First let's introduce me, I'm new in Android and mobile device programming, I previously worked on embedded systems running on QNX.
I hope I will respect the rules of this forum which seem to be quite stricts ;-).
I'm wrinting an application where I declare a layout for a welcome screen populated, between other things with a image view.
There is a first image placed in this image view in the xml file, but I will replace it by an other one later in the application's code and this second image will be potentially of a different size.
My problem is to resize and center my second image. According to my tests, it's quite automatic by using resources in Lint but it seems not so obvious by program, even if I read in the docs that it should be similar.
After reading several posts on the subject, I finally have a doubt; Can I center an image in an ImageView, or do I have to center the ImageView in the available space?
I tried the first solution without success.
So my layout is:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/fragmentInit"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context="com.cabbonline.ndguidelt.MainActivity" >
<TextView
android:id="#+id/textViewAppName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="#+id/textViewAppVersion"
android:layout_centerHorizontal="true"
android:text="#string/app_name" />
<TextView
android:id="#+id/textViewAppVersion"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="#+id/TextViewDevelopCabb"
android:layout_centerHorizontal="true"
android:text="#string/app_version" />
<TextView
android:id="#+id/TextViewDevelopCabb"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="#+id/imagecaBB"
android:layout_centerHorizontal="true"
android:text="#string/develop_cabb" />
<ImageView
android:id="#+id/imagecaBB"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="#+id/textViewCabbUrl"
android:layout_centerHorizontal="true"
android:contentDescription="#string/logo_caBB"
android:maxHeight="150dp"
android:src="#drawable/logo_cabb_100x51_or" />
<TextView
android:id="#+id/textViewCabbUrl"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:text="#string/cabb_url" />
<ImageView
android:id="#+id/imageSite"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_above="#+id/textViewAppName"
android:contentDescription="#string/logo_Site"
android:scaleType="centerInside"
android:src="#drawable/image_guide_320x400" />
</RelativeLayout>
Here I can say tht the "imageSite" ImageView is well displayed, centered and occupies the whole area. Right.
Now I have a piece of code to replace this image in this same ImageView:
Bitmap imageSite = site.getSitePictureBitmap();
if (imageSite != null) {
imageGuide.setImageBitmap(imageSite);
}
If I only do that, despite en center_inside flag, the new bitmap, smaller and rectangular horizontally compare to the first one which is almost sqaure, the image is displayed very small on the bottom right corner of the ImageView, or the area taken by the ImageView, Idon't really know.
So I add this piece of code to resize it:
imageSite = site.getSitePictureBitmap(); // here I read the bitmap in a file.
if (imageSite != null) {
float maxWidth = imageGuide.getWidth();
float maxHeight = imageGuide.getHeight();
float width = imageSite.getWidth();
float height= imageSite.getHeight();
float hRatio = width / maxWidth;
float vRatio = height / maxHeight;
if (Math.abs(1 - hRatio) < Math.abs(1 - vRatio)) {
// We match horizontal available size
width = width / hRatio;
height = height / hRatio;
} else {
width = width / vRatio;
height = height / vRatio;
}
Bitmap reSizedBitmap = Bitmap.createScaledBitmap(imageSite, (int)width, (int)height, true);
imageGuide.setImageBitmap(reSizedBitmap);
So the image is now of the good width but as its vertical dimension is lower than the first picture, it's close to the textViewAppName. So as it's a rule for the ImageView in the layout description, I wonder if my image is not in the center of the ImageView in fact and my problem would come from the fact that the ImageView is now of a smaller height and doesn't fill up the whole space available at the top of the layout.
I also wondered if setting a new image doesn't reset the positionning flags. I didn't see that in the doc AFAIR but...
So I add this line after setImagebitmap() without success:
imageGuide.setScaleType(ScaleType.CENTER_INSIDE);
Can you tell me a bit more about ImageView behavior in this case and how to get my image vertically in the center of the available space. Do I have to calculate padding?
Regards,
Al
Layout:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:background="#android:color/transparent"
android:id="#+id/globeViewStreamInfoPanel"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<ImageView android:id="#+id/streamIndicator"
android:src="#drawable/nv_tidestreamindicator"
android:scaleType="matrix"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_margin="10dp"
android:maxHeight="40dp"
android:maxWidth="40dp"
android:layout_width="40dp"
android:layout_height="40dp"/>
Code (streamIndicator is the ImageView):
streamIndicatorMatrix.reset();
streamIndicatorMatrix.setScale(size,size);
// rotate indicator in the direction of the flow
streamIndicatorMatrix.setRotate((float)(stream.currentStream.direction));
streamIndicator.setImageMatrix(streamIndicatorMatrix);
When I rotate, or scale, or both, the ImageView moves in the layout.
