fix(ui-lvgl): popups no longer shrink when their list is pulled past its end

LVGL 9.2.2 measures a SIZE_CONTENT box from its children as scrolled, so an
elastic pull past the end of a capped popup list shrank it by the overshoot,
again on every pull. lvgl_patches.py fixes calc_content_height in the
downloaded library (a build middleware for PlatformIO, called directly by the
sim's build_wasm.sh).

The five popups that each built the same panel now share popupOpen() (fit to
content / full height / under the status bar).

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

examples/companion_radio/ui-lvgl/MapScreen.h

@@ -710,20 +710,7 @@ void UITask::mapDownloadPopup() {
   if (_dl_zmax < _map_z) _dl_zmax = _map_z + 3;
   if (_dl_zmax > src_max) _dl_zmax = src_max;   // the server has nothing finer
 
-  _dl_overlay = dimOverlay(screen());
-
-  lv_obj_t* panel = lv_obj_create(_dl_overlay);
-  anim::popup(_dl_overlay);
-  lv_obj_set_size(panel, lv_display_get_horizontal_resolution(NULL) - 16, LV_SIZE_CONTENT);
-  lv_obj_align(panel, LV_ALIGN_CENTER, 0, theme::STATUS_H / 2);
-  lv_obj_set_style_bg_color(panel, lv_color_hex(theme::BG), 0);
-  lv_obj_set_style_border_color(panel, lv_color_hex(theme::ACCENT), 0);
-  lv_obj_set_style_border_width(panel, 1, 0);
-  lv_obj_set_style_radius(panel, theme::RADIUS, 0);
-  lv_obj_set_style_pad_all(panel, theme::PAD, 0);
-  lv_obj_set_style_pad_row(panel, 4, 0);
-  lv_obj_set_flex_flow(panel, LV_FLEX_FLOW_COLUMN);
-  lv_obj_set_style_max_height(panel, lv_display_get_vertical_resolution(NULL) - theme::STATUS_H - 12, 0);   // scrolls past that
+  lv_obj_t* panel = popupOpen(screen(), POP_FIT, _dl_overlay);
 
   lv_obj_t* hdr = lv_obj_create(panel);
   styleSurface(hdr, theme::BG);

examples/companion_radio/ui-lvgl/NavMap.h

@@ -476,27 +476,8 @@ void UITask::navToNode(const uint8_t* key, int32_t lat, int32_t lon, const char*
 
 lv_obj_t* UITask::navPopupPanel(const char* title, bool full) {
   navClosePopup();
-  _nav_overlay = dimOverlay(screen());
-
-  lv_obj_t* panel = lv_obj_create(_nav_overlay);
-  anim::popup(_nav_overlay);
-  int w = lv_display_get_horizontal_resolution(NULL) - 16;
-  if (full) {
-    lv_obj_set_size(panel, w, lv_display_get_vertical_resolution(NULL) - theme::STATUS_H - 12);
-    lv_obj_set_pos(panel, 8, theme::STATUS_H + 6);
-  } else {   // as tall as its content, scrolling past the screen's height
-    lv_obj_set_size(panel, w, LV_SIZE_CONTENT);
-    lv_obj_set_style_max_height(panel, lv_display_get_vertical_resolution(NULL) - theme::STATUS_H - 12, 0);
-    lv_obj_align(panel, LV_ALIGN_CENTER, 0, theme::STATUS_H / 2);
-  }
-  lv_obj_set_style_bg_color(panel, lv_color_hex(theme::BG), 0);
-  lv_obj_set_style_border_color(panel, lv_color_hex(theme::ACCENT), 0);
-  lv_obj_set_style_border_width(panel, 1, 0);
-  lv_obj_set_style_radius(panel, theme::RADIUS, 0);
-  lv_obj_set_style_pad_all(panel, theme::PAD, 0);
+  lv_obj_t* panel = popupOpen(screen(), full ? POP_FULL : POP_FIT, _nav_overlay);
   lv_obj_set_style_pad_row(panel, 6, 0);
-  lv_obj_set_flex_flow(panel, LV_FLEX_FLOW_COLUMN);
-  if (full) lv_obj_remove_flag(panel, LV_OBJ_FLAG_SCROLLABLE);   // its own list scrolls
 
   lv_obj_t* hdr = lv_obj_create(panel);
   styleSurface(hdr, theme::BG);

