ladybird/Libraries/LibC/SharedBuffer.h
Andreas Kling 411058b2a3 WindowServer+LibGUI: Implement basic color theming
Color themes are loaded from .ini files in /res/themes/
The theme can be switched from the "Themes" section in the system menu.

The basic mechanism is that WindowServer broadcasts a SharedBuffer with
all of the color values of the current theme. Clients receive this with
the response to their initial WindowServer::Greet handshake.

When the theme is changed, WindowServer tells everyone by sending out
an UpdateSystemTheme message with a new SharedBuffer to use.

This does feel somewhat bloated somehow, but I'm sure we can iterate on
it over time and improve things.

To get one of the theme colors, use the Color(SystemColor) constructor:

    painter.fill_rect(rect, SystemColor::HoverHighlight);

Some things don't work 100% right without a reboot. Specifically, when
constructing a GWidget, it will set its own background and foreground
colors based on the current SystemColor::Window and SystemColor::Text.
The widget is then stuck with these values, and they don't update on
system theme change, only on app restart.

All in all though, this is pretty cool. Merry Christmas! :^)
2019-12-23 20:33:01 +01:00

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#pragma once
#include <AK/RefCounted.h>
#include <AK/RefPtr.h>
class SharedBuffer : public RefCounted<SharedBuffer> {
public:
static RefPtr<SharedBuffer> create_with_size(int);
static RefPtr<SharedBuffer> create_from_shared_buffer_id(int);
~SharedBuffer();
bool share_globally();
bool share_with(pid_t);
int shared_buffer_id() const { return m_shared_buffer_id; }
void seal();
int size() const { return m_size; }
void* data() { return m_data; }
const void* data() const { return m_data; }
void set_volatile();
[[nodiscard]] bool set_nonvolatile();
private:
SharedBuffer(int shared_buffer_id, int size, void*);
int m_shared_buffer_id { -1 };
int m_size { 0 };
void* m_data;
};