What are some alternatives?
When comparing iCalamus and Adobe InDesign, you can also consider the following products
Zmags - Zmags provides solutions create and publish web experiences instantly.
Canva - Canva makes design simple for everyone. Create designs for Web or print: blog graphics, presentations, Facebook covers, flyers, posters, invitations and so much more.
Adobe FrameMaker - A desktop publishing (DTP) and word processing application that is popular for large documents.
Sketch - Professional digital design for Mac.
Readymag - Readymag is a comprehensive solution that allows you to design web publication, magazines, presentations, websites, and all the other publications.
Adobe Photoshop - Adobe Photoshop is a webtop application for editing images and photos online.