examples/companion_radio/ui-lvgl/RadioScreen.h

@@ -141,19 +141,8 @@ void UITask::radioFreqPopup(bool repeater) {
   using namespace radioview;
   if (s_overlay) return;
   s_freq_rpt = repeater;
-  s_overlay = dimOverlay(screen());
-  lv_obj_t* panel = lv_obj_create(s_overlay);
-  anim::popup(s_overlay);
-  lv_obj_set_size(panel, lv_display_get_horizontal_resolution(NULL) - 16, LV_SIZE_CONTENT);
-  lv_obj_align(panel, LV_ALIGN_TOP_MID, 0, theme::STATUS_H + 4);
-  lv_obj_set_style_bg_color(panel, lv_color_hex(theme::BG), 0);
-  lv_obj_set_style_border_color(panel, lv_color_hex(theme::ACCENT), 0);
-  lv_obj_set_style_border_width(panel, 1, 0);
-  lv_obj_set_style_radius(panel, theme::RADIUS, 0);
-  lv_obj_set_style_pad_all(panel, theme::PAD, 0);
+  lv_obj_t* panel = popupOpen(screen(), POP_TOP, s_overlay);
   lv_obj_set_style_pad_row(panel, 6, 0);
-  lv_obj_set_flex_flow(panel, LV_FLEX_FLOW_COLUMN);
-  lv_obj_remove_flag(panel, LV_OBJ_FLAG_SCROLLABLE);
   float lo, hi;
   radio_driver.getFreqBounds(lo, hi);
   char t[48];

examples/companion_radio/ui-lvgl/UITask.cpp

@@ -150,6 +150,41 @@ static lv_obj_t* dimOverlay(lv_obj_t* parent) {
   return o;
 }
 
