mosaic4 bottom left image fix (#1021)

utils/datasets.py

@@ -661,7 +661,7 @@ def load_mosaic(self, index):
             x1b, y1b, x2b, y2b = 0, h - (y2a - y1a), min(w, x2a - x1a), h
         elif i == 2:  # bottom left
             x1a, y1a, x2a, y2a = max(xc - w, 0), yc, xc, min(s * 2, yc + h)
-            x1b, y1b, x2b, y2b = w - (x2a - x1a), 0, max(xc, w), min(y2a - y1a, h)
+            x1b, y1b, x2b, y2b = w - (x2a - x1a), 0, w, min(y2a - y1a, h)
         elif i == 3:  # bottom right
             x1a, y1a, x2a, y2a = xc, yc, min(xc + w, s * 2), min(s * 2, yc + h)
             x1b, y1b, x2b, y2b = 0, 0, min(w, x2a - x1a), min(y2a - y1a, h)