I have confusion between android bitmap scaling and sampling here may have two code one for scaling and another for sampling can anyone help me for identifying working of this two code and what is main differences between them.
Scaling :
public static Bitmap getScaleBitmap(Bitmap bitmap, int newWidth, int newHeight) {
int width = bitmap.getWidth();
int height = bitmap.getHeight();
float scaleWidth = ((float) newWidth) / width;
float scaleHeight = ((float) newHeight) / height;
Matrix matrix = new Matrix();
matrix.postScale(scaleWidth, scaleHeight);
return Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, false);
}
Sampling :
mImageView.setImageBitmap(decodeSampledBitmapFromResource(getResources(),R.id.myimage, 100, 100));
public static Bitmap decodeSampledBitmapFromResource(Resources res, int resId,
int reqWidth, int reqHeight) {
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeResource(res, resId, options);
options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
options.inJustDecodeBounds = false;
return BitmapFactory.decodeResource(res, resId, options);
}
public static 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 halfHeight = height / 2;
final int halfWidth = width / 2;
while ((halfHeight / inSampleSize) >= reqHeight
&& (halfWidth / inSampleSize) >= reqWidth) {
inSampleSize *= 2;
}
}
return inSampleSize;
}
here both code perform image resizing but different way so how I can identify which one is good and simple.
First code, takes bitmap and creates new smaller bitmap - you would use memmory for the bigger bitmap.
Second code takes resource. inJustDecodeBounds Makes it so you not load the whole bitmap into memmory just information for it. Then calculate how it should be sized, and then again when set inJustDecodeBounds to false load into memmory reduced version of the image. So you would use memmory only for the decoded image
Oficial docs
Scaling: First, you decode the whole bitmap in memory, then you scale it.
Sampling: You get the required scaled bitmap without loading the whole bitmap in memory.
Related
This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 6 years ago.
From the logcat I understand that the Activity crashes because of NullPointerException causes by this line of code.
mImageView.setImageBitmap(decodeSampledBitmapFromResource(getResources(),
R.id.picture, imageWidth, imageHeight));
I have read articles about similar problem but still getting NullPointerException. I think that mistake right under my nose, but still I can't catch it.
Where should I put this line to avoid NullPointerException?
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
...
ImageView mImageView = (ImageView) findViewById(R.id.picture);
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeResource(getResources(), R.id.picture, options);
int imageHeight = options.outHeight;
int imageWidth = options.outWidth;
mImageView.setImageBitmap(decodeSampledBitmapFromResource(getResources(),
R.id.picture, imageWidth, imageHeight));
}
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) {
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;
}
and here is ImageView from layout.
<ImageView
android:layout_height="240dp"
android:layout_width="199dp"
android:src="#drawable/galaxy"
android:id="#+id/picture"
android:layout_gravity="center_horizontal"
android:scaleType="fitCenter"
android:layout_weight="0.19" />
There is a cleaner alternative to display a bitmap onto a imageview.
Try this:
private Bitmap bitmap_image;
Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//get image from resources
bitmap_image = BitmapFactory.decodeResource(getResources(), R.drawable.picture);
ImageView mImageView = (ImageView) findViewById(R.id.picture);
mImageView.setImageBitmap(bitmap_image);
}
-To retrieve a image from resources and store it into a bitmap, use BitmapFactory.decodeResource(getResources(), R.drawable.yourimagename);
-at this point you can directly set the image to a imageView. If you want to manipulate the size of the image here is a function that will resize a bitmap:
public Bitmap getResizedBitmap(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;
}
-If you need clarification on the re-sizing of the bitmap, refer to this stackoverflow post:
How to Resize a Bitmap in Android?
-if you need a full working example, i have a activity that utilizes retrieving a image from resources and storing it into a bitmap and then displaying it on screen. The only part I do not have that you request, is displaying the bitmap in a imageView.
Github class link:
https://github.com/Rifat-Rashid/thePlatformer/blob/master/MainActivity.java
I am displaying an image in full screen mode,but whenever going to display large image then nothing display in the image view. Below code try to resize bitmap but got same result blank imageview.
public static Bitmap getResizedBitmap(Bitmap bm, int newHeight, int newWidth) {
int width = bm.getWidth();
int height = bm.getHeight();
float scaleWidth = ((float) newWidth) / width;
float scaleHeight = ((float) newHeight) / height;
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;
}
You solve your problem from two mehtods
Method 1
call this method(function)
public Bitmap decodeImage(int resourceId) {
try {
// Decode image size
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;
BitmapFactory.decodeResource(getResources(), resourceId, o);
// The new size we want to scale to
final int REQUIRED_SIZE = 100; // you are free to modify size as your requirement
// Find the correct scale value. It should be the power of 2.
int scale = 1;
while (o.outWidth / scale / 2 >= REQUIRED_SIZE && o.outHeight / scale / 2 >= REQUIRED_SIZE)
scale *= 2;
// Decode with inSampleSize
BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize = scale;
return BitmapFactory.decodeResource(getResources(), resourceId, o2);
} catch (Throwable e) {
e.printStackTrace();
}
return null;
}
add this before your adapter
picture.setImageBitmap((decodeImage(item.drawableId));
instead of
picture.setImageResource(item.drawableId);
Mehtod 2
You need to adjust your image size. The better way is to decode the image to a bitmap, and set the bitmap to the ImageView. For example:
BitmapFactory.Options opts = new BitmapFactory.Options();
opts.inSampleSize = 4;
Bitmap bitmap = BitmapFactory.decodeResource(getResources(), item.drawableId, opts);
picture.setImageBitmap (bitmap);
I had the same problem. Got is solved through the following code.
