  We propose emordle, a conceptual design that animates wordles (compact word
clouds) to deliver their emotional context to the audiences. To inform the
design, we first reviewed online examples of animated texts and animated
wordles, and summarized strategies for injecting emotion into the animations.
We introduced a composite approach that extends an existing animation scheme
for one word to multiple words in a wordle with two global factors: the
randomness of text animation (entropy) and the animation speed (speed). To
create an emordle, general users can choose one predefined animated scheme that
matches the intended emotion class and fine-tune the emotion intensity with the
two parameters. We designed proof-of-concept emordle examples for four basic
emotion classes, namely happiness, sadness, anger, and fear. We conducted two
controlled crowdsourcing studies to evaluate our approach. The first study
confirmed that people generally agreed on the conveyed emotions from
well-crafted animations, and the second one demonstrated that our identified
factors helped fine-tune the delivered emotion extent. We also invited general
users to create emordles on their own based on our proposed framework. Through
this user study, we confirmed the effectiveness of the approach. We concluded
with implications for future research opportunities of supporting emotion
expression in visualizations.
