Adjusting eraser size in drawing applications

Abstract

The method includes identifying, by one or more computer processors, a first location and a second location of input on a touch-sensitive surface. The method further includes calculating, by one or more computer processors, a distance between the first location and the second location. The method further includes identifying, by one or more computer processors, a first elapsed time between creation of the identified first location of input and the identified second location of input. The method further includes calculating, by one or more computer processors, a first size of an eraser based upon the identified first elapsed time. The method further includes generating, by one or more computer processors, an eraser path based upon the identified first location and the identified second location of input on a touch-sensitive surface, and the calculated first size of an eraser.

What is claimed is: 
     
         1 . A method for generating an eraser path, the method comprising:
 identifying, by one or more computer processors, a first location and a second location of input on a touch-sensitive surface;   calculating, by one or more computer processors, a distance between the first location and the second location;   identifying, by one or more computer processors, a first elapsed time between creation of the identified first location of input and the identified second location of input;   calculating, by one or more computer processors, a first size of an eraser based upon the identified first elapsed time; and   generating, by one or more computer processors, an eraser path based upon the identified first location and the identified second location of input on a touch-sensitive surface, and the calculated first size of an eraser.   
     
     
         2 . The method of  claim 1 , further comprising:
 identifying, by one or more computer processors, a third location of input on the touch-sensitive surface;   calculating, by one or more computer processors, a distance between the second location and the third location;   identifying, by one or more computer processors, a second elapsed time between creation of the identified second location of input and the identified third location of input;   calculating, by one or more computer processors, a second size of an eraser based upon the identified second elapsed time; and   generating, by one or more computer processors, an updated eraser path based upon the identified first location, the identified second location, and the identified third location of input on a touch-sensitive surface, and the calculated first size of an eraser and the calculated second size of an eraser.   
     
     
         3 . The method of  claim 2 , wherein generating an eraser path comprises utilizing a Bézier curve to create a curved path between the identified first location, the identified second location, and the third identified location. 
     
     
         4 . The method of  claim 2 , wherein generating an eraser size comprises utilizing a Bézier curve to smooth a change in size between the calculated first size of an eraser and the calculated second size of the eraser. 
     
     
         5 . The method of  claim 1 , further comprising:
 identifying, by one or more computer processors, a preset initial eraser size for the first identified location of input; and   generating, by one or more computer processors, an eraser path based upon the identified first location and the identified second location of input on a touch-sensitive surface, and the identified preset initial eraser size for the first identified location, the calculated first size of an eraser.   
     
     
         6 . The method of  claim 1 , wherein calculating a first size of an eraser based upon the identified first elapsed time comprises:
 calculating, by one or more computer processors, a speed for the input on the touch-sensitive surface to traverse from the first location of input to the second location of input as a function of distance over time; and   generating, by one or more computer processors, an eraser size for the second location of input based upon the calculated speed.   
     
     
         7 . The method of  claim 1 , further comprising:
 identifying, by one or more computer processors, a plurality of locations of input on the touch-sensitive surface;   identifying, by one or more computer processors, a distance between each identified location of input and a subsequent location of input from the plurality of locations of input;   identifying, by one or more computer processors, a time elapsed between each location of input and the subsequent location of input from the plurality of locations of input;   calculating, by one or more computer processors, a size of an eraser for each location of input based upon the identified time elapsed between each location of input and the subsequent location of input from the plurality of locations of input; and   generating, by one or more computer processors, an eraser path based upon the plurality of locations of input and the calculated size of an eraser for each location of input.   
     
     
         8 . A computer program product for generating an eraser path, the computer program product comprising:
 one or more computer readable storage media and program instructions stored on the one or more computer readable storage media, the program instructions comprising:   program instructions to identify a first location and a second location of input on a touch-sensitive surface;   program instructions to calculate a distance between the first location and the second location;   program instructions to identify a first elapsed time between creation of the identified first location of input and the identified second location of input;   program instructions to calculate a first size of an eraser based upon the identified first elapsed time; and   program instructions to generate an eraser path based upon the identified first location and the identified second location of input on a touch-sensitive surface, and the calculated first size of an eraser.   
     