Provide the filepath, desired width and desired height to the method. For more reference see here
public static Bitmap decodeScaledBitmapFromSdCard(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 = calculateInSampleSize(options, reqWidth, reqHeight);
// Decode bitmap with inSampleSize set
options.inJustDecodeBounds = false;
return BitmapFactory.decodeFile(filePath, 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;
}
Probably the image size is too large that the system cannot allocate enough memory to load it.
you can try loading your image after scaling it it with BitmapFactory.Options sampleSize
check this link for more info
http://developer.android.com/training/displaying-bitmaps/load-bitmap.html
may be this will work for you
public static Bitmap decodeSampledBitmapFromResource(String pathName,
int reqWidth, int reqHeight) {
// First decode with inJustDecodeBounds=true to check dimensions
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(pathName, options);
// Calculate inSampleSize
options.inSampleSize = calculateInSampleSize(options, reqWidth,
reqHeight);
// Decode bitmap with inSampleSize set
options.inJustDecodeBounds = false;
return BitmapFactory.decodeFile(pathName, 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) {
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;
}
You solve your problem in Fragment
Add method in adapter
public Bitmap decodeImage(int gridViewImageId) {
try {
// Decode image size
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;
BitmapFactory.decodeResource(mContext.getResources(), gridViewImageId, o);
// The new size we want to scale to
final int REQUIRED_SIZE = 100; // you are free to modify size as your requirement
// Find the correct scale value. It should be the power of 2.
int scale = 1;
while (o.outWidth / scale / 2 >= REQUIRED_SIZE && o.outHeight / scale / 2 >= REQUIRED_SIZE)
scale *= 2;
// Decode with inSampleSize
BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize = scale;
return BitmapFactory.decodeResource(mContext.getResources(), gridViewImageId, o2);
} catch (Throwable e) {
e.printStackTrace();
}
return null;
}
and add this line
imageViewAndroid.setImageBitmap(decodeImage(gridViewImageId[i]));
In my application I use an SQLite database to store the data of a lot of images. Some images can be up to 600x600 pixels. I use a custom list to create the bitmaps. I know there is a method bitmap.recycle(); but I'm not sure how to use that with a listview.
Here is the solution to handle bitmaps in android
First, you should calculate the sampleBitmapSize of the bitmap ( to load the lower version of the same bitmap )
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);
}
Below is the util function to calculate InSampleSize ( an integer that defines the value (rating) of quality of a bitmap).
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;
}
}
Log.i("ImageUtil", "InSampleSize: "+inSampleSize);
return inSampleSize;
}
I have this
Bitmap appWidgetBitmap = Bitmap.createBitmap(availableWidth, availableHeight, Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(appWidgetBitmap);
And in the log console I see this
"dalvikvm-heap Grow heap (frag case) to......byte allocation
How can I make Bitmap with the lowest resources possible?
I saw something on BitmapFactory, but how to do it because the code above is createBitmap, not from resources.
Use below methods for resizing the image as aspect ratio:
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(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;
// BitmapFactory.decodeResource(res, resId, options);
return Bitmap.createScaledBitmap(
BitmapFactory.decodeResource(res, resId, options), reqWidth,
reqHeight, true);
}
Then decode your image into bitmap format and set into the Canvas:
Bitmap src = decodeSampledBitmapFromResource(getResources(),
R.drawable.ic_bg_box, imgWidth, imgHeight);
Canvas canvas = new Canvas(src);
I hope this will help you.
im having problems with high resolution images.
Im using nodpi-drawable folder for 1280x720 images, and using this code to scale it.
public static Drawable scaleDrawable(Drawable d, int width, Activity cxt)
{
BitmapDrawable bd = (BitmapDrawable)d;
double oldWidth = bd.getBitmap().getWidth();
double scaleFactor = width / oldWidth;
int newHeight = (int) (d.getIntrinsicHeight() * scaleFactor);
int newWidth = (int) (oldWidth * scaleFactor);
Drawable drawable = new BitmapDrawable(cxt.getResources(),MainScreen.getResizedBitmap(bd.getBitmap(),newHeight,newWidth));
BitmapDrawable bd2 = (BitmapDrawable)drawable;
return drawable;
}
public static Bitmap getResizedBitmap(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;
}
I use that code to scale images to screen witdh so if the screen is 320x480 the image will scale to 320 and keep proportions, i dont care if image go out of screen from bottom.
All its working fine, but when trying in a xhdpi device specifically a Samsung Galaxy Note 2 with a screen of exactly 720x1280.
It crash with Out Of Memory Exception in the line:
Bitmap resizedBitmap = Bitmap.createBitmap(bm, 0, 0, width, height, matrix, false);
I cant understand why, the image should be scaled from 720 to 720 but my code must be really bad optimized or something.
I havent tried on a 1080x1920 device but it seems it will crash too.
Someone can see something bad when looking at the code?
use this method to resize your bitmap-
Bitmap bm=decodeSampledBitmapFromPath(src, reqWidth, reqHeight);
use this Defination-
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;
}
If you are using resource then replace method with BitmapFactory's decodeResource method..
public static Bitmap decodeSampledBitmapFromResource(Resources res, int resId,
int reqWidth, int reqHeight) {
....
.....
return BitmapFactory.decodeResource(res, resId, options);
}
You should use the utility class BitmapFactory for image-processing-operations. Also use BitmapFactory.Options to adjust the input/output sizes of the bitmaps. After a bitmap is not needed anymore, you should free the related memory.