[cl-cairo2-cvs] r12 - tutorial

[tpapp at common-lisp.net]

Author: tpapp
Date: Tue Aug 14 03:53:12 2007
New Revision: 12

Modified:
   transformations.lisp
   tutorial/   (props changed)
   tutorial/example.lisp
   tutorial/tutorial.tex
Log:
minor fixes in transformations code

Modified: transformations.lisp
==============================================================================
--- transformations.lisp	(original)
+++ transformations.lisp	Tue Aug 14 03:53:12 2007
@@ -5,13 +5,16 @@
 ;;;;  cairo-matrix-init is not defined, as we have a structure in lisp
 ;;;;    with an appropriate constructor
 ;;;;  
-;;;;  cairo_identity_matrix is reset-matrix
+;;;;  cairo_identity_matrix is reset-trans-matrix
 ;;;;  
 ;;;;  functions that manipulate transformation matrices have
 ;;;;    trans-matrix instead of matrix in their name
 ;;;;
 ;;;;  cairo_matrix_transform_distance and cairo_matrix_transform_point
 ;;;;    are simply transform-distance and transform-point
+;;;; 
+;;;;  cairo_matrix_init is not defined, make-trans-matrix will give
+;;;;    you an identity matrix
 
 ;;;;
 ;;;;  simple functions
@@ -22,7 +25,7 @@
   (scale sx sy)
   (rotate angle))
 
-(define-flexible (reset-matrix pointer)
+(define-flexible (reset-trans-matrix pointer)
   (cairo_identity_matrix pointer))
   
 
@@ -30,7 +33,13 @@
 ;;;;  transition matrix structure and helper functions/macros
 ;;;;
 
-(defstruct trans-matrix xx yx xy yy x0 y0)
+(defstruct trans-matrix
+  (xx 1d0 :type double-float)
+  (yx 0d0 :type double-float)
+  (xy 0d0 :type double-float)
+  (yy 1d0 :type double-float)
+  (x0 0d0 :type double-float)
+  (y0 0d0 :type double-float))
 
 (defun trans-matrix-copy-in (pointer matrix)
   "Copy matrix to a memory location."
@@ -108,7 +117,7 @@
 
 (define-flexible (get-trans-matrix pointer)
   (with-trans-matrix-out matrix-pointer
-    (cairo_set_matrix pointer matrix-pointer)))
+    (cairo_get_matrix pointer matrix-pointer)))
 
 (define-with-x-y user-to-device)
 (define-with-x-y user-to-device-distance)
@@ -129,7 +138,6 @@
 	  matrix-pointer
 	  , at args)))))
 
-(define-matrix-init identity)
 (define-matrix-init translate tx ty)
 (define-matrix-init scale sx sy)
 (define-matrix-init rotate radians)

Modified: tutorial/example.lisp
==============================================================================
--- tutorial/example.lisp	(original)
+++ tutorial/example.lisp	Tue Aug 14 03:53:12 2007
@@ -167,7 +167,7 @@
   ;; draw the hearts
   (dotimes (i 200)
      (let ((scaling (+ 5d0 (random 40d0))))
-       (reset-matrix)		; reset matrix
+       (reset-trans-matrix)			  ; reset matrix
        (translate (random width) (random height)) ; move the origin
        (scale scaling scaling)			  ; scale
        (rotate (deg-to-rad (- (random (* 2 max-angle)) max-angle 180))) ; rotate

Modified: tutorial/tutorial.tex
==============================================================================
--- tutorial/tutorial.tex	(original)
+++ tutorial/tutorial.tex	Tue Aug 14 03:53:12 2007
@@ -189,7 +189,8 @@
     \verb!cairo_fill! (would conflict with \lstinline!cl:fill!) 
     & \lstinline!fill-path! \\
     \verb!cairo_identity_matrix! (would
-    conflict with matrix algebra packages)& \lstinline!reset-matrix! \\
+    conflict with matrix algebra packages)& \lstinline!reset-trans-matrix! \\
+    \verb!cairo_matrix_init_identity! & use \lstinline!(make-trans-matrix)!\\
     \verb!cairo_matrix_transform_distance! 
     & \lstinline!transform-distance!\\
     \verb!cairo_matrix_transform_point! &
@@ -320,10 +321,12 @@
 
 cl-cairo2 defines the structure \lstinline!trans-matrix! with the
 slots \lstinline!xx!, \lstinline!yx!, \lstinline!xy!, \lstinline!yy!,
-\lstinline!x0!, \lstinline!y0!.  All the functions that use
-transformation matrices use this structure.  Consequently,
-\verb!cairo_matrix_init! has no corresponding function in cl-cairo2:
-you can construct a translation matrix using
+\lstinline!x0!, \lstinline!y0!.  The defaults for these slots give you
+the identity matrix.
+
+All the functions that use transformation matrices use this structure.
+Consequently, \verb!cairo_matrix_init! has no corresponding function
+in cl-cairo2: you can construct a translation matrix using
 \lstinline!make-trans-matrix!.
 
 Some functions are renamed, see Table~\ref{tab:naming}.  Generally,