     
         9 . The computer program product of  claim 8 , further comprising program instructions to:
 identify a third location of input on the touch-sensitive surface;   calculate a distance between the second location and the third location;   identify a second elapsed time between creation of the identified second location of input and the identified third location of input;   calculate a second size of an eraser based upon the identified second elapsed time; and   generate an updated eraser path based upon the identified first location, the identified second location, and the identified third location of input on a touch-sensitive surface, and the calculated first size of an eraser and the calculated second size of an eraser.   
     
     
         10 . The computer program product of  claim 9 , wherein program instructions to generate an eraser path comprises utilizing a Bézier curve to create a curved path between the identified first location, the identified second location, and the third identified location. 
     
     
         11 . The computer program product of  claim 9 , wherein program instructions to generate an eraser size comprises utilizing a Bézier curve to smooth a change in size between the calculated first size of an eraser and the calculated second size of the eraser. 
     
     
         12 . The computer program product of  claim 8 , further comprising program instructions to:
 identify a preset initial eraser size for the first identified location of input; and   generate an eraser path based upon the identified first location and the identified second location of input on a touch-sensitive surface, and the identified preset initial eraser size for the first identified location, the calculated first size of an eraser.   
     
     
         13 . The computer program product of  claim 8 , wherein program instructions to calculate a first size of an eraser based upon the identified first elapsed time comprises program instructions to:
 calculate a speed for the input on the touch-sensitive surface to traverse from the first location of input to the second location of input as a function of distance over time; and   generate an eraser size for the second location of input based upon the calculated speed.   
     
     
         14 . The computer program product of  claim 8 , further comprising program instructions to:
 identify a plurality of locations of input on the touch-sensitive surface;   identify a distance between each identified location of input and a subsequent location of input from the plurality of locations of input;   identify a time elapsed between each location of input and the subsequent location of input from the plurality of locations of input;   calculate a size of an eraser for each location of input based upon the identified time elapsed between each location of input and the subsequent location of input from the plurality of locations of input; and   generate an eraser path based upon the plurality of locations of input and the calculated size of an eraser for each location of input.   
     
     
         15 . A computer system for generating an eraser path, the computer system comprising:
 one or more computer processors;   one or more computer readable storage media;   program instructions stored on the computer readable storage media for execution by at least one of the one or more computer processors, the program instructions comprising:   program instructions to identify a first location and a second location of input on a touch-sensitive surface;   program instructions to calculate a distance between the first location and the second location;   program instructions to identify a first elapsed time between creation of the identified first location of input and the identified second location of input;   program instructions to calculate a first size of an eraser based upon the identified first elapsed time; and   program instructions to generate an eraser path based upon the identified first location and the identified second location of input on a touch-sensitive surface, and the calculated first size of an eraser.   
     
     
         16 . The computer system of  claim 15 , further comprising program instructions to:
 identify a third location of input on the touch-sensitive surface;   calculate a distance between the second location and the third location;   identify a second elapsed time between creation of the identified second location of input and the identified third location of input;   calculate a second size of an eraser based upon the identified second elapsed time; and   generate an updated eraser path based upon the identified first location, the identified second location, and the identified third location of input on a touch-sensitive surface, and the calculated first size of an eraser and the calculated second size of an eraser.   
     
     
         17 . The computer system of  claim 16 , wherein program instructions to generate an eraser path comprises utilizing a Bézier curve to create a curved path between the identified first location, the identified second location, and the third identified location. 
     
     
         18 . The computer system of  claim 16 , wherein program instructions to generate an eraser size comprises utilizing a Bézier curve to smooth a change in size between the calculated first size of an eraser and the calculated second size of the eraser. 
     
     
         19 . The computer system of  claim 15 , further comprising program instructions to:
 identify a preset initial eraser size for the first identified location of input; and   generate an eraser path based upon the identified first location and the identified second location of input on a touch-sensitive surface, and the identified preset initial eraser size for the first identified location, the calculated first size of an eraser.   
     
     
         20 . The computer system of  claim 15 , wherein program instructions to calculate a first size of an eraser based upon the identified first elapsed time comprises program instructions to:
 calculate a speed for the input on the touch-sensitive surface to traverse from the first location of input to the second location of input as a function of distance over time; and   generate an eraser size for the second location of input based upon the calculated speed.