[vector_graphics_compiler] fix: Stroke opacity not applied (flutter#8986)

Fixes [#158735](flutter/flutter#158735)

## Pre-Review Checklist

[^1]: Regular contributors who have demonstrated familiarity with the repository guidelines only need to comment if the PR is not auto-exempted by repo tooling.

Author: sysint64

AUTHORS

@@ -79,3 +79,4 @@ Alexander Rabin <alex.rabin@sentracam.com>
 LinXunFeng <linxunfeng@yeah.net>
 Hashir Shoaib <hashirshoaeb@gmail.com>
 Ricardo Dalarme <ricardodalarme@outlook.com>
+Andrei Kabylin <sys.int64@gmail.com>

packages/vector_graphics_compiler/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 1.1.17
+
+* Fixes a bug where stroke opacity not applied by color mapper.
+
 ## 1.1.16
 
 * Sets stroke-width to 1 by default when an invalid value is parsed instead of throwing an exception.

packages/vector_graphics_compiler/lib/src/svg/parser.dart

@@ -2306,7 +2306,7 @@ class SvgStrokeAttributes {
     }
 
     return Stroke(
-      color: color.color!.withOpacity(opacity ?? 1.0),
+      color: opacity == null ? color.color : color.color!.withOpacity(opacity!),
       shader: shader,
       join: join,
       cap: cap,

packages/vector_graphics_compiler/lib/vector_graphics_compiler.dart

@@ -40,6 +40,7 @@ VectorInstructions parseWithoutOptimizers(
   String key = '',
   bool warningsAsErrors = false,
   SvgTheme theme = const SvgTheme(),
+  ColorMapper? colorMapper,
 }) {
   return parse(
     xml,
@@ -49,6 +50,7 @@ VectorInstructions parseWithoutOptimizers(
     enableClippingOptimizer: false,
     enableMaskingOptimizer: false,
     enableOverdrawOptimizer: false,
+    colorMapper: colorMapper,
   );
 }
 

packages/vector_graphics_compiler/pubspec.yaml

@@ -2,7 +2,7 @@ name: vector_graphics_compiler
 description: A compiler to convert SVGs to the binary format used by `package:vector_graphics`.
 repository: https://github.com/flutter/packages/tree/main/packages/vector_graphics_compiler
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+vector_graphics%22
-version: 1.1.16
+version: 1.1.17
 
 executables:
   vector_graphics_compiler:

packages/vector_graphics_compiler/test/parser_test.dart

@@ -10,6 +10,24 @@ import 'package:vector_graphics_compiler/vector_graphics_compiler.dart';
 
 import 'test_svg_strings.dart';
 
+class _TestOpacityColorMapper implements ColorMapper {
+  const _TestOpacityColorMapper();
+
+  @override
+  Color substitute(
+    String? id,
+    String elementName,
+    String attributeName,
+    Color color,
+  ) {
+    if (color.value == 0xff000000) {
+      return const Color(0x7fff0000);
+    } else {
+      return color;
+    }
+  }
+}
+
 void main() {
   test('Reuse ID self-referentially', () {
     final VectorInstructions instructions = parseWithoutOptimizers('''
@@ -266,6 +284,24 @@ void main() {
     );
   });
 
+  test('preserve opacity from color mapper for strokes', () {
+    const String strokeOpacitySvg = '''
+<svg viewBox="0 0 10 10" fill="none">
+  <rect x="0" y="0" width="5" height="5" stroke="#000000" />
+</svg>
+''';
+
+    final VectorInstructions instructions = parseWithoutOptimizers(
+      strokeOpacitySvg,
+      colorMapper: const _TestOpacityColorMapper(),
+    );
+
+    expect(
+      instructions.paints.single,
+      const Paint(stroke: Stroke(color: Color(0x7fff0000))),
+    );
+  });
+
   test('text attributes are preserved', () {
     final VectorInstructions instructions = parseWithoutOptimizers(textTspan);
     expect(
@@ -352,6 +388,39 @@ void main() {
     );
   });
 
+  test('currentColor stoke opacity', () {
+    const String currentColorSvg = '''
+<svg viewBox="0 0 10 10">
+  <rect x="0" y="0" width="5" height="5" fill="currentColor" stroke="currentColor" />
+</svg>
+''';
+
+    final VectorInstructions blueInstructions = parseWithoutOptimizers(
+      currentColorSvg,
+      theme: const SvgTheme(currentColor: Color(0x7F0000FF)),
+    );
+    final VectorInstructions redInstructions = parseWithoutOptimizers(
+      currentColorSvg,
+      theme: const SvgTheme(currentColor: Color(0x7FFF0000)),
+    );
+
+    expect(
+      blueInstructions.paints.single,
+      const Paint(
+        fill: Fill(color: Color(0x7F0000FF)),
+        stroke: Stroke(color: Color(0x7F0000FF)),
+      ),
+    );
+
+    expect(
+      redInstructions.paints.single,
+      const Paint(
+        fill: Fill(color: Color(0x7FFF0000)),
+        stroke: Stroke(color: Color(0x7FFF0000)),
+      ),
+    );
+  });
+
   test('Opacity with a save layer does not continue to inherit', () {
     final VectorInstructions instructions = parseWithoutOptimizers('''
 <svg width="283" height="180" viewBox="0 0 283 180" fill="none" xmlns="http://www.w3.org/2000/svg">