CaretDrawable.java revision 016eaeea99e163f0b5385cf660297e6c21ff21e5 
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;
25
26import com.android.launcher3.R;
27
28import android.graphics.drawable.Drawable;
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(res.getColor(R.color.all_apps_caret_color));
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.all_apps_caret_shadow_color));
56        mShadowPaint.setAntiAlias(true);
57        mShadowPaint.setStrokeWidth(strokeWidth + (shadowSpread * 2));
58        mShadowPaint.setStyle(Paint.Style.STROKE);
59        mShadowPaint.setStrokeCap(Paint.Cap.ROUND);
60        mShadowPaint.setStrokeJoin(Paint.Join.ROUND);
61
62        mCaretSizePx = res.getDimensionPixelSize(R.dimen.all_apps_caret_size);
63    }
64
65    @Override
66    public int getIntrinsicHeight() {
67        return mCaretSizePx;
68    }
69
70    @Override
71    public int getIntrinsicWidth() {
72        return mCaretSizePx;
73    }
74
75    @Override
76    public void draw(Canvas canvas) {
77        // Assumes caret paint is more important than shadow paint
78        if (Float.compare(mCaretPaint.getAlpha(), 0f) == 0) {
79            return;
80        }
81
82        // Assumes shadow stroke width is larger
83        final float width = getBounds().width() - mShadowPaint.getStrokeWidth();
84        final float height = getBounds().height() - mShadowPaint.getStrokeWidth();
85        final float left = getBounds().left + (mShadowPaint.getStrokeWidth() / 2);
86        final float top = getBounds().top + (mShadowPaint.getStrokeWidth() / 2);
87
88        // When the bounds are square, this will result in a caret with a right angle
89        final float verticalInset = (height / 4);
90        final float caretHeight = (height - (verticalInset * 2));
91
92        mPath.reset();
93        mPath.moveTo(left, top + caretHeight * (1 - getNormalizedCaretProgress()));
94        mPath.lineTo(left + (width / 2), top + caretHeight * getNormalizedCaretProgress());
95        mPath.lineTo(left + width, top + caretHeight * (1 - getNormalizedCaretProgress()));
96
97        canvas.drawPath(mPath, mShadowPaint);
98        canvas.drawPath(mPath, mCaretPaint);
99    }
100
101    /**
102     * Sets the caret progress
103     *
104     * @param progress The progress ({@value #PROGRESS_CARET_POINTING_UP} for pointing up,
105     * {@value #PROGRESS_CARET_POINTING_DOWN} for pointing down, {@value #PROGRESS_CARET_NEUTRAL}
106     * for neutral)
107     */
108    public void setCaretProgress(float progress) {
109        mCaretProgress = progress;
110        invalidateSelf();
111    }
112
113    /**
114     * Returns the caret progress
115     *
116     * @return The progress
117     */
118    public float getCaretProgress() {
119        return mCaretProgress;
120    }
121
122    /**
123     * Returns the caret progress normalized to [0..1]
124     *
125     * @return The normalized progress
126     */
127    public float getNormalizedCaretProgress() {
128        return (mCaretProgress - PROGRESS_CARET_POINTING_UP) /
129                (PROGRESS_CARET_POINTING_DOWN - PROGRESS_CARET_POINTING_UP);
130    }
131
132    @Override
133    public int getOpacity() {
134        return PixelFormat.TRANSLUCENT;
135    }
136
137    @Override
138    public void setAlpha(int alpha) {
139        mCaretPaint.setAlpha(alpha);
140        mShadowPaint.setAlpha(alpha);
141        invalidateSelf();
142    }
143
144    @Override
145    public void setColorFilter(ColorFilter cf) {
146        // no-op
147    }
148}
149