Operators

# distance_pl (Operator)

## Name

distance_pl — Calculate the distance between one point and one line.

## Signature

distance_pl( : : Row, Column, Row1, Column1, Row2, Column2 : Distance)

## Description

The operator distance_pl calculates the orthogonal distance between points (Row,Column) and lines, given by two arbitrary points on the line. The result is passed in Distance.

distance_pl calculates the distances between a set of n points and one line as well as the distances between a set of n points and n lines.

## Parallelization

• Multithreading type: reentrant (runs in parallel with non-exclusive operators).
• Processed without parallelization.

## Parameters

Row (input_control)  point.y(-array) (real / integer)

Row coordinate of the point.

Column (input_control)  point.x(-array) (real / integer)

Column of the point.

Row1 (input_control)  point.y(-array) (real / integer)

Row coordinate of the first point of the line.

Column1 (input_control)  point.x(-array) (real / integer)

Column coordinate of the first point of the line.

Row2 (input_control)  point.y(-array) (real / integer)

Row coordinate of the second point of the line.

Column2 (input_control)  point.x(-array) (real / integer)

Column coordinate of the second point of the line.

Distance (output_control)  real(-array) (real)

Distance between the points.

## Example (HDevelop)

```read_image (Image, 'mreut')
dev_open_window (0, 0, 512, 512, 'white', WindowHandle)
dev_display (Image)
dev_set_color ('black')
threshold (Image, Region, 180, 255)
dev_clear_window ()
dev_display (Region)
connection (Region, ConnectedRegions)
select_shape (ConnectedRegions, SelectedRegions, 'area', 'and', \
10000, 100000000)
get_region_contour (SelectedRegions, Rows, Columns)
RowLine1 := 5
ColLine1 := 300
RowLine2 := 300
ColLine2 := 400
NumberTuple := |Rows|
dev_set_color ('red')
disp_line (WindowHandle, RowLine1, ColLine1, RowLine2, ColLine2)
dev_set_color ('green')
for i := 1 to NumberTuple by 5
disp_line (WindowHandle, Rows[i], Columns[i]-2, Rows[i], Columns[i]+2)
disp_line (WindowHandle, Rows[i]-2, Columns[i], Rows[i]+2, Columns[i])
distance_pl (Rows[i], Columns[i], RowLine1, ColLine1, \
RowLine2, ColLine2, Distance)
endfor
```

## Result

distance_pl returns 2 (H_MSG_TRUE).