+// A popup: the dimmed layer (into `overlay`, to close it by) and its panel --
+// the page colour, the accent hairline, a flex column -- rising into view.
+// POP_FIT: as tall as its content, centred below the status bar, scrolling
+// past that height. POP_FULL: all of that height; its own list scrolls.
+// POP_TOP: as tall as its content, under the status bar, clear of a keyboard.
+enum PopFit : uint8_t { POP_FIT, POP_FULL, POP_TOP };
+static lv_obj_t* popupOpen(lv_obj_t* parent, PopFit fit, lv_obj_t*& overlay, int32_t inset = 8) {
+  overlay = dimOverlay(parent);
+  lv_obj_t* panel = lv_obj_create(overlay);
+  int32_t w = lv_display_get_horizontal_resolution(NULL), h = lv_display_get_vertical_resolution(NULL);
+  lv_obj_set_width(panel, w - 2 * inset);
+  if (fit == POP_FULL) {
+    lv_obj_set_height(panel, h - theme::STATUS_H - 12);
+    lv_obj_set_pos(panel, inset, theme::STATUS_H + 6);
+  } else if (fit == POP_TOP) {
+    lv_obj_set_height(panel, LV_SIZE_CONTENT);
+    lv_obj_align(panel, LV_ALIGN_TOP_MID, 0, theme::STATUS_H + 4);
+  } else {
+    lv_obj_set_height(panel, LV_SIZE_CONTENT);
+    lv_obj_set_style_max_height(panel, h - theme::STATUS_H - 12, 0);
+    lv_obj_align(panel, LV_ALIGN_CENTER, 0, theme::STATUS_H / 2);
+    lv_obj_set_scrollbar_mode(panel, LV_SCROLLBAR_MODE_ACTIVE);
+  }
+  if (fit != POP_FIT) lv_obj_remove_flag(panel, LV_OBJ_FLAG_SCROLLABLE);
+  lv_obj_set_style_bg_color(panel, lv_color_hex(theme::BG), 0);
+  lv_obj_set_style_border_color(panel, lv_color_hex(theme::ACCENT), 0);
+  lv_obj_set_style_border_width(panel, 1, 0);
+  lv_obj_set_style_radius(panel, theme::RADIUS, 0);
+  lv_obj_set_style_pad_all(panel, theme::PAD, 0);
+  lv_obj_set_style_pad_row(panel, 4, 0);
+  lv_obj_set_flex_flow(panel, LV_FLEX_FLOW_COLUMN);
+  anim::popup(overlay);
+  return panel;
+}
+
 // ── Info cards ──
 // Label / value rows on a card (Diagnostics, GPS, node detail, About): the
 // label small and muted on the left, the value on the right -- wrapping,
@@ -429,23 +464,11 @@ static void pickerOpen(lv_obj_t* c) {
   Choice* ch = choiceOf(c);
   pickerClose();
   s_pick_target = c;
-  s_pick_overlay = dimOverlay(lv_layer_top());
+  lv_obj_t* panel = popupOpen(lv_layer_top(), POP_FIT, s_pick_overlay, 24);
   lv_obj_add_event_cb(s_pick_overlay, [](lv_event_t* e) {   // a tap beside the list: nothing changes
     if (lv_event_get_target(e) == lv_event_get_current_target(e)) pickerClose();
   }, LV_EVENT_CLICKED, NULL);
-  lv_obj_t* panel = lv_obj_create(s_pick_overlay);
-  styleSurface(panel, theme::BG);
-  lv_obj_set_width(panel, lv_display_get_horizontal_resolution(NULL) - 48);
-  lv_obj_set_height(panel, LV_SIZE_CONTENT);
-  lv_obj_set_style_max_height(panel, lv_display_get_vertical_resolution(NULL) - theme::STATUS_H - 16, 0);
-  lv_obj_align(panel, LV_ALIGN_CENTER, 0, theme::STATUS_H / 2);
-  lv_obj_set_style_radius(panel, theme::RADIUS, 0);
-  lv_obj_set_style_border_color(panel, lv_color_hex(theme::ACCENT), 0);
-  lv_obj_set_style_border_width(panel, 1, 0);
   lv_obj_set_style_pad_all(panel, 6, 0);
-  lv_obj_set_style_pad_row(panel, 4, 0);
-  lv_obj_set_flex_flow(panel, LV_FLEX_FLOW_COLUMN);
-  lv_obj_set_scrollbar_mode(panel, LV_SCROLLBAR_MODE_ACTIVE);
   lv_obj_t* t = label(panel, ch->title, THEME_FONT_SMALL, theme::TEXT_MUTED);
   lv_obj_set_style_pad_hor(t, 4, 0);
   lv_obj_t* card = group(panel, nullptr);
@@ -459,7 +482,6 @@ static void pickerOpen(lv_obj_t* c) {
     if (cur) { label(r, LV_SYMBOL_OK, THEME_FONT_BODY, theme::ACCENT); sel_row = r; }
     lv_obj_add_event_cb(r, onPickOption, LV_EVENT_CLICKED, (void*)(uintptr_t)i);
   }
-  anim::popup(s_pick_overlay);
   if (sel_row) { lv_obj_update_layout(panel); lv_obj_scroll_to_view_recursive(sel_row, LV_ANIM_OFF); }
 }
 
@@ -1812,21 +1834,7 @@ void UITask::startNearbyScan() {
 // Dimmed full-screen overlay (swallows taps) holding a panel with the results.
 // A child of the current screen, so it goes away with it.
 void UITask::showScanPopup() {
-  _scan_overlay = dimOverlay(screen());
-
-  lv_obj_t* panel = lv_obj_create(_scan_overlay);
-  anim::popup(_scan_overlay);
-  lv_obj_set_size(panel, lv_display_get_horizontal_resolution(NULL) - 16,
-                  lv_display_get_vertical_resolution(NULL) - theme::STATUS_H - 12);
-  lv_obj_set_pos(panel, 8, theme::STATUS_H + 6);
-  lv_obj_set_style_bg_color(panel, lv_color_hex(theme::BG), 0);
-  lv_obj_set_style_border_color(panel, lv_color_hex(theme::ACCENT), 0);
-  lv_obj_set_style_border_width(panel, 1, 0);
-  lv_obj_set_style_radius(panel, theme::RADIUS, 0);
-  lv_obj_set_style_pad_all(panel, theme::PAD, 0);
-  lv_obj_set_style_pad_row(panel, 4, 0);
-  lv_obj_set_flex_flow(panel, LV_FLEX_FLOW_COLUMN);
-  lv_obj_remove_flag(panel, LV_OBJ_FLAG_SCROLLABLE);
+  lv_obj_t* panel = popupOpen(screen(), POP_FULL, _scan_overlay);
 
   lv_obj_t* hdr = lv_obj_create(panel);
   styleSurface(hdr, theme::BG);

