Printer: allow alignment of picture

Show the picture on a canvas and allow to swipe it to align left, middle or right.
Also simplify the activity layout by removing the incoming picture and only showing the preview.

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/devices/thermalprinter/SendToPrinterActivity.java

@@ -6,6 +6,8 @@ import android.graphics.Bitmap;
 import android.graphics.BitmapFactory;
 import android.net.Uri;
 import android.os.Bundle;
+import android.view.GestureDetector;
+import android.view.MotionEvent;
 import android.view.View;
 import android.widget.Button;
 import android.widget.ImageView;
@@ -40,15 +42,39 @@ import nodomain.freeyourgadget.gadgetbridge.util.UriHelper;
 public class SendToPrinterActivity extends AbstractGBActivity {
     private static final Logger LOG = LoggerFactory.getLogger(SendToPrinterActivity.class);
     private final ExecutorService executor = Executors.newSingleThreadExecutor();
+    GenericThermalPrinterSupport.PrintAlignment alignment = GenericThermalPrinterSupport.PrintAlignment.ALIGN_CENTER;
     private Bitmap bitmap;
     private Bitmap incoming;
     private ImageView previewImage;
-    private ImageView incomingImage;
     private MaterialSwitch dithering;
     private MaterialSwitch upscale;
-    private BitmapToBitSet bitmapToBitSet;
+    private final GestureDetector.SimpleOnGestureListener gestureListener = new GestureDetector.SimpleOnGestureListener() {
-    private File printPicture = null;
+        private static final int SWIPE_THRESHOLD = 100;
 
+        @Override
+        public boolean onDown(MotionEvent e) {
+            return true; // needed to enable fling detection
+        }
+
+        @Override
+        public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
+            float diffX = e2.getX() - e1.getX();
+
+            if (Math.abs(diffX) > Math.abs(e2.getY() - e1.getY())) {
+                if (Math.abs(diffX) > SWIPE_THRESHOLD) {
+                    if (diffX > 0) {
+                        alignment = alignment == GenericThermalPrinterSupport.PrintAlignment.ALIGN_LEFT ? GenericThermalPrinterSupport.PrintAlignment.ALIGN_CENTER : GenericThermalPrinterSupport.PrintAlignment.ALIGN_RIGHT;
+                    } else {
+                        alignment = alignment == GenericThermalPrinterSupport.PrintAlignment.ALIGN_RIGHT ? GenericThermalPrinterSupport.PrintAlignment.ALIGN_CENTER : GenericThermalPrinterSupport.PrintAlignment.ALIGN_LEFT;
+                    }
+                    updatePreview();
+                    return true;
+                }
+            }
+            return false;
+        }
+    };
+    private File printPicture = null;
     ActivityResultLauncher<Intent> pickImageLauncher = registerForActivityResult(
             new ActivityResultContracts.StartActivityForResult(),
             result -> {
@@ -58,13 +84,13 @@ public class SendToPrinterActivity extends AbstractGBActivity {
                 }
             }
     );
+    private GestureDetector gestureDetector;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
 
         setContentView(R.layout.activity_print_image);
-        incomingImage = findViewById(R.id.incomingImage);
         previewImage = findViewById(R.id.convertedImage);
         Button sendToPrinter = findViewById(R.id.sendToPrinterButton);
         dithering = findViewById(R.id.switchDithering);
@@ -88,6 +114,9 @@ public class SendToPrinterActivity extends AbstractGBActivity {
                 sendToPrinter.setEnabled(false);
         }
 
+        gestureDetector = new GestureDetector(this, gestureListener);
+
+        previewImage.setOnTouchListener((v, event) -> gestureDetector.onTouchEvent(event));
         dithering.setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View view) {
@@ -169,9 +198,7 @@ public class SendToPrinterActivity extends AbstractGBActivity {
     }
 
     private void updatePreview() {
-        incomingImage.setImageBitmap(bitmap);
+        final BitmapToBitSet bitmapToBitSet = new BitmapToBitSet(GenericThermalPrinterSupport.createAlignedBitmap(bitmap, alignment));
-
-        bitmapToBitSet = new BitmapToBitSet(bitmap);
         bitmapToBitSet.toBlackAndWhite(dithering.isChecked());
 
