Fix "Show next" staleness bug; add location/date/share-QR to manage overlay

Two changes, bundled since they landed in the same session and touch
overlapping files:

1. Fix: "Show next" sent the browser's full queue snapshot to
   POST /api/queue/reorder, which hard-rejected if the server's queue
   had shifted since the last fetch (e.g. right after a queue-length
   trim). New POST /api/queue/promote moves one photo to the front
   authoritatively, with no dependency on client staleness. /reorder
   itself is now tolerant too -- unrecognized IDs are dropped and
   missing ones appended, instead of rejecting the whole request.

2. Feature: the manage button's overlay now also shows the photo's
   location (top-left, only if Immich reverse-geocoded it from GPS
   EXIF), the date it was taken (bottom-right), and a QR code (bottom-
   left) linking to a 30-minute public Immich share link -- created
   lazily when someone actually scans it, not when the button's
   pressed. New server endpoints GET /frame/photo-info and
   GET /frame/share/{asset_id} (scoped to the frame's current/queued
   photos, not any arbitrary Immich asset). Firmware-side, the overlay
   mechanism generalizes from one spliced region to up to four
   (manage_qr_overlay.c), each its own small buffer, still never
   holding the full frame in RAM.

firmware/main/frame_client.c

@@ -146,6 +146,48 @@ static bool json_extract_uint(const char *json, const char *key, uint32_t *out)
     return true;
 }
 
+/* Finds the string value associated with "key" in a small, flat JSON
+ * blob, e.g. "San Francisco, CA" in {"location": "San Francisco, CA"}.
+ * Same rationale as json_extract_uint() -- not a general parser. Returns
+ * false if the key is missing or its value is JSON null. Only unescapes
+ * \" -- values from this server need nothing fancier. */
+static bool json_extract_string(const char *json, const char *key, char *out, size_t out_size)
+{
+    char needle[48];
+    snprintf(needle, sizeof(needle), "\"%s\"", key);
+    const char *pos = strstr(json, needle);
+    if (pos == NULL) {
+        return false;
+    }
+    pos = strchr(pos, ':');
+    if (pos == NULL) {
+        return false;
+    }
+    pos++;
+    while (*pos == ' ') {
+        pos++;
+    }
+    if (strncmp(pos, "null", 4) == 0) {
+        return false;
+    }
+    if (*pos != '"') {
+        return false;
+    }
+    pos++;
+
+    size_t i = 0;
+    while (*pos != '\0' && *pos != '"' && i + 1 < out_size) {
+        if (pos[0] == '\\' && pos[1] == '"') {
+            out[i++] = '"';
+            pos += 2;
+        } else {
+            out[i++] = *pos++;
+        }
+    }
+    out[i] = '\0';
+    return true;
+}
+
 /* GETs the server's /frame/config -- doubles as both the reachability
  * check (any completed HTTP response means the socket-level connection
  * succeeded) and the source of the server-configurable refresh interval. */
@@ -199,24 +241,87 @@ static frame_server_config_t fetch_frame_config(const char *toolsserver)
     return result;
 }
 
