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.layout;
17
18import static com.android.SdkConstants.ANDROID_URI;
19import static com.android.SdkConstants.ATTR_LAYOUT_GRAVITY;
20import static com.android.SdkConstants.GRAVITY_VALUE_BOTTOM;
21import static com.android.SdkConstants.GRAVITY_VALUE_CENTER;
22import static com.android.SdkConstants.GRAVITY_VALUE_CENTER_HORIZONTAL;
23import static com.android.SdkConstants.GRAVITY_VALUE_CENTER_VERTICAL;
24import static com.android.SdkConstants.GRAVITY_VALUE_FILL;
25import static com.android.SdkConstants.GRAVITY_VALUE_FILL_HORIZONTAL;
26import static com.android.SdkConstants.GRAVITY_VALUE_FILL_VERTICAL;
27import static com.android.SdkConstants.GRAVITY_VALUE_LEFT;
28import static com.android.SdkConstants.GRAVITY_VALUE_RIGHT;
29import static com.android.SdkConstants.GRAVITY_VALUE_TOP;
30
31import org.w3c.dom.Element;
32
33/** Helper class for looking up the gravity masks of gravity attributes */
34public class GravityHelper {
35    // From SDK constants; temporary
36    public static final String GRAVITY_VALUE_START = "start";                         //$NON-NLS-1$
37    public static final String GRAVITY_VALUE_END = "end";                             //$NON-NLS-1$
38
39    /** Bitmask for a gravity which includes left */
40    @SuppressWarnings("PointlessBitwiseExpression") // for symmetry with other fields
41    public static final int GRAVITY_LEFT         = 1 << 0;
42
43    /** Bitmask for a gravity which includes right */
44    public static final int GRAVITY_RIGHT        = 1 << 1;
45
46    /** Bitmask for a gravity which includes center horizontal */
47    public static final int GRAVITY_CENTER_HORIZ = 1 << 2;
48
49    /** Bitmask for a gravity which includes fill horizontal */
50    public static final int GRAVITY_FILL_HORIZ   = 1 << 3;
51
52    /** Bitmask for a gravity which includes center vertical */
53    public static final int GRAVITY_CENTER_VERT  = 1 << 4;
54
55    /** Bitmask for a gravity which includes fill vertical */
56    public static final int GRAVITY_FILL_VERT    = 1 << 5;
57
58    /** Bitmask for a gravity which includes top */
59    public static final int GRAVITY_TOP          = 1 << 6;
60
61    /** Bitmask for a gravity which includes bottom */
62    public static final int GRAVITY_BOTTOM       = 1 << 7;
63
64    /** Bitmask for a gravity which includes start */
65    public static final int GRAVITY_START        = 1 << 8;
66
67    /** Bitmask for a gravity which includes end */
68    public static final int GRAVITY_END          = 1 << 9;
69
70    /** Bitmask for a gravity which includes any horizontal constraint */
71    public static final int GRAVITY_HORIZ_MASK = GRAVITY_CENTER_HORIZ | GRAVITY_FILL_HORIZ
72            | GRAVITY_LEFT | GRAVITY_RIGHT | GRAVITY_START | GRAVITY_END;
73
74    /** Bitmask for a gravity which any vertical constraint */
75    public static final int GRAVITY_VERT_MASK = GRAVITY_CENTER_VERT | GRAVITY_FILL_VERT
76            | GRAVITY_TOP | GRAVITY_BOTTOM;
77
78    /**
79     * Returns the gravity of the given element
80     *
81     * @param element the element to look up the gravity for
82     * @return a bit mask corresponding to the selected gravities
83     */
84    public static int getGravity(Element element) {
85        String gravityString = element.getAttributeNS(ANDROID_URI, ATTR_LAYOUT_GRAVITY);
86        return getGravity(gravityString, GRAVITY_LEFT | GRAVITY_TOP);
87    }
88
89    /**
90     * Returns the gravity bitmask for the given gravity string description
91     *
92     * @param gravityString the gravity string description
93     * @param defaultMask the default/initial bitmask to start with
94     * @return a bitmask corresponding to the gravity description
95     */
96    public static int getGravity(String gravityString, int defaultMask) {
97        int gravity = defaultMask;
98        if (gravityString != null && !gravityString.isEmpty()) {
99            String[] anchors = gravityString.split("\\|"); //$NON-NLS-1$
100            for (String anchor : anchors) {
101                if (GRAVITY_VALUE_CENTER.equals(anchor)) {
102                    gravity = GRAVITY_CENTER_HORIZ | GRAVITY_CENTER_VERT;
103                } else if (GRAVITY_VALUE_FILL.equals(anchor)) {
104                    gravity = GRAVITY_FILL_HORIZ | GRAVITY_FILL_VERT;
105                } else if (GRAVITY_VALUE_CENTER_VERTICAL.equals(anchor)) {
106                    gravity = (gravity & GRAVITY_HORIZ_MASK) | GRAVITY_CENTER_VERT;
107                } else if (GRAVITY_VALUE_CENTER_HORIZONTAL.equals(anchor)) {
108                    gravity = (gravity & GRAVITY_VERT_MASK) | GRAVITY_CENTER_HORIZ;
109                } else if (GRAVITY_VALUE_FILL_VERTICAL.equals(anchor)) {
110                    gravity = (gravity & GRAVITY_HORIZ_MASK) | GRAVITY_FILL_VERT;
111                } else if (GRAVITY_VALUE_FILL_HORIZONTAL.equals(anchor)) {
112                    gravity = (gravity & GRAVITY_VERT_MASK) | GRAVITY_FILL_HORIZ;
