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Set android bitmap size keeping aspect ratio based on minimum height and width

I'm currently loading an image that can be either landscape or portrait.
I'm then wanting to resize the bitmap to draw directly onto a canvas for a full screen image.
I need keep the aspect ratio but have the image not fit to the screen but crop off any image that's bigger than the screen.
I can resize it and fit it to the screen with the following:
Matrix m = new Matrix();
m.setRectToRect(new RectF(0, 0, b.getWidth(), b.getHeight()), new RectF(0, 0, MyWallpaperService.this.width, MyWallpaperService.this.height), Matrix.ScaleToFit.CENTER);
b = Bitmap.createBitmap(b, 0, 0, b.getWidth(), b.getHeight(), m, true);
but I don't want to have the black bars at the top/bottom or sides, but I can't think of the routine to resize correctly for this.

As you are drawing the image onto the canvas yourself the first step is to calculate the dimensions required for the final image based on the screen size and the original image aspect ratio.
Then use the static function createScaledBitmap from the Bitmap class to resize your bitmap to match the calculated dimensions. Make sure you only call this function once and store the bitmap for use in the drawing routine.
Finally draw the bitmap so only the area of the bitmap you want to see is on the screen.
A more memory friendly approach is to add another step to crop the image using Bitmap.createBitmap before calling Bitmap.createScaledBitmap. This reduces the chance of encountering memory issues caused by the user selecting a source image that is thin and long.

Scale Bitmap lower than 4096x4096

I am currently working on an application that shows a Bitmap on an ImageView. Now the problem is, whenever trying to show a Bitmap larger than 4096x4096, it simply won't show up, stating that the image is too large to be shown.
For example: I want to load up an image that's 4128x2322 pixels
I to resize it to be smaller than 4096x4096.
I thought about something like this:
Bitmap bitmap;
if(b.getHeight() >= 4096) {
double f = b.getHeight() / 4096;
b = Bitmap.createScaledBitmap(b, (int)(b.getWidth() / f), (int)(b.getHeight() / f), false);
}else if(b.getWidth() >= 4096) {
double f = b.getWidth() / 4096;
b = Bitmap.createScaledBitmap(b, (int)(b.getWidth() / f), (int)(b.getHeight() / f), false);
}
imageview.setImageBitmap(b);
Somehow it won't work...
Any advices on how to scale properly?
Thanks in advance!

I got an intent which takes a picture and returns the image
That image will be stored somewhere else, which you will reference via a File or perhaps a content: Uri.
But to show the taken picture I need to scale it down first
Use BitmapFactory to load the bitmap. Use BitmapFactory.Options and its inSampleSize field to indicate how you want the image to be downsampled. This is covered in the documentation.

There is no device with resolution 4096X4096, your image going to be scaled any way. So instead trying to scale it up just top let the system to scale it down. How about taking the screen size in to calculation and provide the final scale by your self. Not only that you will save space but also improve performance.

Poor Image Quality on scaling image in android

I am working on android application development...when i click on thumbnail image, it enlarges but give extreme poor quality...please help me how to resolve it
ImageView ivPreview = (ImageView)nagDialog.findViewById(R.id.image1);
int h =200 ; // height in pixels
int w = 200; // width in pixels
Bitmap Scaled = Bitmap.createScaledBitmap(bm, h, w, true);
ivPreview.setImageBitmap(Scaled);

If I understand correctly you want to enlarge a thumbnail. This is a bad idea because a thumbnails' size is a small image and enhancing it only makes it look worse. The Bitmap.createScaledBitmap() method stretches the bitmap resulting in quality loss. You should use a bigger original image, create the thubmnail from that image and load the original image when you click on it. Here's some code to get you going:
Bitmap original = //get original image
Bitmap thumbnail = Bitmap.createScaledBitmap(original, 50, 50, true);
//when the user clicks on the imageview:
imgView.setImageBitmap(original);

