Merge pull request matplotlib#25112 from gokberkgunes/main

Author: ksunden

doc/api/next_api_changes/behavior/25112-GG.rst

@@ -0,0 +1,8 @@
+Streamplot now draws streamlines as one piece if no width or no color variance
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Since there is no need to draw streamlines piece by piece if there is no color
+change or width change, now streamplot will draw each streamline in one piece.
+
+The behavior for varying width or varying color is not changed, same logic is
+used for these kinds of streamplots.

lib/matplotlib/streamplot.py

@@ -198,8 +198,13 @@ def streamplot(axes, x, y, u, v, density=1, linewidth=None, color=None,
         tx += grid.x_origin
         ty += grid.y_origin
 
-        points = np.transpose([tx, ty]).reshape(-1, 1, 2)
-        streamlines.extend(np.hstack([points[:-1], points[1:]]))
+        # Create multiple tiny segments if varying width or color is given
+        if isinstance(linewidth, np.ndarray) or use_multicolor_lines:
+            points = np.transpose([tx, ty]).reshape(-1, 1, 2)
+            streamlines.extend(np.hstack([points[:-1], points[1:]]))
+        else:
+            points = np.transpose([tx, ty])
+            streamlines.append(points)
 
         # Add arrows halfway along each trajectory.
         s = np.cumsum(np.hypot(np.diff(tx), np.diff(ty)))