I have a big resolution bitmap, and I'd like to make a thumbnail out of it (of course, it is a dynamic case, I don't have the files in advance, but just to simplify).
However, whatever I do, the bitmap always gets 'nearest neighbour' interpolated image.
I tried setting inDither flag, inPreferQualityOverSpeed, inPrefering RGB_8888 bitmap format, and God only knows what not.
Whatever I try, the image is still pixelated.
Trying to downsample it with GIMP echoed beautiful results, so the image is not faulty.
Any idea of a library or an SDK method somewhere that does downscaling with some smarter interpolation, and not nearest neighbour?
Related
I'm taking whole screenshot of a WebView and display the bitmap on an ImageView. The bitmap can be 7 screen height. (E.g. 1440x14000 px)
I'm frequently face with
OutOfMemoryError.
I've seen this
This says that load a scaled down version into memory but I don't want to lose image quality. There are the same approaches on the web.
Is there any way to handle OutOfMemoryError without loading scaled down version?
The bitmap can be 7 screen height. (E.g. 1440x14000 px)
Note that this means that the user cannot see the whole image at once at full resolution.
I'm frequently face with OutOfMemoryError
On most devices, you will have a very difficult time loading an image that large, as you cannot get a single contiguous memory block that big.
This says that load a scaled down version into memory but I don't want to lose image quality
To some extent, you do not have much of a choice. If you want the user to see the full extent of the picture at once, the image has to be scaled to fit the screen.
Is there any way to handle OutOfMemoryError without loading scaled down version?
There are ImageView replacements that offer pan and zoom. Some of those, such as this one, handle loading in pieces of the image at a time, with whatever scaling is necessary for the current zoom level, to make it more likely that you will be able to show the user the entire image.
It is not a solution, of course, but I'm also not familiar with your exact needs, so maybe this may help you a little - you can try to play with bitmap options during decoding. Try to use Bitmap.Config.inPreferredConfig as RGB_565 - this will reduce size of your bitmap twice comparing to default ARGB_8888. But, of course, if you use complex images in your web page this may reduce their quality.
I've been having problems with large images being resized for UI use in Android.
Look at this image, it's an ImageView:
The original image (That arc is a progressbar) is around 10 times bigger than what you see here. In UWP (Windows Platform) we had no problem using a very large image, but here in Android, I beleive it's the Nearest Neighbour method used for fitting images into UI elements, which as you see, causes sharp edges.
Is there any way to switch it into another method? Like Bicubic? It happens in all Android versions I've tested (4.1, 5.0, 6.0).
Just to mention, I'm using Xamarin 4, which I don't beleive as a contributing factor here.
No luck searching through the internet, I'm afraid I'm the only one having this problem.
Thanks.
As mentioned above, you should prefer to use vector image instead of pixel image.
But if you have to use pixel image, maybe you could use BitmapRegionDecoder to decode lines of image and write your own resample algorithm(like Bilinear Interpolation, it's much better than the Near Neighbor) to resize the image, typically in JNI side.
Another possible way is to use "filter" parameter while calling Bitmap.createBitmap method as your original image would not cause OOM issue, just set it to true, it works to reduce the artifacts.
You should use Vector Images instead of Bitmap Images.
Bitmap x Vector
A bitmap represents an image by a series of colored pixels. Whereas a vector image is represented by geometric shapes (lines, curves) using colors.
The main utility of a vector image is allowing to scale without losing definition.
I don't have any problem managing textures. But I didn't work that much with loading textures from images. All I know is that the texture needs to be of size 2^i by 2^i.
But what's the best technique to load any images into a texture. If the images is not a square, I can fit it in the square and add two black parts to fill what is missing. But I'm not sure how to do the stretching.
So, if I have an image of let say 800x600 and I want to put it in a 512x512 square, what's the best trick to copy the pixels into texture ? Or, specially on Android, is there some functions that exists that would do that for me ? In short, it's like I want to resize the 800x600 image to be 512x384 and put it in the texture. But I want to preserve as much information as I can.
The OP Answered his own question with:
SOLVED: a friend showed me some references that covers what I want.
To resize, you can do it with the Bitmap class of Android. You can specify a Matrix, just like the one used for OpenGL to resize the Bitmap. From that point, I expect the pixels to be well preserved and will be able to put them in the texture.
If they come back and put the answer here themselves and accept it then I will delete this answer.
