/*
* Copyright (C) 2015 Zhang Rui <bbcallen@gmail.com>
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.dl7.player.media;
import android.view.View;
import java.lang.ref.WeakReference;
/**
* 测量帮助类
*/
public final class MeasureHelper {
// 测量的视图
private WeakReference<View> mWeakView;
// 视频宽高
private int mVideoWidth;
private int mVideoHeight;
// 视频宽高比采样率???
private int mVideoSarNum;
private int mVideoSarDen;
// 视频旋转角度
private int mVideoRotationDegree;
// 测量宽高
private int mMeasuredWidth;
private int mMeasuredHeight;
// 视频显示模式
private int mCurrentAspectRatio = IRenderView.AR_ASPECT_FIT_PARENT;
public MeasureHelper(View view) {
mWeakView = new WeakReference<View>(view);
}
public View getView() {
if (mWeakView == null)
return null;
return mWeakView.get();
}
public void setVideoSize(int videoWidth, int videoHeight) {
mVideoWidth = videoWidth;
mVideoHeight = videoHeight;
}
public void setVideoSampleAspectRatio(int videoSarNum, int videoSarDen) {
mVideoSarNum = videoSarNum;
mVideoSarDen = videoSarDen;
}
public void setVideoRotation(int videoRotationDegree) {
mVideoRotationDegree = videoRotationDegree;
}
/**
* Must be called by View.onMeasure(int, int)
*
* @param widthMeasureSpec
* @param heightMeasureSpec
*/
public void doMeasure(int widthMeasureSpec, int heightMeasureSpec) {
if (mVideoRotationDegree == 90 || mVideoRotationDegree == 270) {
// 如果旋转了90°或270°则宽高测量值进行互换
int tempSpec = widthMeasureSpec;
widthMeasureSpec = heightMeasureSpec;
heightMeasureSpec = tempSpec;
}
// 获取默认的测量宽高值
int width = View.getDefaultSize(mVideoWidth, widthMeasureSpec);
int height = View.getDefaultSize(mVideoHeight, heightMeasureSpec);
if (mCurrentAspectRatio == IRenderView.AR_MATCH_PARENT) {
// 在 AR_MATCH_PARENT 模式下直接用原始测量值
width = widthMeasureSpec;
height = heightMeasureSpec;
} else if (mVideoWidth > 0 && mVideoHeight > 0) {
int widthSpecMode = View.MeasureSpec.getMode(widthMeasureSpec);
int widthSpecSize = View.MeasureSpec.getSize(widthMeasureSpec);
int heightSpecMode = View.MeasureSpec.getMode(heightMeasureSpec);
int heightSpecSize = View.MeasureSpec.getSize(heightMeasureSpec);
// modify，把&&操作符换为||
if (widthSpecMode == View.MeasureSpec.AT_MOST || heightSpecMode == View.MeasureSpec.AT_MOST) {
// 测量宽高比，对应的视图的宽高比
float specAspectRatio = (float) widthSpecSize / (float) heightSpecSize;
// 显示宽高比，要显示的视频宽高比
float displayAspectRatio;
// 这里计算显示宽高比
switch (mCurrentAspectRatio) {
case IRenderView.AR_16_9_FIT_PARENT:
// 16：9
displayAspectRatio = 16.0f / 9.0f;
if (mVideoRotationDegree == 90 || mVideoRotationDegree == 270)
displayAspectRatio = 1.0f / displayAspectRatio;
break;
case IRenderView.AR_4_3_FIT_PARENT:
// 4：3
displayAspectRatio = 4.0f / 3.0f;
if (mVideoRotationDegree == 90 || mVideoRotationDegree == 270)
displayAspectRatio = 1.0f / displayAspectRatio;
break;
case IRenderView.AR_ASPECT_FIT_PARENT:
case IRenderView.AR_ASPECT_FILL_PARENT:
case IRenderView.AR_ASPECT_WRAP_CONTENT:
default:
// 按视频来源宽高比
displayAspectRatio = (float) mVideoWidth / (float) mVideoHeight;
if (mVideoSarNum > 0 && mVideoSarDen > 0)
displayAspectRatio = displayAspectRatio * mVideoSarNum / mVideoSarDen;
break;
}
// 是否要显示视频宽度比例较大
boolean shouldBeWider = displayAspectRatio > specAspectRatio;