113                } else if (GRAVITY_VALUE_TOP.equals(anchor)) {
114                    gravity = (gravity & GRAVITY_HORIZ_MASK) | GRAVITY_TOP;
115                } else if (GRAVITY_VALUE_BOTTOM.equals(anchor)) {
116                    gravity = (gravity & GRAVITY_HORIZ_MASK) | GRAVITY_BOTTOM;
117                } else if (GRAVITY_VALUE_LEFT.equals(anchor)) {
118                    gravity = (gravity & (GRAVITY_VERT_MASK|GRAVITY_START)) | GRAVITY_LEFT;
119                } else if (GRAVITY_VALUE_RIGHT.equals(anchor)) {
120                    gravity = (gravity & (GRAVITY_VERT_MASK|GRAVITY_END)) | GRAVITY_RIGHT;
121                } else if (GRAVITY_VALUE_START.equals(anchor)) {
122                    gravity = (gravity & (GRAVITY_VERT_MASK|GRAVITY_LEFT)) | GRAVITY_START;
123                } else if (GRAVITY_VALUE_END.equals(anchor)) {
124                    gravity = (gravity & (GRAVITY_VERT_MASK|GRAVITY_RIGHT)) | GRAVITY_END;
125                } // else: "clip" not supported
126            }
127        }
128
129        return gravity;
130    }
131
132    /**
133     * Returns true if the given gravity bitmask is constrained horizontally
134     *
135     * @param gravity the gravity bitmask
136     * @return true if the given gravity bitmask is constrained horizontally
137     */
138    public static boolean isConstrainedHorizontally(int gravity) {
139        return (gravity & GRAVITY_HORIZ_MASK) != 0;
140    }
141
142    /**
143     * Returns true if the given gravity bitmask is constrained vertically
144     *
145     * @param gravity the gravity bitmask
146     * @return true if the given gravity bitmask is constrained vertically
147     */
148    public static boolean isConstrainedVertically(int gravity) {
149        return (gravity & GRAVITY_VERT_MASK) != 0;
150    }
151
152    /**
153     * Returns true if the given gravity bitmask is left aligned
154     *
155     * @param gravity the gravity bitmask
156     * @return true if the given gravity bitmask is left aligned
157     */
158    public static boolean isLeftAligned(int gravity) {
159        return (gravity & (GRAVITY_LEFT|GRAVITY_START)) != 0;
160    }
161
162    /**
163     * Returns true if the given gravity bitmask is top aligned
164     *
165     * @param gravity the gravity bitmask
166     * @return true if the given gravity bitmask is aligned
167     */
168    public static boolean isTopAligned(int gravity) {
169        return (gravity & GRAVITY_TOP) != 0;
170    }
171
172    /** Returns a gravity value string from the given gravity bitmask
173     *
174     * @param gravity the gravity bitmask
175     * @return the corresponding gravity string suitable as an XML attribute value
176     */
177    public static String getGravity(int gravity) {
178        if (gravity == 0) {
179            return "";
180        }
181
182        if ((gravity & (GRAVITY_CENTER_HORIZ | GRAVITY_CENTER_VERT)) ==
183                (GRAVITY_CENTER_HORIZ | GRAVITY_CENTER_VERT)) {
184            return GRAVITY_VALUE_CENTER;
185        }
186
187        StringBuilder sb = new StringBuilder(30);
188        int horizontal = gravity & GRAVITY_HORIZ_MASK;
189        int vertical = gravity & GRAVITY_VERT_MASK;
190
191        if ((horizontal & (GRAVITY_LEFT|GRAVITY_START)) != 0) {
192            if ((horizontal & GRAVITY_LEFT) != 0) {
193                sb.append(GRAVITY_VALUE_LEFT);
194            }
195            if ((horizontal & GRAVITY_START) != 0) {
196                if (sb.length() > 0) {
197                    sb.append('|');
198                }
199                sb.append(GRAVITY_VALUE_START);
200            }
201        } else if ((horizontal & (GRAVITY_RIGHT|GRAVITY_END)) != 0) {
202            if ((horizontal & GRAVITY_RIGHT) != 0) {
203                sb.append(GRAVITY_VALUE_RIGHT);
204            }
205            if ((horizontal & GRAVITY_END) != 0) {
206                if (sb.length() > 0) {
207                    sb.append('|');
208                }
209                sb.append(GRAVITY_VALUE_END);
210            }
211        } else if ((horizontal & GRAVITY_CENTER_HORIZ) != 0) {
212            sb.append(GRAVITY_VALUE_CENTER_HORIZONTAL);
213        } else if ((horizontal & GRAVITY_FILL_HORIZ) != 0) {
214            sb.append(GRAVITY_VALUE_FILL_HORIZONTAL);
215        }
216
217        if (sb.length() > 0 && vertical != 0) {
218            sb.append('|');
219        }
220
221        if ((vertical & GRAVITY_TOP) != 0) {
222            sb.append(GRAVITY_VALUE_TOP);
223        } else if ((vertical & GRAVITY_BOTTOM) != 0) {
224            sb.append(GRAVITY_VALUE_BOTTOM);
225        } else if ((vertical & GRAVITY_CENTER_VERT) != 0) {
226            sb.append(GRAVITY_VALUE_CENTER_VERTICAL);
227        } else if ((vertical & GRAVITY_FILL_VERT) != 0) {
228            sb.append(GRAVITY_VALUE_FILL_VERTICAL);
229        }
230
231        return sb.toString();
232    }
233}
234