docs: update API comments

examples/widgets/imagebutton/lv_example_imagebutton_1.c

@@ -0,0 +1,42 @@
+#include "../../lv_examples.h"
+#if LV_USE_IMAGEBUTTON && LV_BUILD_EXAMPLES
+
+void lv_example_imagebutton_1(void)
+{
+    LV_IMAGE_DECLARE(imagebutton_left);
+    LV_IMAGE_DECLARE(imagebutton_right);
+    LV_IMAGE_DECLARE(imagebutton_mid);
+
+    /*Create a transition animation on width transformation and recolor.*/
+    static lv_style_prop_t tr_prop[] = {LV_STYLE_TRANSFORM_WIDTH, LV_STYLE_IMAGE_RECOLOR_OPA, 0};
+    static lv_style_transition_dsc_t tr;
+    lv_style_transition_dsc_init(&tr, tr_prop, lv_anim_path_linear, 200, 0, NULL);
+
+    static lv_style_t style_def;
+    lv_style_init(&style_def);
+    lv_style_set_text_color(&style_def, lv_color_white());
+    lv_style_set_transition(&style_def, &tr);
+
+    /*Darken the button when pressed and make it wider*/
+    static lv_style_t style_pr;
+    lv_style_init(&style_pr);
+    lv_style_set_image_recolor_opa(&style_pr, LV_OPA_30);
+    lv_style_set_image_recolor(&style_pr, lv_color_black());
+    lv_style_set_transform_width(&style_pr, 20);
+
+    /*Create an image button*/
+    lv_obj_t * imagebutton1 = lv_imagebutton_create(lv_screen_active());
+    lv_imagebutton_set_src(imagebutton1, LV_IMAGEBUTTON_STATE_RELEASED, &imagebutton_left, &imagebutton_mid,
+                           &imagebutton_right);
+    lv_obj_add_style(imagebutton1, &style_def, 0);
+    lv_obj_add_style(imagebutton1, &style_pr, LV_STATE_PRESSED);
+
+    lv_obj_align(imagebutton1, LV_ALIGN_CENTER, 0, 0);
+
+    /*Create a label on the image button*/
+    lv_obj_t * label = lv_label_create(imagebutton1);
+    lv_label_set_text(label, "Button");
+    lv_obj_align(label, LV_ALIGN_CENTER, 0, -4);
+}
+
+#endif