OutOfMemory error while joining large images_问答_开发者

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.recyc开发者_开发问答le();
    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.