Develop Reference

Android studio - Center non-transparent part of picture

I'm making an app that can freehand crop a picture using a canvas in android studio. My problem is that after cropping the picture, the cropped part stays in the same exact position as it was originally, whereas i want it to get centered and enlargened. Is there any way to take the non-transparent part and center it, or maybe remove the transparent part all-together?
Screenshot of my app where i want the banana to be centered
https://i.stack.imgur.com/8OKNT.png
Bitmap bitmap;
Path path = new Path();
Paint paint;
int width;
int height;
Rect src;
Rect dest;
public CutImage(Context context, Bitmap bitmap2) {
super(context);
bitmap = bitmap2;
paint = new Paint();
paint.setStyle(Paint.Style.STROKE);
paint.setColor(Color.RED);
paint.setStrokeWidth(5f);
width = getWindowManager().getDefaultDisplay().getWidth();
height = getWindowManager().getDefaultDisplay().getHeight();
src = new Rect(0, 0, bitmap.getWidth() - 1, bitmap.getHeight() - 1);
dest = new Rect(0, 0, width - 1, height - 1);
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.getHeight();
canvas.drawBitmap(bitmap,src,dest, null);
canvas.drawPath(path, paint);
}
private void crop() {
Bitmap croppedBitmap =
Bitmap.createBitmap(bitmap.getWidth(),bitmap.getHeight(),bitmap.getConfig());
Canvas cropCanvas = new Canvas(croppedBitmap);
Paint paint = new Paint();
cropCanvas.drawPath(path,paint);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
cropCanvas.drawBitmap(bitmap,src,dest,paint);
bitmap = croppedBitmap;
showImage2(bitmap);
}
} ```

How to make images on Bitmap smaller?

I am trying to build a simple game on android and while setting the background image and other image assets on my main screen it is appearing too big as shown in the below image.
The actual size of the image is 1920x1080 and I want it to fit my screen like the image shown below:
The code for I have used is:
public class PoliceView extends View {
private Bitmap police;
private Bitmap background;
private Paint scorePaint = new Paint();
private Bitmap life[] = new Bitmap[2];
public PoliceView(Context context) {
super(context);
police = BitmapFactory.decodeResource(getResources(),R.drawable.police);
background = BitmapFactory.decodeResource(getResources(),R.drawable.gamebackground);
scorePaint.setColor(Color.BLACK);
scorePaint.setTextSize(70);
scorePaint.setTypeface(Typeface.DEFAULT_BOLD);
scorePaint.setAntiAlias(true);
life[0] = BitmapFactory.decodeResource(getResources(),R.drawable.heart);
life[1] = BitmapFactory.decodeResource(getResources(),R.drawable.brokenheart);
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
//The order of draw matters as objects are drawn in this same order
canvas.drawBitmap(background,0,0,null);
canvas.drawBitmap(police, 0, 0, null);
canvas.drawText("Score:",20, 60, scorePaint);
//Three lives for the police
canvas.drawBitmap(life[0],580, 10, null);
canvas.drawBitmap(life[0],680, 10, null);
canvas.drawBitmap(life[0],780, 10, null);
}}
How can I resize the images to fit the screen??

i use this code for resize image
Bitmap tmp = BitmapFactory.decodeFile(mPath);
ResizeWidth = (int) (your size);
ResizeHeight = (int) (your size);
Bitmap bitmap = Bitmap.createBitmap(ResizeWidth, ResizeHeight, Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
Bitmap scaled = Bitmap.createScaledBitmap(tmp, ResizeWidth, ResizeHeight, true);
int leftOffset = 0;
int topOffset = 0;
canvas.drawBitmap(scaled, leftOffset, topOffset, null);

How to resize bitmap in canvas?
canvas.save(); // Save current canvas params (not only scale)
canvas.scale(scaleX, scaleY);
canvas.restore(); // Restore current canvas params
scale = 1.0f will draw the same visible size bitmap

Android: How to draw over downloaded bitmap and then populate it to ImageView?

