The subject disclosure is directed towards saving undo state information for a digital art program. Changed state data is computed (e.g., via GPU-side logic) based upon the state information of the current state of a canvas and the previous state information, e.g., via an XOR operation or parallel XOR operations. The changed state data is compressed into compressed state data, e.g., via run-length encoding, and the compressed state data is stored, e.g., in a circular buffer in GPU memory. For an undo command, the compressed data is decompressed into the changed state data, and the bitwise operation reversed.