Scaling image without losing quality - android

Is it possible to scale image without loosing its quality?I have seen posts that say to use Ninepatch images but how can we download an image and convert it to ninepatch image so that i can show it in ImageView.
Is there any other way so that my images with smaller size can be scaled like in whats app

Everytime you scale an image it's losing quality, the only thing you can do to keep the quality is keeping a copy of the original image (which doesn't make much sense since you can just load it again from resources).
If you mean the problem was that android was scaling your images (and changing the quality) you can put images on a folder named "raw" inside res.
Ninepatch images can be made manually by you, you just paint an image that has two extra pixels on width and two on height, and when you save it , name it something.9.png
if you want to know how to draw them correctly follow this: http://developer.android.com/tools/help/draw9patch.html

Related

Loading images into big size imageviews

I know that ,according to android docs, that if you have a big image. Then you scale it down to size of the image view you are loading it to (using the decodeResources and Options class).
Now my question is, lets say you want to load background picture and the source image is of similar size, do you just load the image? Or do you actually scale it down a bit and then using the FITXY to stretch it?
I am trying to avoid Out Of Memory exceptions here
Thank you

PIcture size 4 times actual image

I'm making an Android game.
I loaded a 128x240 PNG image with my sprites into a Bitmap object and tried to retrieve a 16x16 tile from it via createBitmap(bitmap, x, y, w, h), but got a 1/4 smaller section of the picture instead.
The width/height of the picture according to getWidth/getHeight is 512x960.
What am I doing wrong?
Probably you have the picture in your drawable folder and testing it on a device with high resolution? Android automatically scales up pictures according to http://developer.android.com/guide/practices/screens_support.html
I think the quick solution is to put the image to a drawable-xhdpi (or according other drawable folder).
EDIT: based on a comment at I don't want Android to resize my bitmap Automatically, you can add a folder "drawable-nodpi" to prevent the resizing

Android imageview image quality matter?

I am writing a Android app which need to display some high quality picture(took from professional DSLR). The problem is it can't be display from gallery.
I choose a photo in Gallery first. The target picture is 2464*1632 JPEG, roughly 4.5M;
Then I just need to compress it to 800*600 and display it in imageview:
image.setImageBitmap(this.bmp);
Thing is that I have tested other image I downloaded form internet(really low quality), and it works without any problem. Can anybody tell me why it can't be displayed? I will be really appericiated
Large images are tricky to handle due to limited memory. You have several choices:
Use a WebView (this allows you to have pinch and zoom functionality to make use of those extra pixels
Decode the image down to the size of the display and then put it in an ImageView using BitmapOpts http://developer.android.com/reference/android/graphics/BitmapFactory.Options.html and changing inSampleSize. It seems you may be having difficulty with that, so consider using createScaledBitmap which just needs the dest width and height.

how to edit big images in android?

I am trying to save small images from the original which I load from SDcard. Android doesn't allow me to create bitmap of bigger image sizes so I had to use options, doing so my images' resolution is altered so now how i am supposed to edit the original image??
And saving images, do I have the bitmap.compress option alone? If so, this reduces the quality of the image when i open and save it in JPG
And how can I display them independent of the screen???
I found a way to display big image in Android by using BitmapRegionDecoder. http://developer.android.com/reference/android/graphics/BitmapRegionDecoder.html

Merging multiple picture to form one complete picture in Android

i would like to know whether is it possible to merge several images to form one complete image. For my case, is a floor plan that is split in 18 small images and i would like to merge them into one. I had one idea but not sure whether is it workable. My idea is this:
I would first place the top left most image first, with the x and y coordinates as (0,0).
Next for the subsequent images (right/bottom of this first image), using the width and height of the image, i would find out the coordinates where the next image would be placed. Doing this i presume would required 18 ImageView to achieve that.
Btw, these 18 images are .gif format and so do i need to like convert them to Bitmap or something before i can display them using ImageView?
You could merge the images to a bigger images by drawing the small images to a canvas associated with the resulting big bitmap
Canvas c=new Canvas(result_bitmapenter);
and then draw your small images onto the canvas
c.drawBitmap(small,...);
But that might not be the best way as big images eat lots of memory - perhaps you should concider dynamic loading instead of merging then
Yes its possible create a Bitmap object large enough to hold the whole floor plan and use Canvas to paint them into to the large bitmap. Be sure to cache it or you'll be recreating it every time and you'll have to convert it to png for compatibility with older devices.

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