createBitmap() returns a bitmap without drawn

createBitmap() returns a bitmap without drawn - android

I want to scale an existing bitmap. So I use Bitmap.createBitmap(Bitmap b, int x, int y, int width, int height, Matrix m, boolean filter) to create a scaled bitmap. If the scale ratio of the Matrix object is less than 1, this method works well. However, if the ratio is equal to or greater than 1, the method returns a bitmap with the width and height i desire but without an image (is transparent). I wonder why and how to solve this.
Bitmap imageBitmap;
imageBitmap = weiboView.getDrawingCache();
Log.d("cosmo", "bitmap generated: "+imageBitmap.getWidth()+" * "+imageBitmap.getHeight());
//Init and configure and load the image view
ImageView imageView = new ImageView(this);
imageView.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT));
imageView.setScaleType(ScaleType.FIT_CENTER);
containerLayout.addView(imageView);
//create a scaled bitmap to assign to the image view
Bitmap scaledImageBitmap = MyBitmapUtils.getBitmapScaledToFitWidth(getWindowManager().getDefaultDisplay().getWidth(), imageBitmap);
Log.d("cosmo", "scaled: "+scaledImageBitmap.getWidth()+" * "+scaledImageBitmap.getHeight());
//Here if I set imageBitmap as the image of imageView it works well
imageView.setImageBitmap(scaledImageBitmap);
Here is MyBitmapUtils.getBitmapScaledToFitWidth:
public static Bitmap getBitmapScaledToFitWidth(int targetWidth, Bitmap bitmap) {
float ratio = (float)targetWidth/(float)bitmap.getWidth();
Log.d("cosmo", "ratio is "+ratio);
//ratio = 0.5f;
Matrix matrix = new Matrix();
matrix.postScale(ratio, ratio);
Bitmap target = Bitmap.createBitmap(bitmap,0,0,bitmap.getWidth(),bitmap.getHeight(),matrix,false);
return target;
}
I have known how did this happen. It's because that the height of the Image is greater than 2048, and in android's system creating a bitmap bigger than 2048*2048 will cause OOM (My logcat didn't report this error, oddly)

Why don't you just use createScaledBitmap?
Bitmap scaledBitmap = Bitmap.createScaledBitmap(bitmap, targetWidth, targetHeight, true);
You can supply the targetWidth and targetHeight directly and it should be more reliable than scaling the bitmap yourself with a Matrix.
If you just supply the targetWidth to your method then you have to calculate the targetHeight which would look something like this:
float ratio = (float)targetWidth/(float)bitmap.getWidth();
int targetHeight = (int)((float)bitmap.getHeight * ratio);
And if you put that in your method it would look like this:
public static Bitmap getBitmapScaledToFitWidth(double targetWidth, Bitmap bitmap) {
double bitmapWidth = bitmap.getWidth();
double bitmapHeight = bitmap.getHeight();
double widthRatio = targetWidth / bitmapWidth;
double targetHeight = widthRatio * bitmapHeight;
Bitmap target = Bitmap.createScaledBitmap(bitmap, (int)targetWidth, (int)targetHeight, true);
return target;
}
Also don't forget to recycle() not needed bitmaps as often and as soon as possible. That can prevent you from running into memory problems, for example if you don't need the not scaled bitmap anymore after scaling it you can recycle it directly in your helper method:
public static Bitmap getBitmapScaledToFitWidth(double targetWidth, Bitmap bitmap) {
double bitmapWidth = bitmap.getWidth();
double bitmapHeight = bitmap.getHeight();
double widthRatio = targetWidth / bitmapWidth;
double targetHeight = widthRatio * bitmapHeight;
Bitmap target = Bitmap.createScaledBitmap(bitmap, (int)targetWidth, (int)targetHeight, true);
// Recycle old bitmap to free up memory.
bitmap.recycle();
return target;
}

Related

How to compress an image?

I am working on a project in android studio where I am uploading images. Some of the images are very large in size and I want to compress before upload them in the app. Can anyone please suggest me soemthing?

You can use this code to compress images
Bitmap imageBitmap;
int newHeight = 20 // define your height here
int newWidth = 30 //define new height
Bitmap resizedBitmap = Bitmap.createScaledBitmap(imageBitmap,newWidth,
newHeight,
true);
https://developer.android.com/reference/android/graphics/Bitmap.html see documentation for details.

use this library to compress any file :
https://github.com/zetbaitsu/Compressor

try this function
public static Bitmap scaleDown(Bitmap realImage, float maxImageSize, boolean filter) {
float ratio = Math.min(
maxImageSize / realImage.getWidth(),
maxImageSize / realImage.getHeight());
int width = Math.round(ratio * realImage.getWidth());
int height = Math.round(ratio * realImage.getHeight());
Bitmap newBitmap = Bitmap.createScaledBitmap(realImage, width,
height, filter);
return newBitmap;
}

