CGDisplayListImageBufferBackend.mm

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#import "config.h"
#import "CGDisplayListImageBufferBackend.h"

#if ENABLE(CG_DISPLAY_LIST_BACKED_IMAGE_BUFFER)

#import "CGDisplayList.h"
#import "Logging.h"
#import <WebCore/GraphicsContextCG.h>
#import <WebCore/PixelBuffer.h>
#import <WebKitAdditions/CGDisplayListImageBufferAdditions.h>
#import <pal/spi/cocoa/QuartzCoreSPI.h>
#import <wtf/IsoMallocInlines.h>
#import <wtf/MachSendRight.h>
#import <wtf/cocoa/TypeCastsCocoa.h>
#import <wtf/cocoa/VectorCocoa.h>

template<> struct WTF::CFTypeTrait<CAMachPortRef> {
    static inline CFTypeID typeID(void) { return CAMachPortGetTypeID(); }
};

namespace WebKit {

static CFDictionaryRef makeContextOptions(const CGDisplayListImageBufferBackend::Parameters& parameters)
{
    RetainPtr colorSpace = parameters.colorSpace.platformColorSpace();
    if (!colorSpace)
        return nil;
    return (CFDictionaryRef)@{
        @"colorspace" : (id)colorSpace.get()
    };
}

class GraphicsContextCGDisplayList : public WebCore::GraphicsContextCG {
public:
    GraphicsContextCGDisplayList(const CGDisplayListImageBufferBackend::Parameters& parameters)
        : GraphicsContextCG(adoptCF(WKCGCommandsContextCreate(parameters.logicalSize, makeContextOptions(parameters))).autorelease())
    {
        m_immutableBaseTransform.scale(1, -1);
        m_immutableBaseTransform.translate(0, -ceilf(parameters.logicalSize.height() * parameters.resolutionScale));
        m_immutableBaseTransform.scale(parameters.resolutionScale);
        m_inverseImmutableBaseTransform = *m_immutableBaseTransform.inverse();
        m_resolutionScale = parameters.resolutionScale;
    }

    void setCTM(const WebCore::AffineTransform& transform) final
    {
        GraphicsContextCG::setCTM(m_inverseImmutableBaseTransform * transform);
    }

    WebCore::AffineTransform getCTM(IncludeDeviceScale includeDeviceScale) const final
    {
        return m_immutableBaseTransform * GraphicsContextCG::getCTM(includeDeviceScale);
    }

    WebCore::FloatRect roundToDevicePixels(const WebCore::FloatRect& rect, RoundingMode = RoundAllSides) const final
    {
        return rect;
    }

    bool canUseShadowBlur() const final { return false; }

protected:
    void setCGShadow(WebCore::RenderingMode renderingMode, const WebCore::FloatSize& offset, float blur, const WebCore::Color& color, bool shadowsIgnoreTransforms) override
    {
        // This doesn't use `m_immutableBaseTransform.mapSize` because it doesn't output negative lengths.
        WebCore::FloatSize scaledOffset = offset;
        scaledOffset.scale(m_resolutionScale, -m_resolutionScale);
        GraphicsContextCG::setCGShadow(renderingMode, scaledOffset, blur * m_resolutionScale, color, shadowsIgnoreTransforms);
    }

private:
    WebCore::AffineTransform m_immutableBaseTransform;
    WebCore::AffineTransform m_inverseImmutableBaseTransform;
    float m_resolutionScale;
};

WTF_MAKE_ISO_ALLOCATED_IMPL(CGDisplayListImageBufferBackend);

size_t CGDisplayListImageBufferBackend::calculateMemoryCost(const Parameters& parameters)
{
    // FIXME: This is fairly meaningless, because we don't actually have a bitmap, and
    // should really be based on the encoded data size.
    auto backendSize = calculateBackendSize(parameters);
    return WebCore::ImageBufferBackend::calculateMemoryCost(backendSize, calculateBytesPerRow(backendSize));
}

std::unique_ptr<CGDisplayListImageBufferBackend> CGDisplayListImageBufferBackend::create(const Parameters& parameters, const WebCore::ImageBufferCreationContext& creationContext)
{
    if (parameters.logicalSize.isEmpty())
        return nullptr;

    return std::unique_ptr<CGDisplayListImageBufferBackend>(new CGDisplayListImageBufferBackend(parameters, creationContext));
}

