/
frame_subscriber.cc
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/
frame_subscriber.cc
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// Copyright (c) 2015 GitHub, Inc.
// Use of this source code is governed by the MIT license that can be
// found in the LICENSE file.
#include "shell/browser/api/frame_subscriber.h"
#include <utility>
#include "content/public/browser/render_view_host.h"
#include "content/public/browser/render_widget_host.h"
#include "content/public/browser/render_widget_host_view.h"
#include "media/capture/mojom/video_capture_buffer.mojom.h"
#include "media/capture/mojom/video_capture_types.mojom.h"
#include "mojo/public/cpp/bindings/remote.h"
#include "services/viz/privileged/mojom/compositing/frame_sink_video_capture.mojom-shared.h"
#include "ui/gfx/geometry/size_conversions.h"
#include "ui/gfx/image/image.h"
#include "ui/gfx/skbitmap_operations.h"
namespace electron::api {
constexpr static int kMaxFrameRate = 30;
FrameSubscriber::FrameSubscriber(content::WebContents* web_contents,
const FrameCaptureCallback& callback,
bool only_dirty)
: content::WebContentsObserver(web_contents),
callback_(callback),
only_dirty_(only_dirty) {
AttachToHost(web_contents->GetPrimaryMainFrame()->GetRenderWidgetHost());
}
FrameSubscriber::~FrameSubscriber() = default;
void FrameSubscriber::AttachToHost(content::RenderWidgetHost* host) {
host_ = host;
// The view can be null if the renderer process has crashed.
// (https://crbug.com/847363)
if (!host_->GetView())
return;
// Create and configure the video capturer.
gfx::Size size = GetRenderViewSize();
DCHECK(!size.IsEmpty());
video_capturer_ = host_->GetView()->CreateVideoCapturer();
video_capturer_->SetResolutionConstraints(size, size, true);
video_capturer_->SetAutoThrottlingEnabled(false);
video_capturer_->SetMinSizeChangePeriod(base::TimeDelta());
video_capturer_->SetFormat(media::PIXEL_FORMAT_ARGB);
video_capturer_->SetMinCapturePeriod(base::Seconds(1) / kMaxFrameRate);
video_capturer_->Start(this, viz::mojom::BufferFormatPreference::kDefault);
}
void FrameSubscriber::DetachFromHost() {
if (!host_)
return;
video_capturer_.reset();
host_ = nullptr;
}
void FrameSubscriber::RenderFrameCreated(
content::RenderFrameHost* render_frame_host) {
if (!host_)
AttachToHost(render_frame_host->GetRenderWidgetHost());
}
void FrameSubscriber::RenderViewDeleted(content::RenderViewHost* host) {
if (host->GetWidget() == host_) {
DetachFromHost();
}
}
void FrameSubscriber::PrimaryPageChanged(content::Page& page) {
if (auto* host = page.GetMainDocument().GetMainFrame()->GetRenderWidgetHost();
host_ != host) {
DetachFromHost();
AttachToHost(host);
}
}
void FrameSubscriber::OnFrameCaptured(
::media::mojom::VideoBufferHandlePtr data,
::media::mojom::VideoFrameInfoPtr info,
const gfx::Rect& content_rect,
mojo::PendingRemote<viz::mojom::FrameSinkVideoConsumerFrameCallbacks>
callbacks) {
auto& data_region = data->get_read_only_shmem_region();
gfx::Size size = GetRenderViewSize();
if (size != content_rect.size()) {
video_capturer_->SetResolutionConstraints(size, size, true);
video_capturer_->RequestRefreshFrame();
return;
}
mojo::Remote<viz::mojom::FrameSinkVideoConsumerFrameCallbacks>
callbacks_remote(std::move(callbacks));
if (!data_region.IsValid()) {
callbacks_remote->Done();
return;
}
base::ReadOnlySharedMemoryMapping mapping = data_region.Map();
if (!mapping.IsValid()) {
DLOG(ERROR) << "Shared memory mapping failed.";
return;
}
if (mapping.size() <
media::VideoFrame::AllocationSize(info->pixel_format, info->coded_size)) {
DLOG(ERROR) << "Shared memory size was less than expected.";
return;
}
// The SkBitmap's pixels will be marked as immutable, but the installPixels()
// API requires a non-const pointer. So, cast away the const.
void* const pixels = const_cast<void*>(mapping.memory());
// Call installPixels() with a |releaseProc| that: 1) notifies the capturer
// that this consumer has finished with the frame, and 2) releases the shared
// memory mapping.
struct FramePinner {
// Keeps the shared memory that backs |frame_| mapped.
base::ReadOnlySharedMemoryMapping mapping;
// Prevents FrameSinkVideoCapturer from recycling the shared memory that
// backs |frame_|.
mojo::Remote<viz::mojom::FrameSinkVideoConsumerFrameCallbacks> releaser;
};
SkBitmap bitmap;
bitmap.installPixels(
SkImageInfo::MakeN32(content_rect.width(), content_rect.height(),
kPremul_SkAlphaType),
pixels,
media::VideoFrame::RowBytes(media::VideoFrame::kARGBPlane,
info->pixel_format, info->coded_size.width()),
[](void* addr, void* context) {
delete static_cast<FramePinner*>(context);
},
new FramePinner{std::move(mapping), std::move(callbacks_remote)});
bitmap.setImmutable();
Done(content_rect, bitmap);
}
void FrameSubscriber::OnNewSubCaptureTargetVersion(uint32_t crop_version) {}
void FrameSubscriber::OnFrameWithEmptyRegionCapture() {}
void FrameSubscriber::OnStopped() {}
void FrameSubscriber::OnLog(const std::string& message) {}
void FrameSubscriber::Done(const gfx::Rect& damage, const SkBitmap& frame) {
if (frame.drawsNothing())
return;
const SkBitmap& bitmap = only_dirty_ ? SkBitmapOperations::CreateTiledBitmap(
frame, damage.x(), damage.y(),
damage.width(), damage.height())
: frame;
// Copying SkBitmap does not copy the internal pixels, we have to manually
// allocate and write pixels otherwise crash may happen when the original
// frame is modified.
SkBitmap copy;
copy.allocPixels(SkImageInfo::Make(bitmap.width(), bitmap.height(),
kN32_SkColorType, kPremul_SkAlphaType));
SkPixmap pixmap;
bool success = bitmap.peekPixels(&pixmap) && copy.writePixels(pixmap, 0, 0);
CHECK(success);
callback_.Run(gfx::Image::CreateFrom1xBitmap(copy), damage);
}
gfx::Size FrameSubscriber::GetRenderViewSize() const {
content::RenderWidgetHostView* view = host_->GetView();
gfx::Size size = view->GetViewBounds().size();
return gfx::ToRoundedSize(
gfx::ScaleSize(gfx::SizeF(size), view->GetDeviceScaleFactor()));
}
} // namespace electron::api