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 Image Resize basic

I like to resize an bitmap,if it is big make it small and place it on an specific location in the surface view, I need to get device width and height and then bitmap size and place them in an surface view and then take another image resize it and place it in any location has i like.
How to know the location co ordinates first(to place second image - this should be device independent if larger/smaller screen layout should not change)
and how to scale an big bitmap and set as background so i can draw an image over it.
my code :
final int canvasWidth = getWidth();
final int canvasHeight = getHeight();
int imageWidth = img.getWidth();
int imageHeight = img.getHeight();
float scaleFactor = Math.min( (float)canvasWidth / imageWidth,
(float)canvasHeight / imageHeight );
Bitmap scaled = Bitmap.createScaledBitmap( img,
(int)(scaleFactor * imageWidth),
(int)(scaleFactor * imageHeight),
true );
canvas.drawColor(Color.BLACK);
canvas.drawBitmap(scaled, 10, 10, null);
this scale the big image but it doesn't fit the whole screen "img - bitmap is like an background image "
Someone can help me to understand the resize basics (I'm new so finding hard to understand resizing) to resize image to fit screen and resize any image to smaller one and place it in any location i like .

Store your bitmap as a source for manipulation and display it using ImageView:
Bitmap realImage = BitmapFactory.decodeFile(filePathFromActivity.toString());
Bitmap newBitmap = scaleDown(realImage, MAX_IMAGE_SIZE, true);
imageView.setImageBitmap(newBitmap);
//scale down method
public static Bitmap scaleDown(Bitmap realImage, float maxImageSize,
boolean filter) {
float ratio = Math.min(
(float) maxImageSize / realImage.getWidth(),
(float) maxImageSize / realImage.getHeight());
int width = Math.round((float) ratio * realImage.getWidth());
int height = Math.round((float) ratio * realImage.getHeight());
Bitmap newBitmap = Bitmap.createScaledBitmap(realImage, width,
height, filter);
return newBitmap;
}
And set your ImageView's width and height to "fill_parent".

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)

Resizing bitmaps

I'm writing a Music application and I have already gotten the album arts. However, they came up in various sizes. So, how do I standardized the size of the returned bitmap ?

You'd do something like this:
// load the origial BitMap (500 x 500 px)
Bitmap bitmapOrg = BitmapFactory.decodeResource(getResources(),
R.drawable.android);
int width = bitmapOrg.width();
int height = bitmapOrg.height();
int newWidth = 200;
int newHeight = 200;
// calculate the scale - in this case = 0.4f
float scaleWidth = ((float) newWidth) / width;
float scaleHeight = ((float) newHeight) / height;
// createa matrix for the manipulation
Matrix matrix = new Matrix();
// resize the bit map
matrix.postScale(scaleWidth, scaleHeight);
// recreate the new Bitmap
Bitmap resizedBitmap = Bitmap.createBitmap(bitmapOrg, 0, 0,
width, height, matrix, true);

Or you could scale the bitmap to the required size when you draw it on the canvas:
From the android documentation:
drawBitmap(Bitmap bitmap, Rect src, Rect dst, Paint paint)
Draw the specified bitmap, scaling/translating automatically to fill the destination rectangle.
Make src null and dst is a Rect the size/position you want it on the canvas, set up like
Rect rect = new Rect(0, 0, width, height)
canvas.drawBitmap(bitmap, null, rect)

In my experience the code in the accepted answer does not work, at least on some platforms.
Bitmap.createBitmap(bitmapOrg, 0, 0, width, height, matrix, true);
will give you a downsampled image at the full size of the original - so just a blurry image.
Interestingly enough, the code
Bitmap resizedBitmap = Bitmap.createScaledBitmap(square, (int) targetWidth, (int) targetHeight, false);
also gives the blurry image. In my case it was necessary to do this:
// RESIZE THE BIT MAP
// According to a variety of resources, this function should give us pixels from the dp of the screen
// From http://stackoverflow.com/questions/4605527/converting-pixels-to-dp-in-android
float targetHeight = DWUtilities.convertDpToPixel(80, getActivity());
float targetWidth = DWUtilities.convertDpToPixel(80, getActivity());
// However, the above pixel dimension are still too small to show in my 80dp image view
// On the Nexus 4, a factor of 4 seems to get us up to the right size
// No idea why.
targetHeight *= 4;
targetWidth *= 4;
matrix.postScale( (float) targetHeight / square.getWidth(), (float) targetWidth / square.getHeight());
Bitmap resizedBitmap = Bitmap.createBitmap(square, 0, 0, square.getWidth(), square.getHeight(), matrix, false);
// By the way, the below code also gives a full size, but blurry image
// Bitmap resizedBitmap = Bitmap.createScaledBitmap(square, (int) targetWidth, (int) targetHeight, false
I don't have a further solution on this yet, but hopefully this is helpful to someone.

Develop Reference

The Android operating system is a mobile operating system that was developed by Google (GOOGL?) to be primarily used for touchscreen devices, cell phones, and tablets.

createBitmap() returns a bitmap without drawn - android

Related

How to compress an image?

How to scale already existing bitmap in android?

Android Image Resize basic

Android Crop Center of Bitmap

Resizing bitmaps

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