android 图片缩放

// 获得图片的宽高
int width = bm.getWidth();
int height = bm.getHeight();
// 设置想要的大小
int newWidth = 320;
int newHeight = 480;
// 计算缩放比例
float scaleWidth = ((float) newWidth) / width;
float scaleHeight = ((float) newHeight) / height;
// 取得想要缩放的matrix参数
Matrix matrix = new Matrix();
matrix.postScale(scaleWidth, scaleHeight);
// 得到新的图片
Bitmap newbm = Bitmap.createBitmap(bm, 0, 0, width, height, matrix,
true);

[java] view plain copy print?在CODE上查看代码片派生到我的代码片
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import android.content.Context;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.net.Uri;
import android.util.Log;
public class Bitmaptest
{
private static final String TAG = "BitmapUtil";
/**
* 通过资源id转化成Bitmap
*
* @param context
* @param resId
* @return
*/
public static Bitmap ReadBitmapById(Context context, int resId)
{
BitmapFactory.Options opt = new BitmapFactory.Options();
opt.inPreferredConfig = Bitmap.Config.RGB_565;
opt.inPurgeable = true;
opt.inInputShareable = true;
InputStream is = context.getResources().openRawResource(resId);
return BitmapFactory.decodeStream(is, null, opt);
}
/**
* 缩放Bitmap满屏
*
* @param bitmap
* @param screenWidth
* @param screenHight
* @return
*/
public static Bitmap getBitmap(Bitmap bitmap, int screenWidth,
int screenHight)
{
int w = bitmap.getWidth();
int h = bitmap.getHeight();
Matrix matrix = new Matrix();
float scale = (float) screenWidth / w;
float scale2 = (float) screenHight / h;
// scale = scale < scale2 ? scale : scale2;
matrix.postScale(scale, scale);
Bitmap bmp = Bitmap.createBitmap(bitmap, 0, 0, w, h, matrix, true);
if (bitmap != null && !bitmap.equals(bmp) && !bitmap.isRecycled())
{
bitmap.recycle();
bitmap = null;
}
return bmp;// Bitmap.createBitmap(bitmap, 0, 0, w, h, matrix, true);
}

/**
* 按最大边按一定大小缩放图片
* */
public static Bitmap scaleImage(byte[] buffer, float size)
{
// 获取原图宽度
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
options.inPurgeable = true;
options.inInputShareable = true;
Bitmap bm = BitmapFactory.decodeByteArray(buffer, 0, buffer.length,
options);
// 计算缩放比例
float reSize = options.outWidth / size;
if (options.outWidth < options.outHeight)
{
reSize = options.outHeight / size;
}
// 如果是小图则放大
if (reSize <= 1)
{
int newWidth = 0;
int newHeight = 0;
if (options.outWidth > options.outHeight)
{
newWidth = (int) size;
newHeight = options.outHeight * (int) size / options.outWidth;
} else
{
newHeight = (int) size;
newWidth = options.outWidth * (int) size / options.outHeight;
}
bm = BitmapFactory.decodeByteArray(buffer, 0, buffer.length);
bm = scaleImage(bm, newWidth, newHeight);
if (bm == null)
{
Log.e(TAG, "convertToThumb, decode fail:" + null);
return null;
}
return bm;
}
// 缩放
options.inJustDecodeBounds = false;
options.inSampleSize = (int) reSize;
bm = BitmapFactory.decodeByteArray(buffer, 0, buffer.length, options);
if (bm == null)
{
Log.e(TAG, "convertToThumb, decode fail:" + null);
return null;
}
return bm;
}
/**
* 检查图片是否超过一定值，是则缩小
*
* @param view
* @param strFileName
*/
public static Bitmap convertToThumb(byte[] buffer, float size)
{
// 获取原图宽度
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
options.inPurgeable = true;
options.inInputShareable = true;
Bitmap bm = BitmapFactory.decodeByteArray(buffer, 0, buffer.length,
options);
// 计算缩放比例
float reSize = options.outWidth / size;
if (options.outWidth > options.outHeight)
{
reSize = options.outHeight / size;
}
if (reSize <= 0)
{
reSize = 1;
}
Log.d(TAG, "convertToThumb, reSize:" + reSize);
// 缩放
options.inJustDecodeBounds = false;
options.inSampleSize = (int) reSize;
if (bm != null && !bm.isRecycled())
{
bm.recycle();
bm = null;
Log.e(TAG, "convertToThumb, recyle");
}
bm = BitmapFactory.decodeByteArray(buffer, 0, buffer.length, options);
if (bm == null)
{
Log.e(TAG, "convertToThumb, decode fail:" + null);
return null;
}
return bm;
}
/**
* Bitmap --> byte[]
*
* @param bmp
* @return
*/
private static byte[] readBitmap(Bitmap bmp)
{
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bmp.compress(Bitmap.CompressFormat.JPEG, 60, baos);
try
{
baos.flush();
baos.close();
} catch (IOException e)
{
e.printStackTrace();
}
return baos.toByteArray();
}
/**
* Bitmap --> byte[]
*
* @param bmp
* @return
*/
public static byte[] readBitmapFromBuffer(byte[] buffer, float size)
{
return readBitmap(convertToThumb(buffer, size));
}
/**
* 以屏幕宽度为基准，显示图片
*
* @param iv
* @param path
* @param screenW
* @return
*/
public static Bitmap decodeStream(Context context, Intent data, float size)
{
Bitmap image = null;
try
{
Uri dataUri = data.getData();
// 获取原图宽度
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
options.inPurgeable = true;
options.inInputShareable = true;
BitmapFactory.decodeStream(context.getContentResolver()
.openInputStream(dataUri), null, options);
// 计算缩放比例
float reSize = (int) (options.outWidth / size);
if (reSize <= 0)
{
reSize = 1;
}
Log.d(TAG, "old-w:" + options.outWidth + ", llyt-w:" + size
+ ", resize:" + reSize);
// 缩放
options.inJustDecodeBounds = false;
options.inSampleSize = (int) reSize;
image = BitmapFactory.decodeStream(context.getContentResolver()
.openInputStream(dataUri), null, options);
} catch (Exception e)
{
e.printStackTrace();
}
return image;
}

