As part of MovingImages I wrote a number of command line tools that can take advantage of MovingImages. The command line tools are written in ruby and most of them come with the MovingImages ruby gem so after installing MovingImages these command line tools are installed. If you haven’t already you’ll need to download and install MovingImages.

This blog post is about the ‘dotransition’ command line tool. This tool provides access to CoreImage’s transition filters. A CoreImage transition filter takes a source and target images and provides a way of transitioning from the source image to the target image by generating a sequence of images that represents the transition between the two images.

The command line tools all take the “–help” option which describes how to call the command line tool with the various options, and they all also take the “–verbose” option which can be useful when you get an error calling the script.

In all the examples I am going to assume that the source image is an jpeg image file in your Pictures folder called “sourceimage.jpg” and that the destination image is an image file in your Pictures folder called “targetimage.jpg”. The generated images are saved in a sub folder of a folder called transition on your desktop. The first example uses the long form of the command line options as they are more descriptive but it does result in longer commands. The other examples use a mixture of long and short form demonstrating that they can be mixed. The filter specific options are only available in the long form. The ‘dotransition’ command line tool assumes that source and target images are the same size.

The bar swipe transition uses the CoreImage filter CIBarsSwipeTransition

dotransition --transitionfilter CIBarsSwipeTransition --basename image --outputdir ~/Desktop/transition/barswipe --baroffset 60 --angle 2.0 --width 20 --sourceimage ~/Pictures/sourceimage.jpg --targetimage ~/Pictures/targetimage.jpg --exportfiletype public.jpeg --count 20

I’ll cover the command line options that are common to all the transition filters first. The “–transitionfilter” option specifies the transition filter to use. To get a list of the available transition filters call the do transition command line tool like so:

dotransition -l

The ‘dotransition’ command generates a sequence of image files. These images are created in the directory specified after the –outputdir option. If the path to the directory contains a space or other non standard character then the path will need to be quoted or escaped. To generate the file names ‘dotransition’ takes a –basename option which specifies the beginning of the filename, which is then followed by the image sequence number and then the file extension for the file type of the generated image. The –sourceimage option specifies the image file that the transition starts with, and the the –targetimage option specifies the transition ends with. Like the –outputdir option if the path contains spaces or other non standard path character then the path will need to be quoted or escaped. The –exportfiletype is optional and defaults to public.tiff if not specified. The –count option specifies the number of images in the image sequence to be generated.

The bar swipe transition takes a number of filter specific properties. These are –baroffset, –angle, –width. To determine the filter properties that belong to a specific filter you can request that from the dotransition command line tool.

dotransition --filterproperties CIBarsSwipeTransition

Which outputs the information about each property. You can use the filter key value to match with the equivalent command line option.

The ripple transition filter creates a ripple effect when transitioning from one image to another. The following example assumes that the input images have a width of 2272 and a height of 1704 pixels. The ripple effect is to center itself on the image.

dotransition --transitionfilter CIRippleTransition -b image -o ~/Desktop/transition/ripple --center 1136,852 --scale=40.0 --width 50 --extent 0,0,2272,1704 -s ~/Pictures/sourceimage.jpg -d ~/Pictures/targetimage.jpg -c 20

The swipe transition replaces the source image with the destination by swiping away the source image.

dotransition --transitionfilter CISwipeTransition -b image -o ~/Desktop/transition/swipe --angle 2.0 --width 150 --color 0.3,0.2,0.8,1.0 --extent 0,0,2272,1704 --opacity 0.7 -s ~/Pictures/sourceimage.jpg -d ~/Pictures/targetimage.jpg -t public.jpeg -c 20

The copy machine transition, imitates the action of a photocopier, but replaces the source image with the target as it passes.

dotransition --transitionfilter CICopyMachineTransition -b image -o ~/Desktop/transition/copymachine --angle=-2.0 --width 100 --color 0.8,0.2,0.6,1.0 --extent 0,0,2272,1704 --opacity 0.85 -s ~/Pictures/sourceimage.jpg -d ~/Pictures/targetimage.jpg -c 30

The disintegrate with mask transition takes a mask image which it applies to the transition effect. For best results the mask image should be black and white and the same dimensions as the source and destination images.

dotransition --transitionfilter CIDisintegrateWithMaskTransition -b image -o ~/Desktop/transition/disintegratemask --maskimage ~/Pictures/maskimage.jpg --shadowradius 80 --shadowdensity 0.8 --shadowoffset 10,25 -s ~/Pictures/sourceimage.jpg -d ~/Pictures/targetimage.jpg -c 20

The flash transition filter generates a flash image over the source image which is then replaced by the target image.

dotransition --transitionfilter CIFlashTransition -b image -o ~/Desktop/transition/flash --extent 0,0,2272,1704 --color 0.0,0.2,0.8,1.0 --striationcontrast 2.0 --fadethreshold 0.8 --striationstrength 1.0 --center 1136,852 -s ~/Pictures/sourceimage.jpg -d ~/Pictures/targetimage.jpg -c 40 -t public.jpeg

The dissolve transition is the simplest of the transition filters, where the source image is gradually replaced with the target image. This example shows exporting the images as a png sequence. Exporting as png files is considerably slower than jpeg or tiff.

dotransition --transitionfilter CIDissolveTransition -b image -o ~/Desktop/transition/dissolve --exportfiletype public.png -s ~/Pictures/sourceimage.jpg -d ~/Pictures/targetimage.jpg -c 20

The mod transition filter creates oblated oval shapes that move and grow, gradually replace the source image with the target.

dotransition --transitionfilter CIModTransition -b image -o ~/Desktop/transition/mod  -s ~/Pictures/sourceimage.jpg -d ~/Pictures/targetimage.jpg -c 20 --angle 3.14159 --radius 340 --compression 300 --center 1136,852

The page curl transition filter, creates a page turning effect to go from the source to the target image.

dotransition --transitionfilter CIPageCurlTransition -b image -o ~/Desktop/transition/pagecurl  -s ~/Pictures/sourceimage.jpg -d ~/Pictures/targetimage.jpg -c 20 --angle 3.2 --radius 250 --extent 0,0,2272,1704 --backsideimage ~/Pictures/sourceimage.jpg

The page curl with shadow transition filter is very similar to the above but generates the shadow of the page being turned differently.

dotransition --transitionfilter CIPageCurlWithShadowTransition -b image -o ~/Desktop/transition/pagecurlwithshadow  -s ~/Pictures/sourceimage.jpg -d ~/Pictures/targetimage.jpg -c 20 --angle 3.2 --radius 350 --extent 0,0,2272,1704 --shadowamount 0.7 --shadowsize 250 --backsideimage ~/Pictures/sourceimage.jpg

Information about all the scripts that work with MovingImages.

And that’s it, please enjoy.