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>
This commit is contained in:
Tor Arne Vestbø 2019-07-31 14:14:00 +02:00
parent f8d41309c8
commit e1b0dfc1d4
2 changed files with 31 additions and 15 deletions

View File

@ -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()

View File

@ -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;