/**
* 按新的宽高缩放图片
*
* @param bm
* @param newWidth
* @param newHeight
* @return
*/
public static Bitmap scaleImage(Bitmap bm, int newWidth, int newHeight)
{
if (bm == null)
{
return null;
}
int width = bm.getWidth();
int height = bm.getHeight();
float scaleWidth = ((float) newWidth) / width;
float scaleHeight = ((float) newHeight) / height;
Matrix matrix = new Matrix();
matrix.postScale(scaleWidth, scaleHeight);
Bitmap newbm = Bitmap.createBitmap(bm, 0, 0, width, height, matrix,
true);
if (bm != null & !bm.isRecycled())
{
bm.recycle();
bm = null;
}
return newbm;
}
/**
* fuction: 设置固定的宽度，高度随之变化，使图片不会变形
*
* @param target
* 需要转化bitmap参数
* @param newWidth
* 设置新的宽度
* @return
*/
public static Bitmap fitBitmap(Bitmap target, int newWidth)
{
int width = target.getWidth();
int height = target.getHeight();
Matrix matrix = new Matrix();
float scaleWidth = ((float) newWidth) / width;
// float scaleHeight = ((float)newHeight) / height;
int newHeight = (int) (scaleWidth * height);
matrix.postScale(scaleWidth, scaleWidth);
// Bitmap result = Bitmap.createBitmap(target,0,0,width,height,
// matrix,true);
Bitmap bmp = Bitmap.createBitmap(target, 0, 0, width, height, matrix,
true);
if (target != null && !target.equals(bmp) && !target.isRecycled())
{
target.recycle();
target = null;
}
return bmp;// Bitmap.createBitmap(target, 0, 0, width, height, matrix,
// true);
}

/**
* 根据指定的宽度平铺图像
*
* @param width
* @param src
* @return
*/
public static Bitmap createRepeater(int width, Bitmap src)
{
int count = (width + src.getWidth() - 1) / src.getWidth();
Bitmap bitmap = Bitmap.createBitmap(width, src.getHeight(),
Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
for (int idx = 0; idx < count; ++idx)
{
canvas.drawBitmap(src, idx * src.getWidth(), 0, null);
}
return bitmap;
}

