所有在线断点助手都使用像素。例如：iPhone 6 and 6 Plus Responsive Breakpoints。但浏览器不会以同样的方式对待 $agences = $em->getRepository('LocationBundle:Agence')->findAll();
return $this->render('agence/index.html.twig', array(
'agences' => $agences,
));
}
/**
* Creates a new Agence entity.
*
*/
public function newAction(Request $request)
{
$agence = new Agence();
$form = $this->createForm('LocationBundle\Form\AgenceType', $agence);
$form->handleRequest($request);
if ($form->isSubmitted() && $form->isValid()) {
$em = $this->getDoctrine()->getManager();
$em->persist($agence);
$em->flush();
return $this->redirectToRoute('agence_show', array('id' => $agence->getId()));
}
return $this->render('agence/new.html.twig', array(
'agence' => $agence,
'form' => $form->createView(),
));
}
/**
* Finds and displays a Agence entity.
*
*/
public function showAction(Agence $agence)
{
$deleteForm = $this->createDeleteForm($agence);
return $this->render('agence/show.html.twig', array(
'agence' => $agence,
'delete_form' => $deleteForm->createView(),
));
}
/**
* Displays a form to edit an existing Agence entity.
*
*/
public function editAction(Request $request, Agence $agence)
{
$deleteForm = $this->createDeleteForm($agence);
$editForm = $this->createForm('LocationBundle\Form\AgenceType', $agence);
$editForm->handleRequest($request);
if ($editForm->isSubmitted() && $editForm->isValid()) {
$em = $this->getDoctrine()->getManager();
$em->persist($agence);
$em->flush();
return $this->redirectToRoute('agence_edit', array('id' => $agence->getId()));
}
return $this->render('agence/edit.html.twig', array(
'agence' => $agence,
'edit_form' => $editForm->createView(),
'delete_form' => $deleteForm->createView(),
));
}
/**
* Deletes a Agence entity.
*
*/
public function deleteAction(Request $request, Agence $agence)
{
$form = $this->createDeleteForm($agence);
$form->handleRequest($request);
if ($form->isSubmitted() && $form->isValid()) {
$em = $this->getDoctrine()->getManager();
$em->remove($agence);
$em->flush();
}
return $this->redirectToRoute('agence_index');
}
/**
* Creates a form to delete a Agence entity.
*
* @param Agence $agence The Agence entity
*
* @return \Symfony\Component\Form\Form The form
*/
private function createDeleteForm(Agence $agence)
{
return $this->createFormBuilder()
->setAction($this->generateUrl('agence_delete', array('id' => $agence->getId())))
->setMethod('DELETE')
->getForm()
;
}
ss。在所有手机浏览器中，没有设置的“像素到像素”大小相同。那么iPhone（iOS Safari）所说的是em中的宽度/高度是什么？
答案 0 :(得分：1)
em不是固定大小的单位，它是基于父母大小的相对度量。例如，设置12 px的正文字体大小，然后设置字体大小为0.5em的子元素，该子项将有效地具有等于6px（0.5 *父项大小）的字体大小。
由于这是一个相对测量，因此以这种方式定义固定边界是没有意义的。