WindowServer: Add support for background images

WindowServer now looks in _$HOME/.config/WindowServer.conf_ for a
configuration file that can specify a background image.

Also add default background image /usr/share/images/sample.ppm to the
base sysroot provided in the git repo.

userspace/WindowServer/CMakeLists.txt

@@ -11,7 +11,7 @@ set(SOURCES
 
 add_executable(WindowServer ${SOURCES})
 target_compile_options(WindowServer PUBLIC -O2 -g)
-target_link_libraries(WindowServer PUBLIC libc ban libfont libgui libinput)
+target_link_libraries(WindowServer PUBLIC libc ban libfont libgui libimage libinput)
 
 add_custom_target(WindowServer-install
 	COMMAND ${CMAKE_COMMAND} -E copy ${CMAKE_CURRENT_BINARY_DIR}/WindowServer ${BANAN_BIN}/

userspace/WindowServer/WindowServer.cpp

@@ -11,6 +11,15 @@
 #include <sys/mman.h>
 #include <sys/socket.h>
 
+BAN::ErrorOr<void> WindowServer::set_background_image(BAN::UniqPtr<LibImage::Image> image)
+{
+	if (image->width() != (uint64_t)m_framebuffer.width || image->height() != (uint64_t)m_framebuffer.height)
+		image = TRY(image->resize(m_framebuffer.width, m_framebuffer.height));
+	m_background_image = BAN::move(image);
+	invalidate(m_framebuffer.area());
+	return {};
+}
+
 void WindowServer::on_window_packet(int fd, LibGUI::WindowPacket packet)
 {
 	switch (packet.type)
@@ -270,8 +279,19 @@ void WindowServer::invalidate(Rectangle area)
 		return;
 	area = fb_overlap.release_value();
 
+	if (m_background_image)
+	{
+		ASSERT(m_background_image->width() == (uint64_t)m_framebuffer.width);
+		ASSERT(m_background_image->height() == (uint64_t)m_framebuffer.height);
+		for (int32_t y = area.y; y < area.y + area.height; y++)
+			for (int32_t x = area.x; x < area.x + area.width; x++)
+				m_framebuffer.mmap[y * m_framebuffer.width + x] = m_background_image->get_color(x, y).as_rgba();
+	}
+	else
+	{
 		for (int32_t y = area.y; y < area.y + area.height; y++)
 			memset(&m_framebuffer.mmap[y * m_framebuffer.width + area.x], 0x10, area.width * 4);
+	}
 
 	for (auto& pwindow : m_client_windows)
 	{

userspace/WindowServer/WindowServer.h

@@ -10,6 +10,7 @@
 
 #include <LibFont/Font.h>
 #include <LibGUI/Window.h>
+#include <LibImage/Image.h>
 #include <LibInput/KeyEvent.h>
 #include <LibInput/MouseEvent.h>
 
@@ -26,6 +27,8 @@ public:
 		invalidate(m_framebuffer.area());
 	}
 
+	BAN::ErrorOr<void> set_background_image(BAN::UniqPtr<LibImage::Image>);
+
 	void on_window_packet(int fd, LibGUI::WindowPacket);
 
 	void on_key_event(LibInput::KeyEvent event);
@@ -50,6 +53,8 @@ private:
 	BAN::Vector<BAN::RefPtr<Window>> m_client_windows;
 	BAN::Vector<int> m_client_fds;
 
+	BAN::UniqPtr<LibImage::Image> m_background_image;
+
 	bool m_is_mod_key_held { false };
 	bool m_is_moving_window { false };
 	BAN::RefPtr<Window> m_focused_window;

userspace/WindowServer/main.cpp

@@ -1,6 +1,7 @@
 #include "WindowServer.h"
 
 #include <BAN/Debug.h>
+#include <BAN/ScopeGuard.h>
 
 #include <LibGUI/Window.h>
 #include <LibInput/KeyboardLayout.h>
@@ -15,6 +16,88 @@
 #include <sys/un.h>
 #include <unistd.h>
 
+struct Config
+{
+	BAN::UniqPtr<LibImage::Image> background_image;
+};
+
+BAN::Optional<BAN::String> file_read_line(FILE* file)
+{
+	BAN::String line;
+
+	char buffer[128];
+	while (fgets(buffer, sizeof(buffer), file))
+	{
+		MUST(line.append(buffer));
+		if (line.back() == '\n')
+		{
+			line.pop_back();
+			return BAN::move(line);
+		}
+	}
+
+	if (line.empty())
+		return {};
+	return BAN::move(line);
+}
+
+Config parse_config()
+{
+	Config config;
+
+	auto home_env = getenv("HOME");
+	if (!home_env)
+	{
+		dprintln("HOME environment variable not set");
+		return config;
+	}
+
+	auto config_path = BAN::String::formatted("{}/.config/WindowServer.conf", home_env);
+	FILE* fconfig = fopen(config_path.data(), "r");
+	if (!fconfig)
+	{
+		dprintln("Could not open '{}'", config_path);
+		return config;
+	}
+
+	BAN::ScopeGuard _([fconfig] { fclose(fconfig); });
+
+	while (true)
+	{
+		auto line = file_read_line(fconfig);
+		if (!line.has_value())
+			break;
+		if (line->empty())
+			continue;
+
+		auto parts = MUST(line->sv().split('='));
+		if (parts.size() != 2)
+		{
+			dwarnln("Invalid config line: {}", line.value());
+			break;
+		}
+
+		auto variable = parts[0];
+		auto value = parts[1];
+
+		if (variable == "bg"sv)
+		{
+			auto image = LibImage::Image::load_from_file(value);
+			if (image.is_error())
+				dwarnln("Could not load image: {}", image.error());
+			else
+				config.background_image = image.release_value();
+		}
+		else
+		{
+			dwarnln("Unknown config variable: {}", variable);
+			break;
+		}
+	}
+
+	return config;
+}
+
 int open_server_fd()
 {
 	struct stat st;
@@ -91,7 +174,13 @@ int main()
 	window_packet_sizes[LibGUI::WindowPacketType::Invalidate]	= sizeof(LibGUI::WindowInvalidatePacket);
 	static_assert(LibGUI::WindowPacketType::COUNT == 3);
 
+	auto config = parse_config();
+
 	WindowServer window_server(framebuffer);
+	if (config.background_image)
+		if (auto ret = window_server.set_background_image(BAN::move(config.background_image)); ret.is_error())
+			dwarnln("Could not set background image: {}", ret.error());
+
 	while (!window_server.is_stopped())
 	{
 		int max_fd = server_fd;