/**
* 图片的质量压缩方法
*
* @param image
* @return
*/
public static Bitmap compressImage(Bitmap image)
{
ByteArrayOutputStream baos = new ByteArrayOutputStream();
image.compress(Bitmap.CompressFormat.JPEG, 100, baos);// 质量压缩方法，这里100表示不压缩，把压缩后的数据存放到baos中
int options = 100;
while (baos.toByteArray().length / 1024 > 100)
{ // 循环判断如果压缩后图片是否大于100kb,大于继续压缩
baos.reset();// 重置baos即清空baos
image.compress(Bitmap.CompressFormat.JPEG, options, baos);// 这里压缩options%，把压缩后的数据存放到baos中
options -= 10;// 每次都减少10
}
ByteArrayInputStream isBm = new ByteArrayInputStream(baos.toByteArray());// 把压缩后的数据baos存放到ByteArrayInputStream中
Bitmap bitmap = BitmapFactory.decodeStream(isBm, null, null);// 把ByteArrayInputStream数据生成图片
if (baos != null)
{
try
{
baos.close();
} catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (isBm != null)
{
try
{
isBm.close();
} catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (image != null && !image.isRecycled())
{
image.recycle();
image = null;
}
return bitmap;
}

/**
* 图片按比例大小压缩方法(根据Bitmap图片压缩)
*
* @param image
* @return
*/
public static Bitmap getImage(Bitmap image)
{
ByteArrayOutputStream baos = new ByteArrayOutputStream();
image.compress(Bitmap.CompressFormat.JPEG, 100, baos);
if (baos.toByteArray().length / 1024 > 1024)
{// 判断如果图片大于1M,进行压缩避免在生成图片（BitmapFactory.decodeStream）时溢出
baos.reset();// 重置baos即清空baos
image.compress(Bitmap.CompressFormat.JPEG, 50, baos);// 这里压缩50%，把压缩后的数据存放到baos中
}
ByteArrayInputStream isBm = new ByteArrayInputStream(baos.toByteArray());
BitmapFactory.Options newOpts = new BitmapFactory.Options();
// 开始读入图片，此时把options.inJustDecodeBounds 设回true了
newOpts.inJustDecodeBounds = true;
Bitmap bitmap = BitmapFactory.decodeStream(isBm, null, newOpts);
newOpts.inJustDecodeBounds = false;
int w = newOpts.outWidth;
int h = newOpts.outHeight;
// 现在主流手机比较多是800*480分辨率，所以高和宽我们设置为
float hh = 800f;// 这里设置高度为800f
float ww = 480f;// 这里设置宽度为480f
// 缩放比。由于是固定比例缩放，只用高或者宽其中一个数据进行计算即可
int be = 1;// be=1表示不缩放
if (w > h && w > ww)
{// 如果宽度大的话根据宽度固定大小缩放
be = (int) (newOpts.outWidth / ww);
} else if (w < h && h > hh)
{// 如果高度高的话根据宽度固定大小缩放
be = (int) (newOpts.outHeight / hh);
}
if (be <= 0)
be = 1;
newOpts.inSampleSize = be;// 设置缩放比例
// 重新读入图片，注意此时已经把options.inJustDecodeBounds 设回false了
isBm = new ByteArrayInputStream(baos.toByteArray());
bitmap = BitmapFactory.decodeStream(isBm, null, newOpts);
if (isBm != null)
{
try
{
isBm.close();
} catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (image != null && !image.isRecycled())
{
image.recycle();
image = null;
}
return compressImage(bitmap);// 压缩好比例大小后再进行质量压缩
}
/**
* 通过资源id转化成Bitmap 全屏显示
*
* @param context
* @param drawableId
* @param screenWidth
* @param screenHight
* @return
*/
public static Bitmap ReadBitmapById(Context context, int drawableId,
int screenWidth, int screenHight)
{
BitmapFactory.Options options = new BitmapFactory.Options();
options.inPreferredConfig = Config.ARGB_8888;
options.inInputShareable = true;
options.inPurgeable = true;
InputStream stream = context.getResources().openRawResource(drawableId);
Bitmap bitmap = BitmapFactory.decodeStream(stream, null, options);
return getBitmap(bitmap, screenWidth, screenHight);
}

}