49 struct WebPAnimEncoder {  struct
52   const WebPAnimEncoderOptions options_;    // Global encoding options.  argument
54   FrameRectangle prev_rect_;          // Previous WebP frame rectangle.
55   WebPConfig last_config_;            // Cached in case a re-encode is needed.
56   WebPConfig last_config_reversed_;   // If 'last_config_' uses lossless, then
61   WebPPicture* curr_canvas_;          // Only pointer; we don't own memory.
64   WebPPicture curr_canvas_copy_;      // Possibly modified current canvas.
65   int curr_canvas_copy_modified_;     // True if pixels in 'curr_canvas_copy_'
68   WebPPicture prev_canvas_;           // Previous canvas.
69   WebPPicture prev_canvas_disposed_;  // Previous canvas disposed to background.
93   int got_null_frame_;  // True if WebPAnimEncoderAdd() has already been called  argument
105 // Life of WebPAnimEncoder object.  argument