Initial version

Author: buffcode

Dockerfile

@@ -0,0 +1,11 @@
+FROM ubuntu
+MAINTAINER Laurens Stötzel <[email protected]>
+
+# Install JpegTrag
+RUN echo "deb http://archive.ubuntu.com/ubuntu $(lsb_release -sc) main universe" > /etc/apt/sources.list
+RUN apt-get update -y && apt-get install -y libjpeg-progs
+
+RUN mkdir -p /source
+WORKDIR /source
+
+ENTRYPOINT [ "/usr/bin/jpegtran" ]

README.md

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-# docker-jpegtran
+# docker-jpegprogs
+JPG/JPEG image optimization/manipulation via libjpeg-progs within Docker
+
+## Pull image
+```bash
+$ docker pull buffcode/docker-jpegprogs
+```
+
+## Source directory
+This image creates a volume at `/source`, so you can mount a local directory to this remote directory and access any
+file within.
+Please note that `jpegtran` will not overwrite the input file but output the optimized image to STDOUT. As an
+alternative you can use the the `-outfile <filename>` argument with the same path to overwrite the input file.
+
+## Contained applications
+This image makes use of the `libjpeg-progs` package. As such it also other tools like `exifautotran`, `jpegexiforient`,
+`rdjpgcom`, `wrjpgcom`, `cjpeg` and `djpeg`.
+
+## Running jpegtran
+```bash
+$ docker run buffcode/docker-jpegprogs --help
+usage: /usr/bin/jpegtran [switches] [inputfile]
+Switches (names may be abbreviated):
+  -copy none     Copy no extra markers from source file
+  -copy comments Copy only comment markers (default)
+  -copy all      Copy all extra markers
+  -optimize      Optimize Huffman table (smaller file, but slow compression)
+  -progressive   Create progressive JPEG file
+Switches for modifying the image:
+  -crop WxH+X+Y  Crop to a rectangular subarea
+  -grayscale     Reduce to grayscale (omit color data)
+  -flip [horizontal|vertical]  Mirror image (left-right or top-bottom)
+  -perfect       Fail if there is non-transformable edge blocks
+  -rotate [90|180|270]         Rotate image (degrees clockwise)
+  -transpose     Transpose image
+  -transverse    Transverse transpose image
+  -trim          Drop non-transformable edge blocks
+Switches for advanced users:
+  -arithmetic    Use arithmetic coding
+  -restart N     Set restart interval in rows, or in blocks with B
+  -maxmemory N   Maximum memory to use (in kbytes)
+  -outfile name  Specify name for output file
+  -verbose  or  -debug   Emit debug output
+Switches for wizards:
+  -scans file    Create multi-scan JPEG per script file
+```
+
+### Optimize a single image
+```bash
+# output to new file
+$ docker run -v /local-path-to-image:/source buffcode/docker-jpegprogs \
+    -optimize -copy none image.jpg >image-optimized.jpg
+
+# overwrite input file
+$ docker run -v /local-path-to-image:/source buffcode/docker-jpegprogs \
+    -optimize -copy none -outfile image.jpg image.jpg
+```
+
+### Recursivley optimize all images
+The following command finds all images in the current folder (`find...`), mounts it to the Docker volume (`-v ...`) and
+optimizes the image (`-optimize -copy none`).
+```bash
+$ find . -name "*.jpg" | \
+    xargs -I{} docker run -v `pwd`:/source buffcode/docker-jpegprogs \
+    -optimize -copy none -outfile {} {}
+```
+
+### Run another tool
+In case you would like to run another tool than `jpegtran` eg. `exifautotran` use the following command:
+```bash
+$ docker run --entrypoint '/usr/bin/exifautotran' buffcode/docker-jpegprogs --help
+exifautotran [list of files]
+
+Transforms Exif files so that Orientation becomes 1
+```