Develop Reference

How to reduce image size into 1MB

I want my application to upload image with no size limit, but in the code, I want to resize the image into 1MB if the image size exceeds. I have tried many ways but I couldn't find any code for the requirement I have mentioned above.
For once, I have tried this:
public void scaleDown() {
int width = stdImageBmp.getWidth();
int height = stdImageBmp.getHeight();
Matrix matrix = new Matrix();
float scaleWidth = ((float) MAX_WIDTH) / width;
float scaleHeight = ((float) MAX_HEIGHT) / height;
matrix.postScale(scaleWidth, scaleHeight);
stdImageBmp = Bitmap.createBitmap(stdImageBmp, 0, 0, width, height, matrix, true);
File Image = new File("path");
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
//compress bmp
stdImageBmp.compress(Bitmap.CompressFormat.JPEG, 100, byteArrayOutputStream);
byte[] byteArray = byteArrayOutputStream.toByteArray();
imgViewStd.setImageBitmap(stdImageBmp);
Log.d("resizedBitmap", stdImageBmp.toString());
width = stdImageBmp.getWidth();
height = stdImageBmp.getHeight();
System.out.println("imgWidth" + width);
System.out.println("imgHeight" + height);
}

you can use this code to resize a bitmap and for image size < 1MB i recommend use resolution of 480x640
public Bitmap getResizedBitmap(Bitmap bm, int newWidth, int newHeight) {
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
return Bitmap.createBitmap(
bm, 0, 0, width, height, matrix, false);
}

If you really want the Bitmap that scales down to the Bitmap that is the closest to a given amount of bytes, heres the method I use. (It does not uses a while loop)
NOTE: This method only works if passed bitmap is in ARGB_8888 configuration.
See: Compress bitmap to a specific byte size in Android for the conversion method.
/**
* Method to scale the Bitmap to respect the max bytes
*
* #param input the Bitmap to scale if too large
* #param maxBytes the amount of bytes the Image may be
* #return The scaled bitmap or the input if already valid
* #Note: The caller of this function is responsible for recycling once the input is no longer needed
*/
public static Bitmap scaleBitmap(final Bitmap input, final long maxBytes) {
final int currentWidth = input.getWidth();
final int currentHeight = input.getHeight();
final int currentPixels = currentWidth * currentHeight;
// Get the amount of max pixels:
// 1 pixel = 4 bytes (R, G, B, A)
final long maxPixels = maxBytes / 4; // Floored
if (currentPixels <= maxPixels) {
// Already correct size:
return input;
}
// Scaling factor when maintaining aspect ratio is the square root since x and y have a relation:
final double scaleFactor = Math.sqrt(maxPixels / (double) currentPixels);
final int newWidthPx = (int) Math.floor(currentWidth * scaleFactor);
final int newHeightPx = (int) Math.floor(currentHeight * scaleFactor);
Timber.i("Scaled bitmap sizes are %1$s x %2$s when original sizes are %3$s x %4$s and currentPixels %5$s and maxPixels %6$s and scaled total pixels are: %7$s",
newWidthPx, newHeightPx, currentWidth, currentHeight, currentPixels, maxPixels, (newWidthPx * newHeightPx));
final Bitmap output = Bitmap.createScaledBitmap(input, newWidthPx, newHeightPx, true);
return output;
}
Where the Sample use would look something like:
// (1 MB)
final long maxBytes = 1024 * 1024;
// Scale it
final Bitmap scaledBitmap = BitmapUtils.scaleBitmap(yourBitmap, maxBytes);
if(scaledBitmap != yourBitmap){
// Recycle the bitmap since we can use the scaled variant:
yourBitmap.recycle();
}
// ... do something with the scaled bitmap

