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Normalise bitmap orientation, before cropping an image #101

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Normalise bitmap orientation, before cropping an image #101

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97 changes: 83 additions & 14 deletions android/src/main/java/com/example/flutternativeimage/MethodCallHandlerImpl.java
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Original file line number Diff line number Diff line change
Expand Up @@ -3,9 +3,12 @@
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.media.ExifInterface;
import android.util.Log;

import androidx.annotation.Nullable;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
Expand All @@ -21,6 +24,7 @@

public class MethodCallHandlerImpl implements MethodChannel.MethodCallHandler {
private final Context context;
private final String LOG_TAG = "FlutterNativeImage";

MethodCallHandlerImpl(Context context) {
this.context = context;
Expand Down Expand Up @@ -66,7 +70,7 @@ public void onMethodCall(MethodCall call, MethodChannel.Result result) {
OutputStream outputStream = new FileOutputStream(outputFileName);
bos.writeTo(outputStream);

copyExif(fileName, outputFileName);
copyExif(fileName, outputFileName, null);

result.success(outputFileName);
} catch (FileNotFoundException e) {
Expand Down Expand Up @@ -95,13 +99,7 @@ public void onMethodCall(MethodCall call, MethodChannel.Result result) {
properties.put("width", options.outWidth);
properties.put("height", options.outHeight);

int orientation = ExifInterface.ORIENTATION_UNDEFINED;
try {
ExifInterface exif = new ExifInterface(fileName);
orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_UNDEFINED);
} catch(IOException ex) {
// EXIF could not be read from the file; ignore
}
int orientation = getOrientation(fileName);
properties.put("orientation", orientation);

result.success(properties);
Expand All @@ -124,7 +122,7 @@ public void onMethodCall(MethodCall call, MethodChannel.Result result) {
Bitmap.CompressFormat format = isPNG ? Bitmap.CompressFormat.PNG : Bitmap.CompressFormat.JPEG;
String extension = isPNG ? ".png" : ".jpg";

Bitmap bmp = BitmapFactory.decodeFile(fileName);
Bitmap bmp = decodeBitmapWithResolvedOrientation(fileName);
ByteArrayOutputStream bos = new ByteArrayOutputStream();
try {
bmp = Bitmap.createBitmap(bmp, originX, originY, width, height);
Expand All @@ -147,7 +145,7 @@ public void onMethodCall(MethodCall call, MethodChannel.Result result) {
outputStream = new FileOutputStream(outputFileName);
bos.writeTo(outputStream);

copyExif(fileName, outputFileName);
copyExif(fileName, outputFileName, ExifInterface.ORIENTATION_NORMAL);

result.success(outputFileName);
} catch (FileNotFoundException e) {
Expand Down Expand Up @@ -177,7 +175,7 @@ public void onMethodCall(MethodCall call, MethodChannel.Result result) {
}
}

private void copyExif(String filePathOri, String filePathDest) {
private void copyExif(String filePathOri, String filePathDest, @Nullable Integer overwriteOrientationAttr) {
try {
ExifInterface oldExif = new ExifInterface(filePathOri);
ExifInterface newExif = new ExifInterface(filePathDest);
Expand All @@ -201,16 +199,21 @@ private void copyExif(String filePathOri, String filePathDest) {
"GPSLongitude",
"GPSLongitudeRef",
"Make",
"Model",
"Orientation");
"Model");
for (String attribute : attributes) {
setIfNotNull(oldExif, newExif, attribute);
}

if (overwriteOrientationAttr == null) {
setIfNotNull(oldExif, newExif, "Orientation");
} else {
newExif.setAttribute("Orientation", String.valueOf(overwriteOrientationAttr));
}

newExif.saveAttributes();

} catch (Exception ex) {
Log.e("FlutterNativeImagePlugin", "Error preserving Exif data on selected image: " + ex);
Log.e(LOG_TAG, "Error preserving Exif data on selected image: " + ex);
}
}

Expand All @@ -220,6 +223,72 @@ private void setIfNotNull(ExifInterface oldExif, ExifInterface newExif, String p
}
}

/**
* This method resolves the orientation of an image and returns the bitmap normalised.
* @param filePath Path of the image file. Used to decode the {@link Bitmap} and camera rotation
* @return {@link Bitmap} object with normalised orientation.
*/
private Bitmap decodeBitmapWithResolvedOrientation(String filePath) {
Bitmap bitmap = BitmapFactory.decodeFile(filePath);
int orientation = getOrientation(filePath);

Matrix matrix = new Matrix();
switch (orientation) {
case ExifInterface.ORIENTATION_FLIP_HORIZONTAL:
matrix.setScale(-1, 1);
break;
case ExifInterface.ORIENTATION_ROTATE_180:
matrix.setRotate(180);
break;
case ExifInterface.ORIENTATION_FLIP_VERTICAL:
matrix.setRotate(180);
matrix.postScale(-1, 1);
break;
case ExifInterface.ORIENTATION_TRANSPOSE:
matrix.setRotate(90);
matrix.postScale(-1, 1);
break;
case ExifInterface.ORIENTATION_ROTATE_90:
matrix.setRotate(90);
break;
case ExifInterface.ORIENTATION_TRANSVERSE:
matrix.setRotate(-90);
matrix.postScale(-1, 1);
break;
case ExifInterface.ORIENTATION_ROTATE_270:
matrix.setRotate(-90);
break;
case ExifInterface.ORIENTATION_NORMAL:
case ExifInterface.ORIENTATION_UNDEFINED:
default:
return bitmap;
}

try {
Bitmap oriented = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
bitmap.recycle();
return oriented;
} catch (OutOfMemoryError e) {
e.printStackTrace();
return bitmap;
}
}

/**
* Reads the orientation attribute from an image file.
* @param filePath Path of the image file
* @return orientation attribute read by {@link ExifInterface} or the default value {@link ExifInterface#ORIENTATION_NORMAL}
*/
private int getOrientation(String filePath) {
try {
ExifInterface exif = new ExifInterface(filePath);
return exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL);
} catch(IOException ex) {
// EXIF could not be read from the file; return default
return ExifInterface.ORIENTATION_NORMAL;
}
}

private static String pathComponent(String filename) {
int i = filename.lastIndexOf(File.separator);
return (i > -1) ? filename.substring(0, i) : filename;
Expand Down