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canvas.drawBitmap() doesn't scale images

I'm a newbe when it comes to Android coding. As a first project I decided to port ZX Spectrum game. I have prepared bitmap frames of the car and buttons that are about to be scaled depending on screen size. I've put the images both in "drawable" and "drawable-hdpi" folders and it seems to work on my LG Leon phone, but not working on other phones. It looks like the image isn't scaled.
https://mechanism.fr/misc/not_scaled.png
here's my code:
declaration of the variables:
Rect source1;
Rect dest1;
Rect arrow_box;
Rect left_box;
Rect right_box;
Rect up_box1;
Rect down_box1;
Rect up_box2;
Rect down_box2;
example of calculating one pair of the Rect dimensions:
private void calculateDimensions(){
(...)
source1=new Rect(0,0,128,100);
arrow_box=new Rect(0,0,300,300);
left_box=new Rect((int)(0+boxxy/2),(int)(wysokosc*0.7),(int)(0+boxxy/2+boxxy),(int)(wysokosc*0.7+boxxy));
and the code responsible for drawing:
Paint drawPaint2 = new Paint();
canvas.drawBitmap(arrow_left_off,arrow_box,left_box,drawPaint2);
canvas.drawBitmap(arrow_right_off,arrow_box,right_box,drawPaint2);
canvas.drawBitmap(arrow_up_off,arrow_box,up_box1,drawPaint2);
canvas.drawBitmap(arrow_down_off,arrow_box,down_box1,drawPaint2);
canvas.drawBitmap(arrow_up_off,arrow_box,up_box2,drawPaint2);
canvas.drawBitmap(arrow_down_off,arrow_box,down_box2,drawPaint2);
the dimensions are calculated after creating the canvas view:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
kanwas=new CanvasV(this);
this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(kanwas);
getDimensions();
calculateDimensions();
updateScreen();
}
I don't quite understand what seems to be the problem.
I tried to copy the images both to "drawable" and "drawable-hdpi" folders

Also, scale the bitmaps. Scaling the canvas doesn't do anything.
Example of scaling bitmap
bitmap=Bitmap.createScaledBitmap(src, dstWidth, dstHeight, filter)

Is it possible to split an image into many parts in Android?

I'm creating a puzzle game where the player can choose a picture and then the program splits it into multi-parts.
I tried to search on many posts answers for my problem, but all of them are talking about BufferedImage or Graphic components. I'm coding on android studio to export my application later, and BufferedImage, Graphics, and others are not known by android. So I think that I should use BitmapDrawable to manipulate my images.
public void initImage(int image) {
this.base = setImage(puzzle.getApplicationContext(), image, 800, 800);
}
public BitmapDrawable setImage(final Context c, final int ressource, final int w, final int h)
{
try {
Drawable dr = c.getResources().getDrawable(ressource);
Bitmap bitmap = ((BitmapDrawable) dr).getBitmap();
return new BitmapDrawable(c.getResources(), Bitmap.createScaledBitmap(bitmap, w, h, true));
} catch(ClassCastException cce) { cce.printStackTrace(); return null; }
}
#Override
public void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawBitmap(this.base.getBitmap(), 0, 0, null);
}
I draw my first image, and now I want to split it into multi parts.
If anyone could help me, I would be very grateful. :)

Android canvas not drawing

I have found very few tutorials on how to use the android canvas. However, after looking at the official documentation I was able to produce this code. I simply would like to draw a green rectangle.
public class LevelActivity extends AppCompatActivity {
Object shape;
Target target;
Rect r;
Paint paint;
Bitmap b = Bitmap.createBitmap(100, 100, Bitmap.Config.ARGB_8888);
Canvas c = new Canvas(b);
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_level);
paint = new Paint();
paint.setColor(Color.GREEN);
paint.setStyle(Paint.Style.FILL);
r = new Rect();
r.set(0,0,c.getWidth(),c.getHeight()/2);
c.drawRect(r,paint);
shape = new Shape(30,10); //Object setup
//shape.pick(); //Pick random point for target
}
}
I do not want to use a customView to draw, I just want to use pure android canvas. When I run the code I get no errors or any warnings.
Any help is greatly appreciated.
-Kelton