+/* GETs the server's /frame/photo-info for the manage-button overlay:
+ * location/taken_at text (left empty if the server didn't have them --
+ * e.g. no GPS EXIF to geocode, or no capture date) and a share_url built
+ * from the returned asset_id, same construction pattern as
+ * run_fetch_cycle()'s management_url. Any failure (unreachable, no
+ * current photo, etc.) just leaves all three outputs empty -- the caller
+ * treats that as "skip these optional overlay regions", not a hard
+ * error, since the base "scan to manage" QR should still show. */
+static void fetch_photo_info(const char *toolsserver, char *location, size_t location_size, char *taken_at,
+                              size_t taken_at_size, char *share_url, size_t share_url_size)
+{
+    location[0] = '\0';
+    taken_at[0] = '\0';
+    share_url[0] = '\0';
+
+    char url[160];
+    snprintf(url, sizeof(url), "http://%s/frame/photo-info", toolsserver);
+
+    esp_http_client_config_t config = {
+        .url = url,
+        .method = HTTP_METHOD_GET,
+        .timeout_ms = CONFIG_FRAME_SERVER_CHECK_TIMEOUT_MS,
+    };
+    esp_http_client_handle_t client = esp_http_client_init(&config);
+
+    esp_err_t err = esp_http_client_open(client, 0);
+    if (err != ESP_OK) {
+        ESP_LOGW(TAG, "'%s' not reachable: %s", url, esp_err_to_name(err));
+        esp_http_client_cleanup(client);
+        return;
+    }
+
+    int status = esp_http_client_fetch_headers(client) >= 0 ? esp_http_client_get_status_code(client) : -1;
+    if (status != 200) {
+        ESP_LOGW(TAG, "'%s' returned HTTP %d", url, status);
+        esp_http_client_close(client);
+        esp_http_client_cleanup(client);
+        return;
+    }
+
+    char body[384];
+    int total = 0;
+    int n;
+    while (total < (int)sizeof(body) - 1 &&
+           (n = esp_http_client_read(client, body + total, sizeof(body) - 1 - total)) > 0) {
+        total += n;
+    }
+    body[total] = '\0';
+
+    esp_http_client_close(client);
+    esp_http_client_cleanup(client);
+
+    json_extract_string(body, "location", location, location_size);
+    json_extract_string(body, "taken_at", taken_at, taken_at_size);
+
+    char asset_id[48];
+    if (json_extract_string(body, "asset_id", asset_id, sizeof(asset_id))) {
+        snprintf(share_url, share_url_size, "http://%s/frame/share/%s", toolsserver, asset_id);
+    }
+}
+
 typedef struct {
     esp_http_client_handle_t client;
-    size_t stream_pos;                  /* running absolute offset into the frame, for overlay splicing */
-    const manage_qr_overlay_t *overlay; /* NULL = no overlay this fetch */
+    size_t stream_pos;                 /* running absolute offset into the frame, for overlay splicing */
+    const manage_overlay_set_t *overlay; /* NULL = no overlay this fetch */
 } http_read_ctx_t;
 
-/* Splices overlay pixels over the real photo bytes in chunk wherever
- * chunk's absolute byte range [chunk_start, chunk_start+chunk_len) within
- * the full frame intersects the overlay's rectangle. Rows/chunks outside
- * the overlay's footprint are left completely untouched. overlay->x0 is
- * always even (see manage_qr_overlay.h), so byte_x0 below is exact. */
-static void splice_overlay(uint8_t *chunk, size_t chunk_len, size_t chunk_start, const manage_qr_overlay_t *overlay)
+/* Splices one overlay region's pixels over the real photo bytes in chunk
+ * wherever chunk's absolute byte range [chunk_start, chunk_start+chunk_len)
+ * within the full frame intersects that region's rectangle. Rows/chunks
+ * outside the region's footprint are left completely untouched.
+ * region->x0 is always even (see manage_qr_overlay.h), so byte_x0 below
+ * is exact. */
+static void splice_overlay_region(uint8_t *chunk, size_t chunk_len, size_t chunk_start,
+                                   const manage_overlay_region_t *region)
 {
-    int byte_x0 = overlay->x0 / 2;
-    int byte_w = overlay->w / 2;
+    int byte_x0 = region->x0 / 2;
+    int byte_w = region->w / 2;
     size_t chunk_end = chunk_start + chunk_len;
 
-    for (int row = overlay->y0; row < overlay->y0 + overlay->h; row++) {
+    for (int row = region->y0; row < region->y0 + region->h; row++) {
         size_t row_start = (size_t)row * EPD_BYTES_PER_ROW + (size_t)byte_x0;
         size_t row_end = row_start + (size_t)byte_w;
 
@@ -226,14 +331,21 @@ static void splice_overlay(uint8_t *chunk, size_t chunk_len, size_t chunk_start,
             continue;
         }
 
-        size_t overlay_row_offset = (size_t)(row - overlay->y0) * (size_t)byte_w + (lo - row_start);
-        memcpy(chunk + (lo - chunk_start), overlay->buf + overlay_row_offset, hi - lo);
+        size_t region_row_offset = (size_t)(row - region->y0) * (size_t)byte_w + (lo - row_start);
+        memcpy(chunk + (lo - chunk_start), region->buf + region_row_offset, hi - lo);
+    }
+}
+
+static void splice_overlay(uint8_t *chunk, size_t chunk_len, size_t chunk_start, const manage_overlay_set_t *overlay)
+{
+    for (int i = 0; i < overlay->count; i++) {
+        splice_overlay_region(chunk, chunk_len, chunk_start, &overlay->regions[i]);
     }
 }
 
