Develop Reference

draw free hand path on bitmap and create new bitmap from drawing part of bitmap : ANDROID

in detail please refer below image,
i think image clearly describe my problem that i want crop part as selected area not area inside it!
currently i am using canvas for draw free hand path and storing all Points on which user touches and than get crop image like,
Canvas canvas = new Canvas(resultingImage);
Paint paint = new Paint();
paint.setAntiAlias(true);
Path path = new Path();
for (int i = 0; i < SomeView.points.size(); i++)
{
path.lineTo(SomeView.points.get(i).x, SomeView.points.get(i).y);
}
canvas.drawPath(path, paint);
paint.setXfermode(new PorterDuffXfermode(Mode.SRC));
canvas.drawBitmap(bitmap2, 0, 0, paint);
so here resultingImage bitmap is my final cropped bitmap.
how can i achieve my above problem's solution.

Android Mask two Bitmap clear border

I'm using the mask a bitmap with another. The operation succeeds well, unfortunately the result of masking seen a slight black border, as you can see in the image:
How do I remove this border? in the source image is not there.
I'll post the code I'm using:
public Bitmap mask(Bitmap source) {
Bitmap targetBitmap = Bitmap.createBitmap(getWidth(),getHeight(),
Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(targetBitmap);
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));
paint.setAntiAlias(true);
paint.setDither(true);
canvas.drawBitmap(source, 0, 0, null);
canvas.drawBitmap(getMask(), 0, 0, paint);
paint.setXfermode(null);
return targetBitmap;
}
where getMask () returns the Bitmap that represents the figure of the Puzzle.
I hope to receive your help, thank you all
Sorry for my english :-)
UPDATE:
the black border is what I point out in this picture:
UPDATE:
place the sequence of transformation. The third image would be identical to the first but without color. The problem is the black edge of the puzzle.
I hope to be more clear:

The way I draw images with mask is kind of the other way around from what you do.
public Bitmap mask(Bitmap source) {
Bitmap targetBitmap = Bitmap.createBitmap(getWidth(),getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(targetBitmap);
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
// paint.setAntiAlias(true); // you've already set this in the constructor
paint.setDither(true);
canvas.drawBitmap(getMask(), 0, 0, null);
canvas.drawBitmap(source, 0, 0, paint);
// paint.setXfermode(null); // no need for this
return targetBitmap;
}
Note that PorterDuff.Mode is set to SRC_IN (not DST_in) and that the mask is drawn first and then the image on top of that mask. With this approach you can also draw the previous source as the base mask, add the new (puzzle) mask and then draw the final source/image on top of that with SRC_IN paint to add new puzzle pieces each time.
If that doesn't solve the black border, check that your mask doesn't have feathered (transparent) edges that might be causing these problems.
Also, ANTI_ALIAS_FLAG doesn't do anything on textures. If you want smoothly scaled textures use paint.setFilterBitmap(true);

how to set additive overlay of jpg images to achieve transparency

I need to overlay two images in live wallpaper. The overlay images is the jpg which needs to be set to "additive" overlay. it adds the pixel value rather than calculating the transparency. how can i achieve this in android ?

You can make use of Android's Bitmap and Drawable classes mixed with Canvas, and try something like in this snippet:
public static Drawable mergeImage(Drawable orig, Drawable over, int left, int top) {
Bitmap original = ((BitmapDrawable)orig).getBitmap();
Bitmap overlay = ((BitmapDrawable)over).getBitmap();
Bitmap result = Bitmap.createBitmap(original.getWidth(), original.getHeight(), Config.ARGB_8888);
Canvas canvas = new Canvas(result);
Paint paint = new Paint();
paint.setAntiAlias(true);
canvas.drawBitmap(original, 0, 0, paint);
canvas.drawBitmap(overlay, left, top, paint);
return new BitmapDrawable(result);
}
I've coded a photo image gridview overlayered with "online status" using the above lines. Hope that it works for you too.

A more general approach may be to create a PorterDuffXfermode with your wanted PorterDuffMode and then set it on the Paint object that you use with your canvas, as referenced in mthama's answer but substituting some lines. This allows you to use other Porter-Duff modes as wanted/needed.
Paint paint = new Paint();
paint.setAntiAlias(true);
canvas.drawBitmap(original, 0, 0, paint);
paint.setXferMode(new PorterDuffXferMode(PorterDuff.Mode.OVERLAY));
canvas.drawBitmap(overlay, left, top, paint);
Mind you, I haven't tried this, so go with mthama's answer. :)

Canvas.drawBitmap() ignoring the tile mode of the paint

I want to draw subparts of a bitmap, but at a different size. If the size is bigger than the source rectangle in the bitmap, then I want that section of the bitmap to tile to fill the destination area. However, instead of getting tiled they are getting stretched.
I set up all the variables as follows:
Bitmap b = BitmapFactory.decodeResource(getResources(), R.drawable.image);
Rect srcRect = ...
Rect dstRect = ...
Paint p = new Paint();
p.setShader(new BitmapShader(b, Shader.TileMode.REPEAT, Shader.TileMode.REPEAT));
And then in the draw() method I draw as follows:
canvas.drawBitmap(b, srcRect, dstRect, p);
What am I doing wrong? How should I draw srcRect to dstRect such that my subpart of the bitmap gets tiled?

I discovered the problem, put succinctly: shaders on bitmaps don't work that way.
To draw a rectangle tiled with a specific Bitmap you have to use Canvas.drawRect(), with a Paint that has a BitmapShader. However, Android dev can't ever be as simple as that.
First you have to cut out the srcRect to a separate Bitmap (caching this somewhere since I don't think this is a cheap operation), like so:
Bitmap t = Bitmap.createBitmap(b, srcRect.left, srcRect.top, srcRect.right-srcRect.left, srcRect.bottom-srcRect.top);
Then you have to create the Paint and the BitmapShader:
BitmapShader bs = new BitmapShader(t, TileMode.REPEAT, TileMode.REPEAT);
Paint p = new Paint();
p.setShader(bs);
Then you can finally draw to the destination rectangle, but first you have to set up a translation matrix for the shader or else it won't start from the correct place and might bugger up completely if your tile mode is CLAMP:
Matrix m = new Matrix();
m.postTranslate(dstRect.left, dstRect.right);
p.getShader().setMatrix(m);
canvas.drawRect(dstRect, p);

Canvas to ImageView problem in Android

I want to display Canvas contents on ImageView in android,
but ImageView displaying blank.
Bitmap imgBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.image);
Canvas canvas = new Canvas();
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
canvas.drawBitmap(imgBitmap, 0, 0, paint);
paint.setColor(Color.BLACK);
paint.setAlpha(100);
canvas.drawRect(0, 0, 100, 100, paint); // transparent black on image
imgView.draw(canvas);
what is the problem? and what should I do?

When ImageView.draw() is called its actually putting the contents of the ImageView into the provided canvas, you have it logically backwards here. Instead use Canvas(Bitmap) constructor instead (so your canvas will draw on to the bitmap) then ImageView.setImageBitmap() with the same bitmap given to the canvas. You can use Bitmap.createBitmap(int, int, Bitmap.Config) to create the size of Bitmap you want. And remember if you have the canvas draw outside the Bitmap's bounds it is clipped.