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

How to draw multiple points on imageview in android java

I'm setting up an eye detection android project and I want to draw probabilities using Canvas, I'm using Firebase ML kit for custom models
I have successfully drawn only one point.
I would like to draw points ( probabilities from tflite model that I have ).
I tried using those functions :
private void useInferenceResult(float[] probabilities) throws IOException {
// [START mlkit_use_inference_result]
String[] result=new String[80];
float x=0;
float y=0;
ArrayList<Point> listpoint= new ArrayList<Point>();
for (int i = 0; i < probabilities.length; i++) {
Log.i("MLKit", String.format("%1.4f", probabilities[i]));
x=probabilities[i];
y=probabilities[i+1];
Point p=new Point(x,y);
i=i+1;
p.setX(x);
p.setY(y);
Log.i("Information1 ","valeur 1 "+p.getX());
listpoint.add(p);
Log.i("Information2 ","valeur 2 "+p.getX());
}
for(int j=0;j<listpoint.size();j++){
Log.e("Information","work");
Log.e("Resultat","point_"+j+"("+listpoint.get(j).getX()+", "+listpoint.get(j).getY()+")");
float xx=listpoint.get(j).getX()*100;
float yy=listpoint.get(j).getY()*100;
drawpoint(image2,0.20958422f * 100,0.6274962f * 100,1);
drawpoint(image2, 0.20460524f * 100,0.6708223f * 100,1);
}
}
//drawpoint function
private void drawpoint(ImageView imageView,float x,float y, int raduis){
BitmapFactory.Options myOptions = new BitmapFactory.Options();
myOptions.inDither = true;
myOptions.inScaled = false;
myOptions.inPreferredConfig = Bitmap.Config.ARGB_8888;// important
myOptions.inPurgeable = true;
Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.imgg,myOptions);
Paint paint = new Paint();
paint.setAntiAlias(true);
paint.setColor(Color.WHITE);
Bitmap workingBitmap = Bitmap.createBitmap(bitmap);
Bitmap mutableBitmap = workingBitmap.copy(Bitmap.Config.ARGB_8888, true);
Canvas canvas = new Canvas(mutableBitmap);
canvas.drawCircle(x,y, raduis, paint);
imageView = (ImageView)findViewById(R.id.imageView);
imageView.setAdjustViewBounds(true);
imageView.setImageBitmap(mutableBitmap);
}
but I didn't get any result just one point drawn.
How can I draw multiples points on imageView?

I solved my problem by changing some lines of code, I declare those variables on the top and I create objects after setContentView:
BitmapFactory.Options myOptions;
Canvas canvas;
Bitmap mutableBitmap;
Bitmap workingBitmap;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn_open= findViewById(R.id.btn_open);
image2= findViewById(R.id.imageView);
myOptions = new BitmapFactory.Options();
bitmap = BitmapFactory.decodeResource(getResources(),
R.drawable.image000880,myOptions);
paint= new Paint();
paint.setAntiAlias(true);
paint.setColor(Color.WHITE);
workingBitmap = Bitmap.createBitmap(bitmap);
mutableBitmap = workingBitmap.copy(Bitmap.Config.ARGB_8888, true);
canvas = new Canvas(mutableBitmap);
private void drawpoint(ImageView imageView,float x,float y, int raduis){
myOptions.inDither = true;
myOptions.inScaled = false;
myOptions.inPreferredConfig = Bitmap.Config.ARGB_8888;// important
myOptions.inPurgeable = true;
// ArrayList<Point> list= new ArrayList<>();
canvas.drawCircle(x,y, raduis, paint);
imageView = (ImageView)findViewById(R.id.imageView);
imageView.setAdjustViewBounds(true);
imageView.setImageBitmap(mutableBitmap);
}
Hope this solution will help others who have the same situation

Simple ImageView Descendent class.
public class CiclesImageView extends AppCompatImageView {
private ArrayList<PointF> theDots = new ArrayList<>();
private Paint paint=new Paint(Paint.ANTI_ALIAS_FLAG);
public CirclesImageView(Context context) {
super(context);
setOnTouchListener(new OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
if(event.getAction()==MotionEvent.ACTION_DOWN)
drawDot(new PointF(event.getX(),event.getY()));
return performClick();
}
});
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
paint.setColor(Color.BLACK);
paint.setStyle(Paint.Style.STROKE);
for (PointF pt:theDots)canvas.drawCircle(pt.x,pt.y,5,paint);
}
public void drawDot(PointF dotPoint){
theDots.add(dotPoint);
invalidate();
}
}
This imageView is used the same way you use any other imageView, except if you touch it, it will draw a circle on itself. If you want to draw your own circles, the drawDot(pointF) is public.

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 live wallpapers parallax-scrolling effect

when we scroll, the foreground of the home screen (icons, widgets, etc.) moves to the left or right by the full screen width, but the background image (or live wallpaper) only moves by a fraction of that width.
My question is how get this effect.
till now have done this.
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();
}
Now how to put live wallpapers parallax-scrolling effect.
#Override
public void onOffsetsChanged(float xOffset, float yOffset,
float xOffsetStep, float yOffsetStep, int xPixelOffset,
int yPixelOffset) {
super.onOffsetsChanged(xOffset, yOffset, xOffsetStep, yOffsetStep,
xPixelOffset, yPixelOffset);
WallpaperManager myWallpaperManager = WallpaperManager.getInstance(getApplicationContext());
View view=new View(getBaseContext());
myWallpaperManager.setWallpaperOffsets(view.getWindowToken(),xOffset, 0f);
}
Not working yet.................

Call WallpaperManager.setWallpaperOffsets to instruct the wallpaper to scroll.
Documentation
So this should center the wallpaper:
WallpaperManager.setWallpaperOffsets(getWindowToken(), 0.5f, 0f);
This should scroll it to the side:
WallpaperManager.setWallpaperOffsets(getWindowToken(), 0f, 0f);
This should scroll it to the other side:
WallpaperManager.setWallpaperOffsets(getWindowToken(), 1f, 0f);
If you're going to do this, you ought to ensure that you know that the wallpaper can actually be scrolled, or that the user has asked you to enable scrolling. Many devices are configured with wallpaper that is the same size as the screen and does not scroll.