 /* Pulls the next chunk straight out of the in-progress HTTP response --
  * epd_write_frame() calls this to feed the panel without ever holding
- * the full ~192KB frame in RAM. Splices in ctx->overlay's pixels (if
+ * the full ~192KB frame in RAM. Splices in ctx->overlay's regions (if
  * set) as chunks pass through, so the panel driver never needs to know
  * an overlay exists at all. */
 static size_t http_read_fn(uint8_t *chunk, size_t chunk_size, void *ctx_)
@@ -259,7 +371,8 @@ static size_t http_read_fn(uint8_t *chunk, size_t chunk_size, void *ctx_)
  * epd_display_stream() (see epd7in3e.c) refuses to trigger a physical
  * refresh on a short/wrong-size stream, so a failure here always leaves
  * the visible screen exactly as it was. */
-static esp_err_t fetch_and_display(const frame_config_t *cfg, bool force_advance, const manage_qr_overlay_t *overlay)
+static esp_err_t fetch_and_display(const frame_config_t *cfg, bool force_advance,
+                                    const manage_overlay_set_t *overlay)
 {
     char url[160];
     snprintf(url, sizeof(url), "http://%s/%s", cfg->toolsserver, force_advance ? "frame/advance" : "frame/image");
@@ -317,12 +430,15 @@ static esp_err_t fetch_and_display(const frame_config_t *cfg, bool force_advance
 }
 
 /* Runs the appropriate fetch for this cycle: a plain fetch, or -- if
- * show_management_qr -- a fetch with the "scan to manage" QR overlay
- * spliced in, held on screen for 30s (device stays awake, doesn't sleep
- * the panel or the chip), then reverted with a second plain fetch.
- * Returns non-ESP_OK only if the FIRST fetch failed; a revert failure
- * afterward is logged but doesn't count as an overall failure -- the QR
- * itself displayed fine, which was the point of the button. */
+ * show_management_qr -- a fetch with the manage overlay spliced in (the
+ * top-right "scan to manage" QR always, plus location/date-taken/
+ * share-QR corners wherever the server had that data -- see
+ * fetch_photo_info()), held on screen for 30s (device stays awake,
+ * doesn't sleep the panel or the chip), then reverted with a second
+ * plain fetch. Returns non-ESP_OK only if the FIRST fetch failed; a
+ * revert failure afterward is logged but doesn't count as an overall
+ * failure -- the overlay itself displayed fine, which was the point of
+ * the button. */
 static esp_err_t run_fetch_cycle(const frame_config_t *cfg, bool force_advance, bool show_management_qr)
 {
     if (!show_management_qr) {
@@ -332,28 +448,42 @@ static esp_err_t run_fetch_cycle(const frame_config_t *cfg, bool force_advance,
     char management_url[160];
     snprintf(management_url, sizeof(management_url), "http://%s/", cfg->toolsserver);
 
-    manage_qr_overlay_t overlay;
-    esp_err_t overlay_err = manage_qr_overlay_render(management_url, &overlay);
+    char location[64];
+    char taken_at[32];
+    char share_url[160];
+    fetch_photo_info(cfg->toolsserver, location, sizeof(location), taken_at, sizeof(taken_at), share_url,
+                      sizeof(share_url));
+
+    manage_overlay_content_t content = {
+        .management_url = management_url,
+        .location = location[0] != '\0' ? location : NULL,
+        .taken_at = taken_at[0] != '\0' ? taken_at : NULL,
+        .share_url = share_url[0] != '\0' ? share_url : NULL,
+    };
+
+    manage_overlay_set_t overlay;
+    esp_err_t overlay_err = manage_overlay_render(&content, &overlay);
     if (overlay_err != ESP_OK) {
-        ESP_LOGW(TAG, "Could not render management QR overlay (%s), showing photo normally",
+        manage_overlay_free(&overlay);
+        ESP_LOGW(TAG, "Could not render management overlay (%s), showing photo normally",
                  esp_err_to_name(overlay_err));
         return fetch_and_display(cfg, force_advance, NULL);
     }
 
     esp_err_t err = fetch_and_display(cfg, force_advance, &overlay);
-    manage_qr_overlay_free(&overlay);
+    manage_overlay_free(&overlay);
     if (err != ESP_OK) {
         return err;
     }
 
-    ESP_LOGI(TAG, "Showing management QR for 30s");
+    ESP_LOGI(TAG, "Showing management overlay for 30s");
     vTaskDelay(pdMS_TO_TICKS(30000));
 