         TextView imageSizeText = findViewById(R.id.imageSizeText);
@@ -185,6 +212,7 @@ public class SendToPrinterActivity extends AbstractGBActivity {
         intent.putExtra(GenericThermalPrinterSupport.INTENT_EXTRA_BITMAP_CACHE_FILE_PATH, printPicture.getAbsolutePath());
         intent.putExtra(GenericThermalPrinterSupport.INTENT_EXTRA_APPLY_DITHERING, dithering.isChecked());
         intent.putExtra(GenericThermalPrinterSupport.INTENT_EXTRA_UPSCALE, upscale.isChecked());
+        intent.putExtra(GenericThermalPrinterSupport.INTENT_EXTRA_ALIGNMENT, alignment);
         LocalBroadcastManager.getInstance(this).sendBroadcast(intent);
     }
 

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/thermalprinter/GenericThermalPrinterSupport.java

@@ -43,15 +43,15 @@ import nodomain.freeyourgadget.gadgetbridge.service.btle.actions.SetDeviceStateA
 import nodomain.freeyourgadget.gadgetbridge.util.GB;
 
 public class GenericThermalPrinterSupport extends AbstractBTLESingleDeviceSupport {
-    private static final Logger LOG = LoggerFactory.getLogger(GenericThermalPrinterSupport.class);
     public static final int IMAGE_WIDTH = 384;
     public static final String INTENT_ACTION_PRINT_BITMAP = "print_bitmap";
     public static final String INTENT_EXTRA_URI = "picture_uri";
     public static final String INTENT_EXTRA_BITMAP_CACHE_FILE_PATH = "bitmap_cache_file_path";
     public static final String INTENT_EXTRA_APPLY_DITHERING = "apply_dithering";
     public static final String INTENT_EXTRA_UPSCALE = "upscale";
-
+    public static final String INTENT_EXTRA_ALIGNMENT = "alignment";
     public static final UUID discoveryService = UUID.fromString("0000af30-0000-1000-8000-00805f9b34fb");
+    private static final Logger LOG = LoggerFactory.getLogger(GenericThermalPrinterSupport.class);
     private final UUID writeCharUUID = UUID.fromString("0000ae01-0000-1000-8000-00805f9b34fb");
     private final UUID notifCharUUID = UUID.fromString("0000ae02-0000-1000-8000-00805f9b34fb");
     private final Handler handler = new Handler(Looper.getMainLooper());
@@ -59,13 +59,11 @@ public class GenericThermalPrinterSupport extends AbstractBTLESingleDeviceSuppor
         LOG.info("Running retrieving battery through runner.");
         send("getDevState", PrinterCommand.getDevState.message(new byte[]{0x00}));
     };
-    private boolean useRunLengthEncoding = false;
-    private boolean canPrint = false;
-
     private final int PRINT_INTENSITY = 8000;
     private final int PRINT_SPEED = 10;
     private final int PRINT_TYPE = 0; //1 also observed
-
+    private boolean useRunLengthEncoding = false;
+    private boolean canPrint = false;
     private final BroadcastReceiver printCommandReceiver = new BroadcastReceiver() {
         @Override
         public void onReceive(Context context, Intent intent) {
@@ -87,7 +85,8 @@ public class GenericThermalPrinterSupport extends AbstractBTLESingleDeviceSuppor
                         return;
                     }
                     boolean dither = intent.getBooleanExtra(INTENT_EXTRA_APPLY_DITHERING, false);
-                    printImage(bitmap, dither);
+                    PrintAlignment alignment = (PrintAlignment) intent.getSerializableExtra(INTENT_EXTRA_ALIGNMENT);
+                    printImage(bitmap, dither, alignment);
             }
         }
     };
@@ -98,19 +97,7 @@ public class GenericThermalPrinterSupport extends AbstractBTLESingleDeviceSuppor
 
     }
 
-    private static byte[] byteBufferToArray(final ByteBuffer input) {
+    private static Bitmap createBitmapFromString(String text) {
-        input.flip();
-        final byte[] result = new byte[input.limit()];
-        input.get(result);
-        return result;
-    }
-
-    @Override
-    public void onNotification(NotificationSpec notificationSpec) {
-//        printImage(createNotificationBitmap(notificationSpec), true);
-    }
-
-    public Bitmap createNotificationBitmap(NotificationSpec spec) {
         float textSize = 24f; // Approx 10pt at 200 dpi
 
