplier) that fills it
 	bool bar_frame = true;   // Bar: a line around it, filled inside
+	// Added in page format 6
+	int8_t day_offset = 0;   // Date: days after today (0-DAY_OFFSET_MAX), e.g. 1: tomorrow
 };
 
 struct DynamicPage
@@ -181,6 +186,13 @@ struct DynamicPage
 	PageElement elements[PAGE_ELEMENTS];
 };
 
+// Back to an empty page with the defaults, without `page = DynamicPage()`: that can put a
+// copy (about 4 KB) on the stack
+inline void clearPage(DynamicPage &page)
+{
+	new (&page) DynamicPage();
+}
+
 // Returns nullptr when the page is fine, otherwise a message for the user. Does not check
 // that the bitmaps and fonts exist.
 const char *validatePage(const DynamicPage &page);
@@ -241,5 +253,8 @@ bool parseTimestamp(const char *text, int64_t &seconds);
 bool parseTarget(const char *text, uint32_t &minutes);
 // out must hold 17 characters
 void formatTarget(uint32_t minutes, char *out);
+// The date `days` (0 or more) after this one, with the weekday; the time stays
+LocalTime addDays(const LocalTime &time, int days);
+
 // The local time in minutes since 2000-01-01 00:00 (seconds left out)
 uint32_t minutesSince2000(const LocalTime &time);