My application is downloading a bitmap which is later populated into custom ImageView. However I want this bitmap to be updated before it is actually drawn on a canvas (I want to add some points over it). However as the result I see only populated bitmap without changes I made. Can anyone help?
Here is my onDraw method. "bitmap" object is set via setImageBitmap received from AsyncTask in onPostExecute() method.
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (bitmap != null) {
Display display = ((WindowManager) getContext().getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
Point size = new Point();
display.getSize(size);
int width = size.x;
int padding = (width - bitmap.getWidth()) / 2;
canvas.drawBitmap(bitmap, padding, 0, null);
paint.setColor(Color.RED);
paint.setStrokeWidth(5f);
for (Face face : getPhotoObject().getFaces()) {
canvas.drawPoint(face.getLeftEye().x, face.getLeftEye().y, paint);
canvas.drawPoint(face.getRightEye().x, face.getRightEye().y, paint);
}
}
}

You can create a canvas with a bitmap at any time:
Canvas canvas = new Canvas(myBitmap);
// draw code
// the resulting bitmap will be edited.
Hope this helps

Android: Moving background image while navigating through five home screen views

I want to Move background image while navigating through 5 home screen Views.
just like when we select an image from gallery and set as wallpaper and then it scrolls with the change of home screen view(offset).
SurfaceHolder holder = getSurfaceHolder();
Canvas canvas = null;
try {
canvas = holder.lockCanvas();
if (canvas != null) {
drawCircles(canvas);
}
} finally {
if (canvas != null)
holder.unlockCanvasAndPost(canvas);
}
the draw function is
{
private void draw(Canvas canvas) {
Paint paint = new Paint();
DisplayMetrics metdisplayMatrics = new DisplayMetrics();
Display display = ((WindowManager) getSystemService(WINDOW_SERVICE)).getDefaultDisplay();
display.getMetrics(metdisplayMatrics);
canvas.save();
canvas.drawColor(0xff000000);
mRecscreenRectangleFrame = new Rect(0, 0, (int) (metdisplayMatrics.widthPixels*2.0), metdisplayMatrics.heightPixels);
photo1= BitmapFactory.decodeResource(getResources(), R.drawable.img1);
canvas.drawBitmap(photo1, null,mRecscreenRectangleFrame, paint);
photo1.recycle();
System.gc();
}

Aspect ratio is off when scaling down and drawing a bitmap

The image I am using is from a 4x6. So the aspect ratio should be about .66. When I calculate the aspect ration in my code , I get around .66. However, the height of the displayed image looks squashed. The image only looks right if I set the aspect ratio manually to around .85.
Since setting the aspect ratio manually is not perfect, how can I get the can I keep the height of my image from appearing to be squashed.
public class SpotGameActivity extends Activity {
private Bitmap mBitmap;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.dpi2b);
setContentView(new BitMapView(this, mBitmap));
}
class BitMapView extends View {
Bitmap mBitmap = null;
public BitMapView(Context context, Bitmap bm) {
super(context);
mBitmap = bm;
}
#Override
protected void onDraw(Canvas canvas) {
// called when view is drawn
Paint paint = new Paint();
paint.setFilterBitmap(true);
// The image will be scaled so it will fill the width, and the
// height will preserve the image’s aspect ration
float aspectRatio = ((float) mBitmap.getWidth()) / mBitmap.getHeight();
Rect dest = new Rect(0, 0, this.getWidth(),(int) (this.getHeight() * aspectRatio));
String AR = Double.toString(aspectRatio);
//Rect dest = new Rect(0, 0, getWidth(), getHeight());
canvas.drawBitmap(mBitmap, null, dest, paint);
Toast.makeText(SpotGameActivity.this, AR, Toast.LENGTH_SHORT).show();
}
}
}

Aspect = width/height
newHeight = newWidth/Aspect
Do this,
Rect dest = new Rect(0, 0, this.getWidth(),(int) (this.getWidth() / aspectRatio));