Apple: Use automatic rendering mode for icon engine

When requesting symbol icons the OS automatically chooses a rendering
mode per icon. Most icons use the monochrome rendering mode by default,
but some of them use the hierarchical.

We don't want to override this choice by always using hierarchical,
as that doesn't match the look of most icons in the system and may
be surprising to the user.

We still want to support tinted icons, based on the QPalette. For
iOS this is easy via [UIImage withTintColor:] but for macOS we
have to do an extra render pass. Unfortunately we can't use
configurationWithPaletteColors with a single color, as for the
hierarchical icons this will produce a different looking icon
than if we tint the entire icon.

[ChangeLog][macOS/iOS] The Apple icon engine, used for theme
icons on macOS and iOS, will now use the default rendering
mode for icons, typically monochrome, instead of always
using hierarchical icons.

Pick-to: 6.8
Change-Id: I9e66d848222e8ed0f7f20897454f27446bf0fd81
Reviewed-by: Volker Hilsheimer <[email protected]>
(cherry picked from commit 9f392c0)
Reviewed-by: Qt Cherry-pick Bot <[email protected]>

src/gui/platform/darwin/qappleiconengine.mm

@@ -362,17 +362,23 @@
     auto *config = [NSImageSymbolConfiguration configurationWithPointSize:48
                                                weight:NSFontWeightRegular
                                                scale:NSImageSymbolScaleLarge];
-    if (@available(macOS 12, *)) {
-        auto *primaryColor = [NSColor colorWithSRGBRed:color.redF()
-                                                 green:color.greenF()
-                                                  blue:color.blueF()
-                                                 alpha:color.alphaF()];
-
-        auto *colorConfig = [NSImageSymbolConfiguration configurationWithHierarchicalColor:primaryColor];
-        config = [config configurationByApplyingConfiguration:colorConfig];
-    }
 
-    return [image imageWithSymbolConfiguration:config];
+    NSImage *configuredImage = [image imageWithSymbolConfiguration:config];
+
+    auto *primaryColor = [NSColor colorWithSRGBRed:color.redF()
+                                             green:color.greenF()
+                                              blue:color.blueF()
+                                             alpha:color.alphaF()];
+
+    NSImage *tintedImage = [NSImage imageWithSize:configuredImage.size flipped:NO
+        drawingHandler:^BOOL(NSRect) {
+            [primaryColor set];
+            NSRect imageRect = {NSZeroPoint, configuredImage.size};
+            [configuredImage drawInRect:imageRect];
+            NSRectFillUsingOperation(imageRect, NSCompositingOperationSourceIn);
+            return YES;
+        }];
+    return tintedImage;
 }
 #elif defined(QT_PLATFORM_UIKIT)
 auto *configuredImage(const UIImage *image, const QColor &color)
@@ -381,16 +387,12 @@
                                                weight:UIImageSymbolWeightRegular
                                                scale:UIImageSymbolScaleLarge];
 
-    if (@available(iOS 15, *)) {
-        auto *primaryColor = [UIColor colorWithRed:color.redF()
-                                             green:color.greenF()
-                                              blue:color.blueF()
-                                             alpha:color.alphaF()];
+    auto *primaryColor = [UIColor colorWithRed:color.redF()
+                                     green:color.greenF()
+                                      blue:color.blueF()
+                                     alpha:color.alphaF()];
 
-        auto *colorConfig = [UIImageSymbolConfiguration configurationWithHierarchicalColor:primaryColor];
-        config = [config configurationByApplyingConfiguration:colorConfig];
-    }
-    return [image imageByApplyingSymbolConfiguration:config];
+    return [[image imageByApplyingSymbolConfiguration:config] imageWithTintColor:primaryColor];
 }
 #endif
 }