缩放图像不会丢失图像质量没有工作 [英] Scale image without losing image quality did not work
本文介绍了缩放图像不会丢失图像质量没有工作的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
有谁知道如何不失画质缩放位图图像？目前我面临这个<一个href=\"http://stackoverflow.com/questions/34315387/will-the-image-too-big-caused-app-return-to-$p$pvious-activity\">problem,其中，选择图像的大小可能过大引起的应用程序回归到另一个活动。
所以，现在我使用这种方法，而不会失去其质量缩放选定的图像尝试。我得到的code从<一个href=\"http://adilatwork.blogspot.my/2012/10/android-how-to-scale-bitmap-and-retain.html\">here.
保护无效的onActivityResult（INT申请code，INT结果code，
意图数据）{
super.onActivityResult（要求code，结果code，数据）;
开关（要求code）{
案例RESULT_LOAD_IMAGE：
如果（要求code == RESULT_LOAD_IMAGE＆放大器;＆安培;结果code == RESULT_OK＆安培;！NULL =数据）{
乌里selectedImage = data.getData（）;
的String [] = filePathColumn {MediaStore.Images.Media.DATA};
光标光标= getContentResolver（）
.query（selectedImage，filePathColumn，NULL，NULL，
空值）;
cursor.moveToFirst（）;
INT参数：columnIndex = cursor.getColumnIndex（filePathColumn [0]）;
字符串picturePath = cursor.getString（参数：columnIndex）;
cursor.close（）;
位图=（BitmapFactory.de codeFILE（picturePath））;
相片= scaleBitmap（一，200，200）;
imageView.setImageBitmap（照片）;
}
打破;
} 公共静态位图scaleBitmap（位图位图，诠释newWidth，诠释newHeight）{
位图scaledBitmap = Bitmap.createBitmap（newWidth，newHeight，Bitmap.Config.ARGB_8888）; 漂浮的scaleX = newWidth /（浮点）bitmap.getWidth（）;
漂浮的scaleY = newHeight /（浮点）bitmap.getHeight（）;
浮pivotX = 0;
浮pivotY = 0; 矩阵scaleMatrix =新的Matrix（）;
scaleMatrix.setScale（将scaleX，的scaleY，pivotX，pivotY）; 帆布帆布=新的Canvas（scaledBitmap）;
canvas.setMatrix（scaleMatrix）;
canvas.drawBitmap（位图，0，0，新涂料（Paint.FILTER_BITMAP_FLAG））; 返回scaledBitmap;
}
答案似乎有助于大多数人，但它为什么不为我工作？我错过了什么？
上的ImageView 选择的图像显示
解决方案
使用此它一定会帮助你减少大小没有松动质量。
公共位图COM pressImage（字符串imageUri）{ 字符串文件路径= imageUri;
//字符串文件路径= getRealPathFromURI（imageUri）;
位图scaledBitmap = NULL; BitmapFactory.Options选项=新BitmapFactory.Options（）; //通过设置此字段为真，实际的位图像素不是
//加载在存储器中。就在边界被加载。如果
//您尝试使用位图在这里，你会得到空。
options.inJustDe codeBounds = TRUE;
BMP位图= BitmapFactory.de codeFILE（文件路径，期权）; INT的ActualHeight = options.outHeight;
INT ActualWidth的= options.outWidth; 在COM pressed形象//最大高度和宽度值取为
// 816x612 / *
*浮了maxHeight = 816.0f;浮了maxWidth = 612.0f;
* /
浮了maxHeight = 1080.0f;
浮了maxWidth = 800.0f; 浮imgRatio = ActualWidth的/（浮动）的ActualHeight;
浮maxRatio =了maxWidth /（浮点）了maxHeight; //宽度和高度值被设置保持的纵横比
// 图片 如果（的ActualHeight＆GT;了maxHeight || ActualWidth的＆GT;了maxWidth）{
如果（imgRatio＆LT; maxRatio）{
imgRatio =了maxHeight /的ActualHeight;
ActualWidth的=（INT）（imgRatio * ActualWidth的）;
的ActualHeight =（INT）了maxHeight;
}否则如果（imgRatio＆GT; maxRatio）{
imgRatio =了maxWidth / ActualWidth的;
的ActualHeight =（INT）（imgRatio *的ActualHeight）;
ActualWidth的=（INT）了maxWidth;
}其他{
的ActualHeight =（INT）了maxHeight;
ActualWidth的=（INT）了maxWidth; }
} //设置inSampleSize值允许装载的缩小版本
//原始图像 options.inSampleSize = calculateInSampleSize（选项，ActualWidth的，的ActualHeight）; //设置为false inJustDe codeBounds加载实际的位图
options.inJustDe codeBounds = FALSE; //这个选项允许权利要求的位图内存的Android，如果电量不足
//内存
options.inPurgeable = TRUE;
