Develop Reference

Android - Black BG color issue in canvas masking

I an creating an android application in which i am going to crop a bitmap image using path in canvas.
I am able to cut the bitmap using path but it leaves black background on the remaining portion of the bitmap.
Below is my code to cut a bitmap with path and mask in canvas.
public Bitmap cropBitmap(Path path){
Bitmap maskImage = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Bitmap.Config.ARGB_8888);
Canvas maskCanvas = new Canvas(maskImage);
maskCanvas.drawColor(0, PorterDuff.Mode.CLEAR);
Paint pathPaint = new Paint();
pathPaint.setAntiAlias(true);
pathPaint.setXfermode(null);
pathPaint.setStyle(Style.FILL);
pathPaint.setColor(Color.WHITE);
maskCanvas.drawPath(path,pathPaint);
Bitmap resultImg = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Bitmap.Config.ARGB_8888);
Canvas mCanvas = new Canvas(resultImg);
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
mCanvas.drawBitmap(bitmap, 0, 0, null);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));
mCanvas.drawBitmap(maskImage, 0, 0, paint);
return resultImg;
}
and below is the input image with path.
and below is the result which i am getting right now.
I want to remove that black background portion.
that black portion should be transparent.
Is there any way i can remove that black portion and make it transparent?

Fit image inside png Image (Frame)

I have a png image which I want to use as a frame for images in ImageView.
Sorry, it's white that's why invisible
Like this but with sides curved
What is the solution?
I've tried by converting png to patch 9, setting background of parent and source of image view, but none worked. Image doesn't fit inside.

I've done it using PorterDuff. Designed an extra image just with curved border and applied PorterDuff.Mode.SRC_OVER inside setImageResource of Custom Image View.
Here is the overriden function
#Override
public void setImageResource(int resId) {
Bitmap rawBmp = BitmapFactory.decodeResource(getContext().getResources(), resId);
Bitmap rawMask = BitmapFactory.decodeResource(getContext().getResources(), R.drawable.image_frame_arc_filled);
Bitmap rawBorderMask = BitmapFactory.decodeResource(getContext().getResources(), R.drawable.image_frame_arc);
Bitmap bmp = Bitmap.createScaledBitmap(rawBmp, rawBmp.getWidth(), rawBmp.getHeight(), true);
Bitmap mask = Bitmap.createScaledBitmap(rawMask, bmp.getWidth(), bmp.getHeight(), true);
Bitmap borderMask = Bitmap.createScaledBitmap(rawBorderMask, mask.getWidth(), mask.getHeight(), true);
Bitmap bitmap = Bitmap.createBitmap(mask.getWidth(), mask.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
canvas.drawBitmap(bmp, 0, 0, null);
Paint maskPaint = new Paint();
maskPaint.setXfermode(
new PorterDuffXfermode(PorterDuff.Mode.DST_IN));
canvas.drawBitmap(mask, 0, 0, maskPaint);
maskPaint = new Paint();
maskPaint.setXfermode(
new PorterDuffXfermode(PorterDuff.Mode.SRC_OVER));
canvas.drawBitmap(borderMask, 0, 0, maskPaint);
this.setImageBitmap(bitmap);
}

Android Image Masking with Rotate & Scale

How to mask image such as we can scale/zoom/rotate the background image but not the mask?
I should be able to zoom the image in this mask but it is scaling whole image.
Suggest me a way to achieve this, I'm creating a photo collage app.
Blue color is background of Layout.
The white color is for mask
I'm able to achieve this type of layout with masking, but when I apply MultiTouchListener to scale and zoom, it will scale the whole image with mask and not the image inside it.
private void getMaskedBitmap() {
Bitmap bgBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.background_drawable);
ImageView bg = (ImageView) findViewById(R.id.bg);
bg.setImageBitmap(bgBitmap);
Bitmap.Config conf = Bitmap.Config.ARGB_8888;
Bitmap emptyBitmap = Bitmap.createBitmap(bgBitmap.getWidth(), bgBitmap.getHeight(), conf);
Canvas canvasBmp = new Canvas(bgBitmap);
ImageView mImageView = (ImageView) findViewById(R.id.troll_face);
Bitmap original = BitmapFactory.decodeResource(getResources(), R.drawable.random_drawable);
Bitmap mask = BitmapFactory.decodeResource(getResources(), R.drawable.mask_drawable);
original = Bitmap.createScaledBitmap(original, mask.getWidth(), mask.getHeight(), true);
Bitmap result = Bitmap.createBitmap(mask.getWidth(), mask.getHeight(), Config.ARGB_8888);
Canvas mCanvas = new Canvas(result);
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));
mCanvas.drawBitmap(original, 0, 0, null);
mCanvas.drawBitmap(mask, 0, 0, paint);
paint.setXfermode(null);
mImageView.setImageBitmap(result);
//mImageView.setScaleType(ScaleType.FIT_XY);
mImageView.setBackgroundResource(R.drawable.background_drawable);
bg.setOnTouchListener(new MultiTouchListener());
mImageView.invalidate();
}
Exception on line
Canvas canvasBmp = new Canvas(bgBitmap);
java.lang.IllegalStateException: Immutable bitmap passed to Canvas constructor

