Merge pull request fluttercandies#63 from coder-with-a-bushido/karthi/fix-img-export

fix: getImageData outputs image with extra padding

Author: xSILENCEx

lib/src/drawing_board.dart

@@ -194,27 +194,27 @@ class _DrawingBoardState extends State<DrawingBoard> {
 
   /// 构建画板
   Widget get _buildBoard {
-    return RepaintBoundary(
-      key: _controller.painterKey,
-      child: ExValueBuilder<DrawConfig>(
-        valueListenable: _controller.drawConfig,
-        shouldRebuild: (DrawConfig p, DrawConfig n) =>
-            p.angle != n.angle || p.size != n.size,
-        builder: (_, DrawConfig dc, Widget? child) {
-          Widget c = child!;
-
-          if (dc.size != null) {
-            final bool isHorizontal = dc.angle.toDouble() % 2 == 0;
-            final double max = dc.size!.longestSide;
-
-            if (!isHorizontal) {
-              c = SizedBox(width: max, height: max, child: c);
-            }
+    return ExValueBuilder<DrawConfig>(
+      valueListenable: _controller.drawConfig,
+      shouldRebuild: (DrawConfig p, DrawConfig n) =>
+          p.angle != n.angle || p.size != n.size,
+      builder: (_, DrawConfig dc, Widget? child) {
+        Widget c = child!;
+
+        if (dc.size != null) {
+          final bool isHorizontal = dc.angle.toDouble() % 2 == 0;
+          final double max = dc.size!.longestSide;
+
+          if (!isHorizontal) {
+            c = SizedBox(width: max, height: max, child: c);
           }
+        }
 
-          return Transform.rotate(angle: dc.angle * pi / 2, child: c);
-        },
-        child: Center(
+        return Transform.rotate(angle: dc.angle * pi / 2, child: c);
+      },
+      child: Center(
+        child: RepaintBoundary(
+          key: _controller.painterKey,
           child: Stack(
             alignment: Alignment.center,
             children: <Widget>[_buildImage, _buildPainter],