options.inInputShareable = TRUE;
options.inTempStorage =新的字节[16 * 1024]; 尝试{
//来自其路径加载位图
BMP = BitmapFactory.de codeFILE（文件路径，期权）;
}赶上（例外的OutOfMemoryError）{
exception.printStackTrace（）; }
尝试{
scaledBitmap = Bitmap.createBitmap（ActualWidth的，的ActualHeight，Bitmap.Config.ARGB_8888）;
}赶上（例外的OutOfMemoryError）{
exception.printStackTrace（）;
} 浮ratioX = ActualWidth的/（浮点）options.outWidth;
浮ratioY =的ActualHeight /（浮点）options.outHeight;
浮middleX = ActualWidth的/ 2.0F;
浮middleY =的ActualHeight / 2.0F; 矩阵scaleMatrix =新的Matrix（）;
scaleMatrix.setScale（ratioX，ratioY，middleX，middleY）; 帆布帆布=新的Canvas（scaledBitmap）;
canvas.setMatrix（scaleMatrix）;
canvas.drawBitmap（BMP，middleX - bmp.getWidth（）/ 2，middleY - bmp.getHeight（）/ 2，新油漆（Paint.FILTER_BITMAP_FLAG））; //检查图像的旋转并正确显示
ExifInterface EXIF;
尝试{
EXIF =新ExifInterface（文件路径）; INT方向= exif.getAttributeInt（ExifInterface.TAG_ORIENTATION，0）;
displayLogs（EXIF，的Exif：+方向）;
字模=新的Matrix（）;
如果（方向== 6）{
matrix.postRotate（90）;
displayLogs（EXIF，的Exif：+方向）;
}否则如果（取向== 3）{
matrix.postRotate（180）;
displayLogs（EXIF，的Exif：+方向）;
}否则如果（方向== 8）{
matrix.postRotate（270）;
displayLogs（EXIF，的Exif：+方向）;
} scaledBitmap = Bitmap.createBitmap（scaledBitmap，0，0，scaledBitmap.getWidth（），scaledBitmap.getHeight（），矩阵，真）;
}赶上（IOException异常五）{
e.printStackTrace（）;
} FileOutputStream中走出= NULL;
字符串的文件名的getFileName =（文件路径）;
//文件图像=新的文件（用GetFileName（），System.currentTimeMillis的（）+
//.JPG）;
尝试{
OUT =新的FileOutputStream（文件名）; //写COM pressed位在被指定的目标
// 文件名。
布尔didWrite = scaledBitmap.com preSS（Bitmap.Com pressFormat.JPEG，80出）; out.close（）; 的System.out.println（didWrite）;
}赶上（FileNotFoundException异常五）{
e.printStackTrace（）;
}赶上（IOException异常五）{ e.printStackTrace（）;
} 返回scaledBitmap; } 私人字符串getRealPathFromURI（字符串contentURI）{
乌里contentUri = Uri.parse（contentURI）;
。光标光标= getContentResolver（）查询（contentUri，NULL，NULL，NULL，NULL）;
如果（光标== NULL）{
返回contentUri.getPath（）;
}其他{
cursor.moveToFirst（）;
INT指数= cursor.getColumnIndex（MediaStore.Images.ImageColumns.DATA）;
返回cursor.getString（索引）;
}
} 公众诠释calculateInSampleSize（BitmapFactory.Options选项，诠释reqWidth，诠释reqHeight）{
最终诠释身高= options.outHeight;
最终诠释宽度= options.outWidth;
INT inSampleSize = 1; 如果（高度＆GT; reqHeight ||宽度GT; reqWidth）{
最终诠释heightRatio = Math.round（（浮点）高度/（浮点）reqHeight）;
最终诠释widthRatio = Math.round（（浮点）宽/（浮点）reqWidth）;
inSampleSize = heightRatio＆LT; widthRatio？ heightRatio：widthRatio;
}
最终浮动totalPixels =宽*高;
最终浮动totalReqPixelsCap = reqWidth * reqHeight * 2;
而（totalPixels /（inSampleSize * inSampleSize）GT; totalReqPixelsCap）{
inSampleSize ++;
} 返回inSampleSize;
} 公众的getFileName字符串（字符串ORIGINALNAME）{ ImageCache imageCache =新ImageCache（本）;
档案文件=新的文件（您的文件夹路径）; //返回文件;
串uriSting =（file.getAbsolutePath（）+/+F_+ System.currentTimeMillis的（）+.PNG）;
返回uriSting; }
Does anyone know how to scale the bitmap image without losing the image quality ? Currently I facing this problem, where the size of selected image maybe too big caused the app return to another activity.
