ResizePolicy.java revision 5d7dc30638953195ed55d32bc9dc37102a613ff8 
1/*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Eclipse Public License, Version 1.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.eclipse.org/org/documents/epl-v10.php
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16package com.android.ide.common.api;
17
18import com.android.annotations.NonNull;
19import com.google.common.annotations.Beta;
20
21/**
22 * A {@link ResizePolicy} records state for whether a widget is resizable, and if so, in
23 * which directions
24 * <p>
25 * <b>NOTE: This is not a public or final API; if you rely on this be prepared
26 * to adjust your code for the next tools release.</b>
27 */
28@Beta
29public class ResizePolicy {
30    private static final int NONE = 0;
31    private static final int LEFT_EDGE = 1;
32    private static final int RIGHT_EDGE = 2;
33    private static final int TOP_EDGE = 4;
34    private static final int BOTTOM_EDGE = 8;
35    private static final int PRESERVE_RATIO = 16;
36
37    // Aliases
38    private static final int HORIZONTAL = LEFT_EDGE | RIGHT_EDGE;
39    private static final int VERTICAL = TOP_EDGE | BOTTOM_EDGE;
40    private static final int ANY = HORIZONTAL | VERTICAL;
41
42    // Shared objects for common policies
43
44    private static final ResizePolicy sAny = new ResizePolicy(ANY);
45    private static final ResizePolicy sNone = new ResizePolicy(NONE);
46    private static final ResizePolicy sHorizontal = new ResizePolicy(HORIZONTAL);
47    private static final ResizePolicy sVertical = new ResizePolicy(VERTICAL);
48    private static final ResizePolicy sScaled = new ResizePolicy(ANY | PRESERVE_RATIO);
49
50    private final int mFlags;
51
52
53    // Use factory methods to construct
54    private ResizePolicy(int flags) {
55        mFlags = flags;
56    }
57
58    /**
59     * Returns true if this policy allows resizing in at least one direction
60     *
61     * @return true if this policy allows resizing in at least one direction
62     */
63    public boolean isResizable() {
64        return (mFlags & ANY) != 0;
65    }
66
67    /**
68     * Returns true if this policy allows resizing the top edge
69     *
70     * @return true if this policy allows resizing the top edge
71     */
72    public boolean topAllowed() {
73        return (mFlags & TOP_EDGE) != 0;
74    }
75
76    /**
77     * Returns true if this policy allows resizing the right edge
78     *
79     * @return true if this policy allows resizing the right edge
80     */
81    public boolean rightAllowed() {
82        return (mFlags & RIGHT_EDGE) != 0;
83    }
84
85    /**
86     * Returns true if this policy allows resizing the bottom edge
87     *
88     * @return true if this policy allows resizing the bottom edge
89     */
90    public boolean bottomAllowed() {
91        return (mFlags & BOTTOM_EDGE) != 0;
92    }
93
94    /**
95     * Returns true if this policy allows resizing the left edge
96     *
97     * @return true if this policy allows resizing the left edge
98     */
99    public boolean leftAllowed() {
100        return (mFlags & LEFT_EDGE) != 0;
101    }
102
103    /**
104     * Returns true if this policy requires resizing in an aspect-ratio preserving manner
105     *
106     * @return true if this policy requires resizing in an aspect-ratio preserving manner
107     */
108    public boolean isAspectPreserving() {
109        return (mFlags & PRESERVE_RATIO) != 0;
110    }
111
112    /**
113     * Returns a resize policy allowing resizing in any direction
114     *
115     * @return a resize policy allowing resizing in any direction
116     */
117    @NonNull
118    public static ResizePolicy full() {
119        return sAny;
120    }
121
122    /**
123     * Returns a resize policy not allowing any resizing
124     *
125     * @return a policy which does not allow any resizing
126     */
127    @NonNull
128    public static ResizePolicy none() {
129        return sNone;
130    }
131
132    /**
133     * Returns a resize policy allowing horizontal resizing only
134     *
135     * @return a policy which allows horizontal resizing only
136     */
137    @NonNull
138    public static ResizePolicy horizontal() {
139        return sHorizontal;
140    }
141
142    /**
143     * Returns a resize policy allowing vertical resizing only
144     *
145     * @return a policy which allows vertical resizing only
146     */
147    @NonNull
148    public static ResizePolicy vertical() {
149        return sVertical;
150    }
151
152    /**
153     * Returns a resize policy allowing scaled / aspect-ratio preserving resizing only
154     *
155     * @return a resize policy allowing scaled / aspect-ratio preserving resizing only
156     */
157    @NonNull
158    public static ResizePolicy scaled() {
159        return sScaled;
160    }
161
162    /**
163     * Returns a resize policy with the specified resizability along the edges and the
164     * given aspect ratio behavior
165     * @param top whether the top edge is resizable
166     * @param right whether the right edge is resizable
167     * @param bottom whether the bottom edge is resizable
168     * @param left whether the left edge is resizable
169     * @param preserve whether the policy requires the aspect ratio to be preserved
170     * @return a resize policy recording the constraints required by the parameters
171     */
172    @NonNull
173    public static ResizePolicy create(boolean top, boolean right, boolean bottom, boolean left,
174            boolean preserve) {
175        int mask = NONE;
176        if (top) mask |= TOP_EDGE;
177        if (right) mask |= RIGHT_EDGE;
178        if (bottom) mask |= BOTTOM_EDGE;
179        if (left) mask |= LEFT_EDGE;
180        if (preserve) mask |= PRESERVE_RATIO;
181
182        return new ResizePolicy(mask);
183    }
184}
185