Make bucket-lines and related packages more robust

bucket-lines would crash for any line that didn't have a corresponding image.

Lines which weren't grayscale would also cause crashes; now they are just
converted to grayscale if necessary.

As a bonus, lines in jpeg can also be decoded successfull.

1 files changed, 3 insertions, 1 deletions

diff --git a/bucket-lines/main.go b/bucket-lines/main.go
index 6ae506a..af81b44 100644
--- a/bucket-lines/main.go
+++ b/bucket-lines/main.go
@@ -74,7 +74,9 @@ func main() {
 		}
 
 		for _, l := range newlines {
-			lines = append(lines, l)
+			if l.Img != nil {
+				lines = append(lines, l)
+			}
 		}
 	}