Well, you have a Canvas c with an underlying Bitmap b. Now anything that you draw on the Canvas c will actually be drawn on the Bitmap b. And you have done the drawing part in the above code. The Bitmap b has your drawn rectangle. But now to view that you need to load this Bitmap b in some view, like an ImageView. You can have an ImageView in your activity_level layout and then use ImageView.setImageBitmap(b) to load the Bitmap onto the view.

you need to add the following 2 lines at the end:
ImageView iv= (ImageView) findViewById(R.id.imageview_where_i_will_put_my_awesome_green_rectangle);
iv.setImageBitmap(b);

You have to create a ImageView and set the Bitmap as the one you created with canvas.
ImageView imageView = new ImageView(this);
imageView.setBitmap(bitmap);
addContentView(imageView, new LayoutParams(MATCH_PARENT, MATCH_PARENT));

Animate rotation of an image in Android

I have a gear image which I want to continuously rotate about a fixed point.
Earlier I was accomplishing this by including the image in my Android class as an ImageView and applying a RotateAnimation to it.
#InjectView(R.id.gear00) ImageView gear00;
RotateAnimation ra07 = new RotateAnimation(0, 359, 129, 186);
ra07.setDuration(10000);
ra07.setRepeatCount(RotateAnimation.INFINITE);
ra07.setInterpolator(new LinearInterpolator());
gear00.setAnimation(ra07);
Basically, I was injecting the ImageView into the class and applying a rotation animation.
However, I dont have the luxury of using an ImageView anymore. I have to use a Bitmap and rotate it on the canvas.
How can I go about accomplishing what I was doing earlier in the onDraw() method with a bitmap rotating about a fixed point continiously on the canvas?
Edit1:
I tried one of the suggestions mentioned below my code looks a little like the following
in onCreate():
Matrix matrix = new Matrix();
matrix.setRotate(10, 100, 200);
Then in onDraw() (where gear00Scaled is a bitmap to be rotated on the canvas):
canvas.drawBitmap(gear00Scaled, matrix, new Paint());
Another method I tried involved saving the canvas, rotating it, then restoring it:
canvas.save();
canvas.rotate(10);
canvas.drawBitmap(gear00Scaled, 100, 200, null);
canvas.restore();
Neither seem to be working though!

Make an XML class (suppose: rotate.xml) and place it in res/anim folder and then write the following code in it:
<?xml version="1.0" encoding="utf-8"?>
<rotate xmlns:android="http://schemas.android.com/apk/res/android"
android:fromDegrees="0"
android:interpolator="#android:anim/linear_interpolator"
android:pivotX="50%"
android:pivotY="50%"
android:repeatCount="infinite"
android:toDegrees="360" />
Then in your java class, do the following in OnCreate:
final Animation a = AnimationUtils.loadAnimation(CustomActivity.this,
R.anim.rotate);
a.setDuration(3000);
gear00.startAnimation(a);
OR
To do it using bitmap, I hope the following sequence of code helps you:
Bitmap targetBitmap = Bitmap.createBitmap(targetWidth, targetHeight, config);
Canvas canvas = new Canvas(targetBitmap);
Matrix matrix = new Matrix();
matrix.setRotate(mRotation,source.getWidth()/2,source.getHeight()/2);
canvas.drawBitmap(source, matrix, new Paint());
If you check the following method from:
~frameworks\base\graphics\java\android\graphics\Bitmap.java
public static Bitmap createBitmap(Bitmap source, int x, int y, int width, int height,
Matrix m, boolean filter)
this would explain what it does with rotation and translate.