I've tried to comment it but the comment become too big.
So, I've tested many solutions and it seems like there are only TWO solutions for this problem, which give some results.
Lets discuss Koen solution first. What it actually does is creates a scaled JPG
Bitmap.createScaledBitmap(input, newWidthPx, newHeightPx, true)
Seems like it does not compress it at all but just cuts off the resolution.
I've tested this code and when I pass MAX_IMAGE_SIZE = 1024000 it gives me 350kb compressed image out of 2.33Mb original image. Bug?
Also it lacks quality. I was unable to recognize a text on A4 sheet of paper photo made by Google Pixel.
There is another solution to this problem, which gives good quality, but lacks in speed.
A WHILE LOOP!
Basically you just loop through image size, until you get the desired size
private fun scaleBitmap() {
if (originalFile.length() > MAX_IMAGE_SIZE) {
var streamLength = MAX_IMAGE_SIZE
var compressQuality = 100
val bmpStream = ByteArrayOutputStream()
while (streamLength >= MAX_IMAGE_SIZE) {
bmpStream.use {
it.flush()
it.reset()
}
compressQuality -= 8
val bitmap = BitmapFactory.decodeFile(originalFile.absolutePath, BitmapFactory.Options())
bitmap.compress(Bitmap.CompressFormat.JPEG, compressQuality, bmpStream)
streamLength = bmpStream.toByteArray().size
}
FileOutputStream(compressedFile).use {
it.write(bmpStream.toByteArray())
}
}
}
I think that this approach will consume exponential time depending on image resolution.
9mb image takes up to 12 seconds to compress down to 1mb.
Quality is good.
You can tweak this by reducing the original bitmap resolution(which seems like a constant operation), by doing:
options.inSampleSize = 2;
What we need to do is to somehow calculate compressQuality for any image.
There should be a math around this, so we can determinate compressQuality from original image size or width + height.

Android - Does an ImageView resizes the image (and doesn't save the original)?

Quite a simple questions, can't find an answer..
I'm asking in order to know if even though the ImageView shows a smaller version of the original image - does it still use the full memory size of the original .. ?
(I refer to an image which was loaded from the SD-card and not from resources)

Yes, it will use the original size. You have to resize all your bitmaps before assign then to an ImageView, otherwise you will have a lot of problems with Out Of Memory Error.
You should also calculate the final size of you ImageView and resize the Bitmap.
Some code to get you going.
private static Bitmap createBitmap(#NonNull String filePath, int width )
{
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(filePath , options );
// Getting original image properties
int imageHeight = options.outHeight;
int imageWidth = options.outWidth;
int scale = -1;
if ( imageWidth < imageHeight ) {
scale = Math.round( imageHeight / width );
} else {
scale = Math.round(imageWidth / width);
}
if ( scale <= 0 )
scale = 1;
options.inSampleSize = scale;
options.inJustDecodeBounds = false;
// Create a resized bitmap
Bitmap scaledBitmap = BitmapFactory.decodeFile(filePath , options);
return scaledBitmap;
}
You should also consider:
Maintain all Bitmap operations outside the main Thread.
Handle Concurrency correctly
Make use of some open source lib, like this one

Reducing load image time and RAM

i am loading some bitmap from the gallery using the following code:
bitmap = (BitmapFactory.decodeFile(picturePath)).copy(Bitmap.Config.ARGB_8888, true);
bitmap = Bitmap.createScaledBitmap(bitmap, screenWidth, screenHeight, true);
bitmapCanvas = new Canvas(bitmap);
invalidate(); // refresh the screen
Question:
It seems that it takes so long time to load an image by first decode fully and copy, and then making scaling to fit for the screen width and height. It really actually does not need to load the pic with full density because I would not let the user to enlarge the imported image anyway.
In that way, are there any method to reduce the load time and RAM? (directly load a scaled-down image) How to further modify the above coding?

