+#ifdef PNG_WRITE_APNG_SUPPORTED
+void PNGAPI
+png_write_frame_head(png_structp png_ptr, png_infop info_ptr,
+ png_bytepp row_pointers, png_uint_32 width, png_uint_32 height,
+ png_uint_32 x_offset, png_uint_32 y_offset,
+ png_uint_16 delay_num, png_uint_16 delay_den, png_byte dispose_op,
+ png_byte blend_op)
+{
+ png_debug(1, "in png_write_frame_head");
+
+ /* there is a chance this has been set after png_write_info was called,
+ * so it would be set but not written. is there a way to be sure? */
+ if (!(info_ptr->valid & PNG_INFO_acTL))
+ png_error(png_ptr, "png_write_frame_head(): acTL not set");
+
+ png_write_reset(png_ptr);
+
+ png_write_reinit(png_ptr, info_ptr, width, height);
+
+ if ( !(png_ptr->num_frames_written == 0 &&
+ (png_ptr->apng_flags & PNG_FIRST_FRAME_HIDDEN) ) )
+ png_write_fcTL(png_ptr, width, height, x_offset, y_offset,
+ delay_num, delay_den, dispose_op, blend_op);
+
+ PNG_UNUSED(row_pointers)
+}
+
+void PNGAPI
+png_write_frame_tail(png_structp png_ptr, png_infop info_ptr)
+{
+ png_debug(1, "in png_write_frame_tail");
+
+ png_ptr->num_frames_written++;
+
+ PNG_UNUSED(info_ptr)
+}
+#endif /* PNG_WRITE_APNG_SUPPORTED */