Draw a sphere: Difference between revisions

=={{header|Common Lisp}}==

{{libheader|cl-cairo2}}

Saved as a png file and rendered in a X-Window.

[[File:cl-sphere.png|thumb|right]]

<lang lisp>;; * Loading the cairo bindings

(eval-when (:compile-toplevel :load-toplevel)

(ql:quickload '("cl-cairo2" "cl-cairo2-xlib")))

;; * The package definition

(defpackage :sphere

(:use :common-lisp :cl-cairo2))

(in-package :sphere)

(defparameter *context* nil)

(defparameter *size* 400)

(defparameter *middle* (/ *size* 2))

;; Opening a display and draw a sphere

(let ((width *size*)

(height *size*))

;; Draw to a X-Window

(setf *context*

(create-xlib-image-context width height :window-name "Sphere"))

;; Clear the whole canvas with gray

(rectangle 0 0 width height)

(set-source-rgb 127 127 127)

(fill-path)

;; Draw a the sphere as circa with a radial pattern

(with-patterns ((pat (create-radial-pattern (* 0.9 *middle*) (* 0.8 *middle*) (* 0.2 *middle*)

(* 0.8 *middle*) (* 0.8 *middle*) *middle*)))

(pattern-add-color-stop-rgba pat 0 1 1 1 1)

(pattern-add-color-stop-rgba pat 1 0 0 0 1)

(set-source pat)

(arc *middle* *middle* 180 0 (* 2 pi))

(fill-path))

;; Draw to a png file

(with-png-file ("sphere.png" :rgb24 width height)

;; Clear the whole canvas with gray

(rectangle 0 0 width height)

(set-source-rgb 127 127 127)

(fill-path)

;; Draw a the sphere as circa with a radial pattern

(with-patterns ((pat (create-radial-pattern (* 0.9 *middle*) (* 0.8 *middle*) (* 0.2 *middle*)

(* 0.8 *middle*) (* 0.8 *middle*) *middle*)))

(pattern-add-color-stop-rgba pat 0 1 1 1 1)

(pattern-add-color-stop-rgba pat 1 0 0 0 1)

(set-source pat)

(arc *middle* *middle* 180 0 (* 2 pi))

(fill-path))))</lang>