Improve image buffer management

@@ -11,6 +11,7 @@
 - Uniformize examples
 - Uniformize examples
 - Fix context painting empty Table
 - Fix context painting empty Table
 - Fix Text decoration placements
 - Fix Text decoration placements
+- Improve image buffer management
 
 
 ## 1.5.0
 ## 1.5.0
 
 

@@ -33,11 +33,6 @@ enum PdfImageOrientation {
 
 
 class PdfImage extends PdfXObject {
 class PdfImage extends PdfXObject {
   /// Creates a new [PdfImage] instance.
   /// Creates a new [PdfImage] instance.
-  ///
-  /// @param image an [Uint8List] value
-  /// @param width
-  /// @param height
-  /// @param alpha if the image is transparent
   factory PdfImage(
   factory PdfImage(
     PdfDocument pdfDocument, {
     PdfDocument pdfDocument, {
     @required Uint8List image,
     @required Uint8List image,
@@ -45,68 +40,41 @@ class PdfImage extends PdfXObject {
     @required int height,
     @required int height,
     bool alpha = true,
     bool alpha = true,
     PdfImageOrientation orientation = PdfImageOrientation.topLeft,
     PdfImageOrientation orientation = PdfImageOrientation.topLeft,
-  }) =>
-      PdfImage._(
+  }) {
+    final PdfImage im = PdfImage._(
       pdfDocument,
       pdfDocument,
-        image: image,
-        width: width,
-        height: height,
-        alpha: alpha,
-        alphaChannel: false,
-        isRGB: true,
-        jpeg: false,
-        orientation: orientation,
+      width,
+      height,
+      orientation,
     );
     );
 
 
-  PdfImage._(
-    PdfDocument pdfDocument, {
-    @required this.image,
-    @required int width,
-    @required int height,
-    @required this.alpha,
-    @required this.alphaChannel,
-    @required this.isRGB,
-    @required this.jpeg,
-    @required this.orientation,
-  })  : assert(alphaChannel == false || alpha == true),
-        assert(width != null),
-        assert(height != null),
-        assert(jpeg != null),
-        assert(isRGB != null),
-        assert(orientation != null),
-        _width = width,
-        _height = height,
-        super(pdfDocument, '/Image', isBinary: true) {
-    _name = '/Image$objser';
-    params['/Width'] = PdfNum(width);
-    params['/Height'] = PdfNum(height);
-    params['/BitsPerComponent'] = const PdfNum(8);
-    params['/Name'] = PdfName(_name);
-
-    if (alphaChannel == false && alpha) {
-      final PdfImage _sMask = PdfImage._(
+    im.params['/BitsPerComponent'] = const PdfNum(8);
+    im.params['/Name'] = PdfName(im.name);
+    im.params['/ColorSpace'] = const PdfName('/DeviceRGB');
+
+    if (alpha) {
+      final PdfImage _sMask = PdfImage._alpha(
         pdfDocument,
         pdfDocument,
-        image: image,
-        width: width,
-        height: height,
-        alpha: alpha,
-        alphaChannel: true,
-        isRGB: false,
-        jpeg: jpeg,
-        orientation: orientation,
+        image,
+        width,
+        height,
+        orientation,
       );
       );
-      params['/SMask'] = PdfIndirect(_sMask.objser, 0);
+      im.params['/SMask'] = PdfIndirect(_sMask.objser, 0);
     }
     }
 
 
-    if (isRGB) {
-      params['/ColorSpace'] = const PdfName('/DeviceRGB');
-    } else {
-      params['/ColorSpace'] = const PdfName('/DeviceGray');
+    final int w = width;
+    final int h = height;
+    final int s = w * h;
+    final Uint8List out = Uint8List(s * 3);
+    for (int i = 0; i < s; i++) {
+      out[i * 3] = image[i * 4];
+      out[i * 3 + 1] = image[i * 4 + 1];
+      out[i * 3 + 2] = image[i * 4 + 2];
     }
     }
 
 
-    if (jpeg) {
-      params['/Intent'] = const PdfName('/RelativeColorimetric');
-    }
+    im.buf.putBytes(out);
+    return im;
   }
   }
 
 
   factory PdfImage.jpeg(
   factory PdfImage.jpeg(
@@ -115,84 +83,83 @@ class PdfImage extends PdfXObject {
     PdfImageOrientation orientation,
     PdfImageOrientation orientation,
   }) {
   }) {
     assert(image != null);
     assert(image != null);
-    final PdfJpegInfo info = PdfJpegInfo(image);
 