I cannot provide you code but here is what you should do:
Get background image as bitmap and draw it on view's canvas.
Create an new (empty) bitmap of same size (use Bitmap.Config.ARGB_8888) and get its canvas, here you will draw mask.
Canvas canvasBmp = new Canvas(bmp);
Now draw bmp on view's canvas. So, that you can get mask effect on image.
Zoom (re-size etc whatever you want) background bitmap image.
Invalidate your view, and follow all steps again

How to mask only certain parts of a bitmap in Android

I want to be able to use the following image to mask other bitmap. So basically, I'm trying to get the mask image and replace it's black content with another bitmap. Like this for example:
I'm able to use this mask and create a round version of the original bitmap, but that does not retain that orange border around it. Any thoughts on how I can accomplish this effect? Thanks.
The code that I am using (that only creates a round image) is the following:
private static Bitmap applyMask(ImageView imageView, Bitmap mainImage) {
Canvas canvas = new Canvas();
Bitmap result result = Bitmap.createBitmap(50, 50, Bitmap.Config.ARGB_8888);
canvas.setBitmap(result);
Paint paint = new Paint();
// resize image fills the whole canvas
canvas.drawBitmap(mainImage, null, new Rect(0, 0, 50, 50), paint);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));
canvas.drawBitmap(sMaskImage, 0, 0, paint);
paint.setXfermode(null);
return result;
}

I use below code snipped to set masked images, this sample "bm" is my bitmap and "mMaskSource" is the resource id of mask object position in my drawable folder.
Bitmap mask = BitmapFactory.decodeResource(getResources(), mMaskSource);
Bitmap result = Bitmap.createBitmap(mask.getWidth(), mask.getHeight(),
Config.ARGB_8888);
Canvas mCanvas = new Canvas(result);
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));
bm = Bitmap.createScaledBitmap(bm, mask.getWidth(), mask.getHeight(),
true);
mCanvas.drawBitmap(bm, 0, 0, null);
mCanvas.drawBitmap(mask, 0, 0, paint);
paint.setXfermode(null);
And finally you can use "result" bitmap object however you wish.

draw circle on bitmap

i've written an app that captures a picture and saves it on the sdcard. i then can load that image into an imageview to display it. i'd like to draw a circle on the bitmap before i display it. the code below displays the bitmap but no circle, any ideas why the circle is not there?
thanks.
BitmapFactory.Options bfo = new BitmapFactory.Options();
bfo.inSampleSize = 5;
Bitmap bm = BitmapFactory.decodeByteArray(imageArray, 0, imageArray.length, bfo);
Log.e(TAG, bm.toString());
//imageview.setImageBitmap(bm);
Bitmap bmOverlay = Bitmap.createBitmap(bm.getWidth(), bm.getHeight(), bm.getConfig());
canvas = new Canvas(bmOverlay);
Paint paint = new Paint();
paint.setColor(Color.RED);
canvas.drawBitmap(bm, new Matrix(), null);
canvas.drawCircle(750, 14, 11, paint);
imageview.setImageBitmap(bmOverlay);

You might check bm.getWidth. If you are using a sample size of 5 then your image will be 5 times smaller than the original, causing your circle to disappear off the right side of the image.
You could try:
paint.setStrokeWidth(10);
canvas.drawCircle(50, 50, 25);
just as a sanity check.