So now I tried using this method to scale the selected image without losing its quality. I get the code from here.
protected void onActivityResult(int requestCode, int resultCode,
Intent data) {
super.onActivityResult(requestCode, resultCode, data);
switch (requestCode) {
case RESULT_LOAD_IMAGE:
if (requestCode == RESULT_LOAD_IMAGE && resultCode == RESULT_OK & null != data) {
Uri selectedImage = data.getData();
String[] filePathColumn = {MediaStore.Images.Media.DATA};
Cursor cursor = getContentResolver()
.query(selectedImage, filePathColumn, null, null,
null);
cursor.moveToFirst();
int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
String picturePath = cursor.getString(columnIndex);
cursor.close();
Bitmap a = (BitmapFactory.decodeFile(picturePath));
photo = scaleBitmap(a, 200, 200);
imageView.setImageBitmap(photo);
}
break;
}
public static Bitmap scaleBitmap(Bitmap bitmap, int newWidth, int newHeight) {
Bitmap scaledBitmap = Bitmap.createBitmap(newWidth, newHeight, Bitmap.Config.ARGB_8888);
float scaleX = newWidth / (float) bitmap.getWidth();
float scaleY = newHeight / (float) bitmap.getHeight();
float pivotX = 0;
float pivotY = 0;
Matrix scaleMatrix = new Matrix();
scaleMatrix.setScale(scaleX, scaleY, pivotX, pivotY);
Canvas canvas = new Canvas(scaledBitmap);
canvas.setMatrix(scaleMatrix);
canvas.drawBitmap(bitmap, 0, 0, new Paint(Paint.FILTER_BITMAP_FLAG));
return scaledBitmap;
}
The answer seems helpful for most of the people, but why it doesn't work for me ? Have I missed anything?
selected image display on imageView
解决方案
Use this it will definitely help you to reduce the size without loosing quality.
public Bitmap compressImage(String imageUri) {
String filePath = imageUri;
// String filePath = getRealPathFromURI(imageUri);
Bitmap scaledBitmap = null;
BitmapFactory.Options options = new BitmapFactory.Options();
// by setting this field as true, the actual bitmap pixels are not
// loaded in the memory. Just the bounds are loaded. If
// you try the use the bitmap here, you will get null.
