Using BIRT

The BIRT window is split in to four sections:

  1.  File Section, where the files to be resized are selected.
  2.  Processing Options, where the output size and various options affecting the resize process can be configured.
  3.  Output Options, configures where the resized files will be written to and how the filenames will be generated.
  4.  Commands, contains the application controls.
File Selection

The file selection area consists of a list of selected files and buttons to update this selection.

Screenshot of file selection

To add files click on the Add Files button and select the files to be resized. To select multiple files use the standard Ctrl-click and Shift-click methods. Note that any given file can only be resized once per run, so multiple selections of the same file will be ignored.

To add a large number of files contained within a directory tree use the Add Directory Tree. Select the directory that will be the root of the search and click "OK". This bring up a dialog showing the search process. Clicking stop on this dialog will terminate the search and add the image files found thus far to the selection list.

To remove files select the file(s) that are no longer required (again the standard multiple select methods are support by the list box) and click Remove Files.

The Remove All button will remove every file in the select box (whether selected or not).

The Clear Selection button will clear any file selection and leave the files untouched.

Processing Options

The processing options area is the most complex part of the interface. It consists of the output size (the maximum size of the new images), the strategy for handling the image width/height ratio, the quality of the resized images and the quality of the outputted image (affects only lossy compression formats such as JPEG).

Screenshot of the processing options

The new size of the output images is obvious, however the images are only guaranteed to be this size if the ratio option is set to "Ignore Source Ratio". The current ratio options are:

Ignore Source Ratio
Always resize the images to dimensions specified in the New Size boxes.
Match New Width
Maintain the ratio of the original image, but scale it such that the image width matches the width component of the New Size. For example an image of 1920x1200 will be resized to 640x400 if the new size is 640x480 and the ratio option is "Match New Width".
Match New Height
As above, but for the height instead of the width. Maintains the ratio of the original image but scales it such that the image height matches the height component of the New Size. For example an image of 1920x1200 will be resized to 768x480 if the new size is 640x480 and the raio option is "Match New Height".
Preserve Source Orientation
Resize the image such that the larger of the source dimensions (i.e. the longer of the width or height) will be resized to be the larger of the target dimensions. Likewise the smaller of the source dimensions will be resized to be the smaller of the target dimensions.

For example, assume that the New Size is 640x480 and the "Preserve Source Orientation" option is selected. An image of 1028x800 would be resized 640x480 while an image of 800x1024 will be resized to 480x640. Basically the images are resized to the target dimensions (ignoring the source ratio) but retaining their orientation (landscape or portrait).

Because of this the orientation of the target dimensions is irrevlevant, if the example above has New Size of 480x640 the resulting images would be exactly the same.

Below is a table showing an example of each of the ratio handling strategies. In all cases the target size was 160x200.

Ratio Strategy Dimensions Image
Original 320x240 Original Image
Ignore Source Ratio 160x200 Ignore Ratio
Match New Width 160x120 Match New Width
Match New Height 266x200 Match New Height
Preserve Source Orientation 200x160 Preserve Source Orientation

The Scaling Quality option provides a choice between a slower but smoother scaling process and a faster but unfiltered one. Unless it is necessary to resize a huge number of images in a very short time there is no reason to use "Fast Scale".

Fast Scaling Smooth Scaling
Fast Scaling Smooth Scaling

The JPEG Quality slider does exactly what it says: the lower the quality the worse the output images look but the smaller the file sizes (and vice-versa). For other image formats this option is ignored.

Output Options

The output options area is where the destination and names of the new images are specified.

Screenshot of the output options

The Output Directory is simply the location where the new images will be created. This directory must exist and be writable for the resize process to be successful.

The Prefix and Suffix fields are added to the original name of the image file. The prefix is prepended to the start of the basename (i.e. after the last directory separator) while the suffix is appended to the basename, but before the extension (i.e. before the last period).

So with a prefix of prefix_ and a suffix of _suffix the following filenames ...

  1. /tmp/test.jpeg
  2. /home/user/example.image.png
.. will generate new images with filenames of ...
  1. /tmp/prefix_test_suffix.jpeg
  2. /home/user/prefix_example.image_suffix.png

Rather obvious this bit:

Quit
Exits the application.
Help
Displays this help screen. Note that only one help screen will be displayed per instance of BIRT that is running.
Go
Resizes the images in the file selection window using the processing and output options set in their respective sections. This button is only available if at least one file has been added to the selection list.
Screenshot of the commands bar