Develop Reference

Bitmap null when attempting to load scaled down version

I'm attempting to scale down a bitmap to load a smaller version into memory. I'm pretty much following Google's example (search Loading Large Bitmaps Efficiently), except that I'm loading from the image gallery instead of a resource. But I seem to be getting back a null bitmap after calculating dimensions. Here's my code:
/** OnActivityResult Method **/
final Uri imageUri = data.getData();
final InputStream imageStream = getActivity().getContentResolver().openInputStream(imageUri);
Bitmap bitmapToLoad = Util.decodeSampledBitmapFromResource(imageStream, 500, 500); // bitmapToLoad is null.
mIvScreenshot.setImageBitmap(bitmapToLoad);
/**Helper Methods **/
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) {
final int halfHeight = height / 2;
final int halfWidth = width / 2;
// Calculate the largest inSampleSize value that is a power of 2 and keeps both
// height and width larger than the requested height and width.
while ((halfHeight / inSampleSize) >= reqHeight
&& (halfWidth / inSampleSize) >= reqWidth) {
inSampleSize *= 2;
}
}
return inSampleSize;
}
public static Bitmap decodeSampledBitmapFromResource(InputStream is,
int reqWidth, int reqHeight) {
Rect rect = new Rect();
// First decode with inJustDecodeBounds = true to check dimensions
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeStream(is, rect, options);
// Calculate inSampleSize
options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
// Decode bitmap with inSampleSize set
options.inJustDecodeBounds = false;
return BitmapFactory.decodeStream(is, rect, options);
}
Can anyone catch what I'm doing wrong?

I managed to get it working. Thanks to Biraj Zalavadia (How to reduce an Image file size before uploading to a server) for the scaling logic, and the cursor code here (How to return workable filepath?). Here is my onActivityResult():
try {
final Uri imageUri = data.getData();
String[] filePath = { MediaStore.Images.Media.DATA };
Cursor cursor = getActivity().getContentResolver().query(imageUri, filePath, null, null, null);
cursor.moveToFirst();
String imagePath = cursor.getString(cursor.getColumnIndex(filePath[0]));
Uri newUri = Uri.parse(ScalingUtilities.scaleFileAndSaveToTmp(imagePath, 500, 500));
final Bitmap selectedImage = BitmapFactory.decodeFile(newUri.getEncodedPath());
mIvScreenshot.setImageBitmap(selectedImage);
} catch (Exception e) {
// Handle
}

Sampling a bitmap from url

I am trying to reduce the size of bitmap from a url. I saw many posts, but all were about sampling a local file. I want to sample the image at url. Here is my code:
public Bitmap getScaledFromUrl(String url) {
BitmapFactory.Options bmOptions = new BitmapFactory.Options();
bmOptions.inSampleSize = 1 / 10;
try {
return BitmapFactory.decodeStream((InputStream) new URL(url)
.getContent());
} catch (MalformedURLException e) {
e.printStackTrace();
return null;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
Is this approach correct? I am getting out of memory crashes in my app at this function. Any ideas?

This works. I found it at http://blog.vandzi.com/2013/01/get-scaled-image-from-url-in-android.html . Use the following snippet of code, pass params as you like.
private static Bitmap getScaledBitmapFromUrl(String imageUrl, int requiredWidth, int requiredHeight) throws IOException {
URL url = new URL(imageUrl);
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeStream(url.openConnection().getInputStream(), null, options);
options.inSampleSize = calculateInSampleSize(options, requiredWidth, requiredHeight);
options.inJustDecodeBounds = false;
//don't use same inputstream object as in decodestream above. It will not work because
//decode stream edit input stream. So if you create
//InputStream is =url.openConnection().getInputStream(); and you use this in decodeStream
//above and bellow it will not work!
Bitmap bm = BitmapFactory.decodeStream(url.openConnection().getInputStream(), null, options);
return bm;
}
private 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);
}
}
return inSampleSize;
}
It's really flexible.. I think you should try it out.

You are using it wrong. You are asking to make the picture 10 times bigger :) You should give the command in normal numbers, not fraction. For example:
final BitmapFactory.Options options2 = new BitmapFactory.Options();
options2.inSampleSize = 8;
b = BitmapFactory.decodeFile(image, options2);
with this configuration you obtain 8 times smaller picture than the original.
UPDATE: To load image from internet add this class to the project and do the following:
ImageLoader loader = new ImageLoader(context);
Bitmap image = loader.getBitmap(URL);

Image is not downloading?

