CaretDrawable.java revision 9b29ca5add472b6bdebfa7936142b3aad6cbe3c5 
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;
27import com.android.launcher3.util.Themes;
28
29import android.graphics.drawable.Drawable;
30
31public class CaretDrawable extends Drawable {
32    public static final float PROGRESS_CARET_POINTING_UP = -1f;
33    public static final float PROGRESS_CARET_POINTING_DOWN = 1f;
34    public static final float PROGRESS_CARET_NEUTRAL = 0;
35
36    private float mCaretProgress = PROGRESS_CARET_NEUTRAL;
37
38    private Paint mShadowPaint = new Paint();
39    private Paint mCaretPaint = new Paint();
40    private Path mPath = new Path();
41    private final int mCaretSizePx;
42
43    public CaretDrawable(Context context) {
44        final Resources res = context.getResources();
45
46        final int strokeWidth = res.getDimensionPixelSize(R.dimen.all_apps_caret_stroke_width);
47        final int shadowSpread = res.getDimensionPixelSize(R.dimen.all_apps_caret_shadow_spread);
48
49        mCaretPaint.setColor(Themes.getAttrColor(context, android.R.attr.textColorPrimary));
50        mCaretPaint.setAntiAlias(true);
51        mCaretPaint.setStrokeWidth(strokeWidth);
52        mCaretPaint.setStyle(Paint.Style.STROKE);
53        mCaretPaint.setStrokeCap(Paint.Cap.SQUARE);
54        mCaretPaint.setStrokeJoin(Paint.Join.MITER);
55
56        mShadowPaint.setColor(res.getColor(R.color.default_shadow_color_no_alpha));
57        mShadowPaint.setAlpha(Themes.getAlpha(context, android.R.attr.spotShadowAlpha));
58        mShadowPaint.setAntiAlias(true);
59        mShadowPaint.setStrokeWidth(strokeWidth + (shadowSpread * 2));
60        mShadowPaint.setStyle(Paint.Style.STROKE);
61        mShadowPaint.setStrokeCap(Paint.Cap.ROUND);
62        mShadowPaint.setStrokeJoin(Paint.Join.ROUND);
63
64        mCaretSizePx = res.getDimensionPixelSize(R.dimen.all_apps_caret_size);
65    }
66
67    @Override
68    public int getIntrinsicHeight() {
69        return mCaretSizePx;
70    }
71
72    @Override
73    public int getIntrinsicWidth() {
74        return mCaretSizePx;
75    }
76
77    @Override
78    public void draw(Canvas canvas) {
79        // Assumes caret paint is more important than shadow paint
80        if (Float.compare(mCaretPaint.getAlpha(), 0f) == 0) {
81            return;
82        }
83
84        // Assumes shadow stroke width is larger
85        final float width = getBounds().width() - mShadowPaint.getStrokeWidth();
86        final float height = getBounds().height() - mShadowPaint.getStrokeWidth();
87        final float left = getBounds().left + (mShadowPaint.getStrokeWidth() / 2);
88        final float top = getBounds().top + (mShadowPaint.getStrokeWidth() / 2);
89
90        // When the bounds are square, this will result in a caret with a right angle
91        final float verticalInset = (height / 4);
92        final float caretHeight = (height - (verticalInset * 2));
93
94        mPath.reset();
95        mPath.moveTo(left, top + caretHeight * (1 - getNormalizedCaretProgress()));
96        mPath.lineTo(left + (width / 2), top + caretHeight * getNormalizedCaretProgress());
97        mPath.lineTo(left + width, top + caretHeight * (1 - getNormalizedCaretProgress()));
98
99        canvas.drawPath(mPath, mShadowPaint);
100        canvas.drawPath(mPath, mCaretPaint);
101    }
102
103    /**
104     * Sets the caret progress
105     *
106     * @param progress The progress ({@value #PROGRESS_CARET_POINTING_UP} for pointing up,
107     * {@value #PROGRESS_CARET_POINTING_DOWN} for pointing down, {@value #PROGRESS_CARET_NEUTRAL}
108     * for neutral)
109     */
110    public void setCaretProgress(float progress) {
111        mCaretProgress = progress;
112        invalidateSelf();
113    }
114
115    /**
116     * Returns the caret progress
117     *
118     * @return The progress
119     */
120    public float getCaretProgress() {
121        return mCaretProgress;
122    }
123
124    /**
125     * Returns the caret progress normalized to [0..1]
126     *
127     * @return The normalized progress
128     */
129    public float getNormalizedCaretProgress() {
130        return (mCaretProgress - PROGRESS_CARET_POINTING_UP) /
131                (PROGRESS_CARET_POINTING_DOWN - PROGRESS_CARET_POINTING_UP);
132    }
133
134    @Override
135    public int getOpacity() {
136        return PixelFormat.TRANSLUCENT;
137    }
138
139    @Override
140    public void setAlpha(int alpha) {
141        mCaretPaint.setAlpha(alpha);
142        mShadowPaint.setAlpha(alpha);
143        invalidateSelf();
144    }
145
146    @Override
147    public void setColorFilter(ColorFilter cf) {
148        // no-op
149    }
150}
151