Weird thing is, when I break on the line after setImagematrix and inspect streamIndicator, mTop, mLeft, mWidth and mHeight all look correct. size and my rotation angle are always legal, sensible values.
I just know this is something stupid, what have I missed?
Thanks!
[EDIT]
Here's a pic, the red arrow was added by me to point to the errant ImageView:
Matrix.setRotate uses the (0, 0) pivot point by default. This is the reason your image moves in the layout. There is a overloaded version of the Matrix.setRotate method that allows you to speficy the pivot point.
final float density = getResources().getDisplayMetrics().density;
final int center = Math.round(20 * density);
streamIndicatorMatrix.setScale(size,size, center, center);
streamIndicatorMatrix.setRotate((float)(stream.currentStream.direction), center, center);
I want to put and ImageView with a large Y margin on my screen device, which would imply that part of the image would be out of screen, and then that the image would be cropped.
The problem is that Android is scaling the image all the time, so that it fits inside the screen, but I don't want that, I want the image to be cropped.
How can I force the ImageView to be cropped and not resized?
P.S. I tried all the possible ScaleType properties and none of them worked for me!
Code :
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="200dp"
android:background="#drawable/my_image"
android:scaleType="centerCrop"
/>
</RelativeLayout>
Try replacing android:background with android:src.
First problem with your code is that you used:
android:background="#drawable/my_image"
instead of:
android:src="#drawable/my_image"
(with background none of the scaleType options work).
Now if this still doesn't help, you probably have to use scaleType="matrix" and then simply create a matrix that will do the required job. For example, let's assume that you want to:
keep the ratio of your image
scale the image so that the width parameter will equal X (for example: X can be the width of the screen)
make the top of the image visible (so crop the bottom of the image) - I'm assuming this is why centerCrop might not work for you
Here's the code:
ImageView imgView = (ImageView)findViewById(R.id.my_image_view);
Bitmap bitmap = BitmapFactory.decodeResource(getResources(),
R.drawable.my_image);
Matrix matrix = new Matrix();
// Let's assume X = 400
float scale = ((float) 400) / bitmap.getWidth();
matrix.setScale(scale, scale);
imgView.setImageMatrix(matrix);
And remember to make the necessary changes in the xml file.
How do I make a background image fit the view but keep its aspect ratio when using <bitmap /> as a background drawable XML?
None of <bitmap>'s android:gravity values gives the desired effect.
It is impossible to achieve manipulating background attribute within xml-files only. There are two options:
You cut/scale the bitmap programmatically with
Bitmap.createScaledBitmap(Bitmap src, int dstWidth, int dstHeight,
boolean filter) and set it as some View's background.
You use ImageView instead of background placing it as the first layout's element and specify android:scaleType attribute for it:
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/backgrnd"
android:scaleType="centerCrop" />
...
rest layout components here
...
</RelativeLayout>
There is an easy way to do this from the drawable:
your_drawable.xml
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
<item android:drawable="#color/bg_color"/>
<item>
<bitmap
android:gravity="center|bottom|clip_vertical"
android:src="#drawable/your_image" />
</item>
</layer-list>
The only downside is that if there is not enough space, your image won't be fully shown, but it will be clipped, I couldn't find an way to do this directly from a drawable. But from the tests I did it works pretty well, and it doesn't clip that much of the image. You could play more with the gravity options.
Another way will be to just create an layout, where you will use an ImageView and set the scaleType to fitCenter.
Hope this information helps you achieve what you want.
I wanted to do something similar in my custom Drawable class.
