MQL wrappers in guipro.mqh (defaults match Object reference).

int guiInit(int autostate_enabled = 1);

int guiAddButton(int gui_id, int pos_x, int pos_y, int width, int height, string text,
                 color text_color = clrBlack, uint text_style = GUI_TEXT_NONE,
                 string font_name = "Segoe UI", int font_size = 10,
                 color bg_color = clrWhite, int border_style = GUI_BORDER_3D,
                 int border_width = 2, color border_color1 = GUI_AUTO, color border_color2 = GUI_AUTO);

int guiAddCheckbox(int gui_id, int pos_x, int pos_y, int width, int height, string text,
                   color text_color = clrBlack, uint text_style = GUI_TEXT_NONE,
                   string font_name = "Segoe UI", int font_size = 10,
                   color bg_color = clrWhite, int border_style = GUI_BORDER_FLAT,
                   int border_width = 2, color border_color1 = GUI_AUTO, color border_color2 = GUI_AUTO,
                   bool initial_checked = false);

int guiAddRadio(int gui_id, int pos_x, int pos_y, int width, int height, string text,
                color text_color = clrBlack, uint text_style = GUI_TEXT_NONE,
                string font_name = "Segoe UI", int font_size = 10,
                color bg_color = clrWhite, int radio_group = 0,
                int border_style = GUI_BORDER_FLAT, int border_width = 2,
                color border_color1 = GUI_AUTO, color border_color2 = GUI_AUTO,
                bool initial_selected = false);

int guiAddRadioGroup(int gui_id);

int guiAddLabel(int gui_id, int pos_x, int pos_y, int width, int height, string text,
                color text_color = clrBlack, uint text_style = GUI_TEXT_NONE,
                string font_name = "Segoe UI", int font_size = 10,
                color bg_color = clrWhite, int border_style = GUI_BORDER_FLAT,
                int border_width = 2, color border_color1 = GUI_AUTO, color border_color2 = GUI_AUTO);

int guiAddText(int gui_id, int pos_x, int pos_y, int width, int height, string text,
               color text_color = clrBlack, uint text_style = GUI_TEXT_NONE,
               string font_name = "Segoe UI", int font_size = 10,
               color bg_color = clrWhite, int border_style = GUI_BORDER_FLAT,
               int border_width = 2, color border_color1 = GUI_AUTO, color border_color2 = GUI_AUTO);

int guiAddLink(int gui_id, int pos_x, int pos_y, int width, int height, string text, string url,
               color text_color = clrBlack, uint text_style = GUI_TEXT_UNDERLINE,
               string font_name = "Segoe UI", int font_size = 10,
               color bg_color = clrWhite, int border_style = GUI_BORDER_FLAT,
               int border_width = 2, color border_color1 = GUI_AUTO, color border_color2 = GUI_AUTO);

int guiAddEditbox(int gui_id, int pos_x, int pos_y, int width, int height, string text,
                  color text_color = clrBlack, uint text_style = GUI_TEXT_NONE,
                  string font_name = "Segoe UI", int font_size = 10,
                  color bg_color = clrWhite, int border_style = GUI_BORDER_FLAT,
                  int border_width = 2, color border_color1 = GUI_AUTO, color border_color2 = GUI_AUTO);

int guiAddDropDown(int gui_id, int pos_x, int pos_y, int width, int drop_down_max_height,
                   string &dropdown_items[], int selected_index = -1, string placeholder = "",
                   color text_color = clrBlack, uint text_style = GUI_TEXT_NONE,
                   string font_name = "Segoe UI", int font_size = 10,
                   color bg_color = clrWhite, int border_style = GUI_BORDER_3D,
                   int border_width = 2, color border_color1 = GUI_AUTO, color border_color2 = GUI_AUTO);

int guiAddGroupBox(int gui_id, int pos_x, int pos_y, int width, int height, string text = "",
                   color text_color = clrBlack, uint text_style = GUI_TEXT_NONE,
                   string font_name = "Segoe UI", int font_size = 10,
                   color bg_color = clrWhite, int border_width = 1,
                   color border_color = GUI_AUTO);

string guiErrorDescription(int err_code);