I want to rotate a custom image as progress dialog in my application. You can use the code below to rotate an image:
RotateAnimation anim = new RotateAnimation(0.0f, 360.0f ,
Animation.RELATIVE_TO_SELF, .5f, Animation.RELATIVE_TO_SELF, .5f);
anim.setInterpolator(new LinearInterpolator());
anim.setRepeatCount(Animation.INFINITE);
anim.setDuration(1000);
imageView.setAnimation(anim);
imageView.startAnimation(anim);

In your onCreate() do
Matrix matrix = new Matrix();
And in onDraw
float angle = (float) (System.currentTimeMillis() % ROTATE_TIME_MILLIS)
/ ROTATE_TIME_MILLIS * 360;
matrix.reset();
matrix.postTranslate(-source.getWidth() / 2, -source.getHeight() / 2);
matrix.postRotate(angle);
matrix.postTranslate(centerX, centerY)
canvas.drawBitmap(source, matrix, null);
invalidate(); // Cause a re-draw
ROTATE_TIME_MILLIS is the full circle time, e.g. 2000 is 2 seconds.

Two things before the code:
You can't use imageview at all at all? Cause you could link it to a canvas and use a bitmap, but it is still an imageview.
I believe the main issue you are having is the other answer is not animating it and you are missing the call to invalidate() the view and redraw it as rotated.
So there are two approaches:
1st is with the imageview, personally I think it is easier and nicer. Below is a method in my activity class and mLittleChef is an ImageView.
public void doCanvas(){
//Create our resources
Bitmap bitmap = Bitmap.createBitmap(mLittleChef.getWidth(), mLittleChef.getHeight(), Bitmap.Config.ARGB_8888);
final Canvas canvas = new Canvas(bitmap);
final Bitmap chefBitmap = BitmapFactory.decodeResource(getResources(),R.drawable.dish_special);
//Link the canvas to our ImageView
mLittleChef.setImageBitmap(bitmap);
ValueAnimator animation= ValueAnimator.ofFloat(0, 359, 129, 186);
animation.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
#Override
public void onAnimationUpdate(ValueAnimator animation) {
float value = (Float) animation.getAnimatedValue();
//Clear the canvas
canvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR);
canvas.save();
canvas.rotate(value, canvas.getWidth()/2, canvas.getHeight()/2);
canvas.drawBitmap(chefBitmap, 0, 0, null);
canvas.restore();
mLittleChef.invalidate();
}
});
animation.setInterpolator(new LinearInterpolator());
animation.setDuration(1000);
animation.start();
}
The other way to do it is with a custom canvas class. Instead of an ImageView, I create my own custom view class for ExampleDrawView mLittleChefDraw; in my layout. You will probably have to monkey with this one a bit to get exactly what you are looking for in terms of rotation, I made it just do a 360 degree turn using the middle of the canvas as the pivot point.
public class ExampleDrawView extends View {
Bitmap bitmap;
Float mRotate= 0f;
Handler h;
//State variables
final int STATE_PAUSE = 2;
final int STATE_ROTATE = 3;
int STATE_CURRENT;
public ExampleDrawView(Context context, AttributeSet attrs) {
super(context, attrs);
h = new Handler();
bitmap= BitmapFactory.decodeResource(getResources(), R.drawable.dish_special);
STATE_CURRENT= STATE_PAUSE;
}
Runnable move = new Runnable() {
#Override
public void run() {
switch (STATE_CURRENT){
case STATE_ROTATE:
if (mRotate<360){
mRotate++;
invalidate();
}else{
STATE_CURRENT= STATE_PAUSE;
}
h.postDelayed(move, 20);
break;
}
}
};
public void startDrawing(){
if(STATE_CURRENT == STATE_PAUSE){
STATE_CURRENT= STATE_ROTATE;
mRotate=(float) 0;
h.postDelayed(move, 20);
}
}
#Override
protected void onDraw(Canvas canvas){
super.onDraw(canvas);
//change your rotate point here, i just made it the middle of the canvas
canvas.rotate(mRotate,getWidth()/2,getHeight()/2);
canvas.drawBitmap(bitmap, 0, 0, null);
}
}
And then back in the activity call this to start it:
public void doCanvasCustomView(){
mLittleChefDraw.startDrawing();
}