Here are the important pieces:
public class CustomBackgroundDrawable extends Drawable
{
private Rect mTempRect = new Rect();
private Paint mBitmapPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
...
public void draw(#NonNull Canvas canvas)
{
Rect bounds = getBounds();
if (mBitmap != null ) {
if (mScaleType == ScaleType.SCALE_FILL) {
//bitmap scales to fill the whole bounds area (bitmap can be cropped)
if (bounds.height() > 0 && bounds.height() > 0) {
float scale = Math.min(mBitmap.getWidth()/(float)bounds.width(), mBitmap.getHeight()/(float)bounds.height());
float bitmapVisibleWidth = scale * bounds.width();
float bitmapVisibleHeight = scale * bounds.height();
mTempRect.set((int)(mBitmap.getWidth()-bitmapVisibleWidth)/2, 0, (int)(bitmapVisibleWidth+mBitmap.getWidth())/2, (int)bitmapVisibleHeight);
canvas.drawBitmap(mBitmap, mTempRect, bounds, mBitmapPaint);
}
} else if (mScaleType == ScaleType.SCALE_FIT) {
//bitmap scales to fit in bounds area
if (bounds.height() > 0 && bounds.height() > 0) {
float scale = Math.min((float)bounds.width()/mBitmap.getWidth(), (float)bounds.height()/mBitmap.getHeight());
float bitmapScaledWidth = scale * mBitmap.getWidth();
float bitmapScaledHeight = scale * mBitmap.getHeight();
int centerPadding = (int)(bounds.width()-bitmapScaledWidth)/2;
mTempRect.set(bounds.left + centerPadding, bounds.top, bounds.right - centerPadding, bounds.top+(int)bitmapScaledHeight);
canvas.drawBitmap(mBitmap, null, mTempRect, mBitmapPaint);
}
}
}
}
With this approach you are flexible to apply any scale logic that you need
Another approach would be to create patch 9 images of your regular image and have it stretch scale the way you want it to.
You could have it center the content by putting 9-patch-dots in the corners that will preserve your ratio obviously (assuming the outer most edge of your image is repeatable/transparent).
Hopefully you get the idea.
If your bitmap is wider than it is tall, use android:gravity="fill_vertical". Otherwise, use android:gravity="fill_horizontal". This has a similar effect as using android:scaleType="centerCrop" on an ImageView.
<bitmap xmlns:android="http://schemas.android.com/apk/res/android"
android:gravity="fill_vertical"
android:src="#drawable/image" />
If you support multiple orientations, you can create one bitmap XML file in the drawable-port folder and the other in the drawable-land folder.
Using the method described by a.ch worked great for me except I used this scale type which worked much better for what I needed:
android:scaleType="centerCrop"
Here is a full list of available scale types:
http://developer.android.com/reference/android/widget/ImageView.ScaleType.html
Try using InsetDrawable (worked well for me).
Just give this your drawable, and insets (or padding) you want from either of the four sides.
InsetDrawable insetDrawable = new InsetDrawable(drawable, insetLeft, insetTop, insetRight, insetBottom);
It is specifically used for setting background drawable, of size smaller or than the View.
See Here :
https://developer.android.com/reference/android/graphics/drawable/InsetDrawable.html
Old question, but none of the other answers worked for me. This xml code did however:
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent" >
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentTop="true"
android:scaleType="centerCrop"
android:src="#drawable/background_image"/>
</RelativeLayout>
In order to fit the image to the available space (or if you have set width and height in dp), I have tried the following approach, also if the image is not too wide.
Here I have set same width and height for square images [or you can wrap_content on both].
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent" >
<ImageView
android:layout_width="80dp"
android:layout_height="80dp"
android:layout_alignParentTop="true"
android:adjustViewBounds="true"
android:scaleType="fitCenter"
android:src="#drawable/background_image"/>
</RelativeLayout>
adjust view bounds and scale type center fit does the trick.
In Android, I defined an ImageView's layout_width to be fill_parent (which takes up the full width of the phone).
If the image I put to ImageView is bigger than the layout_width, Android will scale it, right? But what about the height? When Android scales the image, will it keep the aspect ratio?
What I find out is that there is some white space at the top and bottom of the ImageView when Android scales an image which is bigger than the ImageView. Is that true? If yes, how can I eliminate that white space?
Yes, by default Android will scale your image down to fit the ImageView, maintaining the aspect ratio. However, make sure you're setting the image to the ImageView using android:src="..." rather than android:background="...". src= makes it scale the image maintaining aspect ratio, but background= makes it scale and distort the image to make it fit exactly to the size of the ImageView. (You can use a background and a source at the same time though, which can be useful for things like displaying a frame around the main image, using just one ImageView.)