     /* force_advance is always false here -- reverting shouldn't skip
      * ahead a second time. */
     esp_err_t revert_err = fetch_and_display(cfg, false, NULL);
     if (revert_err != ESP_OK) {
-        ESP_LOGW(TAG, "Failed to revert management QR overlay (%s)", esp_err_to_name(revert_err));
+        ESP_LOGW(TAG, "Failed to revert management overlay (%s)", esp_err_to_name(revert_err));
     }
 
     return ESP_OK;

firmware/main/manage_qr_overlay.c

@@ -14,18 +14,47 @@ static const char *TAG = "manage_qr_overlay";
 
 #define QR_MAX_VERSION 10
 #define QR_BUFFER_LEN qrcodegen_BUFFER_LEN_FOR_VERSION(QR_MAX_VERSION)
-/* Smaller than qr_onboarding.c's QR_MODULE_PX (8) -- this is a compact
- * corner popup, not a full-screen setup step. */
+/* Smaller than qr_onboarding.c's QR_MODULE_PX (8) -- these are compact
+ * corner popups, not a full-screen setup step. */
 #define QR_MODULE_PX 4
 #define PADDING 16
 #define QR_TEXT_GAP 8
 #define LINE_GAP 4
-/* Distance from the panel's top/right edges to the overlay box. Combined
- * with EPD_WIDTH and the forced-even box width below, this guarantees
- * x0 is always even -- required so the overlay's columns land on frame
- * byte boundaries (2px/byte) when spliced into the fetch stream. */
+/* Distance from the panel's edges to each overlay box. Combined with
+ * EPD_WIDTH/EPD_HEIGHT and each region's forced-even width below, this
+ * guarantees x0 is always even -- required so a region's columns land on
+ * frame byte boundaries (2px/byte) when spliced into the fetch stream. */
 #define PANEL_MARGIN 20
 
+typedef enum {
+    CORNER_TOP_LEFT,
+    CORNER_TOP_RIGHT,
+    CORNER_BOTTOM_LEFT,
+    CORNER_BOTTOM_RIGHT,
+} overlay_corner_t;
+
+static void position_region(manage_overlay_region_t *region, overlay_corner_t corner)
+{
+    switch (corner) {
+    case CORNER_TOP_LEFT:
+        region->x0 = PANEL_MARGIN;
+        region->y0 = PANEL_MARGIN;
+        break;
+    case CORNER_TOP_RIGHT:
+        region->x0 = EPD_WIDTH - PANEL_MARGIN - region->w;
+        region->y0 = PANEL_MARGIN;
+        break;
+    case CORNER_BOTTOM_LEFT:
+        region->x0 = PANEL_MARGIN;
+        region->y0 = EPD_HEIGHT - PANEL_MARGIN - region->h;
+        break;
+    case CORNER_BOTTOM_RIGHT:
+        region->x0 = EPD_WIDTH - PANEL_MARGIN - region->w;
+        region->y0 = EPD_HEIGHT - PANEL_MARGIN - region->h;
+        break;
+    }
+}
+
 static void draw_qr(uint8_t *buf, int stride, int width, int height, const uint8_t *qrcode, int origin_x,
                      int origin_y)
 {
@@ -43,13 +72,18 @@ static void draw_qr(uint8_t *buf, int stride, int width, int height, const uint8
     }
 }
 
-esp_err_t manage_qr_overlay_render(const char *management_url, manage_qr_overlay_t *out)
+/* White-padded box with a QR code encoding payload, plus zero, one, or
+ * two centered caption lines beneath it (either may be NULL). Used for
+ * both the top-right "scan to manage" box (two lines) and the
+ * bottom-left share-link box (no lines). */
+static esp_err_t render_qr_region(const char *payload, const char *line1, const char *line2, overlay_corner_t corner,
+                                   manage_overlay_region_t *out)
 {
     uint8_t temp_buffer[QR_BUFFER_LEN];
     uint8_t qrcode[QR_BUFFER_LEN];
-    bool ok = qrcodegen_encodeText(management_url, temp_buffer, qrcode, qrcodegen_Ecc_MEDIUM, qrcodegen_VERSION_MIN,
+    bool ok = qrcodegen_encodeText(payload, temp_buffer, qrcode, qrcodegen_Ecc_MEDIUM, qrcodegen_VERSION_MIN,
                                     QR_MAX_VERSION, qrcodegen_Mask_AUTO, true);
-    ESP_RETURN_ON_FALSE(ok, ESP_FAIL, TAG, "QR encoding failed for '%s' (too long for max version)", management_url);
+    ESP_RETURN_ON_FALSE(ok, ESP_FAIL, TAG, "QR encoding failed for '%s' (too long for max version)", payload);
 