         // Prepare the paint for drawing text
@@ -119,22 +106,6 @@ public class GenericThermalPrinterSupport extends AbstractBTLESingleDeviceSuppor
         textPaint.setTextSize(textSize);
         textPaint.setTypeface(Typeface.DEFAULT);
 
-        StringBuilder textBuilder = new StringBuilder();
-        if (spec.sender != null) {
-            textBuilder.append("Sender: ").append(spec.sender).append("\n");
-        }
-        if (spec.title != null) {
-            textBuilder.append("Title: ").append(spec.title).append("\n");
-        }
-        if (spec.subject != null) {
-            textBuilder.append("Subject: ").append(spec.subject).append("\n\n");
-        }
-        if (spec.body != null) {
-            textBuilder.append(spec.body);
-        }
-
-        String text = textBuilder.toString();
-
         // Create StaticLayout to handle text wrapping
         StaticLayout staticLayout = new StaticLayout(text, textPaint, IMAGE_WIDTH,
                 Layout.Alignment.ALIGN_NORMAL,
@@ -144,7 +115,7 @@ public class GenericThermalPrinterSupport extends AbstractBTLESingleDeviceSuppor
         int bitmapHeight = staticLayout.getHeight();
 
         // Create the bitmap
-        Bitmap bitmap = Bitmap.createBitmap(IMAGE_WIDTH, bitmapHeight, Bitmap.Config.ARGB_8888);
+        final Bitmap bitmap = Bitmap.createBitmap(IMAGE_WIDTH, bitmapHeight, Bitmap.Config.ARGB_8888);
         Canvas canvas = new Canvas(bitmap);
 
         // Draw the text onto the canvas using the StaticLayout
@@ -153,6 +124,13 @@ public class GenericThermalPrinterSupport extends AbstractBTLESingleDeviceSuppor
         return bitmap;
     }
 
+    private static byte[] byteBufferToArray(final ByteBuffer input) {
+        input.flip();
+        final byte[] result = new byte[input.limit()];
+        input.get(result);
+        return result;
+    }
+
     private static int getCrc8(final byte[] seq) {
         int crc = 0x00;
 
@@ -171,6 +149,53 @@ public class GenericThermalPrinterSupport extends AbstractBTLESingleDeviceSuppor
         return (byte) (crc & 0xFF);
     }
 
+    @Override
+    public void onNotification(NotificationSpec notificationSpec) {
+//        printImage(createNotificationBitmap(notificationSpec), true, PrintAlignment.ALIGN_LEFT);
+    }
+
+    public Bitmap createNotificationBitmap(NotificationSpec spec) {
+
+        StringBuilder textBuilder = new StringBuilder();
+        if (spec.sender != null) {
+            textBuilder.append("Sender: ").append(spec.sender).append("\n");
+        }
+        if (spec.title != null) {
+            textBuilder.append("Title: ").append(spec.title).append("\n");
+        }
+        if (spec.subject != null) {
+            textBuilder.append("Subject: ").append(spec.subject).append("\n\n");
+        }
+        if (spec.body != null) {
+            textBuilder.append(spec.body);
+        }
+
+        return createBitmapFromString(textBuilder.toString());
+    }
+
+    public void printImage(Bitmap bitmap, boolean applyDithering, PrintAlignment alignment) {
+        if (!canPrint) {
+            LOG.error("Printer cannot print.");
+            return;
+        }
+
+        final BitmapToBitSet bitmapToBitSet = new BitmapToBitSet(createAlignedBitmap(bitmap, alignment));
+
+        final ByteBuffer result = ByteBuffer.allocate(500 + (int) (Math.ceil(bitmap.getWidth() / 8) + 8) * bitmap.getHeight()); //TODO: approximate better?
+
+        result.put(PrinterCommand.intensity(PRINT_INTENSITY));
+        result.put(PrinterCommand.printSpeed.message(new byte[]{PRINT_SPEED}));
+        result.put(PrinterCommand.printType.message(new byte[]{PRINT_TYPE}));
+        result.put(PrinterCommand.quality(5));
+
+        result.put(encodePictureToPrinterCommands(bitmapToBitSet.toBlackAndWhite(applyDithering), bitmapToBitSet.getWidth(), bitmapToBitSet.getHeight()));
+        result.put(PrinterCommand.feedPaper(72));
+
+        result.put(PrinterCommand.getDevState.message(new byte[]{0})); //to get back the current device status
+
+        send("Print...", byteBufferToArray(result));
+    }
+
     private byte[] encodePictureToPrinterCommands(BitSet imageBits, int imageWidth, int imageHeight) {
         final int maxOctetsPerRow = (imageWidth + 7) / 8; //always round up
         final ByteBuffer result = ByteBuffer.allocate(imageBits.length() + 1000);
@@ -204,26 +229,27 @@ public class GenericThermalPrinterSupport extends AbstractBTLESingleDeviceSuppor
         return false;
     }
 
