rotate.sh ➔ imgRotate.sh

dots/bin/imgRotate.sh

@@ -0,0 +1,44 @@
+#!/usr/bin/env bash
+
+# 26.03.04 :: klevstul
+
+
+rotate() {
+
+    test_integer() {
+        if ! [[ $1 =~ ^[123]$ ]]; then
+            echo "error: variable (times to rotate) must be 1, 2, or 3"
+            exit 1
+        fi
+    }
+
+    filename=$1                                     # ~/syncDir/0_downloads/frodeKlevstul.jpg
+    extension="${filename##*.}"                     # jpg
+    basename_without_ext="${filename%.*}"           # ~/syncDir/0_downloads/frodeKlevstul
+    basename_only="${basename_without_ext##*/}"     # frodeKlevstul
+
+    times_to_rotate=$2                              # how many times to rotate 90 degrees
+    times_to_rotate=${times_to_rotate:=1}           # set to 1 if no value is given
+    test_integer ${times_to_rotate}                 # make sure the input (if given from the user) is valid
+
+    transpose="transpose=1"                         # add a transpose for each time to rotate
+    for ((i = 2; i <= ${times_to_rotate}; i++)); do
+        transpose+=",transpose=1"
+    done
+
+    # 90 degrees clockwise: transpose=1
+    # 90 degrees counterclockwise: transpose=2
+    # `-c:a copy` - ensures audio (if present) is copied without re-encoding (not applicable for images, but safe to include).
+    ffmpeg -i ${filename} -vf ${transpose} -c:a copy ${basename_without_ext}_rot.${extension}
+
+}
+
+
+this_file_name=`basename "$0"`
+if [ $# -lt 1 ]; then
+    echo "error: path to file is missing."
+    echo "usage: '$this_file_name [path_to_file] ([times_to_rotate_90_degrees (1)])'"
+    exit 1
+fi
+
+rotate $1 $2