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

Making Bitmap aspect ratio to centerFit Android

I have searched alot for this but got no proper solution!
i have a drawing area in my android app and i want to take image from camera/gallery and set it as a background of canvas.
I get Bitmap after taking photo from camera/gallery and i pass my bitmap to this method to make it aspect fit to my drawView keeping its aspect ratio.
Here newHeight/newWidth are my drawView's height and width.
public Bitmap scaleCenterCrop(Bitmap source, int newHeight, int newWidth) {
int sourceWidth = source.getWidth();
int sourceHeight = source.getHeight();
// Compute the scaling factors to fit the new height and width, respectively.
// To cover the final image, the final scaling will be the bigger
// of these two.
float xScale = (float) newWidth / sourceWidth;
float yScale = (float) newHeight / sourceHeight;
float scale = Math.min(xScale, yScale);
// Now get the size of the source bitmap when scaled
float scaledWidth = scale * sourceWidth;
float scaledHeight = scale * sourceHeight;
// Let's find out the upper left coordinates if the scaled bitmap
// should be centered in the new size give by the parameters
float left = (newWidth - scaledWidth) / 2;
float top = (newHeight - scaledHeight) / 2;
// The target rectangle for the new, scaled version of the source bitmap will now
// be
RectF targetRect = new RectF(left, top, left + scaledWidth, top + scaledHeight);
// Finally, we create a new bitmap of the specified size and draw our new,
// scaled bitmap onto it.
Bitmap dest = Bitmap.createBitmap(newWidth, newHeight, source.getConfig());
Canvas canvas = new Canvas(dest);
canvas.drawColor(Color.WHITE);
canvas.drawBitmap(source, null, targetRect, null);
return dest;
}
It works good on mt Htc m7 but on my galaxy tab4 it makes image strech so sleek as you can see in image below:
do anyone know any method through which i can set bitmap to my drawView like this
Bitmap backgroundBitMap= c.scaleCenterCrop(bmp, drawView.getHeight(), drawView.getWidth());
String tempPath = getPath(selectedImageUri, MainActivity.this);
backgroundBitMap= c.rotateImage(backgroundBitMap,tempPath);
drawView.setBackgroundDrawable(new BitmapDrawable(backgroundBitMap));
but keeping its aspect ration same. Actually i want CenterFit functionality for a bitmap.
Any help would be appreciated! Thanks

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.

How to crop Bitmap Center like imageview? [duplicate]

This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
How to crop the parsed image in android?
How does one crop the same way as Androids ImageView is doing
android:scaleType="centerCrop"

Your question is a bit short of information on what you want to accomplish, but I guess you have a Bitmap and want to scale that to a new size and that the scaling should be done as "centerCrop" works for ImageViews.
From Docs
Scale the image uniformly (maintain the image's aspect ratio) so that
both dimensions (width and height) of the image will be equal to or
larger than the corresponding dimension of the view (minus padding).
As far as I know, there is no one-liner to do this (please correct me, if I'm wrong), but you could write your own method to do it. The following method calculates how to scale the original bitmap to the new size and draw it centered in the resulting Bitmap.
Hope it helps!
public Bitmap scaleCenterCrop(Bitmap source, int newHeight, int newWidth) {
int sourceWidth = source.getWidth();
int sourceHeight = source.getHeight();
// Compute the scaling factors to fit the new height and width, respectively.
// To cover the final image, the final scaling will be the bigger
// of these two.
float xScale = (float) newWidth / sourceWidth;
float yScale = (float) newHeight / sourceHeight;
float scale = Math.max(xScale, yScale);
// Now get the size of the source bitmap when scaled
float scaledWidth = scale * sourceWidth;
float scaledHeight = scale * sourceHeight;
// Let's find out the upper left coordinates if the scaled bitmap
// should be centered in the new size give by the parameters
float left = (newWidth - scaledWidth) / 2;
float top = (newHeight - scaledHeight) / 2;
// The target rectangle for the new, scaled version of the source bitmap will now
// be
RectF targetRect = new RectF(left, top, left + scaledWidth, top + scaledHeight);
// Finally, we create a new bitmap of the specified size and draw our new,
// scaled bitmap onto it.
Bitmap dest = Bitmap.createBitmap(newWidth, newHeight, source.getConfig());
Canvas canvas = new Canvas(dest);
canvas.drawBitmap(source, null, targetRect, null);
return dest;
}