Case Study: Expert Evaluations of Complex UIs - Cross-Cultural Human-Computer Interaction and User Experience Design - page 67

FIGURE 4.17 GIMP perspective clone plane and tool. Source: The GIMP 2.6.7.
HE analysis
Direct manipulation/see and point; error prevention.
Although the user can use the tool directly on the image, he or she is reminded every
time to select a source region first. Instead of forcing the user to go “backwards,” the
program should allow the user to select the region afterwards. Such a change in the
perceived interaction timeline also violates the principle of error prevention.
Recognition rather than recall.
All of the needed actions are visible and the system provides inline help. However,
the toolbar on the top-left does not show which tools are necessary for the operation
and in which sequence they should be applied (“Modify Perspective” or “Perspective
Clone”?).
Match between system and real world.
The Perspective Clone tool is located under Paint Tools and thus supports the metaphor
of painting on the picture. However, in the virtual environment this could be prob-
lematic as the clone tool is connected with image transformation and/or filtering.