Add initial implementation of macOS and iOS icon theme implementations

From macOS 13 on, AppKit provides an API to get a scalable system image
from a symbolic icon name. We can map those icon names to the XDG-based
icon names we support in Qt, and render the NSImage with palette-based
coloring when needed, in an appropriate scale.
On iOS, we can use the equivalent UIKit APIs. Coloring functionality is
only available from iOS 15 on.

Implement a QAppleIconEngine that does that in its scaledPixmap
implementation. Use basic caching to store a single QPixmap version of
the native vector image. We regenerate the pixmap whenever a different
size, mode, or state is requested.

Add a manual test for browsing all icons we can get from the various Qt
APIs that: standard icons and pixmaps from QStyle, QPlatformTheme, and
QIcon::fromTheme, in addition to showing all icon variations for a
single QIcon.

Task-number: QTBUG-102346
Change-Id: If5ab683ec18d140bd8700ac99b0edada980de9b4
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

1 files changed, 4 insertions, 0 deletions

diff --git a/src/gui/painting/qcoregraphics.mm b/src/gui/painting/qcoregraphics.mm
index e8904dff06..7b64106323 100644
--- a/src/gui/painting/qcoregraphics.mm
+++ b/src/gui/painting/qcoregraphics.mm
@@ -162,6 +162,9 @@ QT_BEGIN_NAMESPACE
 
 QPixmap qt_mac_toQPixmap(const NSImage *image, const QSizeF &size)
 {
+    // ### TODO: add parameter so that we can decide whether to maintain the aspect
+    // ratio of the image (positioning the image inside the pixmap of size \a size),
+    // or whether we want to fill the resulting pixmap by stretching the image.
     const NSSize pixmapSize = NSMakeSize(size.width(), size.height());
     QPixmap pixmap(pixmapSize.width, pixmapSize.height);
     pixmap.fill(Qt::transparent);
@@ -186,6 +189,7 @@ QPixmap qt_mac_toQPixmap(const NSImage *image, const QSizeF &size)
 
 QImage qt_mac_toQImage(const UIImage *image, QSizeF size)
 {
+    // ### TODO: same as above
     QImage ret(size.width(), size.height(), QImage::Format_ARGB32_Premultiplied);
     ret.fill(Qt::transparent);
     QMacCGContext ctx(&ret);