Develop Reference

Stretch ImageView height and maintaining aspect ratio

Is there a way in android to display an ImageView by maintaining it's aspect ratio but increasing the height before doing so.
So for example, I have different images that I store inside an ImageView by maintaining it's aspect ratio:
<ImageView
android:id="#+id/coupon_detail_barcode"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:adjustViewBounds="true"
android:scaleType="fitCenter" />
So, let's say the image that comes in is 40dp height and 40dp width. Instead of maintaining that original ratio, I want to stretch the image out first to 42dp height, 40dp width, THEN having it displayed maintaining those new ratios.
I'm assuming there is no way to do it in XML and would have to do it all programmatically.

Get the image as a byte array then:
Bitmap bitmap = BitmapFactory.decodeByteArray(imageAsBytes, 0, imageAsBytes.length);
// Adjust size here.
Bitmap adjustedBitmap = Bitmap.createScaledBitmap(bitmap, 120, 120, false));
// Set adjustedBitmap into ImageView
someImageView.setImageBitmap(adjustedBitmap);

Keeping ratio of bitmap

I change imageview source with bitmap in code but it does not keep ratio of it. It uses dimensions of the old image.
I set bitmap by;
imageView.setImageBitmap(bitmap);
It stretches bitmap to fit dimensions of old image resource. I want to keep bitmap ratio.

Check out the imageView ScaleTypes: http://developer.android.com/reference/android/widget/ImageView.ScaleType.html
CENTER Center the image in the view, but perform no scaling.
CENTER_CROP 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).
CENTER_INSIDE 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 less than the corresponding dimension of the view (minus
padding).
FIT_CENTER Scale the image using CENTER.
FIT_END Scale the image using END.
FIT_START Scale the image using START.
FIT_XY Scale the image using FILL.
MATRIX Scale using the image matrix when drawing.
You want something like CENTER_CROP or CENTER_INSIDE

How to maintain the aspect ratio of the image if imageview first stretch to fill parent

I want to stretch the image to fill width and adjust the height according to width and maintain the aspect ratio. I want it should cover entire width (fillparent) and height of imageview should adjust like in way so that aspect ratio is maintained.
I tried fit_xy but not working in my case. Please help me

There can two possible workarounds even if you set the scale type fit_xy
1) 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.)
2)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.
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.

I'm not sure when the feature I use was added to the Android SDK but there is a simple solution that does exactly what the OP is looking for:
As expected, set layout:width and layout:height to fill_parent.
As another responder mentioned correctly, use src to find your image, not background.
However instead of trying scaleType of fit_xy (which finds the narrowest side to fit into the view rather than the longest side), use scaleType of centerCrop.
centerCrop will center and fill in the viewport while retaining aspect ratio.
Hope this helps! I used it for the webView loading overlay of a commercial app I developed for my current employer.
Copy/paste solution: in your activity XML file, add the following lines:
<ImageView
android:id="#+id/logo"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:scaleType="centerCrop"
android:src="#drawable/your_image_name"
/>

There are two ways of doing this:
First find the display height and width and call this method
private void scaleImage(int displayWidth) {
// Get the ImageView and its bitmap
width=displayWidth;
Drawable drawing = holder.imagepost.getDrawable();
{
Bitmap bitmap = ((BitmapDrawable) drawing).getBitmap();
int bounding = dpToPx(width);
// Determine how much to scale: the dimension requiring less
// scaling is
// closer to the its side. This way the image always stays
// inside your
// bounding box AND either x/y axis touches it.
float xScale = ((float) bounding) / width;
float yScale = ((float) bounding) / height;
float scale = (xScale <= yScale) ? xScale : yScale;
// Create a matrix for the scaling and add the scaling data
Matrix matrix = new Matrix();
matrix.postScale(scale, scale);
// Create a new bitmap and convert it to a format understood by
// the ImageView
Bitmap scaledBitmap = Bitmap.createBitmap(bitmap, 0, 0, width,
height, matrix, true);
width = scaledBitmap.getWidth(); // re-use
height = scaledBitmap.getHeight(); // re-use
BitmapDrawable result = new BitmapDrawable(scaledBitmap);
// Apply the scaled bitmap
holder.imagepost.setImageDrawable(result);
// Now change ImageView's dimensions to match the scaled image
LinearLayout.LayoutParams params = (LinearLayout.LayoutParams) holder.imagepost
.getLayoutParams();
params.width = width;
params.height = height;
holder.imagepost.setLayoutParams(params);
}
}
private int dpToPx(int dp) {
float density = context.getResources().getDisplayMetrics().density;
return Math.round((float) dp * density);
}
Or the Best way i know is to use Android Query
Here is the link http://code.google.com/p/android-query/ and you can download from there itself.Below id the code to maintain the Aspect Ratio
aq.id(R.id.imageView)
.image(imageString, true, true,
displaywidth, 0, null, AQuery.FADE_IN, AQuery.RATIO_PRESERVE);

Below solution is working fine for me.
Use AQuery Libray option "AQuery.RATIO_PRESERVE" to preserve aspect ratio:
aq.id(R.id.imgView).progress(R.id.imgPb).image(url, true, true,150, 0,null,AQuery.FADE_IN,AQuery.RATIO_PRESERVE);
Use below settings for ImageView:
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scaleType="fitXY"/>
Use below settings for auto GridView Columns:
<GridView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/gridView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:numColumns="auto_fit"
android:columnWidth="150dp"/>

