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 can i make a dynamically created Bitmap to fit an ImageView?

I'd like to create a Bitmap from a String with a given text size and set it as source of an ImageView.
The ImageView in it's layout xml:
<ImageView
android:id="#+id/myImageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:scaleType="fitXY"/>
Setting the Bitmap as src of the ImageView:
myImageView.setImageBitmap(getBitmapFromString("StringToDraw", 30));
My getBitmapFromString method:
private Bitmap getBitmapFromString(String string, float textSize) {
Bitmap bitmap = Bitmap.createBitmap(200, 200, Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
Paint paint = new Paint();
paint.setAntiAlias(true);
paint.setSubpixelText(true);
paint.setStyle(Paint.Style.FILL);
paint.setColor(Color.WHITE);
paint.setTextSize(textSize);
paint.setTextAlign(Paint.Align.LEFT);
canvas.drawText(string, 0, 100, paint);
return bitmap;
}
How can i calculate the proper size for the Bitmap (from the given text size and String length) and how can i make it to fit the ImageView properly?

Found the solution in the following answer to a similar question:
https://stackoverflow.com/a/15252876/3363481
My code looks like this now:
private Bitmap getBitmapFromString(String text, float fontSizeSP, Context context) {
int fontSizePX = convertDiptoPix(context, fontSizeSP);
int pad = (fontSizePX / 9);
Paint paint = new Paint();
paint.setAntiAlias(true);
paint.setColor(Color.WHITE);
paint.setTextSize(fontSizePX);
int textWidth = (int) (paint.measureText(text) + pad * 2);
int height = (int) (fontSizePX / 0.75);
Bitmap bitmap = Bitmap.createBitmap(textWidth, height, Bitmap.Config.ARGB_4444);
Canvas canvas = new Canvas(bitmap);
float xOriginal = pad;
canvas.drawText(text, xOriginal, fontSizePX, paint);
return 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

Java - Making bitmaps scale to your screen size?

I am creating an app and want my ui to scale with the phone. I am importing bitmaps into a canvas and drawing them as follows:
public class MainMenu extends View {
private RectF titleBounds, playBounds, scoreBounds, soundBounds, creditBounds;
private Paint titlePaint, playPaint;
private boolean playClick = false, startPlay = false, scoreClick = false, startScore = false, soundClick = false, startSound = false, creditsClick = false, startCredits = false;
public Bitmap play;
public Bitmap playGlow;
public Bitmap sound;
public Bitmap soundGlow;
public int screenWidth, screenHeight;
public MainMenu(Context context) {
super(context);
titleBounds = new RectF();
playBounds = new RectF();
scoreBounds = new RectF();
soundBounds = new RectF();
creditBounds = new RectF();
titlePaint = new Paint();
playPaint = new Paint();
play = BitmapFactory.decodeResource(getResources(), R.drawable.play);
playGlow = BitmapFactory.decodeResource(getResources(), R.drawable.playglow);
sound = BitmapFactory.decodeResource(getResources(), R.drawable.sound);
soundGlow = BitmapFactory.decodeResource(getResources(), R.drawable.soundglow);
// Get window size and save it to screenWidth and screenHeight.
WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
Display display = wm.getDefaultDisplay();
Point size = new Point();
display.getSize(size);
screenWidth = size.x;
screenHeight = size.y;
}
#Override protected void onDraw(Canvas canvas) {
ViewGroup parent = (ViewGroup)getParent();
playBounds.set(screenWidth / 2 - play.getWidth() / 2, screenHeight * 1/3 - play.getHeight() / 2, playBounds.left + play.getWidth(), playBounds.top + play.getHeight());
soundBounds.set(scoreBounds.centerX() - sound.getWidth() / 2, scoreBounds.bottom + 10, soundBounds.left + sound.getWidth(), soundBounds.top + sound.getHeight());
The problem is theres nothing to scale the image to fit the phone, it just reads the x and y size of the image I import. What method is there for scaling images?

Use the createScaledBitmap of the Bitmap class
bitmap = Bitmap.createScaledBitmap(bitmap, scaledWidth, scaledHeight, true);
It will scale your bitmap but not greater than the width and height that is because it can cause blurriness to your bitmap.
documentation:
Creates a new bitmap, scaled from an existing bitmap, when possible.
If the specified width and height are the same as the current width and height of the source bitmap,
the source bitmap is returned and no new bitmap is created.
for full screen
bitmap = Bitmap.createScaledBitmap(bitmap, screenWidth , screenHeight , true);

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));