-    public void printImage(Bitmap bitmap, boolean applyDithering) {
+    public static Bitmap createAlignedBitmap(Bitmap bitmap, PrintAlignment alignment) {
-        if (!canPrint) {
+        if (bitmap.getWidth() >= IMAGE_WIDTH) {
-            LOG.error("Printer cannot print.");
+            return bitmap;
-            return;
+        } else {//handle alignment
+            Bitmap alignedBitmap = Bitmap.createBitmap(IMAGE_WIDTH, bitmap.getHeight(), Bitmap.Config.ARGB_8888);
+            Canvas canvas = new Canvas(alignedBitmap);
+            canvas.drawColor(Color.WHITE);
+
+            switch (alignment) {
+                case ALIGN_LEFT -> canvas.drawBitmap(bitmap, 0, 0, new Paint());
+                case ALIGN_CENTER ->
+                        canvas.drawBitmap(bitmap, (alignedBitmap.getWidth() - bitmap.getWidth()) / 2, 0, new Paint());
+                case ALIGN_RIGHT ->
+                        canvas.drawBitmap(bitmap, alignedBitmap.getWidth() - bitmap.getWidth(), 0, new Paint());
+            }
+            return alignedBitmap;
         }
-        final BitmapToBitSet bitmapToBitSet = new BitmapToBitSet(bitmap);
+    }
 
-        final ByteBuffer result = ByteBuffer.allocate(500 + (int) (Math.ceil(bitmap.getWidth() / 8) + 8) * bitmap.getHeight()); //TODO: approximate better?
+    private void sendTestPrint() {
-
+        printImage(createBitmapFromString(ZonedDateTime.now().toString()), false, PrintAlignment.ALIGN_CENTER);
-        result.put(PrinterCommand.intensity(PRINT_INTENSITY));
-        result.put(PrinterCommand.printSpeed.message(new byte[]{PRINT_SPEED}));
-        result.put(PrinterCommand.printType.message(new byte[]{PRINT_TYPE}));
-        result.put(PrinterCommand.quality(5));
-
-        result.put(encodePictureToPrinterCommands(bitmapToBitSet.toBlackAndWhite(applyDithering), bitmapToBitSet.getWidth(), bitmapToBitSet.getHeight()));
-        result.put(PrinterCommand.feedPaper(72));
-
-        result.put(PrinterCommand.getDevState.message(new byte[]{0})); //to get back the current device status
-
-        send("Print...", byteBufferToArray(result));
     }
 
     @Override
@@ -380,27 +406,6 @@ public class GenericThermalPrinterSupport extends AbstractBTLESingleDeviceSuppor
             LocalBroadcastManager.getInstance(getContext()).unregisterReceiver(printCommandReceiver);
         }
     }
-    private void sendTestPrint() {
-        Bitmap bitmap = BitmapFactory.decodeResource(GBApplication.app().getResources(), R.drawable.ic_launcher);
-
-        Bitmap newBitmap = Bitmap.createBitmap(IMAGE_WIDTH, bitmap.getHeight(), Bitmap.Config.ARGB_8888);
-        Canvas canvas = new Canvas(newBitmap);
-        canvas.drawColor(Color.WHITE);
-
-        // Calculate the top-left coordinates for centering the original Bitmap
-        int posLeft = 0;
-        int posMiddle = (newBitmap.getWidth() - bitmap.getWidth()) / 2;
-        int posRight = newBitmap.getWidth() - bitmap.getWidth();
-
-        int left = posRight;
-        int top = (newBitmap.getHeight() - bitmap.getHeight()) / 2;
-
-        canvas.drawBitmap(bitmap, left, top, new Paint());
-
-        canvas.drawText(ZonedDateTime.now().toString(), newBitmap.getHeight(), 0, new Paint());
-
-        printImage(newBitmap, false);
-    }
 
