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Magnifier: Use a GUI::DisplayLink to drive the screen captures

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This ensures that we don't try to update more often than the screen
is updated. It also avoids doing synchronous IPC in paint_event().
This commit is contained in:
Andreas Kling 2021-06-07 09:35:07 +02:00
parent 61c56e75f4
commit 0ea1fd2d54
3 changed files with 13 additions and 8 deletions
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16
Userland/Applications/Magnifier/MagnifierWidget.cpp
View file

@ -5,6 +5,7 @@
*/ */
#include "MagnifierWidget.h" #include "MagnifierWidget.h"
#include <LibGUI/DisplayLink.h>
#include <LibGUI/Painter.h> #include <LibGUI/Painter.h>
#include <LibGUI/Window.h> #include <LibGUI/Window.h>
#include <LibGUI/WindowServerConnection.h> #include <LibGUI/WindowServerConnection.h>
@ -12,6 +13,7 @@
MagnifierWidget::MagnifierWidget() MagnifierWidget::MagnifierWidget()
{ {
GUI::DisplayLink::register_callback([this](auto) { sync(); });
} }
MagnifierWidget::~MagnifierWidget() MagnifierWidget::~MagnifierWidget()
@ -35,10 +37,15 @@ void MagnifierWidget::set_scale_factor(int scale_factor)
update(); update();
} }
void MagnifierWidget::timer_event(Core::TimerEvent&) void MagnifierWidget::sync()
{ {
m_mouse_position = GUI::WindowServerConnection::the().get_global_cursor_position(); m_mouse_position = GUI::WindowServerConnection::the().get_global_cursor_position();
m_desktop_display_scale = GUI::WindowServerConnection::the().get_desktop_display_scale(); m_desktop_display_scale = GUI::WindowServerConnection::the().get_desktop_display_scale();
// Grab and paint our screenshot.
Gfx::IntSize region_size { size().width() / m_scale_factor, size().height() / m_scale_factor };
Gfx::Rect region { (m_mouse_position.x() * m_desktop_display_scale) - (region_size.width() / 2), (m_mouse_position.y() * m_desktop_display_scale) - (region_size.height() / 2), region_size.width(), region_size.height() };
m_grabbed_bitmap = GUI::WindowServerConnection::the().get_screen_bitmap(region).bitmap();
update(); update();
} }
@ -46,9 +53,6 @@ void MagnifierWidget::paint_event(GUI::PaintEvent&)
{ {
GUI::Painter painter(*this); GUI::Painter painter(*this);
// Grab and paint our screenshot. if (m_grabbed_bitmap)
Gfx::IntSize region_size { size().width() / m_scale_factor, size().height() / m_scale_factor }; painter.draw_scaled_bitmap(rect(), *m_grabbed_bitmap, m_grabbed_bitmap->rect());
Gfx::Rect region { (m_mouse_position.x() * m_desktop_display_scale) - (region_size.width() / 2), (m_mouse_position.y() * m_desktop_display_scale) - (region_size.height() / 2), region_size.width(), region_size.height() };
auto map = GUI::WindowServerConnection::the().get_screen_bitmap(region);
painter.draw_scaled_bitmap(rect(), *map.bitmap(), map.bitmap()->rect());
} }

4
Userland/Applications/Magnifier/MagnifierWidget.h
View file

@ -19,10 +19,12 @@ public:
void track_cursor_globally(); void track_cursor_globally();
private: private:
virtual void timer_event(Core::TimerEvent&) override;
virtual void paint_event(GUI::PaintEvent&) override; virtual void paint_event(GUI::PaintEvent&) override;
void sync();
Gfx::IntPoint m_mouse_position; Gfx::IntPoint m_mouse_position;
int m_scale_factor { 2 }; int m_scale_factor { 2 };
int m_desktop_display_scale { 1 }; int m_desktop_display_scale { 1 };
RefPtr<Gfx::Bitmap> m_grabbed_bitmap;
}; };

1
Userland/Applications/Magnifier/main.cpp
View file

@ -84,7 +84,6 @@ int main(int argc, char** argv)
window->show(); window->show();
magnifier.track_cursor_globally(); magnifier.track_cursor_globally();
magnifier.start_timer(16);
return app->exec(); return app->exec();
} }