CaretDrawable.java revision c06af333cbcebb183d13d004cccf5c9d69a70af0 
1/*
2 * Copyright (C) 2016 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 */
16package com.android.launcher3.pageindicators;
17
18import android.content.Context;
19import android.content.res.Resources;
20import android.graphics.Canvas;
21import android.graphics.ColorFilter;
22import android.graphics.Paint;
23import android.graphics.Path;
24import android.graphics.PixelFormat;
25import android.graphics.drawable.Drawable;
26
27import com.android.launcher3.R;
28import com.android.launcher3.util.Themes;
29
30public class CaretDrawable extends Drawable {
31    public static final float PROGRESS_CARET_POINTING_UP = -1f;
32    public static final float PROGRESS_CARET_POINTING_DOWN = 1f;
33    public static final float PROGRESS_CARET_NEUTRAL = 0;
34
35    private float mCaretProgress = PROGRESS_CARET_NEUTRAL;
36
37    private Paint mShadowPaint = new Paint();
38    private Paint mCaretPaint = new Paint();
39    private Path mPath = new Path();
40    private final int mCaretSizePx;
41
42    public CaretDrawable(Context context) {
43        final Resources res = context.getResources();
44
45        final int strokeWidth = res.getDimensionPixelSize(R.dimen.all_apps_caret_stroke_width);
46        final int shadowSpread = res.getDimensionPixelSize(R.dimen.all_apps_caret_shadow_spread);
47
48        mCaretPaint.setColor(Themes.getAttrColor(context, android.R.attr.textColorPrimary));
49        mCaretPaint.setAntiAlias(true);
50        mCaretPaint.setStrokeWidth(strokeWidth);
51        mCaretPaint.setStyle(Paint.Style.STROKE);
52        mCaretPaint.setStrokeCap(Paint.Cap.SQUARE);
53        mCaretPaint.setStrokeJoin(Paint.Join.MITER);
54
55        mShadowPaint.setColor(res.getColor(R.color.default_shadow_color_no_alpha));
56        mShadowPaint.setAlpha(Themes.getAlpha(context, android.R.attr.spotShadowAlpha));
57        mShadowPaint.setAntiAlias(true);
58        mShadowPaint.setStrokeWidth(strokeWidth + (shadowSpread * 2));
59        mShadowPaint.setStyle(Paint.Style.STROKE);
60        mShadowPaint.setStrokeCap(Paint.Cap.ROUND);
61        mShadowPaint.setStrokeJoin(Paint.Join.ROUND);
62
63        mCaretSizePx = res.getDimensionPixelSize(R.dimen.all_apps_caret_size);
64    }
65
66    @Override
67    public int getIntrinsicHeight() {
68        return mCaretSizePx;
69    }
70
71    @Override
72    public int getIntrinsicWidth() {
73        return mCaretSizePx;
74    }
75
76    @Override
77    public void draw(Canvas canvas) {
78        // Assumes caret paint is more important than shadow paint
79        if (Float.compare(mCaretPaint.getAlpha(), 0f) == 0) {
80            return;
81        }
82
83        // Assumes shadow stroke width is larger
84        final float width = getBounds().width() - mShadowPaint.getStrokeWidth();
85        final float height = getBounds().height() - mShadowPaint.getStrokeWidth();
86        final float left = getBounds().left + (mShadowPaint.getStrokeWidth() / 2);
87        final float top = getBounds().top + (mShadowPaint.getStrokeWidth() / 2);
88
89        // When the bounds are square, this will result in a caret with a right angle
90        final float verticalInset = (height / 4);
91        final float caretHeight = (height - (verticalInset * 2));
92
93        mPath.reset();
94        mPath.moveTo(left, top + caretHeight * (1 - getNormalizedCaretProgress()));
95        mPath.lineTo(left + (width / 2), top + caretHeight * getNormalizedCaretProgress());
96        mPath.lineTo(left + width, top + caretHeight * (1 - getNormalizedCaretProgress()));
97
98        canvas.drawPath(mPath, mShadowPaint);
99        canvas.drawPath(mPath, mCaretPaint);
100    }
101
102    /**
103     * Sets the caret progress
104     *
105     * @param progress The progress ({@value #PROGRESS_CARET_POINTING_UP} for pointing up,
106     * {@value #PROGRESS_CARET_POINTING_DOWN} for pointing down, {@value #PROGRESS_CARET_NEUTRAL}
107     * for neutral)
108     */
109    public void setCaretProgress(float progress) {
110        mCaretProgress = progress;
111        invalidateSelf();
112    }
113
114    /**
115     * Returns the caret progress
116     *
117     * @return The progress
118     */
119    public float getCaretProgress() {
120        return mCaretProgress;
121    }
122
123    /**
124     * Returns the caret progress normalized to [0..1]
125     *
126     * @return The normalized progress
127     */
128    public float getNormalizedCaretProgress() {
129        return (mCaretProgress - PROGRESS_CARET_POINTING_UP) /
130                (PROGRESS_CARET_POINTING_DOWN - PROGRESS_CARET_POINTING_UP);
131    }
132
133    @Override
134    public int getOpacity() {
135        return PixelFormat.TRANSLUCENT;
136    }
137
138    @Override
139    public void setAlpha(int alpha) {
140        mCaretPaint.setAlpha(alpha);
141        mShadowPaint.setAlpha(alpha);
142        invalidateSelf();
143    }
144
145    @Override
146    public void setColorFilter(ColorFilter cf) {
147        // no-op
148    }
149}
150