It may be worth trying RGB_565 instead of ARGB_8888 if you don't have transparency.

just have found the answer for this reducing RAM and load time and avoid outofmemory error from other similar questions.
//get importing bitmap dimension
Options op = new Options();
op.inJustDecodeBounds = true;
Bitmap pic_to_be_imported = BitmapFactory.decodeFile(picturePath, op);
final int x_pic = op.outWidth;
final int y_pic = op.outHeight;
//The new size we want to scale to
final int IMAGE_MAX_SIZE= (int) Math.max(DrawViewWidth, DrawViewHeight);
int scale = 1;
if (op.outHeight > IMAGE_MAX_SIZE || op.outWidth > IMAGE_MAX_SIZE)
{
scale = (int)Math.pow(2, (int) Math.round(Math.log(IMAGE_MAX_SIZE /
(double) Math.max(op.outHeight, op.outWidth)) / Math.log(0.5)));
}
final BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize = scale;
//Import the file using the o2 options: inSampleSized
bitmap = (BitmapFactory.decodeFile(picturePath, o2));
bitmap = bitmap.copy(Bitmap.Config.ARGB_8888, true);

Resize image generated by BitmapFactory.decodeByteArray()

I am creating audio player,I want to show the song cover to the player, it working with small image but if the mp3 file have large image then it goes out of layout view. I'm re-sizing image to 300x300 by using below code:
BitmapFactory.Options opt = new BitmapFactory.Options();
opt.inDensity = 300;
opt.inTargetDensity = 300;
songCoverView.setImageBitmap(BitmapFactory.decodeByteArray(songCover, 0, songCover.length, opt));
But it still shows larger and goes out of layout.
Whats wrong with this code?

Turns out that there's a bug in Android: decodeByteArray somehow ignores some input options. A known workaround is using decodeStream with input array wrapped into ByteArrayInputStream instead, like this:
BitmapFactory.Options opt = new BitmapFactory.Options();
opt.inDensity = 300;
opt.inTargetDensity = 300;
songCoverView.setImageBitmap(BitmapFactory.decodeStream(new ByteArrayInputStream(songConver), null, opt));

try Bitmap.createScaledBitmap
bitmap = Bitmap.createScaledBitmap(songCover, 300, 300, true);
And you can keep the same aspect ratio for the old image... I use the following logic:
int width = songCover.getWidth();
int height = songCover.getHeight();
float scaleHeight = (float)height/(float)300;
float scaleWidth = (float)width /(float)300;
if (scaleWidth < scaleHeight) scale = scaleHeight;
else scale = scaleWidth;
bitmap = Bitmap.createScaledBitmap(songCover, (int)(width/scale), (int)(height/scale), true);

you can use the property the Bitmap
Bitmap bitmap = Bitmap.createScaledBitmap(image, (int)x, (int)y, true);

Android how to create runtime thumbnail

I have a large sized image. At runtime, I want to read the image from storage and scale it so that its weight and size gets reduced and I can use it as a thumbnail. When a user clicks on the thumbnail, I want to display the full-sized image.

Try this
Bitmap ThumbImage = ThumbnailUtils.extractThumbnail(BitmapFactory.decodeFile(imagePath), THUMBSIZE, THUMBSIZE);
This Utility is available from API_LEVEl 8. [Source]

My Solution
byte[] imageData = null;
try
{
final int THUMBNAIL_SIZE = 64;
FileInputStream fis = new FileInputStream(fileName);
Bitmap imageBitmap = BitmapFactory.decodeStream(fis);
imageBitmap = Bitmap.createScaledBitmap(imageBitmap, THUMBNAIL_SIZE, THUMBNAIL_SIZE, false);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
imageBitmap.compress(Bitmap.CompressFormat.JPEG, 100, baos);
imageData = baos.toByteArray();
}
catch(Exception ex) {
}

