// -----------------------------------------------------------------------------
// Handling diaporama -> ensure requested index is in array bounds
// -----------------------------------------------------------------------------
function diapo(p_newIndex, p_photosArray, p_imageID, p_spanID, p_spanLegend) {

	var v_newIndex = 0;
	if(p_newIndex < 0) {
		v_newIndex = p_photosArray.length - 1;
	} else if(p_newIndex >= p_photosArray.length) {
		v_newIndex = 0;
	} else {
		v_newIndex = p_newIndex;
	}
	return changeDiapo(v_newIndex, p_photosArray, p_imageID, p_spanID, p_spanLegend);
}
// -----------------------------------------------------------------------------
// Changing image -> changes current displayed image and returns current index
// -----------------------------------------------------------------------------
function changeDiapo(p_indexToDisplay, p_photosArray, p_imageID, p_spanID, p_spanLegend) {

	if( document.getElementById(p_imageID) ) {
		if(document.getElementById(p_imageID).src) {
			document.getElementById(p_imageID).src = p_photosArray[p_indexToDisplay][0];
			if( document.getElementById(p_spanID) ) {
				document.getElementById(p_spanID).innerHTML = p_indexToDisplay + 1;
			}
			if( document.getElementById(p_spanLegend) ) {
				document.getElementById(p_spanLegend).innerHTML = p_photosArray[p_indexToDisplay][1];
			}
		} else {
			alert("[diaporama.js / function changeDiapo] '" + p_imageID + "' is not an image.");
		}
	} else {
		alert("[diaporama.js / function changeDiapo] '" + p_imageID + "' is not an object.");
	}
	return p_indexToDisplay;
}