I'm learning to download images, by managing bitmaps. I used BitmapFactory:options.inJustDecodeBounds to download images.When i use this statement,
Bitmap bitmap = BitmapFactory.decodeStream(in) -it works.
But when i used sample size and tried to calculate, its not downloading. i used something like this:
public Bitmap downloadUrlToStream(String urlString, final ImageView imageView) {
HttpURLConnection urlConnection = null;
BufferedInputStream in = null;
try {
final URL url = new URL(urlString);
urlConnection = (HttpURLConnection) url.openConnection();
in = new BufferedInputStream(urlConnection.getInputStream(), IO_BUFFER_SIZE);
return decodeSampledBitmapFromResource(200,200,in);
} catch (final IOException e) {
Log.e(TAG, "Error in downloadBitmap - " + e);
} finally {
if (urlConnection != null) {
urlConnection.disconnect();
}
try {
if (in != null) {
in.close();
}
} catch (final IOException e) {
}
}
return null; }
public static Bitmap decodeSampledBitmapFromResource(int reqWidth, int reqHeight, InputStream is) {
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeStream(is, null, options);
// Calculate inSampleSize
options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
options.inJustDecodeBounds = false;
return BitmapFactory.decodeStream(is, null, options);
}
public static int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) {
// BEGIN_INCLUDE (calculate_sample_size)
// Raw height and width of image
final int height = options.outHeight;
final int width = options.outWidth;
int inSampleSize = 1;
if (height > reqHeight || width > reqWidth) {
final int halfHeight = height / 2;
final int halfWidth = width / 2;
// Calculate the largest inSampleSize value that is a power of 2 and
// keeps both
// height and width larger than the requested height and width.
while ((halfHeight / inSampleSize) > reqHeight && (halfWidth / inSampleSize) > reqWidth) {
inSampleSize *= 2;
}
// 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).
long totalPixels = width * height / inSampleSize;
// Anything more than 2x the requested pixels we'll sample down
// further
final long totalReqPixelsCap = reqWidth * reqHeight * 2;
while (totalPixels > totalReqPixelsCap) {
inSampleSize *= 2;
totalPixels /= 2;
}
}
return inSampleSize;
// END_INCLUDE (calculate_sample_size)
}
Is there a problem with calculateSamplesize() method. Y its not working?

You can able to download and resize the bitmap using Universal imageLoader, here is the sample code,
protected ImageLoader imageLoader = ImageLoader.getInstance();
DisplayImageOptions options;
options = new DisplayImageOptions.Builder().resetViewBeforeLoading()
.cacheOnDisc().imageScaleType(ImageScaleType.IN_SAMPLE_INT)
.bitmapConfig(Bitmap.Config.RGB_565)
.displayer(new FadeInBitmapDisplayer(100)).build();
imageLoader.init(ImageLoaderConfiguration.createDefault(getActivity()));
imageLoader.displayImage(
<Image_URL>,
<Image_view>, options, new ImageLoadingListener() {
#Override
public void onLoadingComplete(String imageUri,
View view, Bitmap loadedImage) {
<Image_view>.setImageBitmap(resizedBitmap(loadedImage,200,200));
}
#Override
public void onLoadingStarted(String imageUri, View view) {
// TODO Auto-generated method stub
}
#Override
public void onLoadingFailed(String imageUri, View view,
FailReason failReason) {
// TODO Auto-generated method stub
}
#Override
public void onLoadingCancelled(String imageUri,
View view) {
// TODO Auto-generated method stub
}
});
// Image resize
public Bitmap resizedBitmap(Bitmap bm, int newHeight, int newWidth) {
int width = bm.getWidth();
int height = bm.getHeight();
float scaleWidth = ((float) newWidth) / width;
float scaleHeight = ((float) newHeight) / height;
// CREATE A MATRIX FOR THE MANIPULATION
Matrix matrix = new Matrix();
// RESIZE THE BIT MAP
matrix.postScale(scaleWidth, scaleHeight);
// RECREATE THE NEW BITMAP
Bitmap resizedBitmap = Bitmap.createBitmap(bm, 0, 0, width, height, matrix, false);
return resizedBitmap;
}
Note:
Don't forget to add universal image loader library.

I recommend you a different way that works like a charm: Android Query.
You can download that jar file from here: http://code.google.com/p/android-query/downloads/list
AQuery androidAQuery=new AQuery(this);
As an example:
androidAQuery.id(YOUR IMAGEVIEW).image(YOUR IMAGE TO LOAD, true, true, getDeviceWidth(), ANY DEFAULT IMAGE YOU WANT TO SHOW);
Using above code you can directly show your Image through url. Now below code is to get Bitmap Directly from the url:
androidAQuery.ajax(YOUR IMAGE URL,Bitmap.class,0,new AjaxCallback<Bitmap>(){
#Override
public void callback(String url, Bitmap object, AjaxStatus status) {
super.callback(url, object, status);
//You will get Bitmap from object.
}
});
This library is provided by Android itself, so use it and see the result whatever you want.
It's very fast and accurate, and using this you can find many more features like Animation when loading, getting a bitmap, if needed, etc.