options.inJustDecodeBounds = true;
Bitmap bmp = BitmapFactory.decodeFile(filePath, options);
int actualHeight = options.outHeight;
int actualWidth = options.outWidth;
// max Height and width values of the compressed image is taken as
// 816x612
/*
* float maxHeight = 816.0f; float maxWidth = 612.0f;
*/
float maxHeight = 1080.0f;
float maxWidth = 800.0f;
float imgRatio = actualWidth / (float) actualHeight;
float maxRatio = maxWidth / (float) maxHeight;
// width and height values are set maintaining the aspect ratio of the
// image
if (actualHeight > maxHeight || actualWidth > maxWidth) {
if (imgRatio < maxRatio) {
imgRatio = maxHeight / actualHeight;
actualWidth = (int) (imgRatio * actualWidth);
actualHeight = (int) maxHeight;
} else if (imgRatio > maxRatio) {
imgRatio = maxWidth / actualWidth;
actualHeight = (int) (imgRatio * actualHeight);
actualWidth = (int) maxWidth;
} else {
actualHeight = (int) maxHeight;
actualWidth = (int) maxWidth;
}
}
// setting inSampleSize value allows to load a scaled down version of
// the original image
options.inSampleSize = calculateInSampleSize(options, actualWidth, actualHeight);
// inJustDecodeBounds set to false to load the actual bitmap
options.inJustDecodeBounds = false;
// this options allow android to claim the bitmap memory if it runs low
// on memory
options.inPurgeable = true;
options.inInputShareable = true;
options.inTempStorage = new byte[16 * 1024];
try {
// load the bitmap from its path
bmp = BitmapFactory.decodeFile(filePath, options);
} catch (OutOfMemoryError exception) {
exception.printStackTrace();
}
try {
scaledBitmap = Bitmap.createBitmap(actualWidth, actualHeight, Bitmap.Config.ARGB_8888);
} catch (OutOfMemoryError exception) {
exception.printStackTrace();
}
float ratioX = actualWidth / (float) options.outWidth;
float ratioY = actualHeight / (float) options.outHeight;
float middleX = actualWidth / 2.0f;
float middleY = actualHeight / 2.0f;
Matrix scaleMatrix = new Matrix();
scaleMatrix.setScale(ratioX, ratioY, middleX, middleY);
Canvas canvas = new Canvas(scaledBitmap);
canvas.setMatrix(scaleMatrix);
canvas.drawBitmap(bmp, middleX - bmp.getWidth() / 2, middleY - bmp.getHeight() / 2, new Paint(Paint.FILTER_BITMAP_FLAG));
// check the rotation of the image and display it properly
ExifInterface exif;
try {
exif = new ExifInterface(filePath);
int orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, 0);
displayLogs("EXIF", "Exif: " + orientation);
Matrix matrix = new Matrix();
if (orientation == 6) {
matrix.postRotate(90);
displayLogs("EXIF", "Exif: " + orientation);
} else if (orientation == 3) {
matrix.postRotate(180);
displayLogs("EXIF", "Exif: " + orientation);
} else if (orientation == 8) {
matrix.postRotate(270);
displayLogs("EXIF", "Exif: " + orientation);
}
scaledBitmap = Bitmap.createBitmap(scaledBitmap, 0, 0, scaledBitmap.getWidth(), scaledBitmap.getHeight(), matrix, true);
} catch (IOException e) {
e.printStackTrace();
}
FileOutputStream out = null;
String filename = getFilename(filePath);
// File image = new File(getFilename(), System.currentTimeMillis() +
// ".jpg");
try {
out = new FileOutputStream(filename);
// write the compressed bitmap at the destination specified by
// filename.
boolean didWrite = scaledBitmap.compress(Bitmap.CompressFormat.JPEG, 80, out);
out.close();
System.out.println(didWrite);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return scaledBitmap;
}
private String getRealPathFromURI(String contentURI) {
Uri contentUri = Uri.parse(contentURI);
Cursor cursor = getContentResolver().query(contentUri, null, null, null, null);
if (cursor == null) {
return contentUri.getPath();
} else {
cursor.moveToFirst();
int index = cursor.getColumnIndex(MediaStore.Images.ImageColumns.DATA);
return cursor.getString(index);
}
}
public int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) {
final int height = options.outHeight;
final int width = options.outWidth;
int inSampleSize = 1;
if (height > reqHeight || width > reqWidth) {
final int heightRatio = Math.round((float) height / (float) reqHeight);
final int widthRatio = Math.round((float) width / (float) reqWidth);
inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;
}
final float totalPixels = width * height;
final float totalReqPixelsCap = reqWidth * reqHeight * 2;
while (totalPixels / (inSampleSize * inSampleSize) > totalReqPixelsCap) {
inSampleSize++;
}
return inSampleSize;
}
public String getFilename(String originalname) {
ImageCache imageCache = new ImageCache(this);
File file = new File("Your folder path");
// return file;
String uriSting = (file.getAbsolutePath() + "/" + "F_" + System.currentTimeMillis() + ".png");
return uriSting;
}
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![原始图像](\"http://i.stack.imgur.com/BaGsn.jpg\"){kind=link}
![上的ImageView](\"http://i.stack.imgur.com/ZGAuZ.jpg\"){kind=link}