     int qr_size = qrcodegen_getSize(qrcode);
     int qr_px = qr_size * QR_MODULE_PX;
@@ -57,15 +91,18 @@ esp_err_t manage_qr_overlay_render(const char *management_url, manage_qr_overlay
     /* Font24 (32x41px uppercase glyphs) is the only font vendored into
      * this project -- see components/epaper_fonts. "SCAN TO MANAGE" on
      * one line would be 448px wide, too wide for a compact corner box,
-     * so it's wrapped across two lines here instead. */
-    static const char *line1 = "SCAN TO";
-    static const char *line2 = "MANAGE";
-    int line1_w = (int)strlen(line1) * Font24.Width;
-    int line2_w = (int)strlen(line2) * Font24.Width;
-    int text_w = line1_w > line2_w ? line1_w : line2_w;
+     * so it's passed in pre-wrapped across two lines instead. */
+    int text_w = 0;
+    int text_h = 0;
+    if (line1 != NULL) {
+        int w1 = (int)strlen(line1) * Font24.Width;
+        int w2 = line2 != NULL ? (int)strlen(line2) * Font24.Width : 0;
+        text_w = w1 > w2 ? w1 : w2;
+        text_h = QR_TEXT_GAP + Font24.Height + (line2 != NULL ? LINE_GAP + Font24.Height : 0);
+    }
 
     int content_w = qr_px > text_w ? qr_px : text_w;
-    int content_h = qr_px + QR_TEXT_GAP + Font24.Height + LINE_GAP + Font24.Height;
+    int content_h = qr_px + text_h;
 
     int w = content_w + PADDING * 2;
     int h = content_h + PADDING * 2;
@@ -73,28 +110,91 @@ esp_err_t manage_qr_overlay_render(const char *management_url, manage_qr_overlay
 
     int stride = w / 2;
     uint8_t *buf = malloc((size_t)stride * h);
-    ESP_RETURN_ON_FALSE(buf != NULL, ESP_ERR_NO_MEM, TAG, "Failed to allocate overlay buffer");
+    ESP_RETURN_ON_FALSE(buf != NULL, ESP_ERR_NO_MEM, TAG, "Failed to allocate overlay region");
     memset(buf, (EPD_COLOR_WHITE << 4) | EPD_COLOR_WHITE, (size_t)stride * h);
 
     int center_x = w / 2;
     int y = PADDING;
     draw_qr(buf, stride, w, h, qrcode, center_x - qr_px / 2, y);
-    y += qr_px + QR_TEXT_GAP;
-    epd_draw_text_centered_ex(buf, stride, w, h, &Font24, line1, center_x, y);
-    y += Font24.Height + LINE_GAP;
-    epd_draw_text_centered_ex(buf, stride, w, h, &Font24, line2, center_x, y);
+    y += qr_px;
+    if (line1 != NULL) {
+        y += QR_TEXT_GAP;
+        epd_draw_text_centered_ex(buf, stride, w, h, &Font24, line1, center_x, y);
+        y += Font24.Height;
+    }
+    if (line2 != NULL) {
+        y += LINE_GAP;
+        epd_draw_text_centered_ex(buf, stride, w, h, &Font24, line2, center_x, y);
+    }
 