There is no reason for it not to work. Make sure your calculateInSampleSize works properly.
options.inSampleSize need to be higher than 1. Make sure you are getting a valid value here.

Try below code:
public void DownloadImageFromPath(String path){
InputStream in =null;
Bitmap bmp=null;
ImageView iv = (ImageView)findViewById(R.id.img1);
int responseCode = -1;
try{
URL url = new URL(path);//"http://192.xx.xx.xx/mypath/img1.jpg
HttpURLConnection con = (HttpURLConnection)url.openConnection();
con.setDoInput(true);
con.connect();
responseCode = con.getResponseCode();
if(responseCode == HttpURLConnection.HTTP_OK)
{
//download
in = con.getInputStream();
bmp = BitmapFactory.decodeStream(in);
in.close();
iv.setImageBitmap(bmp);
}
}
catch(Exception ex){
Log.e("Exception",ex.toString());
}
}

Just get the downloaded file in bitmap and set the bitmap in imageView
URL url = new URL(urlString);
Bitmap bmp = BitmapFactory.decodeStream(url.openConnection().getInputStream());
imageView.setImageBitmap(bmp);
Hope that helps

How to change the size of the image without changing resoultion?

I am developing an app in which i want to reduce the size of my image.For example if size is 1MB then i want it to get reduce into kb.
But resolution should not get changed.
Can anyone help in this?
I tried this code but its not working
public static Bitmap resizeBitMapImage1(String filePath, int targetWidth, int targetHeight) {
Bitmap bitMapImage = null;
try {
Options options = new Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(filePath, options);
double sampleSize = 0;
Boolean scaleByHeight = Math.abs(options.outHeight - targetHeight) >= Math.abs(options.outWidth
- targetWidth);
if (options.outHeight * options.outWidth * 2 >= 1638) {
sampleSize = scaleByHeight ? options.outHeight / targetHeight : options.outWidth / targetWidth;
sampleSize = (int) Math.pow(2d, Math.floor(Math.log(sampleSize) / Math.log(2d)));
}
options.inJustDecodeBounds = false;
options.inTempStorage = new byte[128];
while (true) {
try {
options.inSampleSize = (int) sampleSize;
bitMapImage = BitmapFactory.decodeFile(filePath, options);
break;
} catch (Exception ex) {
try {
sampleSize = sampleSize * 2;
} catch (Exception ex1) {
}
}
}
} catch (Exception ex) {
}
return bitMapImage;
}
Using this code it reduces the resolution but not much size of the image.
I also tried
public static Bitmap reduceImgSizeToHundredKB(Bitmap bitmap) {
Bitmap scaled = bitmap;
try {
ByteArrayOutputStream stream = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.JPEG, 70, stream);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
return null;
}
return scaled;
}

If you don't want to resize your image then your only option is to compress it.
Here is an example on how to do that:
byte[] data = null;
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bi.compress(Bitmap.CompressFormat.JPEG, 100, baos);
data = baos.toByteArray();

In my thought, In most cases, we can't do that. Because it related to resolution of the image and the color range of the image.
so, If we have a large image with a lot of colors, then reduce the size of the image will induce to reduce resolution of it.

There are two aproches: lossy (where you'll lose quality of the image) and lossless.
The answer provided by rickman is lossy so it will work well but reduce the quality of the image - it works particularly well for pictures taken with a camera.
The lossless approach is using PNG, which consists of using Bitmap.CompressFormat.PNG as argument to the compress method.
A not as well known but very efficient format is WebP. It's also available as an argument to the compress method (Bitmap.CompressFormat.PNG). I'd suggest testing with WebP, specially considering it supports both lossy and lossless compression.

Use this method if you are decoding from path
public Bitmap decodeSampledBitmapFromPath(String path, int reqWidth,
int reqHeight) {
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(path, options);
options.inSampleSize = calculateInSampleSize(options, reqWidth,
reqHeight);
// Decode bitmap with inSampleSize set
options.inJustDecodeBounds = false;
Bitmap bmp = BitmapFactory.decodeFile(path, options);
return bmp;
}
}
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) {
if (width > height) {
inSampleSize = Math.round((float) height / (float) reqHeight);
} else {
inSampleSize = Math.round((float) width / (float) reqWidth);
}
}
return inSampleSize;
}
Use this if you are decoding from resources
public static Bitmap decodeSampledBitmapFromResource(Resources res, int resId,
int reqWidth, int reqHeight) {
// First decode with inJustDecodeBounds=true to check dimensions
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeResource(res, resId, options);
// Calculate inSampleSize
options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
// Decode bitmap with inSampleSize set
options.inJustDecodeBounds = false;
return BitmapFactory.decodeResource(res, resId, options);
}
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) {
// Calculate ratios of height and width to requested height and width
final int heightRatio = Math.round((float) height / (float) reqHeight);
final int widthRatio = Math.round((float) width / (float) reqWidth);
// Choose the smallest ratio as inSampleSize value, this will guarantee
// a final image with both dimensions larger than or equal to the
// requested height and width.
inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;
}
return inSampleSize;
}