Resizing ImageView to fit Image

its a little hard to explain but ill try it anyways.
Im displaying an Image within an ImageView, the imageview is set to use 50% of the ScreenHeight using weight attribute.
Now if the ImageAspectRatio doesnt fit the Ratio of the ImageView, i have an empty space at the bottom and onTop of the ImageView.
Basically i want my ImageView to have a maxSize which is 50% of the ScreenHeight, but to shrink in height if the image in it doesnt use its full height, or at least move to the top of the ImageView.
So, what i did here is i set the View to its max size, and i set the image the way the ImageView usually would. After that i way for the ImageView to layout, then get its Height, as thats the max height i want the View to have.
Then i calculate the Scaling i need to apply. I scale the Image and set the view to Wrap content as it should have the views previous height as a bounding.
Now, this works fine on a Samsung GT-I9000 running CyagenoMod (Android 4.2.2) also tried this on a Kindle HD. But when doing the same on a Nexus 4(running android 4.3) it seems to ignore everything i do.
By that i mean, the image appears to scale properly (imageHeight after scaling something like 53x), but the image takes almost the whole Screen. I dont get why it works on the other 2 devices but on the Nexus.
Is there any new API concerning ImageView for Android 4.3 i dont know about?
#Override
public void setImageResource(final int resId) {
// this.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, 0, 0.5f));
super.setImageResource(resId);
getViewTreeObserver().addOnPreDrawListener(new OnPreDrawListener() {
#Override
public boolean onPreDraw() {
Bitmap bitmap = BitmapFactory.decodeResource(getResources(), resId);
int width = bitmap.getWidth();
int height = bitmap.getHeight();
int boundingY = getHeight();
int boundingX = getWidth();
float xScale = ((float) boundingX) / width;
float yScale = ((float) boundingY) / 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);
MyImageView.this.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT,LinearLayout.LayoutParams.WRAP_CONTENT ));
MyImageView.super.setImageBitmap(scaledBitmap);
getViewTreeObserver().removeOnPreDrawListener(this);
return true;
}
});
}
Ok here is a picture of what im trying to do/doing.
Consider the blueish thing the size of the ImageView, and the Black rectangle, the actual Size of the Image. The Blue size is what i get, if i set the Size of the ImageView to width = matchParent and height = 0 with weight 0.5. This is the MAX Height i want my ImageView to have.
Now, it is possible that the Image has a width >= width of the ImageView. in that case, i want to resize the Height, to fit the Height of the Image, so i resize the Image, to find within those bounds and set the Image to WrapContent as the Image is the exact size i want the View to be.
But this is also possible for an Image. 2*width = height
In that case i dont want the ImageView to do anything. Just Maintain its max height and display the give Image.
This works, as i already said on some devices, GT-I9000 and Amazon Kindle HD, but on a Nexus 4 the images that have a much bigger height than width tend to occupy the whole damn screen.
I debugged this and retrieved ImageViewHeight and BitmapHeight. Both stated that the Image and the ImageView is 534 PX high.
I really dont get why i works on the other 2 devices, but not on the nexus.
<include layout="#layout/own_action_bar" />
<*.view.MyImageView
android:id="#+id/drawFragment_iv"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="0.5"
android:adjustViewBounds="true"
android:contentDescription="#string/hello" />
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="0.5" >
something in here
<RelativeLayout/>
<LinearLayout/>

call setBackgroundResource instead of setImageResource on your ImageView object and it will scale the image to fit the ImageView.
Although it is not an efficient way ti achieve this but if don't have a lot of such ImageViews this should do the trick.

Problems with the width of the bitmap. The width is limited by the height of the screen

I'm creating a bitmap wich i need to use as background of a 320 width screen. The problem is that the bitmap is not getting the width i want. It is getting two empty spaces on the left and on the right. It is because it is fitting the height of the screen, but i dont want that, i want to force the bitmap to have the width i want. Doesn't matter if a portion of the height of the bitmap is out of the screen.
i need to force the width when i am adding the image to the layout, i mean that the image must be keep the aspect ratio, but the image must be higher than the height of the screen, and the image must be shown incomplete if the heigh of the image is higher than the height of the screen. Now this is not happening, because the layout is forcing the width to respect the image and show all the height of the image in the height of the screen, then i think the problem is on the layout rules
im creating the bitmap with:
View view;
Bitmap aux = Util.loadImage( filename ); //image loaded but with his original width
Bitmap image = Util.scaleBitmap(aux, 320); //scaling to 320
((ImageView)view).setImageBitmap( resource.image );
RelativeLayout.LayoutParams rlp = new RelativeLayout.LayoutParams( 320 , h );
rlp.addRule( RelativeLayout.CENTER_HORIZONTAL );
rlp.addRule( RelativeLayout.ALIGN_PARENT_TOP );
layout.addView( view , rlp );
What am i doing wrong?

Try using this:
((ImageView)view).setScaleType(ImageView.FitCenter);
To see more options see http://developer.android.com/reference/android/widget/ImageView.html#attr_android:scaleType

Since you don't care about the height you should use CENTER_CROP.
Define the scale type and then set the image.
CENTER_CROP - 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).