Develop Reference

Resize wallpaper to fit screen without cropping or scaling?

I am setting an image from within my application as wallpaper it is working fine on my nokia 5 and image is being set and is filling the entire view but when i try to run the same code on huawei honor 5x or nexus 4 the image is enlarged and goes out of the home screen.
private 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, true);
return resizedBitmap;
}

How to resize image without loosing image content

I want to resize an image to a smaller image like thumbnail. I have used following options
Bitmap imageBitmap = Bitmap.createScaledBitmap(mBitmap, 200, 700, false);
and
ThumbnailUtils.extractThumbnail()
Both of these options cut parts of images. So they don't look good. I just want to reduce image dimensions and don't want to loose image content.

you have to try like this
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;
}

BitmapFactory.Options bmOptions = new BitmapFactory.Options();
Bitmap bitmap = BitmapFactory.decodeFile(filepath,bmOptions);
//Part 1 :withcompression Sacle image 200 pixels x 700 pixels this size you can customize as per your requirement
Bitmap withCompressed = Bitmap.createScaledBitmap(bitmap,200,700,true);

If you want to resize an image without losing quality and images are from drawable/mipmap then you should try pngquant.
https://pngquant.org/

How to pixelize a bitmap in android

I have been searching but i did not find a question about how to pixelize a bitmap in android
Example
Note that i dont mean blur

You could just try and resize that image to a smaller version (and then back up if you need it at the same size as the original for some reason)
{
Bitmap original = ...;
//Calculate proportional size, or make the method accept just a factor of scale.
Bitmap small = getResigetResizedBitmap(original, smallWidth, smallHeight);
Bitmap pixelated = getResigetResizedBitmap(small, normalWidth, normalHeight);
//Recycle small, recycle original if no longer needed.
}
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
Bitmap resizedBitmap = Bitmap.createBitmap(
bm, 0, 0, width, height, matrix, false);
return resizedBitmap;
}
The code is from here

The simplest way to pixelate the image would be to scale image down using "nearest neighbour" algorithm, and then scale up, using the same algorithm.
Filtering over the image trying to find an average takes much more time, but does not actually give any improvements in result quality, after all you do intentionally want your image distorted.

How do I use a matrix to resize a bitmap in SurfaceView?

I found this bit of code on a similar question, but I can't figure out how to use it.
Resizing 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;
}
I'm also confused as to where to place this. With my initial variables? Inside the constructor, or runnable? If the bitmap I wanted to change the size of is called Background, how do I add that to this method?
Thanks in advance.

Why my Bitmap after scaling seems empty

I am trying to scale a Bitmap, doubling its size.
But after the scaling the bitmap shows empty, all plain gray...
here is the code:
Matrix matrix = new Matrix();
// resize the bit map
matrix.postScale(2, 2);
// recreate the new Bitmap and set it back
Bitmap bm2=Bitmap.createBitmap(bm, 0, 0, bm.getWidth(), bm.getHeight(), matrix, true);
//bm.recycle();
EDIT EDIT EDIT EDIT EDIT
I figured it out it's memory issue, if I do it with small images it works fine.
Still the problem remains with large pictures!!!
Thanks for any suggestion!!!

As from the Bitmap Doc it is clearly saying that Bitmap.createBitmap() returns the same bitmap or part of the source bitmap.So may be here it returns the same bitmap object.But here you are recycling it
bm.recycle();
thats why you are getting null
Use this method
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;
Matrix matrix = new Matrix();
matrix.postScale(scaleWidth, scaleHeight);
Bitmap resizedBitmap = Bitmap.createBitmap(bm, 0, 0, width, height,
matrix, false);
return resizedBitmap;
}
and pass width as 1920 and height as 2560