The best solution I found is the following. Compared with the other solutions this one does not need to load the full image for creating a thumbnail, so it is more efficient!
Its limit is that you can not have a thumbnail with exact width and height but the solution as near as possible.
File file = ...; // the image file
Options bitmapOptions = new Options();
bitmapOptions.inJustDecodeBounds = true; // obtain the size of the image, without loading it in memory
BitmapFactory.decodeFile(file.getAbsolutePath(), bitmapOptions);
// find the best scaling factor for the desired dimensions
int desiredWidth = 400;
int desiredHeight = 300;
float widthScale = (float)bitmapOptions.outWidth/desiredWidth;
float heightScale = (float)bitmapOptions.outHeight/desiredHeight;
float scale = Math.min(widthScale, heightScale);
int sampleSize = 1;
while (sampleSize < scale) {
sampleSize *= 2;
}
bitmapOptions.inSampleSize = sampleSize; // this value must be a power of 2,
// this is why you can not have an image scaled as you would like
bitmapOptions.inJustDecodeBounds = false; // now we want to load the image
// Let's load just the part of the image necessary for creating the thumbnail, not the whole image
Bitmap thumbnail = BitmapFactory.decodeFile(file.getAbsolutePath(), bitmapOptions);
// Save the thumbnail
File thumbnailFile = ...;
FileOutputStream fos = new FileOutputStream(thumbnailFile);
thumbnail.compress(Bitmap.CompressFormat.JPEG, 90, fos);
fos.flush();
fos.close();
// Use the thumbail on an ImageView or recycle it!
thumbnail.recycle();

Here is a more complete solution to scaling down a Bitmap to thumbnail size. It expands on the Bitmap.createScaledBitmap solution by maintaining the aspect ratio of the images and also padding them to the same width so that they look good in a ListView.
Also, it would be best to do this scaling once and store the resulting Bitmap as a blob in your Sqlite database. I have included a snippet on how to convert the Bitmap to a byte array for this purpose.
public static final int THUMBNAIL_HEIGHT = 48;
public static final int THUMBNAIL_WIDTH = 66;
imageBitmap = BitmapFactory.decodeByteArray(mImageData, 0, mImageData.length);
Float width = new Float(imageBitmap.getWidth());
Float height = new Float(imageBitmap.getHeight());
Float ratio = width/height;
imageBitmap = Bitmap.createScaledBitmap(imageBitmap, (int)(THUMBNAIL_HEIGHT*ratio), THUMBNAIL_HEIGHT, false);
int padding = (THUMBNAIL_WIDTH - imageBitmap.getWidth())/2;
imageView.setPadding(padding, 0, padding, 0);
imageView.setImageBitmap(imageBitmap);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
imageBitmap.compress(Bitmap.CompressFormat.PNG, 100, baos);
byte[] byteArray = baos.toByteArray();

Use BitmapFactory.decodeFile(...) to get your Bitmap object and set it to an ImageView with ImageView.setImageBitmap().
On the ImageView set the layout dimensions to something small, eg:
android:layout_width="66dip" android:layout_height="48dip"
Add an onClickListener to the ImageView and launch a new activity, where you display the image in full size with
android:layout_width="wrap_content" android:layout_height="wrap_content"
or specify some larger size.

/**
* Creates a centered bitmap of the desired size.
*
* #param source original bitmap source
* #param width targeted width
* #param height targeted height
* #param options options used during thumbnail extraction
*/
public static Bitmap extractThumbnail(
Bitmap source, int width, int height, int options) {
if (source == null) {
return null;
}
float scale;
if (source.getWidth() < source.getHeight()) {
scale = width / (float) source.getWidth();
} else {
scale = height / (float) source.getHeight();
}
Matrix matrix = new Matrix();
matrix.setScale(scale, scale);
Bitmap thumbnail = transform(matrix, source, width, height,
OPTIONS_SCALE_UP | options);
return thumbnail;
}