Resizing images from server

My application load images from server via HTTP and save it into files. Then I use this code to get Drawable and view it:
File f=new File(path);
if(f.exists()) {
Bitmap bmp = BitmapFactory.decodeFile(f.getAbsolutePath());
if(bmp!=null) {
DisplayMetrics dm = m_activity.getResources().getDisplayMetrics();
bmp.setDensity(dm.densityDpi);
Drawable drawable=new BitmapDrawable(context.getResources(), bmp);
drawable.setBounds(0, 0, drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight());
return drawable;
}
}
It working fine on Samsung Galaxy S2. But on Samsung Galaxy S4 this images too small. For example:
On S2:
On S4:
I need to display it equally on all devices with various display's resolution. Is it possible? How to implement this?

I think I can help you. I had this same kind of problem myself. What you need to do is find how much larger this new screen is than your old one, by first getting the dimensions of your device and putting them in for widthOfStandardDevice and heightOfStandardDevice.Once you know how much larger the new screen is then your old one, you would make two multipliers to multiply everything by. You can now say set the size of the bitmap to bitmap_width and bitmap_height.
DisplayMetrics displaymetrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(displaymetrics);
height = displaymetrics.heightPixels;
width = displaymetrics.widthPixels;
float widthMultiplier = width/widthOfStandardDevice;
float heightMultiplier = height/heightOfStandardDevice;
int bitmap_width = (int)(600 * widthMultiplier);
int bitmap_height = (int)(800 * heightMultiplier);

The basic problem is that devices with a HIGHER resolution will make the images appear SMALLER. You need to scale the "intrinsic" size proportionately to your device resolution.
One good solution (as Sheldon suggested) is to use a Scaled Bitmap:
How to scale bitmap to screen size?
Android image on tablets and phones

you don't have to scale the bitmap, since scaling it up will mean it will use more memory.
instead, you can just tell the imageView how large you wish it to be , and let it show the bitmap in the exact size you wish it to be (use dp).
if you do wish to set the bitmap size yourself, check out this link if image quality is important or this link if speed is more important

Android - How to enlarge a bitmap

I usually download images that are larger in size and shrink them using an imageview but lately Im trying to deal with my apps not working on a lesser network connection so I was wondering how can I increase the size of an image once it gets to the device. I tried resizing the image once it was in an imageview but the imageview will get no larger than the original image. Im sure theres a really easy way to increase or blow up an image on the device but I havent come across it yet.
So.....how can I increase the size of an image. Id like to blow it up and use it in an imageview but the images Im dealing with are only 128X256 and Id like to expand them to about 512X1024.

Try using this method:
public static Bitmap scaleBitmap(Bitmap bitmapToScale, float newWidth, float newHeight) {
if(bitmapToScale == null)
return null;
//get the original width and height
int width = bitmapToScale.getWidth();
int height = bitmapToScale.getHeight();
// create a matrix for the manipulation
Matrix matrix = new Matrix();
// resize the bit map
matrix.postScale(newWidth / width, newHeight / height);
// recreate the new Bitmap and set it back
return Bitmap.createBitmap(bitmapToScale, 0, 0, bitmapToScale.getWidth(), bitmapToScale.getHeight(), matrix, true); }
refer to my answer in: ImageView OutofMemoryException

Use matrix to resize the bitmap.
Check this
Resize Bitmap

If you want to scale the Bitmap manually, there is a Bitmap.createScaledBitmap() method that you can use for this.
If you want the ImageView to handle this, you have to set the layout_width/layout_height to something other than wrap_content or it will always shrink to the size of the Bitmap. Then you need to change the scaleType attribute to a type that actually scales the bitmap.

The functionality to scale image up or down is readily available via android.graphics library:
Bitmap bitmapScaled = Bitmap.createScaledBitmap(Bitmap bitmapOrig, int widthNew, int heightNew, boolean filter);