blob: 67a6919b4660ecc1a6ce17cb87f94b06e4f74d72 [file] [log] [blame]
/*
* Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "modules/desktop_capture/desktop_and_cursor_composer.h"
#include <string.h>
#include <utility>
#include "absl/memory/memory.h"
#include "modules/desktop_capture/desktop_capturer.h"
#include "modules/desktop_capture/desktop_frame.h"
#include "modules/desktop_capture/mouse_cursor.h"
#include "modules/desktop_capture/mouse_cursor_monitor.h"
#include "rtc_base/checks.h"
#include "rtc_base/constructormagic.h"
namespace webrtc {
namespace {
// Helper function that blends one image into another. Source image must be
// pre-multiplied with the alpha channel. Destination is assumed to be opaque.
void AlphaBlend(uint8_t* dest,
int dest_stride,
const uint8_t* src,
int src_stride,
const DesktopSize& size) {
for (int y = 0; y < size.height(); ++y) {
for (int x = 0; x < size.width(); ++x) {
uint32_t base_alpha = 255 - src[x * DesktopFrame::kBytesPerPixel + 3];
if (base_alpha == 255) {
continue;
} else if (base_alpha == 0) {
memcpy(dest + x * DesktopFrame::kBytesPerPixel,
src + x * DesktopFrame::kBytesPerPixel,
DesktopFrame::kBytesPerPixel);
} else {
dest[x * DesktopFrame::kBytesPerPixel] =
dest[x * DesktopFrame::kBytesPerPixel] * base_alpha / 255 +
src[x * DesktopFrame::kBytesPerPixel];
dest[x * DesktopFrame::kBytesPerPixel + 1] =
dest[x * DesktopFrame::kBytesPerPixel + 1] * base_alpha / 255 +
src[x * DesktopFrame::kBytesPerPixel + 1];
dest[x * DesktopFrame::kBytesPerPixel + 2] =
dest[x * DesktopFrame::kBytesPerPixel + 2] * base_alpha / 255 +
src[x * DesktopFrame::kBytesPerPixel + 2];
}
}
src += src_stride;
dest += dest_stride;
}
}
// DesktopFrame wrapper that draws mouse on a frame and restores original
// content before releasing the underlying frame.
class DesktopFrameWithCursor : public DesktopFrame {
public:
// Takes ownership of |frame|.
DesktopFrameWithCursor(std::unique_ptr<DesktopFrame> frame,
const MouseCursor& cursor,
const DesktopVector& position);
~DesktopFrameWithCursor() override;
private:
const std::unique_ptr<DesktopFrame> original_frame_;
DesktopVector restore_position_;
std::unique_ptr<DesktopFrame> restore_frame_;
RTC_DISALLOW_COPY_AND_ASSIGN(DesktopFrameWithCursor);
};
DesktopFrameWithCursor::DesktopFrameWithCursor(
std::unique_ptr<DesktopFrame> frame,
const MouseCursor& cursor,
const DesktopVector& position)
: DesktopFrame(frame->size(),
frame->stride(),
frame->data(),
frame->shared_memory()),
original_frame_(std::move(frame)) {
MoveFrameInfoFrom(original_frame_.get());
DesktopVector image_pos = position.subtract(cursor.hotspot());
DesktopRect target_rect = DesktopRect::MakeSize(cursor.image()->size());
target_rect.Translate(image_pos);
DesktopVector target_origin = target_rect.top_left();
target_rect.IntersectWith(DesktopRect::MakeSize(size()));
if (target_rect.is_empty())
return;
// Copy original screen content under cursor to |restore_frame_|.
restore_position_ = target_rect.top_left();
restore_frame_.reset(new BasicDesktopFrame(target_rect.size()));
restore_frame_->CopyPixelsFrom(*this, target_rect.top_left(),
DesktopRect::MakeSize(restore_frame_->size()));
// Blit the cursor.
uint8_t* target_rect_data = reinterpret_cast<uint8_t*>(data()) +
target_rect.top() * stride() +
target_rect.left() * DesktopFrame::kBytesPerPixel;
DesktopVector origin_shift = target_rect.top_left().subtract(target_origin);
AlphaBlend(target_rect_data, stride(),
cursor.image()->data() +
origin_shift.y() * cursor.image()->stride() +
origin_shift.x() * DesktopFrame::kBytesPerPixel,
cursor.image()->stride(), target_rect.size());
}
DesktopFrameWithCursor::~DesktopFrameWithCursor() {
// Restore original content of the frame.
if (restore_frame_) {
DesktopRect target_rect = DesktopRect::MakeSize(restore_frame_->size());
target_rect.Translate(restore_position_);
CopyPixelsFrom(restore_frame_->data(), restore_frame_->stride(),
target_rect);
}
}
} // namespace
DesktopAndCursorComposer::DesktopAndCursorComposer(
std::unique_ptr<DesktopCapturer> desktop_capturer,
const DesktopCaptureOptions& options)
: DesktopAndCursorComposer(desktop_capturer.release(),
MouseCursorMonitor::Create(options).release()) {}
DesktopAndCursorComposer::DesktopAndCursorComposer(
DesktopCapturer* desktop_capturer,
MouseCursorMonitor* mouse_monitor)
: desktop_capturer_(desktop_capturer), mouse_monitor_(mouse_monitor) {
RTC_DCHECK(desktop_capturer_);
}
DesktopAndCursorComposer::~DesktopAndCursorComposer() = default;
void DesktopAndCursorComposer::Start(DesktopCapturer::Callback* callback) {
callback_ = callback;
if (mouse_monitor_)
mouse_monitor_->Init(this, MouseCursorMonitor::SHAPE_AND_POSITION);
desktop_capturer_->Start(this);
}
void DesktopAndCursorComposer::SetSharedMemoryFactory(
std::unique_ptr<SharedMemoryFactory> shared_memory_factory) {
desktop_capturer_->SetSharedMemoryFactory(std::move(shared_memory_factory));
}
void DesktopAndCursorComposer::CaptureFrame() {
if (mouse_monitor_)
mouse_monitor_->Capture();
desktop_capturer_->CaptureFrame();
}
void DesktopAndCursorComposer::SetExcludedWindow(WindowId window) {
desktop_capturer_->SetExcludedWindow(window);
}
void DesktopAndCursorComposer::OnCaptureResult(
DesktopCapturer::Result result,
std::unique_ptr<DesktopFrame> frame) {
if (frame && cursor_) {
if (frame->rect().Contains(cursor_position_) &&
!desktop_capturer_->IsOccluded(cursor_position_)) {
const float scale = frame->scale_factor();
DesktopVector relative_position =
cursor_position_.subtract(frame->top_left());
relative_position.set(relative_position.x() * scale,
relative_position.y() * scale);
frame = absl::make_unique<DesktopFrameWithCursor>(
std::move(frame), *cursor_, relative_position);
}
}
callback_->OnCaptureResult(result, std::move(frame));
}
void DesktopAndCursorComposer::OnMouseCursor(MouseCursor* cursor) {
cursor_.reset(cursor);
}
void DesktopAndCursorComposer::OnMouseCursorPosition(
MouseCursorMonitor::CursorState state,
const DesktopVector& position) {
RTC_NOTREACHED();
}
void DesktopAndCursorComposer::OnMouseCursorPosition(
const DesktopVector& position) {
cursor_position_ = position;
}
} // namespace webrtc