Develop Reference

Scale Bitmap maintaining aspect ratio and fitting both width and height

I want to scale a bitmap maintaining the aspect ratio, but fitting the required dimensions. This answer scales the bitmap and maintains the aspect ratio, but leaves some blank space unless the image is a perfect square. I need to fill both width and height, just like the FIT_XY ScaleType property of an ImageView.

Based on Streets of Boston's answer, I made this method that scales and returns any Bitmap to a desired width and height, fitting both dimensions (no blank space!). It automatically adapts to more horizontal or more vertical images.
public Bitmap resizeBitmapFitXY(int width, int height, Bitmap bitmap){
Bitmap background = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
float originalWidth = bitmap.getWidth(), originalHeight = bitmap.getHeight();
Canvas canvas = new Canvas(background);
float scale, xTranslation = 0.0f, yTranslation = 0.0f;
if (originalWidth > originalHeight) {
scale = height/originalHeight;
xTranslation = (width - originalWidth * scale)/2.0f;
}
else {
scale = width / originalWidth;
yTranslation = (height - originalHeight * scale)/2.0f;
}
Matrix transformation = new Matrix();
transformation.postTranslate(xTranslation, yTranslation);
transformation.preScale(scale, scale);
Paint paint = new Paint();
paint.setFilterBitmap(true);
canvas.drawBitmap(bitmap, transformation, paint);
return background;
}

This will scale the image to fit into sqaure without any solid color padding in the rest of area and no cropping. If Image is not sqaure then there will be transparent area and aspect ratio of image will as original image.
I have tested it with potrait and lanscape images
import android.graphics.*;
public static Bitmap scalePreserveRatio(Bitmap imageToScale, int destinationWidth,
int destinationHeight) {
if (destinationHeight > 0 && destinationWidth > 0 && imageToScale != null) {
int width = imageToScale.getWidth();
int height = imageToScale.getHeight();
//Calculate the max changing amount and decide which dimension to use
float widthRatio = (float) destinationWidth / (float) width;
float heightRatio = (float) destinationHeight / (float) height;
//Use the ratio that will fit the image into the desired sizes
int finalWidth = (int)Math.floor(width * widthRatio);
int finalHeight = (int)Math.floor(height * widthRatio);
if (finalWidth > destinationWidth || finalHeight > destinationHeight) {
finalWidth = (int)Math.floor(width * heightRatio);
finalHeight = (int)Math.floor(height * heightRatio);
}
//Scale given bitmap to fit into the desired area
imageToScale = Bitmap.createScaledBitmap(imageToScale, finalWidth, finalHeight, true);
//Created a bitmap with desired sizes
Bitmap scaledImage = Bitmap.createBitmap(destinationWidth, destinationHeight, Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(scaledImage);
//Draw background color
Paint paint = new Paint();
paint.setColor(Color.TRANSPARENT);
paint.setStyle(Paint.Style.FILL);
canvas.drawRect(0, 0, canvas.getWidth(), canvas.getHeight(), paint);
//Calculate the ratios and decide which part will have empty areas (width or height)
float ratioBitmap = (float)finalWidth / (float)finalHeight;
float destinationRatio = (float) destinationWidth / (float) destinationHeight;
float left = ratioBitmap >= destinationRatio ? 0 : (float)(destinationWidth - finalWidth) / 2;
float top = ratioBitmap < destinationRatio ? 0: (float)(destinationHeight - finalHeight) / 2;
canvas.drawBitmap(imageToScale, left, top, null);
return scaledImage;
} else {
return imageToScale;
}
}
from https://stackoverflow.com/a/32810187/9308731

rotate bitmap and size

I take a picture with camera through intent. After I receive the image, my app has a rotate button. say the image came back width = 900 and height=1200. After I rotate the image, I still want width = 900 and height=1200 as opposed to width = 1200 and height=900. Does anyone know how I might to that?
Here is the code that hasn't worked.
Bitmap bmp = readBitmap(context.getContentResolver(), imageUri, sampleScale, options);
float widthScale = 0.9f * deviceDimension[1] / bmp.getWidth();
float heightScale = 0.8f * deviceDimension[0] / bmp.getHeight();
Matrix matrix = new Matrix();
matrix.preScale(widthScale, heightScale);
matrix.preRotate(angle);//90x
return Bitmap.createBitmap(bmp, 0, 0, bmp.getWidth(), bmp.getHeight(), matrix, true);
So basically, I want the image to still fit a present dimension on the screen no matter how I orient the image. The present area is, say, 900 by 1200

