int startLine = getLineIndex(event.y - topMargin);
int startLine = getLineIndex(event.y);
void handlePaint(Event event) {	// Check if there is work to do	if (event.height == 0) return;	int startLine = getLineIndex(event.y - topMargin);	int startY = getLinePixel(startLine);	int renderHeight = event.y + event.height - startY;	performPaint(event.gc, startLine, startY, renderHeight);}	