imgfont_set_range.patch

diff --git a/src/others/imgfont/lv_imgfont.c b/src/others/imgfont/lv_imgfont.c
index edc69907d..59b4cd521 100644
--- a/src/others/imgfont/lv_imgfont.c
+++ b/src/others/imgfont/lv_imgfont.c
@@ -21,6 +21,13 @@ typedef struct {
     lv_font_t font;
     lv_imgfont_get_path_cb_t path_cb;
     void * user_data;
+    /* Codepoint range filter — see lv_imgfont_set_range().
+     * Default cp_min=0, cp_max=0xFFFFFFFF accepts all codepoints.
+     * Default excl_min=1, excl_max=0 is empty (excl_min > excl_max => no exclusion). */
+    uint32_t cp_min;
+    uint32_t cp_max;
+    uint32_t excl_min;
+    uint32_t excl_max;
 } imgfont_dsc_t;
 
 /**********************
@@ -53,6 +60,13 @@ lv_font_t * lv_imgfont_create(uint16_t height, lv_imgfont_get_path_cb_t path_cb,
 
     dsc->path_cb = path_cb;
     dsc->user_data = user_data;
+    /* Accept-all defaults — backward compatible with callers that never call
+     * lv_imgfont_set_range(). cp_min=0 / cp_max=UINT32_MAX accepts everything,
+     * and excl_min(1) > excl_max(0) means the exclusion window is empty. */
+    dsc->cp_min   = 0;
+    dsc->cp_max   = 0xFFFFFFFFu;
+    dsc->excl_min = 1;
+    dsc->excl_max = 0;
 
     lv_font_t * font = &dsc->font;
     font->dsc = dsc;
@@ -75,6 +89,23 @@ void lv_imgfont_destroy(lv_font_t * font)
     lv_free(dsc);
 }
 
+void lv_imgfont_set_range(lv_font_t * font, uint32_t cp_min, uint32_t cp_max,
+                          uint32_t excl_min, uint32_t excl_max)
+{
+    LV_ASSERT_NULL(font);
+    /* Only valid on fonts created by lv_imgfont_create() — detected by the
+     * get_glyph_dsc fingerprint. Silently ignore on any other lv_font_t to
+     * keep the API safe to call defensively from MicroPython. */
+    if(font->get_glyph_dsc != imgfont_get_glyph_dsc) return;
+
+    imgfont_dsc_t * dsc = (imgfont_dsc_t *)font->dsc;
+    LV_ASSERT_NULL(dsc);
+    dsc->cp_min   = cp_min;
+    dsc->cp_max   = cp_max;
+    dsc->excl_min = excl_min;
+    dsc->excl_max = excl_max;
+}
+
 /**********************
  *   STATIC FUNCTIONS
  **********************/
@@ -96,6 +127,13 @@ static bool imgfont_get_glyph_dsc(const lv_font_t * font, lv_font_glyph_dsc_t *
     LV_ASSERT_NULL(dsc);
     if(dsc->path_cb == NULL) return false;
 
+    /* Fast pre-filter: reject codepoints outside the accept range, or inside
+     * the exclude range, WITHOUT invoking path_cb. This matters when path_cb
+     * crosses into a slow caller (e.g. a MicroPython callback) — for every
+     * non-emoji glyph in a normal text run, we now stay entirely in C. */
+    if(unicode < dsc->cp_min || unicode > dsc->cp_max) return false;
+    if(unicode >= dsc->excl_min && unicode <= dsc->excl_max) return false;
+
     int32_t offset_y = 0;
 
     const void * img_src = dsc->path_cb(font, unicode, unicode_next, &offset_y, dsc->user_data);
diff --git a/src/others/imgfont/lv_imgfont.h b/src/others/imgfont/lv_imgfont.h
index 68c317a6d..a4e2611d9 100644
--- a/src/others/imgfont/lv_imgfont.h
+++ b/src/others/imgfont/lv_imgfont.h
@@ -50,6 +50,24 @@ lv_font_t * lv_imgfont_create(uint16_t height, lv_imgfont_get_path_cb_t path_cb,
  */
 void lv_imgfont_destroy(lv_font_t * font);
 
+/**
+ * Restrict the codepoints this imgfont will answer for. When set, codepoints
+ * outside [cp_min, cp_max] (or inside [excl_min, excl_max]) cause
+ * get_glyph_dsc to return false IMMEDIATELY without invoking path_cb. This
+ * lets LVGL skip the (potentially expensive) path_cb for codepoints that
+ * are known to not be represented in the font, falling back to the next
+ * font in the chain at C speed. Pass cp_min=0/cp_max=0xFFFFFFFF to accept
+ * everything; pass excl_min=1/excl_max=0 (empty range) to disable exclusion.
+ * Has no effect if `font` is not an imgfont.
+ * @param font     pointer to image font handle returned by lv_imgfont_create
+ * @param cp_min   lowest accepted codepoint
+ * @param cp_max   highest accepted codepoint
+ * @param excl_min lowest codepoint in the exclusion window (e.g. PUA 0xE000)
+ * @param excl_max highest codepoint in the exclusion window (e.g. 0xF8FF)
+ */
+void lv_imgfont_set_range(lv_font_t * font, uint32_t cp_min, uint32_t cp_max,
+                          uint32_t excl_min, uint32_t excl_max);
+
 /**********************
  *      MACROS
  **********************/