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Viewport miniature: preserve aspect ratio; draw visible area highlight synchronously.
author Mikhail Kryshen <mikhail@kryshen.net>
date Sun, 28 Nov 2010 03:46:59 +0300
parents 18abc7d66d49
children bf4a46f80851
line source
1 ;;
2 ;; Copyright 2010 Mikhail Kryshen <mikhail@kryshen.net>
3 ;;
4 ;; This file is part of Indyvon.
5 ;;
6 ;; Indyvon is free software: you can redistribute it and/or modify it
7 ;; under the terms of the GNU Lesser General Public License version 3
8 ;; only, as published by the Free Software Foundation.
9 ;;
10 ;; Indyvon is distributed in the hope that it will be useful, but
11 ;; WITHOUT ANY WARRANTY; without even the implied warranty of
12 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 ;; Lesser General Public License for more details.
14 ;;
15 ;; You should have received a copy of the GNU Lesser General Public
16 ;; License along with Indyvon. If not, see
17 ;; <http://www.gnu.org/licenses/>.
18 ;;
19
20 (ns net.kryshen.indyvon.async
21 "Asynchronous drawing."
22 (:use
23 net.kryshen.indyvon.core)
24 (:import
25 (net.kryshen.indyvon.core Size Location)
26 (java.awt Image AlphaComposite)
27 (java.awt.image BufferedImage)
28 (java.util.concurrent ThreadFactory ThreadPoolExecutor
29 ThreadPoolExecutor$DiscardOldestPolicy
30 ArrayBlockingQueue TimeUnit)))
31
32 (defrecord Buffer [id image readers state])
33 ;; Buffer states:
34 ;; :front, readers > 0
35 ;; being copied on screen
36 ;; :back
37 ;; being rendered to (offscreen)
38 ;; :fresh
39 ;; most recently updated
40 ;; :free
41 ;; not in use
42
43 (defn- create-image [async-layer]
44 ;; TODO: support different image types.
45 (BufferedImage. (:width async-layer) (:height async-layer)
46 BufferedImage/TYPE_INT_ARGB_PRE))
47
48 (defn- create-buffer [async-layer]
49 (Buffer. (Object.) (create-image async-layer) 0 :free))
50
51 (defn- find-buffer
52 "Find a buffer with the one of the specified states given
53 in the order of preference."
54 [buffers & states]
55 (some identity
56 (for [state states]
57 (some #(if (= (:state %) state) % nil) buffers))))
58
59 (defn- replace-buffer [buffers buffer]
60 (conj (remove #(= (:id %) (:id buffer)) buffers)
61 buffer))
62
63 (defn- take-buffer [al type]
64 (dosync
65 (let [buffers @(:buffers al)
66 b (case type
67 :front (find-buffer buffers :front :fresh :free)
68 :back (find-buffer buffers :free :fresh)
69 (throw (IllegalArgumentException.)))
70 readers (if (= type :front)
71 (inc (:readers b))
72 (:readers b))
73 b (assoc b
74 :state type
75 :readers readers)]
76 (alter (:buffers al) replace-buffer b)
77 b)))
78
79 (defn- release-buffer [al buffer]
80 (dosync
81 (let [state (:state buffer)
82 readers (if (= state :front)
83 (dec (:readers buffer))
84 (:readers buffer))
85 fresh (delay (find-buffer @(:buffers al) :fresh))
86 state (cond
87 (pos? readers) :front
88 (= :back state) :fresh
89 @fresh :free
90 :default :fresh)]
91 (if (and (= state :fresh) @fresh)
92 ;; Change state of the prefiously fresh buffer to :free.
93 (alter (:buffers al)
94 replace-buffer (assoc @fresh
95 :state :free)))
96 (alter (:buffers al)
97 replace-buffer (assoc buffer
98 :state state
99 :readers readers)))))
100
101 (defmacro with-buffer
102 {:private true}
103 [al type [name] & body]
104 `(let [al# ~al
105 ~name (take-buffer al# ~type)]
106 (try
107 ~@body
108 (finally
109 (release-buffer al# ~name)))))
110
111 (defn- draw-offscreen [async-layer]
112 ;;(Thread/sleep 1000)
113 (with-buffer async-layer :back [b]
114 (let [g (.getGraphics ^Image (:image b))]
115 ;; Clear the buffer.
116 (.setComposite g AlphaComposite/Clear)
117 (.fillRect g 0 0 (:width async-layer) (:height async-layer))
118 (.setComposite g AlphaComposite/Src)
119 (draw-root! (:content async-layer)
120 g
121 (:width async-layer)
122 (:height async-layer)
123 ;; TODO: use operational event dispatcher.
124 dummy-event-dispatcher))
125 (update async-layer)))
126
127 (defn- draw-offscreen-async [async-layer]
128 (.execute ^ThreadPoolExecutor (:executor async-layer)
129 #(draw-offscreen async-layer)))
130
131 (defrecord AsyncLayer [content width height executor buffers]
132 Layer
133 (render! [layer]
134 (repaint-on-update layer)
135 (add-context-observer content (fn [_ _] (draw-offscreen-async layer)))
136 (when-not @buffers
137 ;; TODO: dynamic size, recreate buffers when size increases.
138 (let [new-buffers (repeatedly 2 (partial create-buffer layer))]
139 (dosync
140 (ref-set buffers new-buffers)))
141 (draw-offscreen-async layer))
142 (with-buffer layer :front [b]
143 (.drawImage *graphics* ^Image (:image b) 0 0 nil)))
144 (layer-size [layer]
145 (Size. width height)))
146
147 (defn- create-thread-factory [priority]
148 (reify
149 ThreadFactory
150 (newThread [_ runnable]
151 (let [thread (Thread. runnable)]
152 (when priority
153 (.setPriority thread priority))
154 (.setDaemon thread true)
155 thread))))
156
157 (defn- create-executor [priority]
158 (doto (ThreadPoolExecutor.
159 (int 1) (int 1)
160 (long 0) TimeUnit/SECONDS
161 (ArrayBlockingQueue. 1)
162 (ThreadPoolExecutor$DiscardOldestPolicy.))
163 (.setThreadFactory (create-thread-factory priority))))
164
165 (defn async-layer
166 "Creates layer that draws the content asynchronously using
167 offscreen buffer."
168 ([content width height]
169 (async-layer content width height nil))
170 ([content width height priority]
171 (AsyncLayer. content width height
172 (create-executor priority)
173 (ref nil))))