Merge pull request #43 from brarcher/datamatrix-scaling

Datamatrix scaling

app/src/main/java/protect/card_locker/BarcodeImageWriterTask.java

@@ -0,0 +1,108 @@
+package protect.card_locker;
+
+import android.graphics.Bitmap;
+import android.os.AsyncTask;
+import android.util.Log;
+import android.widget.ImageView;
+
+import com.google.zxing.BarcodeFormat;
+import com.google.zxing.MultiFormatWriter;
+import com.google.zxing.WriterException;
+import com.google.zxing.common.BitMatrix;
+
+import java.lang.ref.WeakReference;
+
+/**
+ * This task will generate a barcode and load it into an ImageView.
+ * Only a weak reference of the ImageView is kept, so this class will not
+ * prevent the ImageView from being garbage collected.
+ */
+class BarcodeImageWriterTask extends AsyncTask<Void, Void, Bitmap>
+{
+    private static final String TAG = "LoyaltyCardLocker";
+
+    private final WeakReference<ImageView> imageViewReference;
+    private final String cardId;
+    private final BarcodeFormat format;
+    private final int imageHeight;
+    private final int imageWidth;
+
+    public BarcodeImageWriterTask(ImageView imageView, String cardIdString,
+                                  BarcodeFormat barcodeFormat)
+    {
+        // Use a WeakReference to ensure the ImageView can be garbage collected
+        imageViewReference = new WeakReference<>(imageView);
+
+        cardId = cardIdString;
+        format = barcodeFormat;
+        imageHeight = imageView.getHeight();
+        imageWidth = imageView.getWidth();
+    }
+
+    public Bitmap doInBackground(Void... params)
+    {
+        MultiFormatWriter writer = new MultiFormatWriter();
+        BitMatrix bitMatrix;
+        try
+        {
+            bitMatrix = writer.encode(cardId, format, imageWidth, imageHeight, null);
+
+            final int WHITE = 0xFFFFFFFF;
+            final int BLACK = 0xFF000000;
+
+            int bitMatrixWidth = bitMatrix.getWidth();
+            int bitMatrixHeight = bitMatrix.getHeight();
+
+            int[] pixels = new int[bitMatrixWidth * bitMatrixHeight];
+
+            for (int y = 0; y < bitMatrixHeight; y++)
+            {
+                int offset = y * bitMatrixWidth;
+                for (int x = 0; x < bitMatrixWidth; x++)
+                {
+                    int color = bitMatrix.get(x, y) ? BLACK : WHITE;
+                    pixels[offset + x] = color;
+                }
+            }
+            Bitmap bitmap = Bitmap.createBitmap(bitMatrixWidth, bitMatrixHeight,
+                    Bitmap.Config.ARGB_8888);
+            bitmap.setPixels(pixels, 0, bitMatrixWidth, 0, 0, bitMatrixWidth, bitMatrixHeight);
+
+            // Determine if the image needs to be scaled.
+            // This is necessary because the datamatrix barcode generator
+            // ignores the requested size and returns the smallest image necessary
+            // to represent the barcode. If we let the ImageView scale the image
+            // it will use bi-linear filtering, which results in a blurry barcode.
+            // To avoid this, if scaling is needed do so without filtering.
+
+            int heightScale = imageHeight / bitMatrixHeight;
+            int widthScale = imageWidth / bitMatrixHeight;
+            int scalingFactor = Math.min(heightScale, widthScale);
+
+            if(scalingFactor > 1)
+            {
+                bitmap = Bitmap.createScaledBitmap(bitmap, bitMatrixWidth * scalingFactor, bitMatrixHeight * scalingFactor, false);
+            }
+
+            return bitmap;
+        }
+        catch (WriterException | IllegalArgumentException e)
+        {
+            Log.e(TAG, "Failed to generate barcode", e);
+        }
+
+        return null;
+    }
+
+    protected void onPostExecute(Bitmap result)
+    {
+        ImageView imageView = imageViewReference.get();
+        if(imageView == null)
+        {
+            // The ImageView no longer exists, nothing to do
+            return;
+        }
+
+        imageView.setImageBitmap(result);
+    }
+}

app/src/main/java/protect/card_locker/LoyaltyCardViewActivity.java

@@ -2,7 +2,6 @@ package protect.card_locker;
 
 
 import android.content.Intent;
-import android.graphics.Bitmap;
 import android.os.Bundle;
 import android.support.design.widget.Snackbar;
 import android.support.v7.app.ActionBar;
@@ -12,14 +11,12 @@ import android.util.Log;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
+import android.view.ViewTreeObserver;
 import android.widget.Button;
 import android.widget.EditText;
 import android.widget.ImageView;
 
 import com.google.zxing.BarcodeFormat;
-import com.google.zxing.MultiFormatWriter;
-import com.google.zxing.WriterException;
-import com.google.zxing.common.BitMatrix;
 import com.google.zxing.integration.android.IntentIntegrator;
 import com.google.zxing.integration.android.IntentResult;
 
