Image.getBytes should convert image if order has different number of …

…channels

lib/src/image/image.dart

@@ -511,9 +511,19 @@ class Image extends Iterable<Pixel> {
 
   /// Similar to toUint8List, but will convert the channels of the image pixels
   /// to the given [order]. If that happens, the returned bytes will be a copy
-  /// and not a direct view of the image data.
-  Uint8List getBytes({ChannelOrder? order}) =>
-      data?.getBytes(order: order) ?? toUint8List();
+  /// and not a direct view of the image data. If the number of channels needed
+  /// by [order] differs from what the image has, the bytes will come from a
+  /// converted image. If the converted image needs an alpha channel added,
+  /// then you can use the [alpha] argument to specify the value of the
+  /// added alpha channel.
+  Uint8List getBytes({ChannelOrder? order, num? alpha}) {
+    var self = this;
+    if (channelOrderLength[order] != numChannels) {
+      self = convert(numChannels: channelOrderLength[order], alpha: alpha);
+    }
+    return self.data?.getBytes(order: order,
+        inPlace: self != this) ?? toUint8List();
+  }
 
   /// The length in bytes of the image data buffer.
   int get lengthInBytes => data?.buffer.lengthInBytes ?? 0;

lib/src/image/image_data.dart

@@ -68,7 +68,7 @@ abstract class ImageData extends Iterable<Pixel> {
   /// Similar to toUint8List, but will convert the channels of the image pixels
   /// to the given [order]. If that happens, the returned bytes will be a copy
   /// and not a direct view of the image data.
-  Uint8List getBytes({ChannelOrder? order}) {
+  Uint8List getBytes({ChannelOrder? order, bool inPlace = false}) {
     if (order == null) {
       return toUint8List();
     }
@@ -77,7 +77,7 @@ abstract class ImageData extends Iterable<Pixel> {
       if (order == ChannelOrder.abgr ||
           order == ChannelOrder.argb ||
           order == ChannelOrder.bgra) {
-        final tempImage = clone();
+        final tempImage = inPlace ? this : clone();
         if (order == ChannelOrder.abgr) {
           for (final p in tempImage) {
             final r = p.r;
@@ -119,7 +119,7 @@ abstract class ImageData extends Iterable<Pixel> {
       }
     } else if (numChannels == 3) {
       if (order == ChannelOrder.bgr) {
-        final tempImage = clone();
+        final tempImage = inPlace ? this : clone();
         for (final p in tempImage) {
           final r = p.r;
           p

test/image/image_test.dart

@@ -200,6 +200,7 @@ void main() {
         }
       }
     });
+
     test('alpha_bmp_1bpp', () async {
       final img = await decodePngFile('test/_data/png/alpha_bmp.png');
       final bg = Image(width: img!.width, height: img.height)
@@ -208,5 +209,16 @@ void main() {
       final bpp1 = bg.convert(format: Format.uint1, numChannels: 1);
       await encodeBmpFile('$testOutputPath/bmp/alpha_bmp_cvt.bmp', bpp1);
     });
+
+    test('GetBytes rgb->argb', () {
+      final i1 = Image(width: 1, height: 1)
+      ..setPixelRgb(0, 0, 32, 64, 128);
+      final b1 = i1.getBytes(order: ChannelOrder.argb);
+      expect(b1.length, equals(4));
+      expect(b1[0], equals(255));
+      expect(b1[1], equals(32));
+      expect(b1[2], equals(64));
+      expect(b1[3], equals(128));
+    });
   });
 }