I found an easy way to do this
Bitmap thumbnail = ThumbnailUtils.extractThumbnail(BitmapFactory.decodeFile(mPath),200,200)
Syntax
Bitmap thumbnail = ThumbnailUtils.extractThumbnail(Bitmap source,int width,int height)
OR
use Picasso dependancy
compile 'com.squareup.picasso:picasso:2.5.2'
Picasso.with(context)
.load("file:///android_asset/DvpvklR.png")
.resize(50, 50)
.into(imageView2);
Reference Picasso

If you want high quality result, so use [RapidDecoder][1] library. It is simple as follow:
import rapid.decoder.BitmapDecoder;
...
Bitmap bitmap = BitmapDecoder.from(getResources(), R.drawable.image)
.scale(width, height)
.useBuiltInDecoder(true)
.decode();
Don't forget to use builtin decoder if you want to scale down less than 50% and a HQ result.

This answer is based on the solution presented in https://developer.android.com/topic/performance/graphics/load-bitmap.html (without using of external libraries) with some changes by me to make its functionality better and more practical.
Some notes about this solution:
It is assumed that you want to keep the aspect ratio. In other words:
finalWidth / finalHeight == sourceBitmap.getWidth() / sourceBitmap.getWidth() (Regardless of casting and rounding issues)
It is assumed that you have two values (maxWidth & maxHeight) that you want any of the dimensions of your final bitmap doesn't exceed its corresponding value. In other words:
finalWidth <= maxWidth && finalHeight <= maxHeight
So minRatio has been placed as the basis of calculations (See the implementation). UNLIKE the basic solution that has placed maxRatio as the basis of calculations in actual. Also, the calculation of inSampleSize has been so much better (more logic, brief and efficient).
It is assumed that you want to (at least) one of the final dimensions has exactly the value of its corresponding maxValue (each one was possible, by considering the above assumptions). In other words:
finalWidth == maxWidth || finalHeight == maxHeight
The final additional step in compare to the basic solution (Bitmap.createScaledBitmap(...)) is for this "exactly" constraint. The very important note is you shouldn't take this step at first (like the accepted answer), because of its significant consumption of memory in case of huge images!
It is for decoding a file. You can change it like the basic solution to decode a resource (or everything that BitmapFactory supports).
The implementation:
public static Bitmap decodeSampledBitmap(String pathName, int maxWidth, int maxHeight) {
// First decode with inJustDecodeBounds=true to check dimensions
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(pathName, options);
final float wRatio_inv = (float) options.outWidth / maxWidth,
hRatio_inv = (float) options.outHeight / maxHeight; // Working with inverse ratios is more comfortable
final int finalW, finalH, minRatio_inv /* = max{Ratio_inv} */;
if (wRatio_inv > hRatio_inv) {
minRatio_inv = (int) wRatio_inv;
finalW = maxWidth;
finalH = Math.round(options.outHeight / wRatio_inv);
} else {
minRatio_inv = (int) hRatio_inv;
finalH = maxHeight;
finalW = Math.round(options.outWidth / hRatio_inv);
}
options.inSampleSize = pow2Ceil(minRatio_inv); // pow2Ceil: A utility function that comes later
options.inJustDecodeBounds = false; // Decode bitmap with inSampleSize set
return Bitmap.createScaledBitmap(BitmapFactory.decodeFile(pathName, options),
finalW, finalH, true);
}
/**
* #return the largest power of 2 that is smaller than or equal to number.
* WARNING: return {0b1000000...000} for ZERO input.
*/
public static int pow2Ceil(int number) {
return 1 << -(Integer.numberOfLeadingZeros(number) + 1); // is equivalent to:
// return Integer.rotateRight(1, Integer.numberOfLeadingZeros(number) + 1);
}
Sample Usage, in case of you have an imageView with a determined value for layout_width (match_parent or a explicit value) and a indeterminate value for layout_height (wrap_content) and instead a determined value for maxHeight:
imageView.setImageBitmap(decodeSampledBitmap(filePath,
imageView.getWidth(), imageView.getMaxHeight()));