Combining Two Png Files in Android

combining two png files in android

I've been trying to figure this out for a little while now.

Here's (essentially) the code I used to make it work.

// Get your images from their files
Bitmap bottomImage = BitmapFactory.decodeFile("myFirstPNG.png");
Bitmap topImage = BitmapFactory.decodeFile("myOtherPNG.png");

// As described by Steve Pomeroy in a previous comment, 
// use the canvas to combine them.
// Start with the first in the constructor..
Canvas comboImage = new Canvas(bottomImage);
// Then draw the second on top of that
comboImage.drawBitmap(topImage, 0f, 0f, null);

// comboImage is now a composite of the two. 

// To write the file out to the SDCard:
OutputStream os = null;
try {
    os = new FileOutputStream("/sdcard/DCIM/Camera/" + "myNewFileName.png");
    comboImage.compress(CompressFormat.PNG, 50, os)
} catch(IOException e) {
    e.printStackTrace();
}

EDIT :

there was a typo,
So, I've changed

image.compress(CompressFormat.PNG, 50, os)

to

bottomImage.compress(CompressFormat.PNG, 50, os)

Merging Two Images into one Image

If you want to create a side-by-side merged image you will need to create a result bitmap with 2 times the width of first image, or, more scalably, the sum of the widths of the images:

Currently, you are creating a result image with width firstImage.getWidth(). They will clearly overlap or be off the canvas.

Also, you will need to place the second image at x == firstImage.getWidth()

Check out this code (untested):

private Bitmap createSingleImageFromMultipleImages(Bitmap firstImage, Bitmap secondImage) {
        Bitmap result = Bitmap.createBitmap(firstImage.getWidth() + secondImage.getWidth(), firstImage.getHeight(), firstImage.getConfig());
        Canvas canvas = new Canvas(result);
        canvas.drawBitmap(firstImage, 0f, 0f, null);
        canvas.drawBitmap(secondImage, firstImage.getWidth(), 0f, null);
        return result;
}

Bitmap mergedImages = createSingleImageFromMultipleImages(firstImage, secondImage);

im.setImageBitmap(mergedImages);

Merging png files programmatically

2 days of trial and error finally hit on the solution.

No need to compress the file or write any new file or use any bitmap as a template and no need to reference the new drawable as a resource (instead just apply the created Bitmap variable) were the issues here.

Bitmap builtFirst = Bitmap.createBitmap(500 * splitFirst.length, 700, ARGB_8888);
    Canvas canvas = new Canvas(builtFirst);

    if (buildFirst.length > 1) {

        for (int i = 0; i < buildFirst.length; i++) {

            canvas.drawBitmap(buildFirst[i], 300 * i, 0, null);
            canvas.drawBitmap(builtFirst, new Matrix(), null);

        }
    }

imageViewFirstNumber.setImageBitmap(builtFirst);

Combining 2 Images overlayed

For overlaying two bitmaps:

public static Bitmap overlay(Bitmap bmp1, Bitmap bmp2) {
        Bitmap bmOverlay = Bitmap.createBitmap(bmp1.getWidth(), bmp1.getHeight(), bmp1.getConfig());
        Canvas canvas = new Canvas(bmOverlay);
        canvas.drawBitmap(bmp1, new Matrix(), null);
        canvas.drawBitmap(bmp2, 0, 0, null);
        return bmOverlay;
    }

And for scaling one first you should check out createScaledBitmap, e.g:

Bitmap scaledBitmap = Bitmap.createScaledBitmap(src, dstWidth, dstHeight, filter);

Android merge two images

Use canvas.setBitmap(Bitmap bitmap). This will send the canvas to the specified Bitmap. You'll want to create a new, mutable bitmap for this. After you call setBitmap you can then save that Bitmap to a file.

Combining two bitmap image (side by side)

You can use Canvas - check out this article:

http://www.jondev.net/articles/Combining_2_Images_in_Android_using_Canvas

Updated code to do it side by side:

public Bitmap combineImages(Bitmap c, Bitmap s) { // can add a 3rd parameter 'String loc' if you want to save the new image - left some code to do that at the bottom 
    Bitmap cs = null; 

    int width, height = 0; 

    if(c.getWidth() > s.getWidth()) { 
      width = c.getWidth() + s.getWidth(); 
      height = c.getHeight(); 
    } else { 
      width = s.getWidth() + s.getWidth(); 
      height = c.getHeight(); 
    } 

    cs = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888); 

    Canvas comboImage = new Canvas(cs); 

    comboImage.drawBitmap(c, 0f, 0f, null); 
    comboImage.drawBitmap(s, c.getWidth(), 0f, null); 

    // this is an extra bit I added, just incase you want to save the new image somewhere and then return the location 
    /*String tmpImg = String.valueOf(System.currentTimeMillis()) + ".png"; 

    OutputStream os = null; 
    try { 
      os = new FileOutputStream(loc + tmpImg); 
      cs.compress(CompressFormat.PNG, 100, os); 
    } catch(IOException e) { 
      Log.e("combineImages", "problem combining images", e); 
    }*/ 

    return cs; 
  } 

Combine Images in android

Try out this code.

private static final String TAG = "JoinImage";
private Bitmap mBackImage, mTopImage, mBackground; 
private BitmapDrawable mBitmapDrawable;
private static String mTempDir;
private String mSavedImageName = null; 
private FileOutputStream mFileOutputStream = null;
private Canvas mCanvas;

in onCreate()

//Create folder in SDCard to store newly generated image
mTempDir = Environment.getExternalStorageDirectory() + "/TestTemp/";
File mTempFile = new File(mTempDir);
if(!mTempFile.exists()) {
    mTempFile.mkdirs();
}
//File name 
mSavedImageName = "Test.png";
//Width = 604, Height = 1024 Change as per your requirement
mBackground = Bitmap.createBitmap(100, 100, Bitmap.Config.ARGB_8888);
//Put back and top images in your res folder
mBackImage = BitmapFactory.decodeResource(getResources(), R.drawable.launcher);
mTopImage = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);

mCanvas = new Canvas(mBackground);
mCanvas.drawBitmap(mBackImage, 0f, 0f, null);
mCanvas.drawBitmap(mTopImage, 12f, 12f, null);

try {
    mBitmapDrawable = new BitmapDrawable(mBackground);
    Bitmap mNewSaving = mBitmapDrawable.getBitmap();
    String FtoSave = mTempDir + mSavedImageName;
    File mFile = new File(FtoSave);
    mFileOutputStream = new FileOutputStream(mFile);
    mNewSaving.compress(CompressFormat.PNG, 95, mFileOutputStream);
    mFileOutputStream.flush();
    mFileOutputStream.close();
} catch(FileNotFoundException e) {
    Log.e(TAG, "FileNotFoundExceptionError " + e.toString());
} catch(IOException e) {
    Log.e(TAG, "IOExceptionError " + e.toString());
}
Log.i(TAG, "Image Created");

in Manifestadd this uses-permission <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

How to combine multiple images into a single image in android?

Bitmap[] parts = new Bitmap[4];
Bitmap result = Bitmap.createBitmap(parts[0].getWidth() * 2, parts[0].getHeight() * 2, Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(result);
Paint paint = new Paint();
for (int i = 0; i < parts.length; i++) {
    canvas.drawBitmap(parts[i], parts[i].getWidth() * (i % 2), parts[i].getHeight() * (i / 2), paint);
}

Something like this =)

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