eraseByLine かぶっている処理をdrawLineに統合
eraseByLine かぶっている処理をdrawLineに統合

nakamurataichi/Parapara-Canvas-Editor,comozilla/Parapara-Canvas-Editor,yusukeendou/Parapara-Canvas-Editor,comozilla/Parapara-Canvas-Editor,yusukeendou/Parapara-Canvas-Editor,nakamurataichi/Parapara-Canvas-Editor