Android Scratch card app

I am doing a small project for college and wondering if someone can tell me how I would go about doing a scratch card app. This app should have one image overlaying another. The one on top should allow the user to remove the image depending on where they rub on the image and thus part of the image that was removed revealing the image underneath. Pretty much like a scratch card. Any help would be great!
This is the code im using at the moment .
public class workinggraphics extends Activity
{
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
//setContentView(R.layout.main);
setContentView(new Panel(this));
LinearLayout l1 = (LinearLayout) findViewById(R.id.LAYOUTTEST1);
Panel p1 = new Panel(null);
}
class Panel extends View{
private Bitmap mBitmap;
private Canvas mCanvas;
private Path mPath;
private Paint mPaint;
// private Paint nPaint;
Bitmap bitmap;
Canvas pcanvas ;
int x = 0;
int y =0;
int r =0;
public Panel(Context context) {
super(context);
Log.v("Panel", "STROKE");
setFocusable(true);
setBackgroundColor(Color.TRANSPARENT);
/*
WallpaperManager wallpaperManager = WallpaperManager.getInstance(context);
//WallpaperDrawable wallpaperDrawable=wallpaperManager.getDrawable();
try {
wallpaperManager.setBitmap(bmp);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}*/
//setBackgroundDrawable(bmp);
// setting paint
/* nPaint = new Paint();
nPaint.setStyle(Paint.Style.FILL);*/
mPaint = new Paint();
mPaint.setAlpha(0);
mPaint.setStyle(Paint.Style.FILL_AND_STROKE);
mPaint.setStrokeCap(Paint.Cap.BUTT);
mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));//.Mode.DST_IN));
mPaint.setAntiAlias(false);
// getting image from resources
Resources r = this.getContext().getResources();
Bitmap bm = BitmapFactory.decodeResource(getResources(), R.drawable.mainscreen_background);
Bitmap bm1 = BitmapFactory.decodeResource(getResources(),R.drawable.foreground_image);
// converting image bitmap into mutable bitmap
bitmap = bm.createBitmap(bm.getWidth(), bm.getHeight(), Config.ARGB_8888);
//bitmap = bm1.createBitmap(bm1.getWidth(),bm1.getHeight(),Config.ARGB_8888);
pcanvas = new Canvas();
pcanvas.setBitmap(bitmap); // drawXY will result on that Bitmap
pcanvas.drawBitmap(bm, 0, 0, null);
pcanvas.drawBitmap(bm1,0,0,null);
}
#Override
protected void onDraw(Canvas canvas) {
Rect cBK = new Rect();
//canvas.set
cBK.set(0,0,canvas.getWidth(),canvas.getHeight());
//pcanvas.drawRect(cBK, nPaint);
// draw a circle that is erasing bitmap
pcanvas.drawCircle(x, y, r, mPaint);
//pcanvas.drawLine(x, y, 0, 0, mPaint);
canvas.drawBitmap(bitmap, 0, 0,null);
super.onDraw(canvas);
}
#Override
public boolean onTouchEvent(MotionEvent event) {
// set paramete to draw circle on touch event
x = (int) event.getX();
y = (int) event.getY();
r =20;
// Atlast invalidate canvas
invalidate();
return true;
}
}
}
Now as you can see above there is a lot of comments for things we have tried. Ideally I would like to be able to create an instance of the Panel class, set the workinggraphics class contextview to a XML LinearLayout (OR SurfaceView w/e would be used I dont really know), and then just set a background image on the defined LinearLayout in XML to be revealed when the canvas erases the bitmap image we have set.
Anyway any suggestions would be appricated thanks alot in advanced!

I created a library call WScrarchView where you can implement scratch view just few lines in layout xml. Hope this can help those who still looking for the solution https://github.com/winsontan520/Android-WScratchView