ZoomRenderer.java revision 4d628bcbaf4e6f2330dc9619f2129770863666dc 
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.camera.ui;
18
19import android.content.Context;
20import android.content.res.Resources;
21import android.graphics.Canvas;
22import android.graphics.Color;
23import android.graphics.Paint;
24import android.util.Log;
25import android.view.MotionEvent;
26import android.view.ScaleGestureDetector;
27
28import com.android.camera.R;
29
30public class ZoomRenderer extends OverlayRenderer
31        implements ScaleGestureDetector.OnScaleGestureListener {
32
33    private static final String TAG = "CAM_Zoom";
34
35    private int mMaxZoom;
36    private int mZoom;
37    private OnZoomChangedListener mListener;
38
39    private ScaleGestureDetector mDetector;
40    private Paint mPaint;
41    private int mCircleSize;
42    private int mCenterX;
43    private int mCenterY;
44    private boolean mScaling;
45    private float mMaxCircle;
46    private float mMinCircle;
47    private float mScale = 1f;
48    private float mMinScale = 1f;
49    private float mMaxScale = 3f;
50
51    public interface OnZoomChangedListener {
52        void onZoomStart();
53        void onZoomEnd();
54        void onZoomValueChanged(int index);  // only for immediate zoom
55    }
56
57    public ZoomRenderer(Context ctx) {
58        Resources res = ctx.getResources();
59        mPaint = new Paint();
60        mPaint.setAntiAlias(true);
61        mPaint.setColor(Color.WHITE);
62        mPaint.setStyle(Paint.Style.STROKE);
63        mPaint.setStrokeWidth(res.getDimensionPixelSize(R.dimen.focus_outer_stroke));
64        mDetector = new ScaleGestureDetector(ctx, this);
65        mMinCircle = res.getDimensionPixelSize(R.dimen.zoom_ring_min);
66    }
67
68    // set from module
69    public void setZoomMax(int zoomMax) {
70        mMaxZoom = zoomMax;
71    }
72
73    // set from module
74    public void setZoomIndex(int index) {
75        mScale = (mMaxScale - mMinScale) * index / mMaxZoom + mMinScale;
76        mZoom = index;
77    }
78
79    public void setOnZoomChangeListener(OnZoomChangedListener listener) {
80        mListener = listener;
81    }
82
83    @Override
84    public void layout(int l, int t, int r, int b) {
85        super.layout(l, t, r, b);
86        mCenterX = (r - l) / 2;
87        mCenterY = (b - t) / 2;
88        mMaxCircle = Math.min(getWidth(), getHeight());
89        mMaxCircle = (mMaxCircle - mMinCircle) / 2;
90    }
91
92    public boolean isScaling() {
93        return mDetector.isInProgress();
94    }
95
96    @Override
97    public void onDraw(Canvas canvas) {
98        if (mScaling) {
99            canvas.drawCircle((float) mCenterX, (float) mCenterY,
100                    (float) mCircleSize, mPaint);
101        }
102    }
103
104    @Override
105    public boolean onScale(ScaleGestureDetector detector) {
106        mScale = mScale * detector.getScaleFactor();
107        if (mScale < 1) mScale = 1;
108        if (mScale > mMaxScale) mScale = mMaxScale;
109        int newzoom = (int) ((mScale - mMinScale) * mMaxZoom / (mMaxScale - mMinScale));
110        if (newzoom > mMaxZoom) newzoom = mMaxZoom;
111        if (newzoom < 0) newzoom = 0;
112        if (mListener != null && newzoom != mZoom) {
113            mListener.onZoomValueChanged(newzoom);
114            mZoom = newzoom;
115        }
116        mCircleSize = (int) (mMinCircle + (mScale - mMinScale) * (mMaxCircle - mMinCircle)
117                / (mMaxScale - mMinScale));
118        return true;
119    }
120
121    @Override
122    public boolean onScaleBegin(ScaleGestureDetector detector) {
123        mScaling = true;
124        if (mListener != null) {
125            mListener.onZoomStart();
126        }
127        mOverlay.postInvalidate();
128        return true;
129    }
130
131    @Override
132    public void onScaleEnd(ScaleGestureDetector detector) {
133        mScaling = false;
134        if (mListener != null) {
135            mListener.onZoomEnd();
136        }
137    }
138
139}
140