/*
* Copyright (C) 2013 WhiteCat 白猫 (www.thinkandroid.cn)
*
* 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.ta.util.bitmap;
import java.io.FileDescriptor;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
public class TAResizerBitmapHandler extends TAProcessBitmapHandler
{
protected int mImageWidth;
protected int mImageHeight;
protected Resources mResources;
/**
* 初始化一个目标提供图像的宽度和高度的来处理图像
*
* @param context
* @param imageWidth
* @param imageHeight
*/
public TAResizerBitmapHandler(Context context, int imageWidth,
int imageHeight)
{
mResources = context.getResources();
setImageSize(imageWidth, imageHeight);
}
/**
* 初始化提供单一目标图像大小(用于宽度和高度);
*
* @param context
* @param imageSize
*/
public TAResizerBitmapHandler(Context context, int imageSize)
{
mResources = context.getResources();
setImageSize(imageSize);
}
/**
* 设置目标图片的宽度高度
*
* @param width
* @param height
*/
public void setImageSize(int width, int height)
{
mImageWidth = width;
mImageHeight = height;
}
/**
* 设置目标图片的宽度高度
*
* @param size
*/
public void setImageSize(int size)
{
setImageSize(size, size);
}
/**
* 一个主要的处理方法，当发生在后台时, 在这种情况下我们只是抽取出来一个位图，并返回资源.
*
* @param resId
* @return
*/
private Bitmap processBitmap(int resId)
{
/*
* if (BuildConfig.DEBUG) { Log.d(TAG, "processBitmap - " + resId); }
*/
return decodeSampledBitmapFromResource(mResources, resId, mImageWidth,
mImageHeight);
}
@Override
protected Bitmap processBitmap(Object data)
{
return processBitmap(Integer.parseInt(String.valueOf(data)));
}
/**
* 按照一定的宽度来从资源解码和抽取一个位图。
*
* @param res
* 资源对象,其中包含了图像数据
* @param 资源id的图像数据
* @param reqWidth
* 请求的宽度产生的位图
* @param reqHeight
* 请求的高度产生的位图
* @return
*
*/
public static Bitmap decodeSampledBitmapFromResource(Resources res,
int resId, int reqWidth, int reqHeight)
{
// 第一解码和inJustDecodeBounds = true来检查维度
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeResource(res, resId, options);
// 计算inSampleSize
options.inSampleSize = calculateInSampleSize(options, reqWidth,
reqHeight);
// 根据inSampleSize解码位图
options.inJustDecodeBounds = false;
return BitmapFactory.decodeResource(res, resId, options);
}
/**
* 按照一定的宽度来从文件解码和抽取一个位图。
*
* @param filename
* 文件名的完整路径文件来解码
* @param reqWidth
* 目标图片宽度
* @param reqHeight
* 目标图片的高度
* @return
*/
public static Bitmap decodeSampledBitmapFromFile(String filename,
int reqWidth, int reqHeight)
{
// 第一解码和inJustDecodeBounds = true来检查维度
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(filename, options);
// 计算inSampleSize
options.inSampleSize = calculateInSampleSize(options, reqWidth,
reqHeight);
// 根据inSampleSize解码位图
options.inJustDecodeBounds = false;
return BitmapFactory.decodeFile(filename, options);
}
/**
* 按照一定的宽度来从输入流解码和抽取一个位图。
*
* @param fileDescriptor
* @param reqWidth
* @param reqHeight
* @return
*/
public static Bitmap decodeSampledBitmapFromDescriptor(
FileDescriptor fileDescriptor, int reqWidth, int reqHeight)
{
// 第一解码和inJustDecodeBounds = true来检查维度
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFileDescriptor(fileDescriptor, null, options);
// 计算inSampleSize
options.inSampleSize = calculateInSampleSize(options, reqWidth,
reqHeight);
// 根据inSampleSize解码位图
options.inJustDecodeBounds = false;
return BitmapFactory
.decodeFileDescriptor(fileDescriptor, null, options);
}
/**
* Calculate an inSampleSize for use in a {@link BitmapFactory.Options}
* object when decoding bitmaps using the decode* methods from
* {@link BitmapFactory}. This implementation calculates the closest
* inSampleSize that will result in the final decoded bitmap having a width
* and height equal to or larger than the requested width and height. This
* implementation does not ensure a power of 2 is returned for inSampleSize
* which can be faster when decoding but results in a larger bitmap which
* isn't as useful for caching purposes.
*
* @param options
* An options object with out* params already populated (run
* through a decode* method with inJustDecodeBounds==true
* @param reqWidth
* The requested width of the resulting bitmap
* @param reqHeight
* The requested height of the resulting bitmap
* @return The value to be used for inSampleSize
*/
public static int calculateInSampleSize(BitmapFactory.Options options,
int reqWidth, int reqHeight)
{
// Raw height and width of image
final int height = options.outHeight;
final int width = options.outWidth;
int inSampleSize = 1;
if (height > reqHeight || width > reqWidth)
{
if (width > height)
{
inSampleSize = Math.round((float) height / (float) reqHeight);
} else
{
inSampleSize = Math.round((float) width / (float) reqWidth);
}
// This offers some additional logic in case the image has a strange
// aspect ratio. For example, a panorama may have a much larger
// width than height. In these cases the total pixels might still
// end up being too large to fit comfortably in memory, so we should
// be more aggressive with sample down the image (=larger
// inSampleSize).
final float totalPixels = width * height;
// Anything more than 2x the requested pixels we'll sample down
// further.
final float totalReqPixelsCap = reqWidth * reqHeight * 2;
while (totalPixels / (inSampleSize * inSampleSize) > totalReqPixelsCap)
{
inSampleSize++;
}
}
return inSampleSize;
}
}