1/*
2 * Copyright (C) 2012 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
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 */
16
17package com.android.inputmethod.keyboard.internal;
18
19import android.graphics.Canvas;
20import android.view.View;
21
22import com.android.inputmethod.keyboard.MainKeyboardView;
23import com.android.inputmethod.keyboard.PointerTracker;
24
25import javax.annotation.Nonnull;
26
27/**
28 * Abstract base class for previews that are drawn on DrawingPreviewPlacerView, e.g.,
29 * GestureFloatingTextDrawingPreview, GestureTrailsDrawingPreview, and
30 * SlidingKeyInputDrawingPreview.
31 */
32public abstract class AbstractDrawingPreview {
33    private View mDrawingView;
34    private boolean mPreviewEnabled;
35    private boolean mHasValidGeometry;
36
37    public void setDrawingView(@Nonnull final DrawingPreviewPlacerView drawingView) {
38        mDrawingView = drawingView;
39        drawingView.addPreview(this);
40    }
41
42    protected void invalidateDrawingView() {
43        if (mDrawingView != null) {
44            mDrawingView.invalidate();
45        }
46    }
47
48    protected final boolean isPreviewEnabled() {
49        return mPreviewEnabled && mHasValidGeometry;
50    }
51
52    public final void setPreviewEnabled(final boolean enabled) {
53        mPreviewEnabled = enabled;
54    }
55
56    /**
57     * Set {@link MainKeyboardView} geometry and position in the window of input method.
58     * The class that is overriding this method must call this super implementation.
59     *
60     * @param originCoords the top-left coordinates of the {@link MainKeyboardView} in
61     *        the input method window coordinate-system. This is unused but has a point in an
62     *        extended class, such as {@link GestureTrailsDrawingPreview}.
63     * @param width the width of {@link MainKeyboardView}.
64     * @param height the height of {@link MainKeyboardView}.
65     */
66    public void setKeyboardViewGeometry(@Nonnull final int[] originCoords, final int width,
67            final int height) {
68        mHasValidGeometry = (width > 0 && height > 0);
69    }
70
71    public abstract void onDeallocateMemory();
72
73    /**
74     * Draws the preview
75     * @param canvas The canvas where the preview is drawn.
76     */
77    public abstract void drawPreview(@Nonnull final Canvas canvas);
78
79    /**
80     * Set the position of the preview.
81     * @param tracker The new location of the preview is based on the points in PointerTracker.
82     */
83    public abstract void setPreviewPosition(@Nonnull final PointerTracker tracker);
84}
85