 
-    return PdfImage._(
+    final PdfJpegInfo info = PdfJpegInfo(image);
+    final PdfImage im = PdfImage._(
       pdfDocument,
       pdfDocument,
-      image: image,
-      width: info.width,
-      height: info.height,
-      jpeg: true,
-      alpha: false,
-      isRGB: info.isRGB,
-      alphaChannel: false,
-      orientation: orientation ?? info.orientation,
+      info.width,
+      info.height,
+      orientation ?? info.orientation,
     );
     );
-  }
-
-  /// RGBA Image Data
-  final Uint8List image;
-
-  /// Image width
-  final int _width;
-  int get width => orientation.index >= 4 ? _height : _width;
-
-  /// Image height
-  final int _height;
-  int get height => orientation.index < 4 ? _height : _width;
-
-  /// Image has alpha channel
-  final bool alpha;
-
-  String _name;
 
 
-  /// Process alphaChannel only
-  final bool alphaChannel;
+    im.params['/BitsPerComponent'] = const PdfNum(8);
+    im.params['/Name'] = PdfName(im.name);
+    im.params['/Intent'] = const PdfName('/RelativeColorimetric');
+    im.params['/Filter'] = const PdfName('/DCTDecode');
 
 
-  /// The image data is a jpeg image
-  final bool jpeg;
+    if (info.isRGB) {
+      im.params['/ColorSpace'] = const PdfName('/DeviceRGB');
+    } else {
+      im.params['/ColorSpace'] = const PdfName('/DeviceGray');
+    }
 
 
-  /// The image data is a color RGB image
-  final bool isRGB;
+    im.buf.putBytes(image);
+    return im;
+  }
 
 
-  /// The internal orientation of the image
-  final PdfImageOrientation orientation;
+  factory PdfImage._alpha(
+    PdfDocument pdfDocument,
+    Uint8List image,
+    int width,
+    int height,
+    PdfImageOrientation orientation,
+  ) {
+    final PdfImage im = PdfImage._(
+      pdfDocument,
+      width,
+      height,
+      orientation,
+    );
 
 
-  /// write the pixels to the stream
-  @override
-  void _prepare() {
-    if (jpeg) {
-      buf.putBytes(image);
-      params['/Filter'] = const PdfName('/DCTDecode');
-      super._prepare();
-      return;
-    }
+    im.params['/BitsPerComponent'] = const PdfNum(8);
+    im.params['/Name'] = PdfName(im.name);
+    im.params['/ColorSpace'] = const PdfName('/DeviceGray');
 
 
-    final int w = _width;
-    final int h = _height;
+    final int w = width;
+    final int h = height;
     final int s = w * h;
     final int s = w * h;
 
 
-    final Uint8List out = Uint8List(alphaChannel ? s : s * 3);
+    final Uint8List out = Uint8List(s);
 
 
-    if (alphaChannel) {
     for (int i = 0; i < s; i++) {
     for (int i = 0; i < s; i++) {
       out[i] = image[i * 4 + 3];
       out[i] = image[i * 4 + 3];
     }
     }
-    } else {
-      for (int i = 0; i < s; i++) {
-        out[i * 3] = image[i * 4];
-        out[i * 3 + 1] = image[i * 4 + 1];
-        out[i * 3 + 2] = image[i * 4 + 2];
+
+    im.buf.putBytes(out);
+    return im;
   }
   }
+
+  PdfImage._(
+    PdfDocument pdfDocument,
+    this._width,
+    this._height,
+    this.orientation,
+  ) : super(pdfDocument, '/Image', isBinary: true) {
+    params['/Width'] = PdfNum(_width);
+    params['/Height'] = PdfNum(_height);
   }
   }
 
 
-    buf.putBytes(out);
+  /// Image width
+  final int _width;
+  int get width => orientation.index >= 4 ? _height : _width;
 
 
-    super._prepare();
-  }
+  /// Image height
+  final int _height;
+  int get height => orientation.index < 4 ? _height : _width;
+
+  /// The internal orientation of the image
+  final PdfImageOrientation orientation;
 
 
-  /// Get the name
-  ///
-  /// @return a String value
-  String get name => _name;
+  /// Name of the image
+  String get name => '/Image$objser';
 }
 }