You should also see android:adjustViewBounds to make the ImageView resize itself to fit the rescaled image. For example, if you have a rectangular image in what would normally be a square ImageView, adjustViewBounds=true will make it resize the ImageView to be rectangular as well. This then affects how other Views are laid out around the ImageView.
Then as Samuh wrote, you can change the way it default scales images using the android:scaleType parameter. By the way, the easiest way to discover how this works would simply have been to experiment a bit yourself! Just remember to look at the layouts in the emulator itself (or an actual phone) as the preview in Eclipse is usually wrong.
See android:adjustViewBounds.
Set this to true if you want the ImageView to adjust its bounds to preserve the aspect ratio of its drawable.
To anyone else having this particular issue. You have an ImageView that you want to have a width of fill_parent and a height scaled proportionately:
Add these two attributes to your ImageView:
android:adjustViewBounds="true"
android:scaleType="centerCrop"
And set the ImageView width to fill_parent and height to wrap_content.
Also, if you don't want your image to be cropped, try this:
android:adjustViewBounds="true"
android:layout_centerInParent="true"
If you want an ImageView that both scales up and down while keeping the proper aspect ratio, add this to your XML:
android:adjustViewBounds="true"
android:scaleType="fitCenter"
Add this to your code:
// We need to adjust the height if the width of the bitmap is
// smaller than the view width, otherwise the image will be boxed.
final double viewWidthToBitmapWidthRatio = (double)image.getWidth() / (double)bitmap.getWidth();
image.getLayoutParams().height = (int) (bitmap.getHeight() * viewWidthToBitmapWidthRatio);
It took me a while to get this working, but this appears to work in the cases both where the image is smaller than the screen width and larger than the screen width, and it does not box the image.
This worked for me:
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:maxWidth="39dip"
android:scaleType="centerCrop"
android:adjustViewBounds ="true"
This is how it worked for me inside a ConstraintLayout:
<ImageView
android:id="#+id/myImg"
android:layout_width="300dp"
android:layout_height="300dp"
android:scaleType="fitCenter"
android:adjustViewBounds="true"/>
Then in code, I set the drawable as:
ImageView imgView = findViewById(R.id.myImg);
imgView.setImageDrawable(ResourcesCompat.getDrawable(getResources(), R.drawable.image_to_show, null));
This fits the image nicely according to its aspect ratio and keeps it in centre.
this solved my problem
android:adjustViewBounds="true"
android:scaleType="fitXY"
Take a look at ImageView.ScaleType to control and understand the way resizing happens in an ImageView. When the image is resized (while maintaining its aspect ratio), chances are that either the image's height or width becomes smaller than ImageView's dimensions.
Below code Working for scale image as aspect ratio:
Bitmap bitmapImage = BitmapFactory.decodeFile("Your path");
int nh = (int) ( bitmapImage.getHeight() * (512.0 / bitmapImage.getWidth()) );
Bitmap scaled = Bitmap.createScaledBitmap(bitmapImage, 512, nh, true);
your_imageview.setImageBitmap(scaled);
I have an image smaller than the screen. To have it stretched proportionally to the max and centered in the view I had to use the following code:
<ImageView
android:id="#+id/my_image"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_centerInParent="true"
android:adjustViewBounds="true"
android:layout_weight="1"
android:scaleType="fitCenter" />
Have in mind though, that if you have a relative layout and have some elements set to be above or below the ImageView, they will be most likely overlapped by the image.
Use these properties in ImageView to keep aspect ratio:
android:adjustViewBounds="true"
android:scaleType="fitXY"
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:adjustViewBounds="true"
android:scaleType="fitXY"
/>
If image quality decreases in:
use
android:adjustViewBounds="true"
instead of
android:adjustViewBounds="true"
android:scaleType="fitXY"
For anyone of you who wants the image to fit exact the imageview with proper scaling and no cropping use
imageView.setScaleType(ScaleType.FIT_XY);
where imageView is the view representing your ImageView
You can calculate screen width. And you can scale bitmap.
public static float getScreenWidth(Activity activity) {
Display display = activity.getWindowManager().getDefaultDisplay();
DisplayMetrics outMetrics = new DisplayMetrics();
display.getMetrics(outMetrics);
float pxWidth = outMetrics.widthPixels;
return pxWidth;
}
calculate screen width and scaled image height by screen width.
float screenWidth=getScreenWidth(act)
float newHeight = screenWidth;
if (bitmap.getWidth() != 0 && bitmap.getHeight() != 0) {
newHeight = (screenWidth * bitmap.getHeight()) / bitmap.getWidth();
}
After you can scale bitmap.