I am joining two images using the code below but it throws an OutOfMemory error my images are around 1MB each.
private Bitmap overlayMark(String first, String second)
{
Bitmap bmp1, bmp2;
bmp1 = BitmapFactory.decodeFile(first);
bmp2 = BitmapFactory.decodeFile(second);
if (bmp1 == null || bmp2 == null)
return bmp1;
int height = bmp1.getHeight();
if (height < bmp2.getHeight())
height = bmp2.getHeight();
Bitmap bmOverlay = Bitmap.createBitmap(bmp1.getWidth() + bmp2.getWidth(), height,
Bitmap.Config.ARGB_8888);// Out of memory
Canvas canvas = new Canvas(bmOverlay);
canvas.drawBitmap(bmp1, 0, 0, null);
canvas.drawBitmap(bmp2, bmp1.getWidth(), 0, null);
bmp1.recycle();
bmp2.recycle();
return bmOverlay;
}
Update: I tried below two answers but it still not allwoing me to create bitmap of such big size the problem is that the resultant bitmap is too large in size around 2400x3200 so its going out of memory.
How can I join large images without running out of memory?
Without loading the image into memory, you CAN get the size of the image, using inJustDecodeBounds. The Bitmap returns null, but all the parameters are set. You can scale down the image accordingly.
If your JPEG images are 1 MiB each, conversion to a BMP will take a lot of memory indeed. You can easily calculate its BMP equivalent by the dimensions of the image. Conversion of such a large image is expected to crash indeed. Android limits its apps to 16 MiB VM only.
Also use RGB_565 instead of ARGB_8888.
So your only solution is:
(a) To use BitmapFactory.Options.inSampleSize to scale down the image
or
(b) Use Android NDK where the 16 MiB limit isn't there.
I use this simple rule of the thumb:
the heavy lifting (both memory/CPU) is done on the server.
So write some servlet that takes the image, resizes it to a specified dimension (probably reduces the pixel depth too) and returns the result.
Piece of cake and it works on any mobile device you need.
Good luck!
I think a solution sort of like Sumon suggests might work.
Figure out the size of the final
image based on what will fit on the
screen.
Get the size of the first image using
the inJustDecodeBounds technique.
Figure out the size of the first
image in the final image. Calculate
re-sizing parameters.
Resize image, loading into memory.
Write resized image back to disk.
Recycle the bitmap. (This will help
when resizing the 2nd image)
Repeat for the second image, only you
can skip the writing to disk part.
Load first image.
If you only need to display, then just do that. If not then you can combine into a single bitmap at this point and write to disk. If this is the case, it may be difficult because you wil have essentially 2x the screen size in memory. In that case I would recommend resizing smaller. If you can't go smaller, then you will have to go the NDK route, thought I'm not sure how much that will help. Here's an amusing intro to the NDK and JNI. Finally, I would highly recommend developing this using a phone running Android 2.3+ since its use of heap-allocated bitmaps will make debugging much easier. More about those here.
It's not necessary that the space taken by in-memory representation of bitmaps correspond closely with file size. So even if you have 3mb memory available to jvm, you might still get OutOfMemoryException.
Your code is creating three in-memory images simultaneously. If you can find the size of both images without reading the complete files, you can modify the code in a way to have only one of the source images in memory at a time. If even that doesn't prove to be sufficient you might need some sort of streaming method of reading the images.
you may get some idea from here.
Are you trying to display this super large image or are you just trying to save it?
If your trying to display it. Cut the images into tiles. Then only display the tiles that are being viewed. If the user zooms out you need to reduce the size of the bitmap before showing the whole thing.
If your trying to save it, try saving it in sections to the same file by cutting the image up.
Loading 2 1m files in memory then creating a 2m file leaves you with 4M in memory for your images alone. Dynamically loading and unloading the memory solves this issue similar to tiles on Google maps or dynamic zooming in other map oriented solutions.
If you need to return that huge 2400x3200 bitmap as your result, there is no way to actually realize this goal. The reason is that 2400*3200*4 bytes ~ 30 Mb! How can you hope to implement this method, when even you can't even fit the return value into your limited heap space (ie 16Mb)?
And even if you used 16-bit color, it would still fail because you would end up using about 15MB, which would not leave you enough space for the language run time.
I would like to read images from InputStreams, and draw them to my canvas. Unfortunately, the images may be very large, and could easily cause out of memory exceptions. BitmapFactory allows me to provide a sample size value, which will down sample the image as it is processed and avoid the memory issues. However, image quality suffers.
Ideally, canvas would provide a paint image method which can paint from an InputStream, as opposed to from a Bitmap, but I haven't found anything of this type. Does this exist, or is there any other way to safely render arbitrarily large images from InputStreams without down sampling?
I am not sure what image format you are using but if you want to send a lossless image (or with less loss than has already occurred), It can't be compressed better than JPEG. so, use JPEG first.
Here is an example for drawing image on Canvas. Override the 'draw' method. http://www.androidsnippets.com/drawing-an-image-as-a-map-overlay2
At the end, hacking it
Probably, pre-splitting the image; compressing each individual one and restoring at the end sounds logical.
Here are few attempts,
http://kalanir.blogspot.com/2010/02/how-to-split-image-into-chunks-java.html
And
http://www.anddev.org/multimedia-problems-f28/chunk-of-a-big-big-image-t6211.html
The answer appears to be: no, there isn't.