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/*
* Copyright (c) 2016 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 <X11/X.h>
#include <X11/Xlib.h>
#include <string.h>
#include <memory>
#include "api/scoped_refptr.h"
#include "modules/desktop_capture/desktop_capture_types.h"
#include "modules/desktop_capture/desktop_geometry.h"
#include "modules/desktop_capture/linux/x11/shared_x_display.h"
#include "modules/desktop_capture/rgba_color.h"
#include "modules/desktop_capture/screen_drawer.h"
#include "modules/desktop_capture/screen_drawer_lock_posix.h"
#include "rtc_base/checks.h"
#include "rtc_base/thread.h"
namespace webrtc {
namespace {
// A ScreenDrawer implementation for X11.
class ScreenDrawerLinux : public ScreenDrawer {
public:
ScreenDrawerLinux();
~ScreenDrawerLinux() override;
// ScreenDrawer interface.
DesktopRect DrawableRegion() override;
void DrawRectangle(DesktopRect rect, RgbaColor color) override;
void Clear() override;
void WaitForPendingDraws() override;
bool MayDrawIncompleteShapes() override;
WindowId window_id() const override;
private:
// Bring the window to the front, this can help to avoid the impact from other
// windows or shadow effect.
void BringToFront();
scoped_refptr<SharedXDisplay> display_;
int screen_num_;
DesktopRect rect_;
Window window_;
GC context_;
Colormap colormap_;
};
ScreenDrawerLinux::ScreenDrawerLinux() {
display_ = SharedXDisplay::CreateDefault();
RTC_CHECK(display_.get());
screen_num_ = DefaultScreen(display_->display());
XWindowAttributes root_attributes;
if (!XGetWindowAttributes(display_->display(),
RootWindow(display_->display(), screen_num_),
&root_attributes)) {
RTC_DCHECK_NOTREACHED() << "Failed to get root window size.";
}
window_ = XCreateSimpleWindow(
display_->display(), RootWindow(display_->display(), screen_num_), 0, 0,
root_attributes.width, root_attributes.height, 0,
BlackPixel(display_->display(), screen_num_),
BlackPixel(display_->display(), screen_num_));
XSelectInput(display_->display(), window_, StructureNotifyMask);
XMapWindow(display_->display(), window_);
while (true) {
XEvent event;
XNextEvent(display_->display(), &event);
if (event.type == MapNotify) {
break;
}
}
XFlush(display_->display());
Window child;
int x, y;
if (!XTranslateCoordinates(display_->display(), window_,
RootWindow(display_->display(), screen_num_), 0, 0,
&x, &y, &child)) {
RTC_DCHECK_NOTREACHED() << "Failed to get window position.";
}
// Some window manager does not allow a window to cover two or more monitors.
// So if the window is on the first monitor of a two-monitor system, the
// second half won't be able to show up without changing configurations of WM,
// and its DrawableRegion() is not accurate.
rect_ = DesktopRect::MakeLTRB(x, y, root_attributes.width,
root_attributes.height);
context_ = DefaultGC(display_->display(), screen_num_);
colormap_ = DefaultColormap(display_->display(), screen_num_);
BringToFront();
// Wait for window animations.
Thread::SleepMs(200);
}
ScreenDrawerLinux::~ScreenDrawerLinux() {
XUnmapWindow(display_->display(), window_);
XDestroyWindow(display_->display(), window_);
}
DesktopRect ScreenDrawerLinux::DrawableRegion() {
return rect_;
}
void ScreenDrawerLinux::DrawRectangle(DesktopRect rect, RgbaColor color) {
rect.Translate(-rect_.left(), -rect_.top());
XColor xcolor;
// X11 does not support Alpha.
// X11 uses 16 bits for each primary color, so we need to slightly normalize
// a 8 bits channel to 16 bits channel, by setting the low 8 bits as its high
// 8 bits to avoid a mismatch of color returned by capturer.
xcolor.red = (color.red << 8) + color.red;
xcolor.green = (color.green << 8) + color.green;
xcolor.blue = (color.blue << 8) + color.blue;
xcolor.flags = DoRed | DoGreen | DoBlue;
XAllocColor(display_->display(), colormap_, &xcolor);
XSetForeground(display_->display(), context_, xcolor.pixel);
XFillRectangle(display_->display(), window_, context_, rect.left(),
rect.top(), rect.width(), rect.height());
XFlush(display_->display());
}
void ScreenDrawerLinux::Clear() {
DrawRectangle(rect_, RgbaColor(0, 0, 0));
}
// TODO(zijiehe): Find the right signal from X11 to indicate the finish of all
// pending paintings.
void ScreenDrawerLinux::WaitForPendingDraws() {
Thread::SleepMs(50);
}
bool ScreenDrawerLinux::MayDrawIncompleteShapes() {
return true;
}
WindowId ScreenDrawerLinux::window_id() const {
return window_;
}
void ScreenDrawerLinux::BringToFront() {
Atom state_above = XInternAtom(display_->display(), "_NET_WM_STATE_ABOVE", 1);
Atom window_state = XInternAtom(display_->display(), "_NET_WM_STATE", 1);
if (state_above == None || window_state == None) {
// Fallback to use XRaiseWindow, it's not reliable if two windows are both
// raise itself to the top.
XRaiseWindow(display_->display(), window_);
return;
}
XEvent event;
memset(&event, 0, sizeof(event));
event.type = ClientMessage;
event.xclient.window = window_;
event.xclient.message_type = window_state;
event.xclient.format = 32;
event.xclient.data.l[0] = 1; // _NET_WM_STATE_ADD
event.xclient.data.l[1] = state_above;
XSendEvent(display_->display(), RootWindow(display_->display(), screen_num_),
False, SubstructureRedirectMask | SubstructureNotifyMask, &event);
}
} // namespace
// static
std::unique_ptr<ScreenDrawerLock> ScreenDrawerLock::Create() {
return std::make_unique<ScreenDrawerLockPosix>();
}
// static
std::unique_ptr<ScreenDrawer> ScreenDrawer::Create() {
if (SharedXDisplay::CreateDefault().get()) {
return std::make_unique<ScreenDrawerLinux>();
}
return nullptr;
}
} // namespace webrtc
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