     out->buf = buf;
     out->w = w;
     out->h = h;
-    out->x0 = EPD_WIDTH - PANEL_MARGIN - w;
-    out->y0 = PANEL_MARGIN;
+    position_region(out, corner);
+    return ESP_OK;
+}
+
+/* White-padded box with a single centered line of text -- used for the
+ * top-left location and bottom-right date-taken labels. */
+static esp_err_t render_text_region(const char *text, overlay_corner_t corner, manage_overlay_region_t *out)
+{
+    int text_w = (int)strlen(text) * Font24.Width;
+    int w = text_w + PADDING * 2;
+    int h = Font24.Height + PADDING * 2;
+    w += w % 2;
+
+    int stride = w / 2;
+    uint8_t *buf = malloc((size_t)stride * h);
+    ESP_RETURN_ON_FALSE(buf != NULL, ESP_ERR_NO_MEM, TAG, "Failed to allocate overlay region");
+    memset(buf, (EPD_COLOR_WHITE << 4) | EPD_COLOR_WHITE, (size_t)stride * h);
+
+    epd_draw_text_centered_ex(buf, stride, w, h, &Font24, text, w / 2, PADDING);
+
+    out->buf = buf;
+    out->w = w;
+    out->h = h;
+    position_region(out, corner);
+    return ESP_OK;
+}
+
+esp_err_t manage_overlay_render(const manage_overlay_content_t *content, manage_overlay_set_t *out)
+{
+    out->count = 0;
+
+    esp_err_t err = render_qr_region(content->management_url, "SCAN TO", "MANAGE", CORNER_TOP_RIGHT,
+                                      &out->regions[out->count]);
+    if (err != ESP_OK) {
+        return err;
+    }
+    out->count++;
+
+    if (content->location != NULL && content->location[0] != '\0') {
+        if (render_text_region(content->location, CORNER_TOP_LEFT, &out->regions[out->count]) == ESP_OK) {
+            out->count++;
+        }
+    }
+
+    if (content->taken_at != NULL && content->taken_at[0] != '\0') {
+        if (render_text_region(content->taken_at, CORNER_BOTTOM_RIGHT, &out->regions[out->count]) == ESP_OK) {
+            out->count++;
+        }
+    }
+
+    if (content->share_url != NULL && content->share_url[0] != '\0') {
+        if (render_qr_region(content->share_url, NULL, NULL, CORNER_BOTTOM_LEFT, &out->regions[out->count]) ==
+            ESP_OK) {
+            out->count++;
+        }
+    }
 
     return ESP_OK;
 }
 
-void manage_qr_overlay_free(manage_qr_overlay_t *overlay)
+void manage_overlay_free(manage_overlay_set_t *overlay)
 {
-    free(overlay->buf);
-    overlay->buf = NULL;
+    for (int i = 0; i < overlay->count; i++) {
+        free(overlay->regions[i].buf);
+        overlay->regions[i].buf = NULL;
+    }
+    overlay->count = 0;
 }

firmware/main/manage_qr_overlay.h

@@ -4,19 +4,38 @@
 
 #include "esp_err.h"
 
+#define MANAGE_OVERLAY_MAX_REGIONS 4
+
 typedef struct {
-    uint8_t *buf; /* malloc'd (w/2)*h bytes, packed 2px/byte; caller must free */
+    uint8_t *buf; /* malloc'd (w/2)*h bytes, packed 2px/byte; owned by the region */
     int x0, y0;   /* top-left corner, panel pixel coordinates (x0 is always even) */
     int w, h;     /* pixel dimensions (w is always even) */
-} manage_qr_overlay_t;
+} manage_overlay_region_t;
+
+typedef struct {
+    manage_overlay_region_t regions[MANAGE_OVERLAY_MAX_REGIONS];
+    int count;
+} manage_overlay_set_t;
+
+typedef struct {
+    const char *management_url; /* top-right QR + "SCAN TO"/"MANAGE" caption -- always shown */
+    const char *location;       /* top-left text; NULL/empty skips this region */
+    const char *taken_at;       /* bottom-right text; NULL/empty skips this region */
+    const char *share_url;      /* bottom-left QR (no caption); NULL/empty skips this region */
+} manage_overlay_content_t;
 
 /**
- * Renders a small "scan to manage" overlay -- a QR code encoding
- * management_url plus a "SCAN TO" / "MANAGE" caption, on a white
- * padded background -- into a freshly allocated buffer sized just for
- * the overlay itself (not a full EPD_FRAME_BYTES frame), positioned for
- * the panel's top-right corner. Caller must call manage_qr_overlay_free().
+ * Renders the manage-button overlay: always a "scan to manage" QR in the
+ * top-right corner, plus whichever of location/taken_at/share_url are
+ * non-NULL/non-empty in their own corners (top-left, bottom-right,
+ * bottom-left respectively). Each region is its own separately malloc'd
+ * small buffer (not a full EPD_FRAME_BYTES frame). A failure rendering
+ * the top-right region fails the whole call; a failure rendering one of
+ * the optional regions just skips that region and keeps going. Caller
+ * must call manage_overlay_free() on out regardless of the return value
+ * (out->count reflects however many regions were actually populated).
  */
-esp_err_t manage_qr_overlay_render(const char *management_url, manage_qr_overlay_t *out);
+esp_err_t manage_overlay_render(const manage_overlay_content_t *content, manage_overlay_set_t *out);
 
-void manage_qr_overlay_free(manage_qr_overlay_t *overlay);
+/** Frees every populated region's buffer in overlay. */
+void manage_overlay_free(manage_overlay_set_t *overlay);