From 88d3b0cc3e739c118c8738295f55e735bea50e42 Mon Sep 17 00:00:00 2001
From: David Thompson <dthompson2@worcester.edu>
Date: Thu, 15 May 2014 22:18:00 -0400
Subject: Add make-transform*.

* 2d/transform.scm (make-transform*): New procedure.
---
 2d/transform.scm | 10 ++++++++++
 1 file changed, 10 insertions(+)

(limited to '2d/transform.scm')

diff --git a/2d/transform.scm b/2d/transform.scm
index e7b5c31..ea3061d 100644
--- a/2d/transform.scm
+++ b/2d/transform.scm
@@ -27,6 +27,7 @@
   #:use-module (srfi srfi-42)
   #:use-module (2d vector2)
   #:export (make-transform
+            make-transform*
             null-transform
             identity-transform
             transform?
@@ -74,6 +75,15 @@ column-major format."
     (array-set! matrix dd 3 3)
     (%make-transform matrix)))
 
+(define* (make-transform* #:optional #:key (translate null-vector2)
+                          (scale (vector2 1 1)) (rotate 0))
+  "Return a new transform that is the result of the composition of the
+given TRANSLATE, SCALE, and ROTATE values.  Both TRANSLATE and SCALE
+are vector2 values, while ROTATE is a number."
+  (transform* (transform-scale scale)
+              (transform-rotate rotate)
+              (transform-translate translate)))
+
 (define null-transform
   (%make-transform (make-4x4-matrix)))
 
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