The control window is shown below.
- Files to process
- This shows the number of files waiting in the queue to be
processed
- Clear file list
- Clicking this button allows the file list to be cleared if you
change your mind about files in the list. It will clear the whole
list.
The main part of the window controls the transformation actions
that may be specified.
- Optimise
- If this is ticked then the entropy encoding parameters are
optimised. If unticked, then default encoding parameters are used.
Optimise usually makes the JPEG file a little smaller. Image quality
is unaffected by optimising.
- Progressive
- If this is ticked then a progressive JPEG file is created. In this
type of JPEG file, the data is stored in multiple scans of increasing
quality. If the file is being transmitted over a slow communications
link, the decoder can use the first scan to display a low-quality
image very quickly, and can then improve the display with each
subsequent scan. The final image is exactly equivalent to a standard
JPEG file of the same quality setting, and the total file size is
about the same.
- Greyscale
- This option discards the chrominance channels if the input image is
YCbCr (ie, a standard color JPEG), resulting in a greyscale JPEG file.
The luminance channel is preserved exactly, so this is a better method
of reducing to greyscale than decompression, conversion, and
recompression.
- Strip EXIF data
- When this is ticked, all EXIF data will be removed from each
processed file. This option overrides the setting in the
Settings window, and may be used either alone, or at
the same time as other transforms.
- Transform
- If this is ticked, then the image will be transformed in one of a
number of ways. The particular transformation to be used is selected
using the group of radio buttons below the transform button. The
transformations that are available are described below.
- AUTO rotate
- This option relies on
- The image file containing valid exif data
- The camera writing an 'orientation flag' into the exif data. This
is sometimes a user setting, rather than a default action
TranJPEG will attempt to read the orientation flag from the exif
data, and if successful, will rotate the image according to the
setting of this flag. Images with no exif data, a 'normal orientation'
flag, or no orientation flag will be ignored.
- Rotate right
- Click SELECT to rotate each of the images 90° to the right.
- Rotate 180°
- Click SELECT to rotate each of the images through 180°.
- Rotate left
- Click SELECT to rotate each of the images 90° to the left.
-
- Flip horizontal
- Click SELECT to flip each of the images left to right.
- Flip vertical
- Click SELECT to flip each of the images top to bottom.
- Transpose
- Click SELECT to transpose each of the images (across the upper left
to lower right axis). This can be thought of as a rotation to the
right followed by a reflection (flip) left to right.
- Transverse
- Click SELECT to carry out the transverse operation on each of the
images (across the upper right to lower left axis). This can be
thought of as a rotation to the left followed by a reflection (flip)
left to right.
- Smartscale
- This results in a 'lossless' scaling. There are a limited range of
options, which can be chosen using the menu button to the right. The
scales available are
- Scale up by a factor of 2
- Reduce image size to one half
- Reduce image size to one quarter
- Reduce image size to one eighth
Currently there are not many RISC OS applications that understand and
can display a smartscaled image.
- Crop images
- This will result in the lossless cropping of each image. The width
and height of the image (in pixels) after cropping is entered,
together with the X and Y offsets for the start of the cropped image
(effectively the top-left coordinate). The X offset is the number of
pixels in from the left side of the image. The Y offset is the number
of pixels down from the top edge.
There are some caveats. The top-left coordinate of the cropping
area must start at the top left of an iMCU block (block sizes are
almost invariably 8 or 16 pixels). If this is not the case, jpegtran
will move the top-left up and left so it does correspond. At the same
time the width and height will be increased appropriately to keep the
bottom-right of the area at the original position.
Destination of transformed file
Below the transformation buttons there is a means of specifying the
destination of the transformed files.
Overwrite original file
If this option is ticked, then TranJPEG will use the input file
path to save the transformed image. This means the original file will
be overwritten with the newly transformed file. It is always wise to
keep backups of the originals if this option is being used.
If this option is not ticked, then the following
will apply.
Use save path
If Use save path is ticked then it is possible to specify
the directory in which the transformed images are to be placed. This
directory can be set in two ways.
- Click on the menu button to the right of the path field and drag
the directory icon in to the destination directory
- Drag the destination directory from a filer display in to the path
field. It must be in to the field, anywhere else will result in
TranJPEG searching the directory for jpegs to be processed.
If Use save path is NOT ticked then TranJPEG will put the
transformed image into a directory (in the same location as the
original image) named for the transformation, e.g. 'rotleft'. This is
to prevent TranJPEG overwriting the original image.
Settings
At the foot of the window is a button Settings...,
which will open a further window allowing further options to be set.
This is described in the next section.
Starting the processing
At the bottom right of the control window is the
Process button. Clicking SELECT on this will start
the batch process off. Assuming there are some JPEG files in the
queue, the control window will close, and the status window will open.
This is shown below.
