Merge v1.0.7

- `PCanvasPainter`:
  - Added `zIndex` to define the painter layer. Previously was fixed to `0`.
- Added `PCanvasFactory`:
  - Allows extra platform dependent implementations: - `pixelsToPNG` and `pixelsToDataUrl`
- `PCanvasBitmap.toPNG`:
  - Ensure `singleFrame: true`

CHANGELOG.md

@@ -1,3 +1,13 @@
+## 1.0.7
+
+- `PCanvasPainter`:
+  - Added `zIndex` to define the painter layer. Previously was fixed to `0`.
+- Added `PCanvasFactory`:
+  - Allows extra platform dependent implementations:
+    - `pixelsToPNG` and `pixelsToDataUrl`
+- `PCanvasBitmap.toPNG`:
+  - Ensure `singleFrame: true`
+
 ## 1.0.6
 
 - `PCanvas`:

lib/src/pcanvas_base.dart

@@ -135,6 +135,12 @@ abstract class PCanvasPainter {
     _pCanvas = pCanvas;
   }
 
+  /// Returns the `z-index` of the painter layer. Default: 0
+  ///
+  /// - Elements with [PCanvasElement.zIndex] `<` than [zIndex] will be painted before the painter layer.
+  /// - Elements with [PCanvasElement.zIndex] `>=` than [zIndex] will be painted after the painter layer.
+  int get zIndex => 0;
+
   FutureOr<bool>? _loadingFuture;
 
   /// Waits the [loadResources].
@@ -260,6 +266,27 @@ class PCanvasPainterDummy extends PCanvasPainter {
   FutureOr<bool> paint(PCanvas pCanvas) => true;
 }
 
+abstract class PCanvasFactory {
+  PCanvasFactory.impl();
+
+  factory PCanvasFactory() {
+    return createPCanvasFactoryImpl();
+  }
+
+  PCanvas createPCanvas(int width, int height, PCanvasPainter painter,
+      {PCanvasPixels? initialPixels});
+
+  FutureOr<Uint8List> pixelsToPNG(PCanvasPixels pixels) {
+    var pCanvas = pixels.toPCanvas();
+    return pCanvas.toPNG();
+  }
+
+  FutureOr<String> pixelsToDataUrl(PCanvasPixels pixels) {
+    var pCanvas = pixels.toPCanvas();
+    return pCanvas.toDataUrl();
+  }
+}
+
 typedef PaintFuntion = FutureOr<bool> Function(PCanvas pCanvas);
 
 /// Portable Canvas.
@@ -288,8 +315,8 @@ abstract class PCanvas
 
   factory PCanvas(int width, int height, PCanvasPainter painter,
       {PCanvasPixels? initialPixels}) {
-    return createPCanvasImpl(width, height, painter,
-        initialPixels: initialPixels);
+    return PCanvasFactory()
+        .createPCanvas(width, height, painter, initialPixels: initialPixels);
   }
 
   /// Sets the canvas pixels.
@@ -519,6 +546,9 @@ abstract class PCanvas
   }
 
   FutureOr<bool> _callPainterImpl() {
+    final painter = this.painter;
+    final painterZIndex = painter.zIndex;
+
     var hasElements = _elements.isNotEmpty;
 
     List<PCanvasElement>? elementsPrev;
@@ -527,17 +557,15 @@ abstract class PCanvas
     if (hasElements) {
       elementsPrev = _elements.where((e) {
         var zIndex = e.zIndex;
-        return zIndex != null && zIndex < 0;
+        return zIndex != null && zIndex < painterZIndex;
       }).toList();
 
       elementsPos = _elements.where((e) {
         var zIndex = e.zIndex;
-        return zIndex == null || zIndex >= 0;
+        return zIndex == null || zIndex >= painterZIndex;
       }).toList();
     }
 
-    final painter = this.painter;
-
     FutureOr<bool> ret = true;
 
     if (elementsPrev != null) {
@@ -1033,15 +1061,9 @@ abstract class PCanvasPixels {
     return pCanvas;
   }
 
-  FutureOr<Uint8List> toPNG() {
-    var pCanvas = toPCanvas();
-    return pCanvas.toPNG();
-  }
+  FutureOr<Uint8List> toPNG() => PCanvasFactory().pixelsToPNG(this);
 
