[vector_graphics_compiler] Set the m4_10 (Z scale) value to 1 when constructing an AffineMatrix from an SVG matrix (#9813)

The 4x4 matrix produced by the SVG matrix() function should have its 10th element set to 1. (see https://developer.mozilla.org/en-US/docs/Web/CSS/transform-function/matrix)

The SVG matrix parser constructs an AffineMatrix from the SVG input.  The AffineMatrix is then converted into a list that is given to Flutter engine APIs.

Before flutter/engine@62cb2c9, the Flutter engine was implicitly overriding the 10th element of the matrix with a 1 value.  After that commit, the engine uses the matrix contents as is and does not override any values.

This PR changes the SVG matrix parser to explicitly set the AffineMatrix m4_10 parameter to 1.  This reflects the SVG spec and produces output that matches the original engine behavior.

See flutter/flutter#171854

Author: jason-simmons

packages/vector_graphics_compiler/CHANGELOG.md

@@ -1,6 +1,7 @@
-## NEXT
+## 1.1.18
 
 * Updates minimum supported SDK version to Flutter 3.27/Dart 3.6.
+* Fixes SVG matrix parsing to explicitly set the Z scale value.
 
 ## 1.1.17
 

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

@@ -93,7 +93,7 @@ AffineMatrix _parseSvgMatrix(List<double> params, AffineMatrix current) {
   final double e = params[4];
   final double f = params[5];
 
-  return AffineMatrix(a, b, c, d, e, f).multiplied(current);
+  return AffineMatrix(a, b, c, d, e, f, 1.0).multiplied(current);
 }
 
 AffineMatrix _parseSvgSkewX(List<double> params, AffineMatrix current) {

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: 1.1.17
+version: 1.1.18
 
 executables:
   vector_graphics_compiler:

packages/vector_graphics_compiler/test/end_to_end_test.dart

@@ -320,7 +320,7 @@ void main() {
         0.0,
         0.0,
         0.0,
-        3.0,
+        1.0,
         0.0,
         30.0,
         40.0,

packages/vector_graphics_compiler/test/parsers_test.dart

@@ -132,12 +132,12 @@ void main() {
 
     expect(
       parseTransform('matrix(1.5, 2.0, 3.0, 4.0, 5.0, 6.0)'),
-      const AffineMatrix(1.5, 2.0, 3.0, 4.0, 5.0, 6.0),
+      const AffineMatrix(1.5, 2.0, 3.0, 4.0, 5.0, 6.0, 1.0),
     );
 
     expect(
       parseTransform('matrix(1.5, 2.0, 3.0, 4.0, 5.0, 6.0 )'),
-      const AffineMatrix(1.5, 2.0, 3.0, 4.0, 5.0, 6.0),
+      const AffineMatrix(1.5, 2.0, 3.0, 4.0, 5.0, 6.0, 1.0),
     );
 
     expect(
@@ -198,7 +198,7 @@ void main() {
         0.70711, -0.70711, //
         0.70711, 0.70711, //
         -640.89, 452.68, //
-        0.70711, //
+        1.0, //
       ),
     );
   });