Use
return Bitmap.createBitmap(bmp, 0, 0, bmp.getHeight(), bmp.getWidth(), matrix, true);
instead of
return Bitmap.createBitmap(bmp, 0, 0, bmp.getWidth(), bmp.getHeight(), matrix, true);

see if this works??
public static Bitmap ScaleBitmap(Bitmap bm, float scalingFactor) {
int scaleHeight = (int) (bm.getHeight() * scalingFactor);
int scaleWidth = (int) (bm.getWidth() * scalingFactor);
return Bitmap.createScaledBitmap(bm, scaleWidth, scaleHeight, true);
}
private float getBitmapScalingFactor(Bitmap bm) {
// Get display width from device
int displayWidth = getWindowManager().getDefaultDisplay().getWidth();
// Get margin to use it for calculating to max width of the ImageView
LinearLayout.LayoutParams layoutParams =
(LinearLayout.LayoutParams)this.imageView.getLayoutParams();
int leftMargin = layoutParams.leftMargin;
int rightMargin = layoutParams.rightMargin;
// Calculate the max width of the imageView
int imageViewWidth = displayWidth - (leftMargin + rightMargin);
// Calculate scaling factor and return it
return ( (float) imageViewWidth / (float) bm.getWidth() );
}

How To Resize Bitmap Without Aspect Ratio in Android

I am new in bitmap.I know how can i resize or scale bitmap in android.But problem is suppose my image is 100x500 or any height & width.Now i want to resize it in square like 100x100.How it is possible
Kindly help me.

For this simple case, the most reasonable thing would be to translate your source image down to the middle, and draw your Bitmap again on a new Canvas. This type of resize is called a center crop in Android. The idea of a center crop is to result in the largest image that fills the entire bounds, and does not change the aspect ratio.
You can implement this yourself, along with other types of resizing and scaling. Basically, you use a Matrix to post your changes, like scaling and moving (translating), and then draw your original Bitmap on a Canvas that takes the Matrix into account.
Here's a method I adopted from another answer here (can't find the original post to properly give credit):
public static Bitmap scaleCenterCrop(Bitmap source, int newHeight, int newWidth)
{
int sourceWidth = source.getWidth();
int sourceHeight = source.getHeight();
float xScale = (float) newWidth / sourceWidth;
float yScale = (float) newHeight / sourceHeight;
float scale = Math.max(xScale, yScale);
//get the resulting size after scaling
float scaledWidth = scale * sourceWidth;
float scaledHeight = scale * sourceHeight;
//figure out where we should translate to
float dx = (newWidth - scaledWidth) / 2;
float dy = (newHeight - scaledHeight) / 2;
Bitmap dest = Bitmap.createBitmap(newWidth, newHeight, source.getConfig());
Canvas canvas = new Canvas(dest);
Matrix matrix = new Matrix();
matrix.postScale(scale, scale);
matrix.postTranslate(dx, dy);
canvas.drawBitmap(source, matrix, null);
return dest;
}

int dstWidth = 100;
int dstHeight = 100;
boolean doFilter = true;
Bitmap scaledBitmap = Bitmap.createScaledBitmap(src, dstWidth, dstHeight, doFilter);

Made a few modifications to the code from wsanville..and it worked for me
Note that I am using the minimum scale (taking what is the least, so that the whole bitmap can be rendered in the screen..if I take max, then it might go beyond the screen
int sourceWidth = mBitmap.getWidth();
int sourceHeight = mBitmap.getHeight();
float xScale = (float) newWidth / sourceWidth;
float yScale = (float) newHeight / sourceHeight;
float scale = Math.min(xScale, yScale);
//get the resulting size after scaling
float scaledWidth = scale * sourceWidth;
float scaledHeight = scale * sourceHeight;
//figure out where we should translate to
float dx = (newWidth - scaledWidth) / 2;
float dy = (newHeight - scaledHeight) / 2;
Matrix defToScreenMatrix = new Matrix();
defToScreenMatrix.postScale(scale, scale);
defToScreenMatrix.postTranslate(dx, dy);
mBitmap = Bitmap.createBitmap(mBitmap, 0, 0, sourceWidth, sourceHeight, defToScreenMatrix, false);

How to scale already existing bitmap in android?