-  FutureOr<String> toDataUrl() {
-    var pCanvas = toPCanvas();
-    return pCanvas.toDataUrl();
-  }
+  FutureOr<String> toDataUrl() => PCanvasFactory().pixelsToDataUrl(this);
 
   @override
   String toString() {

lib/src/pcanvas_bitmap.dart

@@ -6,6 +6,7 @@ import 'package:dio/dio.dart';
 import 'package:image/image.dart' as img;
 
 import 'pcanvas_base.dart';
+import 'pcanvas_bitmap_extension.dart';
 
 /// An in-memory [PCanvas] implementation.
 class PCanvasBitmap extends PCanvas {
@@ -754,7 +755,7 @@ class PCanvasBitmap extends PCanvas {
       PCanvasPixelsABGR.fromBytes(width, height, _bitmap.dataAsUint8List);
 
   @override
-  FutureOr<Uint8List> toPNG() => img.encodePng(_bitmap);
+  FutureOr<Uint8List> toPNG() => img.encodePng(_bitmap, singleFrame: true);
 
   @override
   String toString() {
@@ -904,65 +905,6 @@ class _PCanvasImageMemoryAsync extends PCanvasImageMemory {
   }
 }
 
-extension _PFontExtension on PFont {
-  img.BitmapFont toBitmapFontFamily() {
-    if (size >= 36) {
-      return img.arial48;
-    } else if (size >= 19) {
-      return img.arial24;
-    } else {
-      return img.arial14;
-    }
-  }
-
-  img.BitmapFont toBitmapFont() {
-    var f = toBitmapFontFamily();
-    if (bold) f.bold = true;
-    if (italic) f.italic = true;
-    f.antialias = true;
-    return f;
-  }
-}
-
-extension _PCanvasPixelsExtension on PCanvasPixels {
-  img.Color getImageColor(int x, int y) {
-    var pixels = this;
-
-    var p = pixels.pixel(x, y);
-
-    int r, g, b, a;
-
-    if (pixels is PCanvasPixelsRGBA) {
-      r = (p >> 24) & 0xff;
-      g = (p >> 16) & 0xff;
-      b = (p >> 8) & 0xff;
-      a = ((p) & 0xff);
-    } else if (pixels is PCanvasPixelsARGB) {
-      r = (p >> 16) & 0xff;
-      g = (p >> 8) & 0xff;
-      b = (p) & 0xff;
-      a = ((p >> 24) & 0xff);
-    } else if (pixels is PCanvasPixelsABGR) {
-      r = (p) & 0xff;
-      g = (p >> 8) & 0xff;
-      b = (p >> 16) & 0xff;
-      a = ((p >> 24) & 0xff);
-    } else {
-      throw StateError("Can't pixels type: ${pixels.runtimeType} > $pixels");
-    }
-
-    return img.ColorUint32.rgba(r, g, b, a);
-  }
-}
-
-extension _ImageExtension on img.Image {
-  Uint8List get dataAsUint8List {
-    var imageData = data as img.ImageDataUint8;
-    var dataUint8 = imageData.data;
-    return dataUint8;
-  }
-}
-
 // From package `image 3.3.0`.
 int _findStringHeight(img.BitmapFont font, String string) {
   var stringHeight = 0;