Bitmap scaledBitmap=Bitmap.createScaledBitmap(bitmap, (int) screenWidth, (int) newHeight, true);
When doing this programmatically, be sure to call the setters in the correct order:
imageView.setAdjustViewBounds(true)
imageView.setScaleType(ImageView.ScaleType.CENTER_CROP)
If you want your image occupy the maximum possible space then the best option would be
android:layout_weight="1"
android:scaleType="fitCenter"
Yo don't need any java code. You just have to :
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:adjustViewBounds="true"
android:scaleType="centerCrop" />
The key is in the match parent for width and height
I use this:
<ImageView
android:id="#+id/logo"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_centerInParent="true"
android:scaleType="centerInside"
android:src="#drawable/logo" />
Try using android:layout_gravity for ImageView:
android:layout_width="wrap_content"
android:layout_height="0dp"
android:layout_gravity="center_vertical|center_horizontal"
android:layout_weight="1"
The example above worked for me.
I have an algorithm to scale a bitmap to bestFit the container dimensions, maintaining its aspect ratio. Please find my solution here
Hope this helps someone down the lane!
Pass your ImageView and based on screen height and width you can make it
public void setScaleImage(EventAssetValueListenerView view){
// Get the ImageView and its bitmap
Drawable drawing = view.getDrawable();
Bitmap bitmap = ((BitmapDrawable)drawing).getBitmap();
// Get current dimensions
int width = bitmap.getWidth();
int height = bitmap.getHeight();
float xScale = ((float) 4) / width;
float yScale = ((float) 4) / height;
float scale = (xScale <= yScale) ? xScale : yScale;
Matrix matrix = new Matrix();
matrix.postScale(scale, scale);
Bitmap scaledBitmap = Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, true);
BitmapDrawable result = new BitmapDrawable(scaledBitmap);
width = scaledBitmap.getWidth();
height = scaledBitmap.getHeight();
view.setImageDrawable(result);
LinearLayout.LayoutParams params = (LinearLayout.LayoutParams) view.getLayoutParams();
params.width = width;
params.height = height;
view.setLayoutParams(params);
}
Programatically apply aspect ratio to Imageview:
aspectRatio = imageWidth/imageHeight
ratioOfWidth = imageWidth/maxWidth
ratioOfHeight = imageHeight/maxHeight
if(ratioOfWidth > ratioOfHeight){
imageWidth = maxWidth
imageHeight = imageWidth/aspectRatio
} else if(ratioOfHeight > ratioOfWidth){
imageHeight = maxHeight
imageWidth = imageHeight * aspectRatio
}
After that you can use scaled bitmap to image view
Bitmap scaledBitmap= Bitmap.createScaledBitmap(bitmap, (int) imageWidth , (int) imageHeight , true);
in case of using cardviewfor rounding imageview and fixed android:layout_height for header this worked for me to load image with Glide
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="220dp"
xmlns:card_view="http://schemas.android.com/apk/res-auto"
>
<android.support.v7.widget.CardView
android:id="#+id/card_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center|top"
card_view:cardBackgroundColor="#color/colorPrimary"
card_view:cardCornerRadius="10dp"
card_view:cardElevation="10dp"
card_view:cardPreventCornerOverlap="false"
card_view:cardUseCompatPadding="true">
<ImageView
android:adjustViewBounds="true"
android:maxHeight="220dp"
android:id="#+id/iv_full"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:scaleType="fitCenter"/>
</android.support.v7.widget.CardView>
</FrameLayout>
You can scale image that will also reduce the size of your image.
There is a library for it you can download and use it.
https://github.com/niraj124124/Images-Files-scale-and-compress.git
How to use
1)Import the compressor-v1.0. jar to your project.
2)Add the below sample code to test.
ResizeLimiter resize = ImageResizer.build();
resize.scale("inputImagePath", "outputImagePath",imageWidth, imageHeight);
Many more methods are there according to your requirement
Quick answer:
<ImageView
android:id="#+id/imageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:scaleType="center"
android:src="#drawable/yourImage"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
imageView.setImageBitmap(Bitmap.createScaledBitmap(bitmap, 130, 110, false));