Your e-Business Quality Partner eValid™ -- Automated Web Quality Solution
Browser-Based, Client-Side, Functional Testing & Validation,
Load & Performance Tuning, Page Timing, Website Analysis,
and Rich Internet Application Monitoring.

eValid -- Image Difference Utility
eValid Home

The eValid Image Difference Utility, eVimagediff, provides a capability of comparing two images, masking the comparisons, and producing differences.

Recording to Save A Image
With eValid's exceptional recording capabilities, nearly any task done through eValid shrinks a user workload dramatically! Saving backup images from a site by saving it locally can reduce the workload for a user by automating such task. And, when used in conjunction with the eV.generate feature, one can create a script which periodically downloads and saves it under a new filename every time -- automatically! 

  1. Start your recording normally. 

  2. Navigate to the page where the image is located. 

  3. In the Absolute Events section (eValid: Settings > Record/Play Advanced Preferences > Absolute Events) click the Absolute Right Clicks' check box to enable the recording of the right mouse button. 

  4. Turn on "Application Mode" Recording (F12/eValid: Record > Advanced Recording > Application Mode) in order to record the interaction of saving the image in a local folder. 

  5. Right-click on the image and select "Save Picture As..."  or skip 4. and apply (eValid: Record > Save > ...) utilities.

  6. Set the time on when you want your scripts to be run by adding commands such as "Wait, WaitHH/MM, WaitModHH/MM". 

  7. Playback your script. 

As you will observe, eValid waits for the time specified and runs the script, saving the image to the local folder specified.

Comparing Two Images
The eVimagediff window's utility allows you to compare captured bitmap images. During your recording session screen area images, windows, full screens which you have saved as bitmaps files can be loaded and compared by selecting a baseline and response file from the provided menu/submenu and its responding window pop up options. By applying the Difference menu's Do Diff option, if the images match, then the eVimagediff window should be white; if the images do not match, then the eVimagediff window will display those bitmap differences.

The eVimagediff utility allows you to compare what are the differences that were found during your playback session. As expected images captured during your recording session and actual captured areas during your playback session should be identical. If they are not, your playback test session fails. You can use the eVimagediff window to see if there are any differences.

Constructing Image Masks
eVimagediff has a masking feature which allows you to eliminate/mask out areas of an image so as to eliminate expected differences. You can enable this feature by rubberbanding around the area(s) to be excluded from your image comparison during playback.

Command Line Interface

eVimagediff [basefile] [responsefile]

On the eValid Tool bar, click: Tools > eV-ImageDiff to start eVimagediff.

The frames below present an example of how the image difference utility works.

From the menu, use File > Open Baseline and File > Open Response to select the bitmaps you want to compare.
Select Difference > Do Diff to make the comparison.
Non-white areas are those that differ between the two bitmaps.
You can fine-tune your comparison from the use of image masks.
With Image Masking enabled, draw rectangular boundaries on the areas of the image you do not want compared.
This shows the above result with the two masks on the areas of the image applied during the comparison.