If you want to reduce the file size of the image without losing a great ammount of quality you can do this:
First you need to flatten the image, then save it for web (ctrl+alt+shift+s)
Then select the preset PNG-8 128 Dithered.
You can now customize this preset by setting the colors to "256", then select "selective" under the PNG-8, under "selective" change dither to "diffusion", deselect the "interlaced" option and make shure that the web snap option is set to 0%.

Images does not get displayed in ImageButton

I am displaying images from the string path (which I retrieve from database) and I have no problem displaying one image. But when I have 4 images, only one image (the first image) gets displayed and the others are not displayed. My code is as followed:
try{
name.setText(nameString);
school.setText(schoolString);
psupervisor.setText(info.getPsupervisor());
pdate.setText(info.getPdate());
a.setChecked(Boolean.parseBoolean(info.getPtick1()));
b.setChecked(Boolean.parseBoolean(info.getPtick2()));
c.setChecked(Boolean.parseBoolean(info.getPtick3()));
pcomment1.setText(info.getPcomment1());
psignature1.setImageBitmap(resizeSignatureBitmap(info.getPsignature1()));
pcomment2.setText(info.getPcomment2());
psignature2.setImageBitmap(resizeSignatureBitmap(info.getPsignature2()));
pdate2.setText(info.getPdate2());
d.setChecked(Boolean.parseBoolean(info.getPtick4()));
e.setChecked(Boolean.parseBoolean(info.getPtick5()));
f.setChecked(Boolean.parseBoolean(info.getPtick6()));
pcomment3.setText(info.getPcomment3());
psignature3.setImageBitmap(resizeSignatureBitmap(info.getPsignature3()));
pcomment4.setText(info.getPcomment4());
psignature4.setImageBitmap(resizeSignatureBitmap(info.getPsignature4()));
Log.d("PREPOST: ", log2);
db.close();
}
catch(Exception ex){}
}
//method to resize the bitmap before displaying
public Bitmap resizeSignatureBitmap(String imagePath){
BitmapFactory.Options options = new BitmapFactory.Options();
InputStream is = null;
try {
is = new FileInputStream(imagePath);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
BitmapFactory.decodeStream(is,null,options);
try {
is.close();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
try {
is = new FileInputStream(imagePath);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
// here w and h are the desired width and height
options.inSampleSize = Math.max(options.outWidth/w, options.outHeight/h);
// bitmap is the resized bitmap
Bitmap bitmap = BitmapFactory.decodeStream(is,null,options);
return bitmap;
}
Is there anything wrong with what I'm doing? Please kindly point my mistake out as I can't find my mistake. No errors, nothing, just that it doesn't get displayed. By default, it only displays one image and it's always the first image (psignature1) and if I comment it out, then second image (psignature2) would get displayed but the rest would not be displayed.
Thank you for your time!

//method to resize the bitmap before displaying
public Bitmap resizeSignatureBitmap(String imagePath){
BitmapFactory.Options options = new BitmapFactory.Options();
InputStream is = null;
try {
is = new FileInputStream(imagePath);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
// here w and h are the desired width and height
options.inSampleSize = Math.max(options.outWidth/w, options.outHeight/h);
// bitmap is the resized bitmap
Bitmap bitmap = BitmapFactory.decodeStream(is,null,options);
is=null;
return bitmap;
}
write your method like this..and you are done.

It is possible that your psignature1, psignature2, psignature3
is defined by the same id
Maybe your code is like this
psignature1 = (ImageButton) findViewById(R.id.psignature1);
psignature2 = (ImageButton) findViewById(R.id.psignature1);
psignature3 = (ImageButton) findViewById(R.id.psignature1);
Try changing each id
Here's my bitmap compressor for images in sd card,
just edit it
public Bitmap compressBitmapResource(String filePath, int reqWidth,
int reqHeight) {
// First decode with inJustDecodeBounds=true to check dimensions
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(filePath, options);
// Calculate inSampleSize
options.inSampleSize = calculateBitmapSize(options, reqWidth,
reqHeight);
// Decode bitmap with inSampleSize set
options.inPurgeable = true;
options.inJustDecodeBounds = false;
return BitmapFactory.decodeFile(filePath, options);
}
public int calculateBitmapSize(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);
}
}
return inSampleSize;
}