Abstract
Psychophysical experiments involving moving stimuli require the rapid presentation of animated sequences of images. Although the Macintosh computer is widely used as a color graphics computer in research laboratories, its animation capabilities are generally ignored because of the speed limitations of drawing to the screen. New off-screen color graphics structures help to avoid the speed limitations so that real-time color or gray-scale visual motion stimuli may be generated. Precomputed animation frames are stored in off-screen memory and then rapidly transferred to the screen sequentially. The off-screen graphics structures may also be saved to disk in “Picture” form as “resources” for later retrieval and playback, allowing the experimenter to build in advance a collection of moving stimuli to use in future experiments. Code examples in the C programming language are provided, and the relative strengths and weaknesses of Macin-tosh color-frame animation for psychophysical experimentation are discussed.
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The authors would like to thank Dr. John Baro for many helpful discussions on the Macintosh Toolbox and for comments on early drafts of this manuscript.
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Steinman, S.B., Nawrot, M. Real-time color-frame animation for visual psychophysics on the Macintosh computer. Behavior Research Methods, Instruments, & Computers 24, 439–452 (1992). https://doi.org/10.3758/BF03203578
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DOI: https://doi.org/10.3758/BF03203578