examples/companion_radio/ui-lvgl/lvgl_patches.py

@@ -0,0 +1,60 @@
+# Fixes to LVGL 9.2.2 (lib_deps) that ui-lvgl needs, applied in place to the
+# downloaded library -- idempotent, so every build can run it.
+#
+#   PlatformIO:  extra_scripts = pre:examples/companion_radio/ui-lvgl/lvgl_patches.py
+#                (patches as LVGL is compiled, i.e. after lib_deps are fetched)
+#   The sim:     python3 examples/companion_radio/ui-lvgl/lvgl_patches.py <lvgl dir>
+#
+# Content height counted as scrolled (lv_obj_pos.c, calc_content_height): a
+# SIZE_CONTENT box capped by max_height measures its children where the scroll
+# has moved them, so an elastic pull past its end shrinks it by the overshoot,
+# again on every pull (popups with a list). The function zeroes scroll.y for
+# the count, but the children's coords already carry it; it's added back.
+import os
+import sys
+
+PATCHES = [
+    ("src/core/lv_obj_pos.c", [
+        ("                    /*Normal top aligns. */\n"
+         "                    child_res_tmp = child->coords.y2 - obj->coords.y1 + 1;\n",
+         "                    /*Normal top aligns. */\n"
+         "                    child_res_tmp = child->coords.y2 - obj->coords.y1 + 1 + scroll_y_tmp;\n"),
+        ("        else {\n"
+         "            child_res_tmp = child->coords.y2 - obj->coords.y1 + 1;\n"
+         "        }\n",
+         "        else {\n"
+         "            child_res_tmp = child->coords.y2 - obj->coords.y1 + 1 + scroll_y_tmp;\n"
+         "        }\n"),
+    ]),
+]
+
+
+def apply(lvgl_dir):
+    for rel, subs in PATCHES:
+        path = os.path.join(lvgl_dir, rel)
+        with open(path) as f:
+            src = f.read()
+        out = src
+        for old, new in subs:
+            if new in out:
+                continue
+            if out.count(old) != 1:
+                raise RuntimeError("lvgl_patches: %s changed upstream, re-check the patch" % rel)
+            out = out.replace(old, new)
+        if out != src:
+            with open(path, "w") as f:
+                f.write(out)
+            print("lvgl_patches: patched %s" % rel)
+
+
+if __name__ == "__main__":
+    apply(sys.argv[1])
+else:
+    Import("env")  # noqa: F821 (SCons)
+
+    def _patch(env, node):
+        path = node.srcnode().get_abspath()
+        apply(path[: path.rindex(os.sep + "src" + os.sep)])
+        return node
+
+    env.AddBuildMiddleware(_patch, "*/lvgl/src/core/lv_obj_pos.c")  # noqa: F821

solo/wio-tracker-l2/platformio.ini

@@ -70,6 +70,9 @@ build_flags =
   -D NEARBY_MAX=64
   -D HIST_ARCHIVE          ; message history also on the SD card (ui-lvgl/HistoryStore.h)
   -D GPS_SKYVIEW           ; satellites / signal / DOPs for the GPS screen (helpers/sensors/GpsSky.h)
+extra_scripts =
+  ${esp32_base.extra_scripts}
+  pre:examples/companion_radio/ui-lvgl/lvgl_patches.py   ; fixes to LVGL itself
 build_src_filter = ${Wio_Tracker_L2.build_src_filter}
   +<helpers/esp32/*.cpp>
   +<helpers/ui/LGFXDisplay.cpp>

variants/sim/build_wasm.sh

@@ -246,6 +246,7 @@ if [ "$SIM_UI" = "lvgl" ]; then
   # would shadow the libc <features.h> the C headers include.
   C_FLAGS=(-std=gnu99 "${OPT_FLAGS[@]}" "${DEFINES[@]}" "-I$LVGL_DIR" -Iexamples/companion_radio/ui-lvgl)
   LV_OBJ_DIR="$OUT_DIR/obj_lvgl"
+  python3 examples/companion_radio/ui-lvgl/lvgl_patches.py "$LVGL_DIR"   # as the firmware build does
   C_SRCS=()
   while IFS= read -r f; do C_SRCS+=("$f"); done < <(
     find "$LVGL_DIR/src" -name '*.c' | sed "s|^$REPO_ROOT/||" | sort