Merge pull request fluttercommunity#450 from HaoCherHong/feature/ios-…

…icon-bg-color support ios icon background color when removing alpha
phellowseven · May 7, 2023 · 88ab71c · 88ab71c
2 parents 45bfbfa + 0d2cc40
commit 88ab71c
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Showing 6 changed files with 65 additions and 0 deletions.
diff --git a/lib/config/config.dart b/lib/config/config.dart
@@ -29,6 +29,7 @@ class Config {
     this.adaptiveIconBackground,
     this.minSdkAndroid = constants.androidDefaultAndroidMinSDK,
     this.removeAlphaIOS = false,
+    this.backgroundColorIOS = '#ffffff',
     this.webConfig,
     this.windowsConfig,
     this.macOSConfig,
@@ -131,6 +132,10 @@ class Config {
   @JsonKey(name: 'remove_alpha_ios')
   final bool removeAlphaIOS;
 
+  /// IOS background_color_ios
+  @JsonKey(name: 'background_color_ios')
+  final String backgroundColorIOS;
+
   /// Web platform config
   @JsonKey(name: 'web')
   final WebConfig? webConfig;

diff --git a/lib/config/config.g.dart b/lib/config/config.g.dart
diff --git a/lib/ios.dart b/lib/ios.dart
@@ -60,6 +60,12 @@ void createIcons(Config config, String? flavor) {
     return;
   }
   if (config.removeAlphaIOS && image.hasAlpha) {
+    final backgroundColor = _getBackgroundColor(config);
+    final pixel = image.getPixel(0, 0);
+    do {
+      pixel.set(_alphaBlend(pixel, backgroundColor));
+    } while (pixel.moveNext());
+
     image = image.convert(numChannels: 3);
   }
   if (image.hasAlpha) {
@@ -388,3 +394,37 @@ List<Map<String, String>> createImageList(String fileNamePrefix) {
   ];
   return imageList;
 }
+
+ColorUint8 _getBackgroundColor(Config config) {
+  final backgroundColorHex = config.backgroundColorIOS.startsWith('#')
+      ? config.backgroundColorIOS.substring(1)
+      : config.backgroundColorIOS;
+  if (backgroundColorHex.length != 6) {
+    throw Exception('background_color_ios hex should be 6 characters long');
+  }
+
+  final backgroundByte = int.parse(backgroundColorHex, radix: 16);
+  return ColorUint8.rgba(
+    (backgroundByte >> 16) & 0xff,
+    (backgroundByte >> 8) & 0xff,
+    (backgroundByte >> 0) & 0xff,
+    0xff,
+  );
+}
+
+Color _alphaBlend(Color fg, ColorUint8 bg) {
+  if (fg.format != Format.uint8) {
+    fg = fg.convert(format: Format.uint8);
+  }
+  if (fg.a == 0) {
+    return bg;
+  } else {
+    final invAlpha = 0xff - fg.a;
+    return ColorUint8.rgba(
+      (fg.a * fg.r + invAlpha * bg.g) ~/ 0xff,
+      (fg.a * fg.g + invAlpha * bg.a) ~/ 0xff,
+      (fg.a * fg.b + invAlpha * bg.b) ~/ 0xff,
+      0xff,
+    );
+  }
+}
diff --git a/test/abs/icon_generator_test.mocks.dart b/test/abs/icon_generator_test.mocks.dart
@@ -48,6 +48,11 @@ class MockConfig extends _i1.Mock implements _i3.Config {
         returnValue: false,
       ) as bool);
   @override
+  String get backgroundColorIOS => (super.noSuchMethod(
+        Invocation.getter(#backgroundColorIOS),
+        returnValue: '',
+      ) as String);
+  @override
   bool get hasAndroidAdaptiveConfig => (super.noSuchMethod(
         Invocation.getter(#hasAndroidAdaptiveConfig),
         returnValue: false,

diff --git a/test/macos/macos_icon_generator_test.mocks.dart b/test/macos/macos_icon_generator_test.mocks.dart
@@ -57,6 +57,12 @@ class MockConfig extends _i1.Mock implements _i3.Config {
         returnValueForMissingStub: false,
       ) as bool);
   @override
+  String get backgroundColorIOS => (super.noSuchMethod(
+        Invocation.getter(#backgroundColorIOS),
+        returnValue: '',
+        returnValueForMissingStub: '',
+      ) as String);
+  @override
   bool get hasAndroidAdaptiveConfig => (super.noSuchMethod(
         Invocation.getter(#hasAndroidAdaptiveConfig),
         returnValue: false,

diff --git a/test/windows/windows_icon_generator_test.mocks.dart b/test/windows/windows_icon_generator_test.mocks.dart
@@ -59,6 +59,11 @@ class MockConfig extends _i1.Mock implements _i3.Config {
         returnValue: false,
       ) as bool);
   @override
+  String get backgroundColorIOS => (super.noSuchMethod(
+        Invocation.getter(#backgroundColorIOS),
+        returnValue: '',
+      ) as String);
+  @override
   bool get hasAndroidAdaptiveConfig => (super.noSuchMethod(
         Invocation.getter(#hasAndroidAdaptiveConfig),
         returnValue: false,