1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
|
;;;; canvas-language.lisp -- a drawing api for canvas instances
(in-package #:wheelwork)
(defvar *current-canvas* nil)
(defvar *current-pen-color* '(0 0 0 255))
(defvar *current-pen-width* 1)
(defvar *current-pen-position* '(0 0))
(defvar *saved-state* nil)
(defmacro with-current-pen-state ( &body body)
"Saves the current pen state (color width position) so that it can
be restored from using (restore-pen-state) from within the BODY.
After BODY executes the state is restored to whatever it was
before WITH-CURRENT-PEN-STATE was evaluated."
`(let
((*saved-state*
(list *current-pen-width*
*current-pen-position*
*current-pen-color*)))
,@body))
(defmacro with-pen ((&key position (color nil color-supplied-p) width) &body body)
"Like WITH-CURRENT-PEN-STATE, but lets you set the state of the pen
EXECUTION BODY. After BODY executes, the state is restored to
whatever it was before WITH-PEN-STATE was evaluated."
`(let ((*current-pen-position* ,(if position nil '*current-pen-position*))
(*current-pen-color* ,(if color-supplied-p nil '*current-pen-color*))
(*current-pen-width* ,(if width nil '*current-pen-width*)))
,(when position
`(move-to ,@position))
,(when color-supplied-p
`(canvas-pen-color ,color))
,(when width
`(canvas-pen-width ,width))
(with-current-pen-state
,@body)))
(defmacro with-pen-color (list-or-fn &body body)
"Temporarily bind pen color to the value of LIST-OR-FN and execute BODY."
`(let ((*current-pen-color* nil))
(canvas-pen-color ,list-or-fn)
,@body))
(defmacro with-canvas (canvas &body body)
"Perform drawing commands in BODY using the value of CANVAS as the
target of any drawing operations."
`(let ((*current-canvas* ,canvas)
(*current-pen-width* 1)
(*current-pen-position* (list 0 0))
(*current-pen-color* (list 0 0 0 255)))
(with-current-pen-state
,@body)))
(defun restore-pen ()
"Restore the state of the pan (width position color) as previously
saved by WITH-PEN-STATE"
(destructuring-bind (pw pp pc) *saved-state*
(setf *current-pen-width* pw
*current-pen-position* pp
*current-pen-color* pc)))
(defun colfix (c)
(round (clamp 0 c 255)))
(defun canvas-pen-color (&optional newpen)
"Set the pens color in the current context. NEWPEN, if supplied, can be one of:
NIL - set the color to black.
A list of four unsigned 8 bit integers that looks like (R G B A).
A function (or symbol naming a function) that accepts the
coordinates X Y of the pixel being drawn and returns a list as in
the above case.
All RGBA component values obtained from a pen (either from the
return of a functional pen or as members of a list value) are
clamped between 0 and 255."
(setf *current-pen-color*
(etypecase newpen
(null nil)
((or symbol function)
(lambda (x y)
(mapcar #'colfix (funcall newpen x y))))
(list
(mapcar #'colfix newpen)))))
(defun canvas-pen-width (n)
(setf *current-pen-width* (round n)))
(defun can-fill-canvas-at-p (x y)
(with-slots (pixel-width pixel-height) *current-canvas*
(and (< -1 x pixel-width)
(< -1 y pixel-height))))
(defun rel-to-current-pos (path)
(destructuring-bind (cx cy) *current-pen-position*
(loop for (x y) in path collect (list (+ cx x) (+ cy y)))))
(defun move-to (x y)
(setf *current-pen-position* (list x y)))
(defun move-rel (dx dy)
(setf *current-pen-position*
(mapcar #'+ *current-pen-position* (list dx dy))))
(defun apply-pen-at (x y)
(let ((w
(max 0 (floor (* 0.5 *current-pen-width*)))))
(destructuring-bind
(cr cg cb ca)
(etypecase *current-pen-color*
(null (list 0 0 0 255))
(list *current-pen-color*)
(function (funcall *current-pen-color* x y)))
(with-grid-rect (rx ry) ((- x w) (- y w) (+ x w) (+ y w))
(when (can-fill-canvas-at-p rx ry)
(with-pixel (r g b a) (pixel *current-canvas* rx ry)
(setf r cr g cg b cb a ca)))))))
(defun stroke-to (ex ey)
(destructuring-bind (sx sy) *current-pen-position*
(with-grid-line (x y) (sx sy) (ex ey)
(apply-pen-at x y)))
(setf *current-pen-position* (list ex ey)))
(defun stroke-rel (dx dy)
(apply #'stroke-to (mapcar #'+ *current-pen-position* (list dx dy))))
(defun stroke-path (path)
(with-grid-path (x y) (path) (apply-pen-at x y))
(setf *current-pen-position* (copy-list (first (last path)))))
(defun stroke-rel-path (path)
(stroke-path
(cons *current-pen-position*
(rel-to-current-pos path))))
(defun fill-path (path)
(let ((*current-pen-width* 1))
(with-grid-path (x y) (path :interiorp t)
(apply-pen-at x y))))
(defun fill-rel-path (path)
(fill-path
(cons *current-pen-position*
(rel-to-current-pos path))))
(defun stroke-rect (left bottom right top)
(stroke-path (list (list left bottom)
(list left top)
(list right top)
(list right bottom)
(list left bottom))))
(defun stroke-rel-rect (dx dy)
(destructuring-bind (sx sy) *current-pen-position*
(let ((left
(if (plusp dx) sx (+ sx dx)))
(right
(if (plusp dx) (+ sx dx) sx))
(bottom
(if (plusp dy) sy (+ sy dy)))
(top
(if (plusp dy) (+ sy dy) sy)))
(stroke-rect left bottom right top))))
(defun fill-rect (left bottom right top)
(let ((*current-pen-width* 1))
(with-grid-rect (x y) (left bottom right top)
(apply-pen-at x y)))
(setf *current-pen-position* (list left bottom)))
(defun fill-rel-rect (dx dy)
(destructuring-bind (sx sy) *current-pen-position*
(let ((left
(if (plusp dx) sx (+ sx dx)))
(right
(if (plusp dx) (+ sx dx) sx))
(bottom
(if (plusp dy) sy (+ sy dy)))
(top
(if (plusp dy) (+ sy dy) sy)))
(fill-rect left bottom right top))))
(defun stroke-bezier (control-pts &optional (curve-samples 10))
(let (path)
(with-grid-bezier (x y) (control-pts :count curve-samples)
(push (list x y) path))
(stroke-path (reverse path))))
(defun stroke-rel-bezier (rel-control-points &optional (curve-samples 10))
(stroke-bezier (cons *current-pen-position*
(rel-to-current-pos rel-control-points))
curve-samples))
|
