Develop Reference

How to draw a text at the corner of a bitmap android

I have a bitmap and I am trying to draw a text over the bitmap at the top right corner. But at the first place I am not able to draw any text over it. I am converting a layout to bitmap and then trying to draw text over it. But its not working out. Here is my code:
private Bitmap viewToBitmap(LinearLayout layout) {
Bitmap bitmap = Bitmap.createBitmap(layout.getWidth(), layout.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
layout.draw(canvas);
canvas=new Canvas(bitmap);
Paint paint = new Paint();
paint.setColor(Color.BLACK);
paint.setAntiAlias(true);
paint.setTextSize(14.f);
paint.setTextAlign(Paint.Align.CENTER);
canvas.drawText("Hello Android!", 0, 0, paint);
return bitmap;
}

Please pay much attention to the text position & alignment.
private Bitmap viewToBitmap(View view)
{
Bitmap result = Bitmap.createBitmap(view.getWidth(), view.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(result);
view.draw(canvas);
Paint paint = new Paint();
paint.setColor(Color.BLACK);
paint.setAntiAlias(true);
paint.setTextSize(14);
paint.setTextAlign(Paint.Align.RIGHT);
canvas.drawText("Hello Android!", view.getWidth(), 14, paint); // draw watermark at top right corner
return result;
}

draw over a white bitmap another bitmap

I'm trying to draw over a white painted bitmap another bitmap with doodles, but the result is always white:
Bitmap myBitmap = mBitmap;
Canvas canvas = new Canvas(myBitmap);
Paint paint = new Paint(Paint.FILTER_BITMAP_FLAG);
canvas.drawColor(0xffffffff);
canvas.drawBitmap(mBitmap, 0, 0, paint);
myBitmap.compress(CompressFormat.PNG, 100, output);
How i can make white as background, and paintings as foreground in the picture?

answering my own question for futur askers:
Bitmap bmOverlay = Bitmap.createBitmap(mBitmap.getWidth(), mBitmap.getHeight(), mBitmap.getConfig());
Bitmap bmp2 = Bitmap.createBitmap(mBitmap.getWidth(), mBitmap.getHeight(), mBitmap.getConfig());
Canvas canvas = new Canvas(bmOverlay);
bmp2.eraseColor(0xffffffff);
canvas.drawBitmap(bmp2, new Matrix(), null);
canvas.drawBitmap(mBitmap, new Matrix(), null);
bmOverlay is the final bitmap we want.

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.

Android : Constructing bitmap from RECT

Can we construct a bitmap from a rect.
I draw a bitmap in a rect and want strokes drawn on the bitmap image become part of the image.
I am wondering if I can construct a bitmap from a Rect so the new bitmap has the old image and the strokes as a single image.
Thank You

You can always take a canvas to help you create an already decoded bitmap the way you want:
Bitmap originalBmp = null;//Here goes original Bitmap...
ImageView img = null;//Any imageview holder you are using...
Bitmap modifiedBmp = Bitmap.createBitmap(100, 100, Bitmap.Config.ARGB_8888);//Configure with your proper size and color
Canvas canvas = new Canvas(modifiedBmp);
//At this point the modified bitmap has the original one, starting from here, you can add any overlay you want...
canvas.drawBitmap(originalBmp, 0, 0, new Paint());
//And do all the other modifications you want here...
canvas.drawLines(new float[]{}, null);
canvas.drawCircle(x, y, radius, null);
//At this point the modified bitmap will have anything you added
img.setImageBitmap(modifiedBmp);
// IF YOU ARE OVERRIDING ONDRAW METHOD
public void onDraw(Canvas canvas){
//Here DO your DRAW BITMAP NOTE: paint must be already created...
canvas.drawBitmap(bt, 0, 0, paint);
paint.setColor(Color.BLACK);
paint.setStrokeWidth(3);
canvas.drawRect(30, 30, 80, 80, paint);
super.onDraw(canvas);
}
Regards!

Yes you can , Using canvas you can draw something on your old bimtap .
Bitmap output = Bitmap.createBitmap(bitmap.getWidth(),
bitmap.getHeight(), Config.ARGB_8888);
Canvas canvas = new Canvas(output);
final int color = 0xff424242;
final Paint paint = new Paint();
final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(color);
// do some canvas drawing
canvas.drawBitmap(bitmap, rect, rect, paint);

android mask bitmap

I need to create a custom view amd in onDraw method I need to draw some bitmaps, using a mask. I created a paint:
Paint maskPaint = new Paint();
maskPaint.setAntiAlias(true);
maskPaint.setXfermode(new AvoidXfermode(Color.RED, 0, AvoidXfermode.Mode.TARGET));
and I draw my bitmap on canvas using this paint. My problem is that at the corners, my mask have some pixels with alpha less than 255. Is there a way to draw my bitmap's pixels on the mask with the same alpha that mask image has on those pixels with aplha greater than zero?

private Bitmap maskingImage(Bitmap s, int drawable) {
Bitmap original = s;
Bitmap mask = BitmapFactory.decodeResource(getResources(),drawable);
Bitmap result = Bitmap.createBitmap(mask.getWidth(), mask.getHeight(),Bitmap.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);
return result;
}

Resources resources = this.getResources();
Bitmap mask = BitmapFactory.decodeResource(resources,R.drawable.fx_lightleak2_small);
int width=bMap.getWidth();
int height=bMap.getHeight();
Bitmap resizedbitmap=Bitmap.createScaledBitmap(mask, width, height, true);
Bitmap result = Bitmap.createBitmap(bMap.getWidth(), bMap.getHeight(), Config.ARGB_8888);
Canvas c = new Canvas(result);
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setXfermode(new PorterDuffXfermode(Mode.LIGHTEN));
c.drawBitmap(bMap, 0, 0, null);
paint.setAlpha(200);
c.drawBitmap(resizedbitmap, 0, 0, paint);
paint.setXfermode(null);
effect_5.setImageBitmap(result);