plot_one_box() default color=(128, 128, 128) (ultralytics#3240)

* Color can be none by default

* `plot_one_box()` default `color=(128, 128, 128)`

Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>
(cherry picked from commit 7b0eb95)

utils/plots.py

@@ -68,11 +68,10 @@ def butter_lowpass(cutoff, fs, order):
     return filtfilt(b, a, data)  # forward-backward filter
 
 
-def plot_one_box(x, im, color=None, label=None, line_thickness=3):
+def plot_one_box(x, im, color=(128, 128, 128), label=None, line_thickness=3):
     # Plots one bounding box on image 'im' using OpenCV
     assert im.data.contiguous, 'Image not contiguous. Apply np.ascontiguousarray(im) to plot_on_box() input image.'
     tl = line_thickness or round(0.002 * (im.shape[0] + im.shape[1]) / 2) + 1  # line/font thickness
-    color = color or [random.randint(0, 255) for _ in range(3)]
     c1, c2 = (int(x[0]), int(x[1])), (int(x[2]), int(x[3]))
     cv2.rectangle(im, c1, c2, color, thickness=tl, lineType=cv2.LINE_AA)
     if label:
@@ -83,17 +82,16 @@ def plot_one_box(x, im, color=None, label=None, line_thickness=3):
         cv2.putText(im, label, (c1[0], c1[1] - 2), 0, tl / 3, [225, 255, 255], thickness=tf, lineType=cv2.LINE_AA)
 
 
-def plot_one_box_PIL(box, im, color=None, label=None, line_thickness=None):
+def plot_one_box_PIL(box, im, color=(128, 128, 128), label=None, line_thickness=None):
     # Plots one bounding box on image 'im' using PIL
     im = Image.fromarray(im)
     draw = ImageDraw.Draw(im)
     line_thickness = line_thickness or max(int(min(im.size) / 200), 2)
-    draw.rectangle(box, width=line_thickness, outline=tuple(color))  # plot
+    draw.rectangle(box, width=line_thickness, outline=color)  # plot
     if label:
-        fontsize = max(round(max(im.size) / 40), 12)
-        font = ImageFont.truetype("Arial.ttf", fontsize)
+        font = ImageFont.truetype("Arial.ttf", size=max(round(max(im.size) / 40), 12))
         txt_width, txt_height = font.getsize(label)
-        draw.rectangle([box[0], box[1] - txt_height + 4, box[0] + txt_width, box[1]], fill=tuple(color))
+        draw.rectangle([box[0], box[1] - txt_height + 4, box[0] + txt_width, box[1]], fill=color)
         draw.text((box[0], box[1] - txt_height + 1), label, fill=(255, 255, 255), font=font)
     return np.asarray(im)