From dcbddb4f8cfc73b0e101d30a5f417fa635c53d33 Mon Sep 17 00:00:00 2001
From: Andreas Kling <awesomekling@gmail.com>
Date: Sat, 15 Jun 2019 11:06:02 +0200
Subject: [PATCH] GraphicsBitmap: Provide templated versions of get_pixel() and
 set_pixel().

If we already know the bitmap format used, we can use these functions to
bypass the format checks and go straight to pixel manipulation.
---
 Applications/PaintBrush/BucketTool.cpp |  6 +-
 SharedGraphics/GraphicsBitmap.h        | 92 +++++++++++++++++++-------
 2 files changed, 73 insertions(+), 25 deletions(-)

diff --git a/Applications/PaintBrush/BucketTool.cpp b/Applications/PaintBrush/BucketTool.cpp
index e3fdad5e16..c2b6353418 100644
--- a/Applications/PaintBrush/BucketTool.cpp
+++ b/Applications/PaintBrush/BucketTool.cpp
@@ -16,14 +16,16 @@ BucketTool::~BucketTool()
 
 static void flood_fill(GraphicsBitmap& bitmap, const Point& start_position, Color target_color, Color fill_color)
 {
+    ASSERT(bitmap.format() == GraphicsBitmap::Format::RGB32);
+
     Queue<Point> queue;
     queue.enqueue(Point(start_position));
     while (!queue.is_empty()) {
         auto position = queue.dequeue();
 
-        if (bitmap.get_pixel(position) != target_color)
+        if (bitmap.get_pixel<GraphicsBitmap::Format::RGB32>(position.x(), position.y()) != target_color)
             continue;
-        bitmap.set_pixel(position, fill_color);
+        bitmap.set_pixel<GraphicsBitmap::Format::RGB32>(position.x(), position.y(), fill_color);
 
         if (position.x() != 0)
             queue.enqueue(position.translated(-1, 0));
diff --git a/SharedGraphics/GraphicsBitmap.h b/SharedGraphics/GraphicsBitmap.h
index c73dca70dd..162517de2e 100644
--- a/SharedGraphics/GraphicsBitmap.h
+++ b/SharedGraphics/GraphicsBitmap.h
@@ -51,41 +51,27 @@ public:
     Color palette_color(byte index) const { return Color::from_rgba(m_palette[index]); }
     void set_palette_color(byte index, Color color) { m_palette[index] = color.value(); }
 
+    template<Format>
     Color get_pixel(int x, int y) const
     {
-        switch (m_format) {
-        case Format::RGB32:
-            return Color::from_rgb(scanline(y)[x]);
-        case Format::RGBA32:
-            return Color::from_rgba(scanline(y)[x]);
-        case Format::Indexed8:
-            return Color::from_rgba(m_palette[bits(y)[x]]);
-        default:
-            ASSERT_NOT_REACHED();
-        }
+        ASSERT_NOT_REACHED();
     }
 
+    Color get_pixel(int x, int y) const;
+
     Color get_pixel(const Point& position) const
     {
         return get_pixel(position.x(), position.y());
     }
 
-    void set_pixel(int x, int y, Color color)
+    template<Format>
+    void set_pixel(int x, int y, Color)
     {
-        switch (m_format) {
-        case Format::RGB32:
-            scanline(y)[x] = color.value();
-            break;
-        case Format::RGBA32:
-            scanline(y)[x] = color.value();
-            break;
-        case Format::Indexed8:
-            ASSERT_NOT_REACHED();
-        default:
-            ASSERT_NOT_REACHED();
-        }
+        ASSERT_NOT_REACHED();
     }
 
+    void set_pixel(int x, int y, Color);
+
     void set_pixel(const Point& position, Color color)
     {
         set_pixel(position.x(), position.y(), color);
@@ -126,3 +112,63 @@ inline byte* GraphicsBitmap::bits(int y)
 {
     return reinterpret_cast<byte*>(scanline(y));
 }
+
+template<>
+inline Color GraphicsBitmap::get_pixel<GraphicsBitmap::Format::RGB32>(int x, int y) const
+{
+    return Color::from_rgb(scanline(y)[x]);
+}
+
+template<>
+inline Color GraphicsBitmap::get_pixel<GraphicsBitmap::Format::RGBA32>(int x, int y) const
+{
+    return Color::from_rgba(scanline(y)[x]);
+}
+
+template<>
+inline Color GraphicsBitmap::get_pixel<GraphicsBitmap::Format::Indexed8>(int x, int y) const
+{
+    return Color::from_rgba(m_palette[bits(y)[x]]);
+}
+
+inline Color GraphicsBitmap::get_pixel(int x, int y) const
+{
+    switch (m_format) {
+    case Format::RGB32:
+        return get_pixel<Format::RGB32>(x, y);
+    case Format::RGBA32:
+        return get_pixel<Format::RGBA32>(x, y);
+    case Format::Indexed8:
+        return get_pixel<Format::Indexed8>(x, y);
+    default:
+        ASSERT_NOT_REACHED();
+    }
+}
+
+template<>
+inline void GraphicsBitmap::set_pixel<GraphicsBitmap::Format::RGB32>(int x, int y, Color color)
+{
+    scanline(y)[x] = color.value();
+}
+
+template<>
+inline void GraphicsBitmap::set_pixel<GraphicsBitmap::Format::RGBA32>(int x, int y, Color color)
+{
+    scanline(y)[x] = color.value();
+}
+
+inline void GraphicsBitmap::set_pixel(int x, int y, Color color)
+{
+    switch (m_format) {
+    case Format::RGB32:
+        set_pixel<Format::RGB32>(x, y, color);
+        break;
+    case Format::RGBA32:
+        set_pixel<Format::RGBA32>(x, y, color);
+        break;
+    case Format::Indexed8:
+        ASSERT_NOT_REACHED();
+    default:
+        ASSERT_NOT_REACHED();
+    }
+}