I have an already decoded bitmap that I would like to temporarily scale before drawing it on a canvas. So decoding a file and setting the size before is out of the question. I would like to keep the size of the existing bitmap and just scale it to be smaller before drawing it on the canvas. Is this posible?
using Matrix postScale(sx, sy, px, py) scales it correctly but doesn't position it right. And canvas.drawBitmap doesn't have an option with matrix and x & y position from what I can see.
Any suggestions?

Here is the code:
public static Bitmap scaleBitmap(Bitmap bitmap, int width, int height) {
final int bitmapWidth = bitmap.getWidth();
final int bitmapHeight = bitmap.getHeight();
final float scale = Math.min((float) width / (float) bitmapWidth,
(float) height / (float) bitmapHeight);
final int scaledWidth = (int) (bitmapWidth * scale);
final int scaledHeight = (int) (bitmapHeight * scale);
final Bitmap decoded = Bitmap.createScaledBitmap(bitmap, scaledWidth, scaledHeight, true);
final Canvas canvas = new Canvas(decoded);
return decoded;
}
Please note: Pass the bitmap to scale and it's new height and width.

Android Crop Center of Bitmap

I have bitmaps which are squares or rectangles. I take the shortest side and do something like this:
int value = 0;
if (bitmap.getHeight() <= bitmap.getWidth()) {
value = bitmap.getHeight();
} else {
value = bitmap.getWidth();
}
Bitmap finalBitmap = null;
finalBitmap = Bitmap.createBitmap(bitmap, 0, 0, value, value);
Then I scale it to a 144 x 144 Bitmap using this:
Bitmap lastBitmap = null;
lastBitmap = Bitmap.createScaledBitmap(finalBitmap, 144, 144, true);
Problem is that it crops the top left corner of the original bitmap, Anyone has the code to crop the center of the bitmap?

This can be achieved with: Bitmap.createBitmap(source, x, y, width, height)
if (srcBmp.getWidth() >= srcBmp.getHeight()){
dstBmp = Bitmap.createBitmap(
srcBmp,
srcBmp.getWidth()/2 - srcBmp.getHeight()/2,
0,
srcBmp.getHeight(),
srcBmp.getHeight()
);
}else{
dstBmp = Bitmap.createBitmap(
srcBmp,
0,
srcBmp.getHeight()/2 - srcBmp.getWidth()/2,
srcBmp.getWidth(),
srcBmp.getWidth()
);
}

While most of the above answers provide a way to do this, there is already a built-in way to accomplish this and it's 1 line of code (ThumbnailUtils.extractThumbnail())
int dimension = getSquareCropDimensionForBitmap(bitmap);
bitmap = ThumbnailUtils.extractThumbnail(bitmap, dimension, dimension);
...
//I added this method because people keep asking how
//to calculate the dimensions of the bitmap...see comments below
public int getSquareCropDimensionForBitmap(Bitmap bitmap)
{
//use the smallest dimension of the image to crop to
return Math.min(bitmap.getWidth(), bitmap.getHeight());
}
If you want the bitmap object to be recycled, you can pass options that make it so:
bitmap = ThumbnailUtils.extractThumbnail(bitmap, dimension, dimension, ThumbnailUtils.OPTIONS_RECYCLE_INPUT);
From: ThumbnailUtils Documentation
public static Bitmap extractThumbnail (Bitmap source, int width, int
height)
Added in API level 8 Creates a centered bitmap of the desired size.
Parameters source original bitmap source width targeted width
height targeted height
I was getting out of memory errors sometimes when using the accepted answer, and using ThumbnailUtils resolved those issues for me. Plus, this is much cleaner and more reusable.

Have you considered doing this from the layout.xml ? You could set for your ImageView the ScaleType to android:scaleType="centerCrop" and set the dimensions of the image in the ImageView inside the layout.xml.

