6.6 DUIM-Graphics Module
draw-ellipse
Generic function
Summary
Draws an ellipse with the specified center and radius vectors.
Signature
draw-ellipse drawable center-x center-y radius-1-dx radius-1-dy radius-2-dx radius-2-dy #key start-angle end-angle filled? => ()
draw-ellipse* drawable center radius-1-dx radius-1-dy radius-2-dx radius-2-dy #key start-angle end-angle filled? => ()
Arguments
- drawable
- An instance of type
type-union(<sheet>, <medium>). - radius-1-dx
- An instance of type
<real>. - radius-1-dy
- An instance of type
<real>. - radius-2-dx
- An instance of type
<real>. - radius-2-dy
- An instance of type
<real>. - start-angle
- An instance of type
false-or(<real>). - end-angle
- An instance of type
false-or(<real>). - filled?
- An instance of type
<boolean>. Default value:#t.
The following arguments are specific to draw-ellipse.
- center-x
- An instance of type
<real>. - center-y
- An instance of type
<real>.
The following argument is specific to draw-ellipse*.
- center
- An instance of type
<transform>.
Values
- None.
Library
duim-graphics
Module
duim-graphics
Description
Draws an ellipse on drawable with the specified center and extreme points, using the current pen.
The center of the ellipse is defined by (center-x, center-y), and the extreme points of the ellipse (that is, the points furthest away from the center for each radius) are calculated by adding the radius vectors radius-1-dx and radius-1-dy to center-x and center-y respectively (to calculate the outermost points for the first radius), and adding the radius vectors radius-2-dx and radius-2-dy to center-x and center-y respectively (to calculate the outermost points for the second radius).
Please note that draw-ellipse does not currently support non-axis-aligned ellipses. For all practical purposes, this means that radius-1-dy and radius-2-dx must always be 0.
The arguments start-angle and end-angle let you draw just a section of the ellipse, rather than the whole ellipse.
If filled? is #t then the ellipse will be filled, using the current brush.
The function draw-ellipse* is identical to draw-ellipse, except that it passes composite objects, rather than separate coordinates, in its arguments. You should be aware that using this function may lead to a loss of performance.