A method of manipulating pre-existing ink data in the memory of a device including an input sensor to generate new ink data, comprising: receiving input information including coordinates data from the input sensor; receiving manipulation information indicating whether the input information is configured to transform the pre-existing stroke object of the ink data; selecting a part or a full of a target stroke object to be transformed if a stroke path formed by the coordinates data included in the input information intersects the target stroke object; and when the manipulation information indicates that the input information is configured to slice the pre-existing stroke object, slicing the selected target stroke object at an intersected section to generate two slice objects from the selected target stroke object, wherein the two slice objects provide modification to divide the pre-existing stroke object into two new stroke objects, each of the two slice objects includes a start parameter (301, 1805) indicative of a start point within a starting curve segment of the curve segments at which display of the slice object starts and an end parameter (303, 1803) indicative of an end point within an ending curve segment of the curve segments at which display of the slice object stops when the two new stroke objects generated by finalizing the two slice object are rendered, wherein the starting curve segment and the ending curve segment are those segments at which display operation starts and ends, respectively, characterised in that each of the two slice objects includes: an index of a point object in the pre-existing stroke object indicating a start point object of the slice object, wherein the index is a control point (P0, SP2) index used to maintain the shape of the starting curve segment before and after the manipulation, and an index of a point object in the pre-existing stroke object indicating an end point object of the slice object, wherein the index is a control point (EP1, P12) index used to maintain the shape of the ending curve segment before and after the manipulation. receiving input information including coordinates data from the input sensor; receiving manipulation information indicating whether the input information is configured to transform the pre-existing stroke object of the ink data; selecting a part or a full of a target stroke object to be transformed if a stroke path formed by the coordinates data included in the input information intersects the target stroke object; and when the manipulation information indicates that the input information is configured to slice the pre-existing stroke object, slicing the selected target stroke object at an intersected section to generate two slice objects from the selected target stroke object, wherein the two slice objects provide modification to divide the pre-existing stroke object into two new stroke objects, each of the two slice objects includes a start parameter (301, 1805) indicative of a start point within a starting curve segment of the curve segments at which display of the slice object starts and an end parameter (303, 1803) indicative of an end point within an ending curve segment of the curve segments at which display of the slice object stops when the two new stroke objects generated by finalizing the two slice object are rendered, wherein the starting curve segment and the ending curve segment are those segments at which display operation starts and ends, respectively, characterised in that each of the two slice objects includes: an index of a point object in the pre-existing stroke object indicating a start point object of the slice object, wherein the index is a control point (P0, SP2) index used to maintain the shape of the starting curve segment before and after the manipulation, and an index of a point object in the pre-existing stroke object indicating an end point object of the slice object, wherein the index is a control point (EP1, P12) index used to maintain the shape of the ending curve segment before and after the manipulation. an index of a point object in the pre-existing stroke object indicating a start point object of the slice object, wherein the index is a control point (P0, SP2) index used to maintain the shape of the starting curve segment before and after the manipulation, and an index of a point object in the pre-existing stroke object indicating an end point object of the slice object, wherein the index is a control point (EP1, P12) index used to maintain the shape of the ending curve segment before and after the manipulation.