You can used following code that can solve your problem.
Matrix matrix = new Matrix();
matrix.postScale(0.5f, 0.5f);
Bitmap croppedBitmap = Bitmap.createBitmap(bitmapOriginal, 100, 100,100, 100, matrix, true);
Above method do postScalling of image before cropping, so you can get best result with cropped image without getting OOM error.
For more detail you can refer this blog

Here a more complete snippet that crops out the center of an [bitmap] of arbitrary dimensions and scales the result to your desired [IMAGE_SIZE]. So you will always get a [croppedBitmap] scaled square of the image center with a fixed size. ideal for thumbnailing and such.
Its a more complete combination of the other solutions.
final int IMAGE_SIZE = 255;
boolean landscape = bitmap.getWidth() > bitmap.getHeight();
float scale_factor;
if (landscape) scale_factor = (float)IMAGE_SIZE / bitmap.getHeight();
else scale_factor = (float)IMAGE_SIZE / bitmap.getWidth();
Matrix matrix = new Matrix();
matrix.postScale(scale_factor, scale_factor);
Bitmap croppedBitmap;
if (landscape){
int start = (tempBitmap.getWidth() - tempBitmap.getHeight()) / 2;
croppedBitmap = Bitmap.createBitmap(tempBitmap, start, 0, tempBitmap.getHeight(), tempBitmap.getHeight(), matrix, true);
} else {
int start = (tempBitmap.getHeight() - tempBitmap.getWidth()) / 2;
croppedBitmap = Bitmap.createBitmap(tempBitmap, 0, start, tempBitmap.getWidth(), tempBitmap.getWidth(), matrix, true);
}

Probably the easiest solution so far:
public static Bitmap cropCenter(Bitmap bmp) {
int dimension = Math.min(bmp.getWidth(), bmp.getHeight());
return ThumbnailUtils.extractThumbnail(bmp, dimension, dimension);
}
imports:
import android.media.ThumbnailUtils;
import java.lang.Math;
import android.graphics.Bitmap;

To correct #willsteel solution:
if (landscape){
int start = (tempBitmap.getWidth() - tempBitmap.getHeight()) / 2;
croppedBitmap = Bitmap.createBitmap(tempBitmap, start, 0, tempBitmap.getHeight(), tempBitmap.getHeight(), matrix, true);
} else {
int start = (tempBitmap.getHeight() - tempBitmap.getWidth()) / 2;
croppedBitmap = Bitmap.createBitmap(tempBitmap, 0, start, tempBitmap.getWidth(), tempBitmap.getWidth(), matrix, true);
}

public Bitmap getResizedBitmap(Bitmap bm) {
int width = bm.getWidth();
int height = bm.getHeight();
int narrowSize = Math.min(width, height);
int differ = (int)Math.abs((bm.getHeight() - bm.getWidth())/2.0f);
width = (width == narrowSize) ? 0 : differ;
height = (width == 0) ? differ : 0;
Bitmap resizedBitmap = Bitmap.createBitmap(bm, width, height, narrowSize, narrowSize);
bm.recycle();
return resizedBitmap;
}

public static Bitmap resizeAndCropCenter(Bitmap bitmap, int size, boolean recycle) {
int w = bitmap.getWidth();
int h = bitmap.getHeight();
if (w == size && h == size) return bitmap;
// scale the image so that the shorter side equals to the target;
// the longer side will be center-cropped.
float scale = (float) size / Math.min(w, h);
Bitmap target = Bitmap.createBitmap(size, size, getConfig(bitmap));
int width = Math.round(scale * bitmap.getWidth());
int height = Math.round(scale * bitmap.getHeight());
Canvas canvas = new Canvas(target);
canvas.translate((size - width) / 2f, (size - height) / 2f);
canvas.scale(scale, scale);
Paint paint = new Paint(Paint.FILTER_BITMAP_FLAG | Paint.DITHER_FLAG);
canvas.drawBitmap(bitmap, 0, 0, paint);
if (recycle) bitmap.recycle();
return target;
}
private static Bitmap.Config getConfig(Bitmap bitmap) {
Bitmap.Config config = bitmap.getConfig();
if (config == null) {
config = Bitmap.Config.ARGB_8888;
}
return config;
}

val sourceWidth = source.width
val sourceHeight = source.height
val xScale = newWidth.toFloat() / sourceWidth
val yScale = newHeight.toFloat() / sourceHeight
val scale = xScale.coerceAtLeast(yScale)
val scaledWidth = scale * sourceWidth
val scaledHeight = scale * sourceHeight
val left = (newWidth - scaledWidth) / 2
val top = (newHeight - scaledHeight) / 2
val targetRect = RectF(
left, top, left + scaledWidth, top
+ scaledHeight
)
val dest = Bitmap.createBitmap(
newWidth, newHeight,
source.config
)
val mutableDest = dest.copy(source.config, true)
val canvas = Canvas(mutableDest)
canvas.drawBitmap(source, null, targetRect, null)
binding.imgView.setImageBitmap(mutableDest)