intersection

intersection_ll ( : : RowA1, ColumnA1, RowA2, ColumnA2, RowB1, ColumnB1, RowB2, ColumnB2 : Row, Column, IsParallel )

Calculate the intersection point of two lines.

The operator intersection_ll calculates the intersection point of two lines. As input the two points on each line are expected (RowA1,ColumnA1, RowA2,ColumnA2) and (RowB1,ColumnB1, RowB2,ColumnB2). The parameters Row and Column return the result of the calculation. If the lines are parallel, the values of Row and Column are undefined and IsParallel is 1. Otherwise, IsParallel is 0.

Attention

If the lines are parallel the values of Row and Column are undefined.

Parameters

`RowA1` (input_control)	point.y(-array) `->` real / integer
Row coordinate of the first point of the first line.

`ColumnA1` (input_control)	point.x(-array) `->` real / integer
Column coordinate of the first point of the first line.

`RowA2` (input_control)	point.y(-array) `->` real / integer
Row coordinate of the second point of the first line.

`ColumnA2` (input_control)	point.x(-array) `->` real / integer
Column coordinate of the second point of the first line.

`RowB1` (input_control)	point.y(-array) `->` real / integer
Row coordinate of the first point of the second line.

`ColumnB1` (input_control)	point.x(-array) `->` real / integer
Column coordinate of the first point of the second line.

`RowB2` (input_control)	point.y(-array) `->` real / integer
Row coordinate of the second point of the second line.

`ColumnB2` (input_control)	point.x(-array) `->` real / integer
Column coordinate of the second point of the second line.

`Row` (output_control)	point.y(-array) `->` real
Row coordinate of the intersection point.

`Column` (output_control)	point.x(-array) `->` real
Column coordinate of the intersection point.

`IsParallel` (output_control)	number(-array) `->` integer
Are the two lines parallel?

Example

dev_set_color ('black')
RowLine1 := 350
ColLine1 := 250
RowLine2 := 300
ColLine2 := 300
Rows := 300
Columns := 50
disp_line (WindowHandle, RowLine1, ColLine1, RowLine2, ColLine2)
n := 0
for Rows := 40 to 200 by 4
  dev_set_color ('red')
  disp_line (WindowHandle, Rows, Columns, Rows+n, Columns+n)
  intersection_ll (Rows, Columns, Rows+n, Columns+n, RowLine1, ColLine1,
                   RowLine2, ColLine2, Row, Column, IsParallel)
  dev_set_color ('blue')
  disp_line (WindowHandle, Row, Column-2, Row, Column+2)
  disp_line (WindowHandle, Row-2, Column, Row+2, Column)
  n := n+8
endfor

Result

intersection_ll returns 2 (H_MSG_TRUE).

Parallelization Information

intersection_ll is reentrant and processed without parallelization.

Module

Foundation