Auxiliary active region determination for line width generation in regionalized rasterizer displays

A method for selecting auxiliary screen regions on a screen of a monitor of a computer graphics display system to activate in rendering a straight line segment by a rasterizer assigned to the screen region, wherein the straight line segment has a width, wherein a locus of the straight line segment is specified by equation A*x+B*y+C=0, wherein A, B, and C are respectively a first, second, and third constants, and wherein x and y are respectively Cartesian coordinate system x-axis and y-axis values, the method comprising the steps of:

• overlaying a rectangular grid to screen region boundaries, wherein the screen comprises a screen space divided into multiple screen regions;
• shifting the rectangular grid in a preselected direction parallel to a preselected axis by an amount equal to a fraction of the width of the straight line segment;
• successively selecting once each corner of the shifted rectangular grid until the screen region is marked as selected:
• evaluating expression A*x+B*y+C at the selected corner,
• storing in a memory the algebraic sign of the evaluated expression for the selected corner, and
• if the algebraic sign of the evaluated expression for the selected corner differs from any of the stored algebraic signs, marking the screen region as selected.

A program storage medium readable by a server computer, tangibly embodying a software program of instructions executable by the server to perform method steps for selecting auxiliary screen regions to activate in rendering a straight line segment on a screen of a computer monitor, wherein the straight line segment comprises points defined by an algebraic expression equal to zero, wherein the expression is expressed as a first constant multiplied by a x-axis value plus a second constant multiplied by a y-axis value plus a third constant, wherein the straight line segment has a width, the method steps comprising:

• overlaying a rectangular grid to associated screen region boundaries, wherein the screen comprises a screen space divided into multiple screen regions;
• shifting the rectangular grid in a preselected direction parallel to a preselected axis by a fraction of the width of the straight line segment;
• and
• for each corner point of the shifted rectangular grid,
• computing the expression;
• obtaining an algebraic sign of the result of computing the expression;
• and
• when the algebraic sign just obtained differs from that obtained for the expression for any other shifted rectangular grid corner point, marking the associated screen region as selected.

A program storage medium readable by a server computer, tangibly embodying a software program of instructions executable by the server to perform method steps for selecting auxiliary screen regions on a screen of a monitor of a computer graphics display system to activate in rendering a straight line segment by a rasterizer assigned to the screen region, wherein the straight line segment has a width, wherein a locus of the straight line segment is specified by equation A*x+B*y+C=0, wherein A, B, and C are respectively a first, second, and third constants, and wherein x and y are respectively Cartesian coordinate system x-axis and y-axis values of points on the straight line segment, the method steps comprising:

• overlaying a rectangular grid to screen region boundaries, wherein the screen comprises a screen space divided into multiple screen regions;
• shifting the rectangular grid in a preselected direction parallel to a preselected axis by an amount equal to a fraction of the width of the straight line segment;
• successively selecting once each corner of the shifted rectangular grid until the screen region is marked as selected:
• evaluating expression A*x+B*y+C at the selected corner,
• storing in a memory the algebraic sign of the evaluated expression for the selected corner, and
• if the algebraic sign of the evaluated expression for the selected corner differs from any of the stored algebraic signs, marking the screen region as selected.