skipDiffChannel when updating the the canvas with background
skipDiffChannel when updating the the canvas with background

mengzhaoji/wordcloud,beckyli/tag_cloud,temelal/wordcloud,temelal/wordcloud,mengzhaoji/wordcloud,zxc37880/wordcloud,jell0720/wordcloud,erpframework/wordcloud,jell0720/wordcloud,zxc37880/wordcloud,beckyli/tag_cloud,timdream/wordcloud,zxc37880/wordcloud,erpframework/wordcloud,erpframework/wordcloud,timdream/wordcloud,timdream/wordcloud,beckyli/tag_cloud,jell0720/wordcloud,temelal/wordcloud,mengzhaoji/wordcloud