CGDisplayListImageBufferBackend::CGDisplayListImageBufferBackend(const Parameters& parameters, const WebCore::ImageBufferCreationContext& creationContext)
    : ImageBufferCGBackend { parameters }
{
    if (creationContext.useCGDisplayListImageCache == UseCGDisplayListImageCache::Yes)
        m_resourceCache = bridge_id_cast(adoptCF(WKCGCommandsCacheCreate(nullptr)));
}

ImageBufferBackendHandle CGDisplayListImageBufferBackend::createBackendHandle(SharedMemory::Protection) const
{
    ASSERT(m_context);

    RetainPtr<NSDictionary> options;
    RetainPtr<NSMutableArray> ports;
    if (m_resourceCache) {
        ports = adoptNS([[NSMutableArray alloc] init]);
        options = @{
            @"ports": ports.get(),
            @"cache": m_resourceCache.get()
        };
    }

    auto data = adoptCF(WKCGCommandsContextCopyEncodedDataWithOptions(m_context->platformContext(), bridge_cast(options.get())));
    ASSERT(data);

#if !RELEASE_LOG_DISABLED
    auto size = backendSize();
    RELEASE_LOG(RemoteLayerTree, "CGDisplayListImageBufferBackend of size %dx%d encoded display list of %ld bytes with %ld surfaces (useImageCache: %s)", size.width(), size.height(), CFDataGetLength(data.get()), [ports count], m_resourceCache ? "yes" : "no");
#endif

    Vector<MachSendRight> sendRights;
    if (m_resourceCache) {
        sendRights = makeVector(ports.get(), [] (id port) -> std::optional<MachSendRight> {
            // We `create` instead of `adopt` because CAMachPort has no API to leak its reference.
            return { MachSendRight::create(CAMachPortGetPort(checked_cf_cast<CAMachPortRef>(port))) };
        });
    }

    return CGDisplayList { WebCore::SharedBuffer::create(data.get()), WTFMove(sendRights) };
}

WebCore::GraphicsContext& CGDisplayListImageBufferBackend::context() const
{
    if (!m_context)
        m_context = makeUnique<GraphicsContextCGDisplayList>(m_parameters);
    return *m_context;
}

WebCore::IntSize CGDisplayListImageBufferBackend::backendSize() const
{
    return calculateBackendSize(m_parameters);
}

unsigned CGDisplayListImageBufferBackend::bytesPerRow() const
{
    return calculateBytesPerRow(backendSize());
}

void CGDisplayListImageBufferBackend::clearContents()
{
    m_context = nullptr;
}

RefPtr<WebCore::NativeImage> CGDisplayListImageBufferBackend::copyNativeImage(WebCore::BackingStoreCopy) const
{
    ASSERT_NOT_REACHED();
    return nullptr;
}

RefPtr<WebCore::PixelBuffer> CGDisplayListImageBufferBackend::getPixelBuffer(const WebCore::PixelBufferFormat&, const WebCore::IntRect&, const WebCore::ImageBufferAllocator&) const
{
    ASSERT_NOT_REACHED();
    return nullptr;
}

void CGDisplayListImageBufferBackend::putPixelBuffer(const WebCore::PixelBuffer&, const WebCore::IntRect&, const WebCore::IntPoint&, WebCore::AlphaPremultiplication)
{
    ASSERT_NOT_REACHED();
}

}

#endif // ENABLE(CG_DISPLAY_LIST_BACKED_IMAGE_BUFFER)