@@ -149,52 +146,34 @@ public class LoyaltyCardViewActivity extends AppCompatActivity
 
         if(cardIdField.getText().length() > 0 && barcodeTypeField.getText().length() > 0)
         {
-            MultiFormatWriter writer = new MultiFormatWriter();
-            BitMatrix result;
-            try
+            String formatString = barcodeTypeField.getText().toString();
+            final BarcodeFormat format = BarcodeFormat.valueOf(formatString);
+            final String cardIdString = cardIdField.getText().toString();
+
+            if(barcodeImage.getHeight() == 0)
             {
-                String formatString = barcodeTypeField.getText().toString();
-                BarcodeFormat format = BarcodeFormat.valueOf(formatString);
-                if(format == null)
-                {
-                    throw new IllegalArgumentException("Unrecognized barcode format: " + formatString);
-                }
-
-                int generateWidth = 100;
-                int generateHeight = 100;
-
-                String cardIdString = cardIdField.getText().toString();
-
-                Log.i(TAG, "Card: " + cardIdString);
-
-                result = writer.encode(cardIdString, format, generateWidth, generateHeight, null);
-
-                final int WHITE = 0xFFFFFFFF;
-                final int BLACK = 0xFF000000;
-
-                int width = result.getWidth();
-                int height = result.getHeight();
-                int[] pixels = new int[width * height];
-                for (int y = 0; y < height; y++)
-                {
-                    int offset = y * width;
-                    for (int x = 0; x < width; x++)
+                Log.d(TAG, "ImageView size is not known known at start, waiting for load");
+                // The size of the ImageView is not yet available as it has not
+                // yet been drawn. Wait for it to be drawn so the size is available.
+                barcodeImage.getViewTreeObserver().addOnGlobalLayoutListener(
+                    new ViewTreeObserver.OnGlobalLayoutListener()
                     {
-                        pixels[offset + x] = result.get(x, y) ? BLACK : WHITE;
-                    }
-                }
-                Bitmap bitmap = Bitmap.createBitmap(width, height,
-                        Bitmap.Config.ARGB_8888);
-                bitmap.setPixels(pixels, 0, width, 0, 0, width, height);
-                barcodeImage.setImageBitmap(bitmap);
-
-                barcodeIdLayout.setVisibility(View.VISIBLE);
-                barcodeImageLayout.setVisibility(View.VISIBLE);
+                        @Override
+                        public void onGlobalLayout()
+                        {
+                            Log.d(TAG, "ImageView size now known");
+                            new BarcodeImageWriterTask(barcodeImage, cardIdString, format).execute();
+                        }
+                    });
             }
-            catch (WriterException | IllegalArgumentException e)
+            else
             {
-                Log.e(TAG, "Failed to generate barcode", e);
+                Log.d(TAG, "ImageView size known known, creating barcode");
+                new BarcodeImageWriterTask(barcodeImage, cardIdString, format).execute();
             }
+
+            barcodeIdLayout.setVisibility(View.VISIBLE);
+            barcodeImageLayout.setVisibility(View.VISIBLE);
         }
 
         View.OnClickListener captureCallback = new View.OnClickListener()
@@ -332,4 +311,4 @@ public class LoyaltyCardViewActivity extends AppCompatActivity
             }
         }
     }
-}
+}

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

@@ -5,10 +5,6 @@
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
-    android:paddingBottom="@dimen/activity_vertical_margin"
-    android:paddingLeft="@dimen/activity_horizontal_margin"
-    android:paddingRight="@dimen/activity_horizontal_margin"
-    android:paddingTop="@dimen/activity_vertical_margin"
     app:layout_behavior="@string/appbar_scrolling_view_behavior"
     tools:context="protect.card_locker.MainActivity"
     tools:showIn="@layout/main_activity">

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

@@ -1,11 +1,11 @@
 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout android:orientation="vertical"
-              android:padding="5.0dip"
+              android:padding="10.0dp"
               android:layout_width="fill_parent"
               android:layout_height="fill_parent"
               xmlns:android="http://schemas.android.com/apk/res/android">
     <LinearLayout android:orientation="horizontal"
-                  android:padding="5.0dip"
+                  android:padding="5.0dp"
                   android:layout_width="fill_parent"
                   android:layout_height="wrap_content"
                   android:baselineAligned="true">
@@ -18,7 +18,7 @@
     </LinearLayout>
 
     <LinearLayout android:orientation="horizontal"
-                  android:padding="5.0dip"
+                  android:padding="5.0dp"
                   android:layout_width="fill_parent"
                   android:layout_height="wrap_content"
                   android:baselineAligned="true">