Image Comparisons

Launching a comparison

Use the New image comparison button (Ctrl+i) or use the Document / Comparsion/Merge / New Comparison... (Ctrl+N) menu item to select the sources files to use and/or the options to apply to the new document. The dialog box allows you to open side-by-side or 3 way comparisons. You can as well launch any comparison and select Image Document in the Document Type toolbar combo. Dragging two or three images will also launch an Image comparison.

Working with comparisons

How to display a difference?

Ellié Computing Merge is oriented towards both 2 and 3 way differentiation: in 2-way , there is only left/right differentiation, but in 3-way there 3 differentiations: left/right, left/ancestor and right/ancestor. For this reason we chose a solution which allow to easily display all these differences.
At the top of each source view is a tab selector, letting you choose between the: Original, Diff with left/right, Diff with ancestor. By pressing the according tab label, you select the given differentiation result or the original image.

Images dimensions and placement

You can zoom all the images and stretch or align any image. Alignment can be changed with right click menu options (Align to Top/Bottom/Middle or Left/Right/Middle). You can stretch respecting aspect ratio or not with respect to the biggest or smallest image (pressing stretch buttons).

You can align the images dynamically by activating the "Change images alignment" button , then drag one image relatively to the other, selecting the arrow button aside it will bring the cursor to its normal mode.

Differences

Image differentiation has many parameters related to the algorithms used to obtain the actual difference. You can choose between different algorithm, currently: Difference and Blank similar. See Differentiation Styles for more information about this subject. A summary of the differences is presented in the reports, the comparison statistics box and in the status bar (when a difference view is selected). When a pair of images contains no difference, the text "Images are identical" is displayed in the status bar.

Image Comparisons cannot handle merging, ie it is not possible to mix images with Ellié Computing Merge in order to save a mixed result. The Image Comparison view enables you to understand the differences between 2 or 3 images and view the difference (you can copy this difference to clipboard). You can nonetheless use the menu Edit / Copy (or Ctrl/Apple + C) action which copies current image (difference or original) to the clipboard and let you handle it with your preferred imaging application.

See also