function setImgCorner(objName, expC1,expC2,expC4){
var isexist = ggbApplet.exists(objName);
if(isexist){
var xmlText = '<element type=\"image\" label=\"'+objName+'\"><startPoint number=\"0\" exp=\"'+expC1+'\"/><startPoint number=\"1\" exp=\"'+expC2+'\"/><startPoint number=\"2\" exp=\"'+expC4+'\"/></element>';
ggbApplet.evalXML(xmlText);
}
}