fix: render objects not rendering text (#98)

lib/src/blocked_text_image.dart

@@ -72,8 +72,17 @@ class BlockedTextCanvasAdapter implements Canvas {
   /// Draws a rectangle on the canvas where the [paragraph]
   /// would otherwise be rendered
   @override
-  void drawParagraph(ui.Paragraph paragraph, ui.Offset offset) => parent
-      .drawRect(offset & Size(paragraph.width, paragraph.height), Paint());
+  void drawParagraph(ui.Paragraph paragraph, ui.Offset offset) =>
+      parent.drawRect(
+        offset &
+            Size(
+              paragraph.width.isFinite
+                  ? paragraph.width
+                  : paragraph.longestLine,
+              paragraph.height,
+            ),
+        Paint(),
+      );
 
   @override
   void clipPath(ui.Path path, {bool doAntiAlias = true}) =>

test/smoke_tests/render_object_smoke_test.dart

@@ -0,0 +1,62 @@
+import 'package:alchemist/alchemist.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  group('smoke test', () {
+    goldenTest(
+      'succeeds for custom render object drawing text',
+      fileName: 'render_object_text_smoke_test',
+      builder: () => const SizedBox(
+        height: 400,
+        width: 400,
+        child: _CustomExampleRenderObject(),
+      ),
+    );
+  });
+}
+
+class _CustomExampleRenderObject extends LeafRenderObjectWidget {
+  const _CustomExampleRenderObject({Key? key}) : super(key: key);
+
+  @override
+  _CustomExampleRenderBox createRenderObject(BuildContext context) {
+    return _CustomExampleRenderBox();
+  }
+}
+
+class _CustomExampleRenderBox extends RenderBox {
+  @override
+  void paint(PaintingContext context, Offset offset) {
+    final textPainter = TextPainter(
+      text: const TextSpan(
+        text: 'text',
+        style: TextStyle(
+          fontFamily: 'Roboto',
+          color: Colors.black,
+          fontSize: 24,
+        ),
+      ),
+      textDirection: TextDirection.ltr,
+    )..layout();
+    textPainter.paint(
+      context.canvas,
+      const Offset(200, 200) - textPainter.size.center(Offset.zero),
+    );
+  }
+
+  @override
+  void performLayout() {
+    size = computeDryLayout(constraints);
+  }
+
+  @override
+  Size computeDryLayout(BoxConstraints constraints) {
+    return constraints.constrain(
+      Size(
+        200,
+        constraints.maxHeight,
+      ),
+    );
+  }
+}

test/src/blocked_text_canvas_adapter_test.dart

@@ -18,6 +18,10 @@ void main() {
     late ui.Canvas parent;
     late BlockedTextCanvasAdapter subject;
 
+    setUpAll(() {
+      registerFallbackValue(ui.Paint());
+    });
+
     setUp(() {
       parent = MockCanvas();
       subject = BlockedTextCanvasAdapter(parent);
@@ -31,7 +35,22 @@ void main() {
       subject.drawParagraph(paragraph, offset);
       verify(
         () => parent.drawRect(
-          offset & ui.Size(paragraph.width, paragraph.height),
+          offset & const ui.Size(200, 400),
+          any(that: isA<ui.Paint>()),
+        ),
+      ).called(1);
+    });
+
+    test('drawParagraph draws a rectangle for infinite width', () {
+      const offset = ui.Offset(20, 40);
+      final paragraph = MockParagraph();
+      when(() => paragraph.width).thenReturn(double.infinity);
+      when(() => paragraph.longestLine).thenReturn(400);
+      when(() => paragraph.height).thenReturn(400);
+      subject.drawParagraph(paragraph, offset);
+      verify(
+        () => parent.drawRect(
+          offset & const ui.Size(400, 400),
           any(that: isA<ui.Paint>()),
         ),
       ).called(1);