void ImpressionistUI::cb_load_dissolve_image(Fl_Menu_* o, void* v) {
    ImpressionistDoc *pDoc = whoami(o)->getDocument();

    char* newfile = fl_file_chooser("Open File?", "*.bmp", pDoc->getImageName());
    if (newfile != NULL) {
        pDoc->loadDissolveImage(newfile);
    }
}
void ImpressionistUI::cb_load_dissolve(Fl_Menu_* o, void* v)
{
	ImpressionistDoc *pDoc = whoami(o)->getDocument();
	if (!pDoc->m_ucBitmap) {
		fl_alert("Please load a background image first.");
		return;
	}
	char* newfile = fl_file_chooser("Open File?", "*.bmp", pDoc->getImageName());
	if (newfile != NULL) {
		pDoc->loadDissolveImage(newfile);
	}
}