PreviewFrameLayout.java revision da705aa1c8cbaaba105d9bc7799aef95c416a459 
1/*
2 * Copyright (C) 2009 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;
18
19import com.android.camera.R;
20
21import android.app.Activity;
22import android.content.Context;
23import android.content.pm.ActivityInfo;
24import android.view.View;
25import android.util.AttributeSet;
26import android.widget.RelativeLayout;
27/**
28 * A layout which handles the preview aspect ratio.
29 */
30public class PreviewFrameLayout extends RelativeLayout {
31    /** A callback to be invoked when the preview frame's size changes. */
32    public interface OnSizeChangedListener {
33        public void onSizeChanged();
34    }
35
36    private double mAspectRatio;
37
38    public PreviewFrameLayout(Context context, AttributeSet attrs) {
39        super(context, attrs);
40        setAspectRatio(4.0 / 3.0);
41    }
42
43    public void setAspectRatio(double ratio) {
44        if (ratio <= 0.0) throw new IllegalArgumentException();
45
46        if (((Activity) getContext()).getRequestedOrientation()
47                == ActivityInfo.SCREEN_ORIENTATION_PORTRAIT) {
48            ratio = 1 / ratio;
49        }
50
51        if (mAspectRatio != ratio) {
52            mAspectRatio = ratio;
53            requestLayout();
54        }
55    }
56
57    public void showBorder(boolean enabled) {
58        findViewById(R.id.preview_border).setVisibility(
59                enabled ? View.VISIBLE : View.INVISIBLE);
60    }
61
62    @Override
63    protected void onMeasure(int widthSpec, int heightSpec) {
64        int previewWidth = MeasureSpec.getSize(widthSpec);
65        int previewHeight = MeasureSpec.getSize(heightSpec);
66
67        // Get the padding of the border background.
68        int hPadding = mPaddingLeft + mPaddingRight;
69        int vPadding = mPaddingTop + mPaddingBottom;
70
71        // Resize the preview frame with correct aspect ratio.
72        previewWidth -= hPadding;
73        previewHeight -= vPadding;
74        if (previewWidth > previewHeight * mAspectRatio) {
75            previewWidth = (int) (previewHeight * mAspectRatio + .5);
76        } else {
77            previewHeight = (int) (previewWidth / mAspectRatio + .5);
78        }
79
80        // Add the padding of the border.
81        previewWidth += hPadding;
82        previewHeight += vPadding;
83
84        // Ask children to follow the new preview dimension.
85        super.onMeasure(MeasureSpec.makeMeasureSpec(previewWidth, MeasureSpec.EXACTLY),
86                MeasureSpec.makeMeasureSpec(previewHeight, MeasureSpec.EXACTLY));
87    }
88}
89