lib/src/pcanvas_bitmap_extension.dart

@@ -0,0 +1,87 @@
+import 'dart:typed_data';
+
+import 'package:image/image.dart' as img;
+
+import 'pcanvas_base.dart';
+
+extension PFontExtension on PFont {
+  img.BitmapFont toBitmapFontFamily() {
+    if (size >= 36) {
+      return img.arial48;
+    } else if (size >= 19) {
+      return img.arial24;
+    } else {
+      return img.arial14;
+    }
+  }
+
+  img.BitmapFont toBitmapFont() {
+    var f = toBitmapFontFamily();
+    if (bold) f.bold = true;
+    if (italic) f.italic = true;
+    f.antialias = true;
+    return f;
+  }
+}
+
+extension PCanvasPixelsExtension on PCanvasPixels {
+  img.Color getImageColor(int x, int y) {
+    var pixels = this;
+
+    var p = pixels.pixel(x, y);
+
+    int r, g, b, a;
+
+    if (pixels is PCanvasPixelsRGBA) {
+      r = (p >> 24) & 0xff;
+      g = (p >> 16) & 0xff;
+      b = (p >> 8) & 0xff;
+      a = ((p) & 0xff);
+    } else if (pixels is PCanvasPixelsARGB) {
+      r = (p >> 16) & 0xff;
+      g = (p >> 8) & 0xff;
+      b = (p) & 0xff;
+      a = ((p >> 24) & 0xff);
+    } else if (pixels is PCanvasPixelsABGR) {
+      r = (p) & 0xff;
+      g = (p >> 8) & 0xff;
+      b = (p >> 16) & 0xff;
+      a = ((p >> 24) & 0xff);
+    } else {
+      throw StateError("Can't pixels type: ${pixels.runtimeType} > $pixels");
+    }
+
+    return img.ColorUint32.rgba(r, g, b, a);
+  }
+
+  Uint8List pixelsToImagePNG() {
+    final pixels = this;
+
+    var w = pixels.width;
+    var h = pixels.height;
+
+    var bitmap = img.Image(
+        width: w,
+        height: h,
+        format: img.Format.uint8,
+        numChannels: 4,
+        withPalette: false);
+
+    for (var y = 0; y < h; ++y) {
+      for (var x = 0; x < w; ++x) {
+        var p = pixels.getImageColor(x, y);
+        bitmap.setPixel(x, y, p);
+      }
+    }
+
+    return img.encodePng(bitmap, singleFrame: true);
+  }
+}
+
+extension ImageExtension on img.Image {
+  Uint8List get dataAsUint8List {
+    var imageData = data as img.ImageDataUint8;
+    var dataUint8 = imageData.data;
+    return dataUint8;
+  }
+}

lib/src/pcanvas_impl_bitmap.dart

@@ -1,6 +1,21 @@
+import 'dart:typed_data';
+
 import 'pcanvas_base.dart';
 import 'pcanvas_bitmap.dart';
+import 'pcanvas_bitmap_extension.dart';
+
+class PCanvasFactoryBitmap extends PCanvasFactory {
+  static final PCanvasFactoryBitmap instance = PCanvasFactoryBitmap._();
+
+  PCanvasFactoryBitmap._() : super.impl();
+
+  @override
+  PCanvas createPCanvas(int width, int height, PCanvasPainter painter,
+          {PCanvasPixels? initialPixels}) =>
+      PCanvasBitmap(width, height, painter, initialPixels: initialPixels);
+
+  @override
+  Uint8List pixelsToPNG(PCanvasPixels pixels) => pixels.pixelsToImagePNG();
+}
 
-PCanvas createPCanvasImpl(int width, int height, PCanvasPainter painter,
-        {PCanvasPixels? initialPixels}) =>
-    PCanvasBitmap(width, height, painter, initialPixels: initialPixels);
+PCanvasFactory createPCanvasFactoryImpl() => PCanvasFactoryBitmap.instance;

lib/src/pcanvas_impl_html.dart

@@ -1,6 +1,15 @@
 import 'pcanvas_base.dart';
 import 'pcanvas_html.dart';
 
-PCanvas createPCanvasImpl(int width, int height, PCanvasPainter painter,
-        {PCanvasPixels? initialPixels}) =>
-    PCanvasHTML(width, height, painter, initialPixels: initialPixels);
+class PCanvasFactoryHTML extends PCanvasFactory {
+  static final PCanvasFactoryHTML instance = PCanvasFactoryHTML._();
+
+  PCanvasFactoryHTML._() : super.impl();
+
+  @override
+  PCanvas createPCanvas(int width, int height, PCanvasPainter painter,
+          {PCanvasPixels? initialPixels}) =>
+      PCanvasHTML(width, height, painter, initialPixels: initialPixels);
+}
+
+PCanvasFactory createPCanvasFactoryImpl() => PCanvasFactoryHTML.instance;

pubspec.yaml

@@ -1,6 +1,6 @@
 name: pcanvas
 description: A portable canvas that can work in many platforms (Flutter, Web, Desktop, in-memory Image).
-version: 1.0.6
+version: 1.0.7
 homepage: https://github.com/gmpassos/pcanvas
 
 environment: