From 8f170ff1f029ab7fd2fab60ae39b0961070b985a Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Thu, 3 Aug 2023 12:19:45 +0200
Subject: [PATCH] libui: Add a GUI and graphics library

---
 CMakeLists.txt            |  1 +
 libui/CMakeLists.txt      | 15 ++++++++++++++
 libui/include/ui/Canvas.h | 30 +++++++++++++++++++++++++++
 libui/include/ui/Color.h  | 34 +++++++++++++++++++++++++++++++
 libui/include/ui/Point.h  | 13 ++++++++++++
 libui/include/ui/Rect.h   | 18 ++++++++++++++++
 libui/src/Canvas.cpp      | 43 +++++++++++++++++++++++++++++++++++++++
 libui/src/Color.cpp       |  0
 libui/src/Rect.cpp        | 18 ++++++++++++++++
 tools/install-headers.sh  |  2 ++
 tools/sources.sh          |  2 +-
 11 files changed, 175 insertions(+), 1 deletion(-)
 create mode 100644 libui/CMakeLists.txt
 create mode 100644 libui/include/ui/Canvas.h
 create mode 100644 libui/include/ui/Color.h
 create mode 100644 libui/include/ui/Point.h
 create mode 100644 libui/include/ui/Rect.h
 create mode 100644 libui/src/Canvas.cpp
 create mode 100644 libui/src/Color.cpp
 create mode 100644 libui/src/Rect.cpp

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9740c155..05f81c8b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -45,6 +45,7 @@ endif()
 
 add_subdirectory(libluna)
 add_subdirectory(libos)
+add_subdirectory(libui)
 add_subdirectory(libc)
 add_subdirectory(kernel)
 add_subdirectory(apps)
diff --git a/libui/CMakeLists.txt b/libui/CMakeLists.txt
new file mode 100644
index 00000000..b9bf2e94
--- /dev/null
+++ b/libui/CMakeLists.txt
@@ -0,0 +1,15 @@
+# The UI and graphics library for Luna.
+
+file(GLOB HEADERS include/ui/*.h)
+
+set(SOURCES
+    ${HEADERS}
+    src/Canvas.cpp
+    src/Color.cpp
+    src/Rect.cpp
+)
+
+add_library(ui ${SOURCES})
+target_compile_options(ui PRIVATE ${COMMON_FLAGS})
+target_include_directories(ui PUBLIC ${CMAKE_CURRENT_LIST_DIR}/include/)
+target_include_directories(ui PUBLIC ${LUNA_BASE}/usr/include)
diff --git a/libui/include/ui/Canvas.h b/libui/include/ui/Canvas.h
new file mode 100644
index 00000000..c90f0ae7
--- /dev/null
+++ b/libui/include/ui/Canvas.h
@@ -0,0 +1,30 @@
+#pragma once
+#include <luna/Result.h>
+#include <luna/Types.h>
+#include <ui/Color.h>
+#include <ui/Point.h>
+#include <ui/Rect.h>
+
+namespace ui
+{
+    /**
+     * @brief A drawable surface.
+     */
+    struct Canvas
+    {
+        int width;
+        int height;
+        int stride;
+        u8* ptr;
+
+        static Canvas create(u8* ptr, int width, int height);
+        Result<Canvas> subcanvas(Point begin, int width, int height, bool clamp);
+
+        Rect rect()
+        {
+            return Rect { .begin = { 0, 0 }, .width = width, .height = height };
+        }
+
+        void fill(Color color);
+    };
+};
diff --git a/libui/include/ui/Color.h b/libui/include/ui/Color.h
new file mode 100644
index 00000000..95a8d974
--- /dev/null
+++ b/libui/include/ui/Color.h
@@ -0,0 +1,34 @@
+#pragma once
+#include <luna/Types.h>
+
+namespace ui
+{
+    /**
+     * @brief A 32-bit RGBA color.
+     */
+    struct Color
+    {
+        union {
+            u32 raw;
+            u8 colors[4];
+        };
+
+        static constexpr Color from_u32(u32 raw)
+        {
+            return Color { .raw = raw };
+        }
+
+        static constexpr Color from_rgba(u8 red, u8 green, u8 blue, u8 alpha)
+        {
+            return Color { .colors = { blue, green, red, alpha } };
+        }
+
+        static constexpr Color from_rgb(u8 red, u8 green, u8 blue)
+        {
+            return from_rgba(red, green, blue, 0xff);
+        }
+    };
+
+    static constexpr Color WHITE = Color::from_rgb(0xff, 0xff, 0xff);
+    static constexpr Color BLACK = Color::from_rgb(0x00, 0x00, 0x00);
+};
diff --git a/libui/include/ui/Point.h b/libui/include/ui/Point.h
new file mode 100644
index 00000000..146ea0b8
--- /dev/null
+++ b/libui/include/ui/Point.h
@@ -0,0 +1,13 @@
+#pragma once
+
+namespace ui
+{
+    /**
+     * @brief A point in 2D space.
+     */
+    struct Point
+    {
+        int x { 0 };
+        int y { 0 };
+    };
+}
diff --git a/libui/include/ui/Rect.h b/libui/include/ui/Rect.h
new file mode 100644
index 00000000..6d2bdec6
--- /dev/null
+++ b/libui/include/ui/Rect.h
@@ -0,0 +1,18 @@
+#pragma once
+#include <ui/Point.h>
+
+namespace ui
+{
+    /**
+     * @brief A simple rectangle.
+     */
+    struct Rect
+    {
+        Point begin;
+        int width;
+        int height;
+
+        bool contains(Point point);
+        Point normalize(Point point);
+    };
+}
diff --git a/libui/src/Canvas.cpp b/libui/src/Canvas.cpp
new file mode 100644
index 00000000..812610c0
--- /dev/null
+++ b/libui/src/Canvas.cpp
@@ -0,0 +1,43 @@
+#include <string.h>
+#include <ui/Canvas.h>
+
+namespace ui
+{
+    Canvas Canvas::create(u8* ptr, int width, int height)
+    {
+        return Canvas { .width = width, .height = height, .stride = width, .ptr = ptr };
+    }
+
+    Result<Canvas> Canvas::subcanvas(Point begin, int w, int h, bool clamp)
+    {
+        if (!clamp)
+        {
+            if (begin.x + w > width) return err(ERANGE);
+            if (begin.y + h > height) return err(ERANGE);
+        }
+        else
+        {
+            if (begin.x + w > width) w = width - begin.x;
+            if (begin.y + h > height) h = height - begin.y;
+        }
+
+        u8* p = ptr + begin.x * sizeof(Color) + (begin.y * sizeof(Color) * stride);
+
+        return Canvas { .width = w, .height = h, .stride = stride, .ptr = p };
+    }
+
+    void Canvas::fill(Color color)
+    {
+        u8* p = ptr;
+        for (int i = 0; i < height; i++)
+        {
+            u32* colorp = (u32*)p;
+            for (int j = 0; j < width; j++)
+            {
+                *colorp = color.raw;
+                colorp++;
+            }
+            p += stride * sizeof(Color);
+        }
+    }
+}
diff --git a/libui/src/Color.cpp b/libui/src/Color.cpp
new file mode 100644
index 00000000..e69de29b
diff --git a/libui/src/Rect.cpp b/libui/src/Rect.cpp
new file mode 100644
index 00000000..5d180eab
--- /dev/null
+++ b/libui/src/Rect.cpp
@@ -0,0 +1,18 @@
+#include <ui/Rect.h>
+
+namespace ui
+{
+    bool Rect::contains(Point point)
+    {
+        return point.x >= begin.x && point.y >= begin.y && point.x <= begin.x + width && point.y <= begin.y + height;
+    }
+
+    Point Rect::normalize(Point point)
+    {
+        if (point.x < begin.x) point.x = begin.x;
+        if (point.y < begin.y) point.y = begin.y;
+        if (point.x > begin.x + width) point.x = begin.x + width;
+        if (point.y > begin.y + height) point.y = begin.y + height;
+        return point;
+    }
+};
diff --git a/tools/install-headers.sh b/tools/install-headers.sh
index e7f919dd..999936d2 100755
--- a/tools/install-headers.sh
+++ b/tools/install-headers.sh
@@ -8,10 +8,12 @@ cd $LUNA_ROOT
 mkdir -p $LUNA_BASE
 mkdir -p $LUNA_BASE/usr/include
 mkdir -p $LUNA_BASE/usr/include/luna
+mkdir -p $LUNA_BASE/usr/include/ui
 mkdir -p $LUNA_BASE/usr/include/os
 mkdir -p $LUNA_BASE/usr/include/moon
 
 cp --preserve=timestamps -RT libc/include/ $LUNA_BASE/usr/include
 cp --preserve=timestamps -RT libluna/include/luna/ $LUNA_BASE/usr/include/luna
+cp --preserve=timestamps -RT libui/include/ui/ $LUNA_BASE/usr/include/ui
 cp --preserve=timestamps -RT libos/include/os/ $LUNA_BASE/usr/include/os
 cp --preserve=timestamps -RT kernel/src/api/ $LUNA_BASE/usr/include/moon
diff --git a/tools/sources.sh b/tools/sources.sh
index fcbd49e1..752d1883 100755
--- a/tools/sources.sh
+++ b/tools/sources.sh
@@ -4,7 +4,7 @@ source $(dirname $0)/env.sh
 
 cd $LUNA_ROOT
 
-FOLDERS=(kernel libc libos libluna apps shell tests)
+FOLDERS=(kernel libc libos libui libluna apps shell tests)
 
 SOURCES=($(find ${FOLDERS[@]} -type f -name "*.cpp"))
 SOURCES+=($(find ${FOLDERS[@]} -type f -name "*.h"))