     @Override
     public void onSendConfiguration(String config) {
@@ -438,6 +443,12 @@ public class GenericThermalPrinterSupport extends AbstractBTLESingleDeviceSuppor
         //we just abuse the install functionality to start our own activity
     }
 
+    public enum PrintAlignment {
+        ALIGN_LEFT,
+        ALIGN_CENTER,
+        ALIGN_RIGHT
+    }
+
     private enum PrinterCommand {
         feedPaper(0xa1),
         printRowPlain(0xa2),

app/src/main/res/layout/activity_print_image.xml

@@ -18,41 +18,7 @@
             android:layout_width="match_parent"
             android:layout_height="wrap_content">
 
-            <Button
-                android:id="@+id/sendToPrinterButton"
-                android:layout_width="0dp"
-                android:layout_height="wrap_content"
-                android:layout_marginStart="24dp"
-                android:layout_marginTop="8dp"
-                android:layout_marginEnd="24dp"
-                android:text="@string/activity_print_image_print_button"
-                app:layout_constraintEnd_toEndOf="parent"
-                app:layout_constraintHorizontal_bias="0.0"
-                app:layout_constraintStart_toStartOf="parent"
-                app:layout_constraintTop_toBottomOf="@+id/warning_devices" />
 
-            <ImageView
-                android:id="@+id/incomingImage"
-                android:layout_width="0dp"
-                android:layout_height="wrap_content"
-                android:layout_marginStart="24dp"
-                android:layout_marginTop="16dp"
-                android:layout_marginEnd="24dp"
-                android:adjustViewBounds="true"
-                android:scaleType="fitCenter"
-                app:layout_constraintEnd_toEndOf="parent"
-                app:layout_constraintStart_toStartOf="parent"
-                app:layout_constraintTop_toTopOf="parent" />
-
-            <TextView
-                android:id="@+id/imageSizeText"
-                android:layout_width="wrap_content"
-                android:layout_height="wrap_content"
-                android:layout_marginTop="4dp"
-                android:text="@string/activity_print_label_print_size"
-                app:layout_constraintTop_toBottomOf="@+id/incomingImage"
-                app:layout_constraintStart_toStartOf="parent"
-                app:layout_constraintEnd_toEndOf="parent" />
 
             <com.google.android.material.materialswitch.MaterialSwitch
                 android:id="@+id/switchUpscale"
@@ -62,7 +28,7 @@
                 android:layout_marginTop="8dp"
                 android:layout_marginEnd="24dp"
                 android:text="@string/activity_print_image_upscale_switch"
-                app:layout_constraintTop_toBottomOf="@id/imageSizeText"
+                app:layout_constraintTop_toTopOf="parent"
                 app:layout_constraintStart_toStartOf="parent"
                 app:layout_constraintEnd_toEndOf="parent" />
 
@@ -91,6 +57,17 @@
                 app:layout_constraintStart_toStartOf="parent"
                 app:layout_constraintTop_toBottomOf="@+id/switchDithering" />
 
+            <TextView
+                android:id="@+id/imageSizeText"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="4dp"
+                android:text="@string/activity_print_label_print_size"
+                app:layout_constraintTop_toBottomOf="@+id/convertedImage"
+                app:layout_constraintStart_toStartOf="parent"
+                app:layout_constraintEnd_toEndOf="parent" />
+
+
             <TextView
                 android:id="@+id/warning_devices"
                 android:layout_width="match_parent"
@@ -98,9 +75,21 @@
                 android:layout_marginTop="8dp"
                 android:layout_marginBottom="8dp"
                 android:text=""
-                app:layout_constraintTop_toBottomOf="@+id/convertedImage"
+                app:layout_constraintTop_toBottomOf="@+id/imageSizeText"
                 tools:layout_editor_absoluteX="0dp" />
 
+            <Button
+                android:id="@+id/sendToPrinterButton"
+                android:layout_width="0dp"
+                android:layout_height="wrap_content"
+                android:layout_marginStart="24dp"
+                android:layout_marginTop="8dp"
+                android:layout_marginEnd="24dp"
+                android:text="@string/activity_print_image_print_button"
+                app:layout_constraintEnd_toEndOf="parent"
+                app:layout_constraintHorizontal_bias="0.0"
+                app:layout_constraintStart_toStartOf="parent"
+                app:layout_constraintTop_toBottomOf="@+id/warning_devices" />
 
         </androidx.constraintlayout.widget.ConstraintLayout>