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authorTor Arne Vestbø <tor.arne.vestbo@qt.io>2019-07-31 14:14:00 +0200
committerTor Arne Vestbø <tor.arne.vestbo@qt.io>2019-08-24 02:21:54 +0200
commite1b0dfc1d406e132fd42ecebcc7bd260e9ef8f9b (patch)
tree80f9b2c2b0ff62f0acedd83011ba73059628ae01
parentf8d41309c8a62345c32da180507bcd60316dbb0c (diff)
macOS: Choose appropriate NSWindow depth based on surface format
Change-Id: I67e63412096ca11a8f056f5755525311756906ef Reviewed-by: Andy Nichols <andy.nichols@qt.io> Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>
-rw-r--r--src/plugins/platforms/cocoa/qcocoabackingstore.mm31
-rw-r--r--src/plugins/platforms/cocoa/qcocoawindow.mm15
2 files changed, 31 insertions, 15 deletions
diff --git a/src/plugins/platforms/cocoa/qcocoabackingstore.mm b/src/plugins/platforms/cocoa/qcocoabackingstore.mm
index 5d5e406d8a..cb453f7613 100644
--- a/src/plugins/platforms/cocoa/qcocoabackingstore.mm
+++ b/src/plugins/platforms/cocoa/qcocoabackingstore.mm
@@ -75,6 +75,37 @@ QCFType<CGColorSpaceRef> QCocoaBackingStore::colorSpace() const
QNSWindowBackingStore::QNSWindowBackingStore(QWindow *window)
: QCocoaBackingStore(window)
{
+ // Choose an appropriate window depth based on the requested surface format.
+ // On deep color displays the default bit depth is 16-bit, so unless we need
+ // that level of precision we opt out of it (and the expensive RGB32 -> RGB64
+ // conversions that come with it if our backingstore depth does not match).
+
+ NSWindow *nsWindow = static_cast<QCocoaWindow *>(window->handle())->view().window;
+ auto colorSpaceName = NSColorSpaceFromDepth(nsWindow.depthLimit);
+
+ static const int kDefaultBitDepth = 8;
+ auto surfaceFormat = window->requestedFormat();
+ auto bitsPerSample = qMax(kDefaultBitDepth, qMax(surfaceFormat.redBufferSize(),
+ qMax(surfaceFormat.greenBufferSize(), surfaceFormat.blueBufferSize())));
+
+ // NSBestDepth does not seem to guarantee a window depth deep enough for the
+ // given bits per sample, even if documented as such. For example, requesting
+ // 10 bits per sample will not give us a 16-bit format, even if that's what's
+ // available. Work around this by manually bumping the bit depth.
+ bitsPerSample = !(bitsPerSample & (bitsPerSample - 1))
+ ? bitsPerSample : qNextPowerOfTwo(bitsPerSample);
+
+ auto bestDepth = NSBestDepth(colorSpaceName, bitsPerSample, 0, NO, nullptr);
+
+ // Disable dynamic depth limit, otherwise our depth limit will be overwritten
+ // by AppKit if the window moves to a screen with a different depth. We call
+ // this before setting the depth limit, as the call will reset the depth to 0.
+ [nsWindow setDynamicDepthLimit:NO];
+
+ qCDebug(lcQpaBackingStore) << "Using" << NSBitsPerSampleFromDepth(bestDepth)
+ << "bit window depth for" << nsWindow;
+
+ nsWindow.depthLimit = bestDepth;
}
QNSWindowBackingStore::~QNSWindowBackingStore()
diff --git a/src/plugins/platforms/cocoa/qcocoawindow.mm b/src/plugins/platforms/cocoa/qcocoawindow.mm
index 3008a056a2..a3120f4ccc 100644
--- a/src/plugins/platforms/cocoa/qcocoawindow.mm
+++ b/src/plugins/platforms/cocoa/qcocoawindow.mm
@@ -1659,21 +1659,6 @@ QCocoaNSWindow *QCocoaWindow::createNSWindow(bool shouldBePanel)
applyContentBorderThickness(nsWindow);
- // Prevent CoreGraphics RGB32 -> RGB64 backing store conversions on deep color
- // displays by forcing 8-bit components, unless a deep color format has been
- // requested. This conversion uses significant CPU time.
- QSurface::SurfaceType surfaceType = QPlatformWindow::window()->surfaceType();
- bool usesCoreGraphics = surfaceType == QSurface::RasterSurface || surfaceType == QSurface::RasterGLSurface;
- QSurfaceFormat surfaceFormat = QPlatformWindow::window()->format();
- bool usesDeepColor = surfaceFormat.redBufferSize() > 8 ||
- surfaceFormat.greenBufferSize() > 8 ||
- surfaceFormat.blueBufferSize() > 8;
- bool usesLayer = view().layer;
- if (usesCoreGraphics && !usesDeepColor && !usesLayer) {
- [nsWindow setDynamicDepthLimit:NO];
- [nsWindow setDepthLimit:NSWindowDepthTwentyfourBitRGB];
- }
-
if (format().colorSpace() == QSurfaceFormat::sRGBColorSpace)
nsWindow.colorSpace = NSColorSpace.sRGBColorSpace;