Limit params displayed in mpl drawer (#6443)

* Limit params displayed in mpl drawer

* lint

Co-authored-by: Luciano Bello <bel@zurich.ibm.com>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

qiskit/visualization/matplotlib.py

@@ -436,13 +436,16 @@ def _get_text_width(self, text, fontsize, param=False):
                 sum_text *= self._subfont_factor
             return sum_text
 
-    def _param_parse(self, v):
-        param_parts = [None] * len(v)
-        for i, e in enumerate(v):
+    def _param_parse(self, params):
+        param_parts = []
+        for i, param in enumerate(params):
+            if i > 16:
+                param_parts.append("...")
+                break
             try:
-                param_parts[i] = pi_check(e, output="mpl", ndigits=3)
+                param_parts.append(pi_check(param, output="mpl", ndigits=3))
             except TypeError:
-                param_parts[i] = str(e)
+                param_parts.append(str(param))
         param_parts = ", ".join(param_parts).replace("-", "$-$")
         return param_parts
 

test/ipynb/mpl/test_circuit_matplotlib_drawer.py

@@ -549,6 +549,14 @@ def test_6095(self):
             filename="6095.png",
         )
 
+    def test_overwide_gates(self):
+        """Test gates don't exceed width of default fold"""
+        circuit = QuantumCircuit(5)
+        initial_state = np.zeros(2 ** 5)
+        initial_state[5] = 1
+        circuit.initialize(initial_state)
+        self.circuit_drawer(circuit, filename="wide_params.png")
+
 
 if __name__ == "__main__":
     unittest.main(verbosity=1)