title: How can I do `pushMatrix` or `popMatrix` of GL in CoreGraphics?
body: <p>In GL, I have used some kind of this stuff,</p>
  
  <pre><code>glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
  glPushMatrix();
  glTranslatef();
  
  // Do something
  
  glPopMatrix();
  </code></pre>
  
  <p>To make and work in a derived coordinate system.
  How can I archive this functionality in CoreGraphics?</p>