// 这里确定最终宽高
switch (mCurrentAspectRatio) {
case IRenderView.AR_ASPECT_FIT_PARENT:
case IRenderView.AR_16_9_FIT_PARENT:
case IRenderView.AR_4_3_FIT_PARENT:
if (shouldBeWider) {
// too wide, fix width；宽度比较大，固定宽度，使用测量宽度，按显示比例缩放高度
width = widthSpecSize;
height = (int) (width / displayAspectRatio);
} else {
// too high, fix height；高度比较大，固定高度，使用测量高度，按显示比例缩放宽度
height = heightSpecSize;
width = (int) (height * displayAspectRatio);
}
break;
case IRenderView.AR_ASPECT_FILL_PARENT: // 填充满控件模式
if (shouldBeWider) {
// not high enough, fix height；宽度比较大，固定高度，缩放宽度
height = heightSpecSize;
width = (int) (height * displayAspectRatio);
} else {
// not wide enough, fix width；高度比较大，固定宽度，缩放高度
width = widthSpecSize;
height = (int) (width / displayAspectRatio);
}
break;
case IRenderView.AR_ASPECT_WRAP_CONTENT:
default:
if (shouldBeWider) {
// too wide, fix width；和第一个类似，这里取 (mVideoWidth, widthSpecSize) 最小的值
width = Math.min(mVideoWidth, widthSpecSize);
height = (int) (width / displayAspectRatio);
} else {
// too high, fix height
height = Math.min(mVideoHeight, heightSpecSize);
width = (int) (height * displayAspectRatio);
}
break;
}
} else if (widthSpecMode == View.MeasureSpec.EXACTLY && heightSpecMode == View.MeasureSpec.EXACTLY) {
// the size is fixed
width = widthSpecSize;
height = heightSpecSize;
// for compatibility, we adjust size based on aspect ratio
// 这里做的是缩小某一边的大小以达到和视频原始尺寸的比例
if (mVideoWidth * height < width * mVideoHeight) {
width = height * mVideoWidth / mVideoHeight;
} else if (mVideoWidth * height > width * mVideoHeight) {
height = width * mVideoHeight / mVideoWidth;
}
} else if (widthSpecMode == View.MeasureSpec.EXACTLY) {
// only the width is fixed, adjust the height to match aspect ratio if possible
width = widthSpecSize;
height = width * mVideoHeight / mVideoWidth;
if (heightSpecMode == View.MeasureSpec.AT_MOST && height > heightSpecSize) {
// couldn't match aspect ratio within the constraints，不让高度超出测量高度
height = heightSpecSize;
}
} else if (heightSpecMode == View.MeasureSpec.EXACTLY) {
// only the height is fixed, adjust the width to match aspect ratio if possible
height = heightSpecSize;
width = height * mVideoWidth / mVideoHeight;
if (widthSpecMode == View.MeasureSpec.AT_MOST && width > widthSpecSize) {
// couldn't match aspect ratio within the constraints，不让宽度超出测量宽度
width = widthSpecSize;
}
} else {
// neither the width nor the height are fixed, try to use actual video size
width = mVideoWidth;
height = mVideoHeight;
if (heightSpecMode == View.MeasureSpec.AT_MOST && height > heightSpecSize) {
// too tall, decrease both width and height
height = heightSpecSize;
width = height * mVideoWidth / mVideoHeight;
}
if (widthSpecMode == View.MeasureSpec.AT_MOST && width > widthSpecSize) {
// too wide, decrease both width and height
width = widthSpecSize;
height = width * mVideoHeight / mVideoWidth;
}
}
} else {
// no size yet, just adopt the given spec sizes
}
mMeasuredWidth = width;
mMeasuredHeight = height;
}
public int getMeasuredWidth() {
return mMeasuredWidth;
}
public int getMeasuredHeight() {
return mMeasuredHeight;
}
public void setAspectRatio(int aspectRatio) {
mCurrentAspectRatio = aspectRatio;
}
}