gen_ellipse

gen_ellipse ( : Ellipse : Row, Column, Phi, Radius1, Radius2 : )

Create an ellipse.

The operator gen_ellipse generates one or more ellipses with the center (Row, Column), the orientation Phi and the half-radii Radius1 and Radius2. The angle is indicated in arc measure according to the x axis in mathematically positive direction. More than one region can be created by passing tuples of parameter values.

The center must be located within the image coordinates. The coordinate system runs from (0,0) (upper left corner) to (Width-1,Height-1). See get_system and reset_obj_db in this context. If the ellipse reaches beyond the edge of the image it is clipped to the current image format according to the value of the system flag 'clip_region' (set_system).

Parameters

`Ellipse` (output_object)	region(-array) `->` object
Created ellipse(s).

`Row` (input_control)	ellipse.center.y(-array) `->` real / integer
Line index of center.
Default value: 200.0
Suggested values: 0.0, 10.0, 20.0, 50.0, 100.0, 256.0, 300.0, 400.0
Typical range of values: `1.0 <= Row <= 1024.0` (lin)
Minimum increment: 1.0
Recommended increment: 10.0

`Column` (input_control)	ellipse.center.x(-array) `->` real / integer
Column index of center.
Default value: 200.0
Suggested values: 0.0, 10.0, 20.0, 50.0, 100.0, 256.0, 300.0, 400.0
Typical range of values: `1.0 <= Column <= 1024.0` (lin)
Minimum increment: 1.0
Recommended increment: 10.0

`Phi` (input_control)	ellipse.angle.rad(-array) `->` real / integer
Orientation of the longer radius (Radius1).
Default value: 0.0
Suggested values: -1.178097, -0.785398, -0.392699, 0.0, 0.392699, 0.785398, 1.178097
Typical range of values: `-1.178097 <= Phi <= 1.178097` (lin)
Minimum increment: 0.01
Recommended increment: 0.1

`Radius1` (input_control)	ellipse.radius1(-array) `->` real / integer
Longer radius.
Default value: 100.0
Suggested values: 2.0, 5.0, 10.0, 20.0, 50.0, 100.0, 256.0, 300.0, 400.0
Typical range of values: `1.0 <= Radius1 <= 1024.0` (lin)
Minimum increment: 1.0
Recommended increment: 10.0
Restriction: `Radius1 > 0`

`Radius2` (input_control)	ellipse.radius2(-array) `->` real / integer
Shorter radius.
Default value: 60.0
Suggested values: 1.0, 2.0, 4.0, 5.0, 10.0, 20.0, 50.0, 100.0, 256.0, 300.0, 400.0
Typical range of values: `1.0 <= Radius2 <= 1024.0` (lin)
Minimum increment: 1.0
Recommended increment: 10.0
Restriction: `(Radius2 > 0) && (Radius2 <= Radius1)`

Example

open_window(0,0,-1,-1,'root','visible','',WindowHandle) 
set_insert(WindowHandle,'xor') 
repeat() 
  get_mbutton(WindowHandle,Row,Column,Button) 
  gen_ellipse(Ellipse,Row,Column,Column / 300.0,
         (Row mod 100)+1,(Column mod 50) + 1) 
  disp_region(Ellipse,WindowHandle) 
  clear_obj(Ellipse) 
until(Button = 1).

Complexity

Runtime complexity: O(Radius1 * 2)

Storage complexity (byte): O(Radius1 * 8)

Result

If the parameter values are correct, the operator gen_ellipse returns the value 2 (H_MSG_TRUE). Otherwise an exception handling is raised. The clipping according to the current image format is set via the operator set_system('clip_region',<'true'/'false'>).

Parallelization Information

gen_ellipse is reentrant and processed without parallelization.

Possible Successors

paint_region, reduce_domain

Alternatives

gen_circle, gen_region_polygon_filled, draw_ellipse

Module

Foundation