Make sure all GraphicsBitmap scanlines are 16-byte aligned.

This is a prerequisite for some optimizations.

5 files changed, 29 insertions, 24 deletions

diff --git a/AK/StdLibExtras.h b/AK/StdLibExtras.h
index 6a282b98ab..d090ad861d 100644
--- a/AK/StdLibExtras.h
+++ b/AK/StdLibExtras.h
@@ -41,6 +41,11 @@ extern "C" void* mmx_memcpy(void* to, const void* from, size_t);
     );
 }
 
+inline constexpr dword round_up_to_power_of_two(dword value, dword power_of_two)
+{
+    return ((value - 1) & ~ (power_of_two - 1)) + power_of_two;
+}
+
 namespace AK {
 
 template<typename T>
diff --git a/LibGUI/GWindow.cpp b/LibGUI/GWindow.cpp
index 1dff4f2f74..3d301952f2 100644
--- a/LibGUI/GWindow.cpp
+++ b/LibGUI/GWindow.cpp
@@ -473,7 +473,8 @@ Retained<GraphicsBitmap> GWindow::create_backing_bitmap(const Size& size)
 {
     ASSERT(GEventLoop::server_pid());
     ASSERT(!size.is_empty());
-    size_t size_in_bytes = size.area() * sizeof(RGBA32);
+    size_t pitch = round_up_to_power_of_two(size.width() * sizeof(RGBA32), 16);
+    size_t size_in_bytes = size.height() * pitch;
     auto shared_buffer = SharedBuffer::create(GEventLoop::server_pid(), size_in_bytes);
     ASSERT(shared_buffer);
     auto format = m_has_alpha_channel ? GraphicsBitmap::Format::RGBA32 : GraphicsBitmap::Format::RGB32;
diff --git a/SharedGraphics/GraphicsBitmap.cpp b/SharedGraphics/GraphicsBitmap.cpp
index 160d39762f..d6c9feaf6d 100644
--- a/SharedGraphics/GraphicsBitmap.cpp
+++ b/SharedGraphics/GraphicsBitmap.cpp
@@ -14,11 +14,10 @@ Retained<GraphicsBitmap> GraphicsBitmap::create(Format format, const Size& size)
 
 GraphicsBitmap::GraphicsBitmap(Format format, const Size& size)
     : m_size(size)
-    , m_pitch(size.width() * sizeof(RGBA32))
+    , m_pitch(round_up_to_power_of_two(size.width() * sizeof(RGBA32), 16))
     , m_format(format)
 {
-    size_t size_in_bytes = size.area() * sizeof(RGBA32);
-    m_data = (RGBA32*)mmap(nullptr, size_in_bytes, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
+    m_data = (RGBA32*)mmap(nullptr, size_in_bytes(), PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
     ASSERT(m_data && m_data != (void*)-1);
     m_needs_munmap = true;
     set_mmap_name(String::format("GraphicsBitmap [%dx%d]", width(), height()).characters());
@@ -45,7 +44,7 @@ RetainPtr<GraphicsBitmap> GraphicsBitmap::load_from_file(Format format, const St
 GraphicsBitmap::GraphicsBitmap(Format format, const Size& size, RGBA32* data)
     : m_size(size)
     , m_data(data)
-    , m_pitch(size.width() * sizeof(RGBA32))
+    , m_pitch(round_up_to_power_of_two(size.width() * sizeof(RGBA32), 16))
     , m_format(format)
 {
 }
@@ -53,7 +52,7 @@ GraphicsBitmap::GraphicsBitmap(Format format, const Size& size, RGBA32* data)
 GraphicsBitmap::GraphicsBitmap(Format format, const Size& size, MappedFile&& mapped_file)
     : m_size(size)
     , m_data((RGBA32*)mapped_file.pointer())
-    , m_pitch(size.width() * sizeof(RGBA32))
+    , m_pitch(round_up_to_power_of_two(size.width() * sizeof(RGBA32), 16))
     , m_format(format)
     , m_mapped_file(move(mapped_file))
 {
@@ -67,7 +66,7 @@ Retained<GraphicsBitmap> GraphicsBitmap::create_with_shared_buffer(Format format
 GraphicsBitmap::GraphicsBitmap(Format format, Retained<SharedBuffer>&& shared_buffer, const Size& size)
     : m_size(size)
     , m_data((RGBA32*)shared_buffer->data())
-    , m_pitch(size.width() * sizeof(RGBA32))
+    , m_pitch(round_up_to_power_of_two(size.width() * sizeof(RGBA32), 16))
     , m_format(format)
     , m_shared_buffer(move(shared_buffer))
 {
@@ -76,8 +75,7 @@ GraphicsBitmap::GraphicsBitmap(Format format, Retained<SharedBuffer>&& shared_bu
 GraphicsBitmap::~GraphicsBitmap()
 {
     if (m_needs_munmap) {
-        size_t size_in_bytes = m_size.area() * sizeof(RGBA32);
-        int rc = munmap(m_data, size_in_bytes);
+        int rc = munmap(m_data, size_in_bytes());
         ASSERT(rc == 0);
     }
     m_data = nullptr;
@@ -86,6 +84,5 @@ GraphicsBitmap::~GraphicsBitmap()
 void GraphicsBitmap::set_mmap_name(const String& name)
 {
     ASSERT(m_needs_munmap);
-    size_t size_in_bytes = m_size.area() * sizeof(RGBA32);
-    ::set_mmap_name(m_data, size_in_bytes, name.characters());
+    ::set_mmap_name(m_data, size_in_bytes(), name.characters());
 }
diff --git a/SharedGraphics/GraphicsBitmap.h b/SharedGraphics/GraphicsBitmap.h
index ba7f3fd667..de8630bdf9 100644
--- a/SharedGraphics/GraphicsBitmap.h
+++ b/SharedGraphics/GraphicsBitmap.h
@@ -35,6 +35,8 @@ public:
 
     void set_mmap_name(const String&);
 
+    size_t size_in_bytes() const { return m_pitch * m_size.height() * sizeof(RGBA32); }
+
 private:
     GraphicsBitmap(Format, const Size&);
     GraphicsBitmap(Format, const Size&, RGBA32*);
diff --git a/SharedGraphics/Painter.cpp b/SharedGraphics/Painter.cpp
index 356a6585a4..32fe9ab1a1 100644
--- a/SharedGraphics/Painter.cpp
+++ b/SharedGraphics/Painter.cpp
@@ -29,7 +29,7 @@ void Painter::fill_rect_with_draw_op(const Rect& a_rect, Color color)
         return;
 
     RGBA32* dst = m_target->scanline(rect.top()) + rect.left();
-    const unsigned dst_skip = m_target->width();
+    const size_t dst_skip = m_target->pitch() / sizeof(RGBA32);
 
     for (int i = rect.height() - 1; i >= 0; --i) {
         for (int j = 0; j < rect.width(); ++j)
@@ -52,7 +52,7 @@ void Painter::fill_rect(const Rect& a_rect, Color color)
     ASSERT(m_target->rect().contains(rect));
 
     RGBA32* dst = m_target->scanline(rect.top()) + rect.left();
-    const unsigned dst_skip = m_target->width();
+    const size_t dst_skip = m_target->pitch() / sizeof(RGBA32);
 
     for (int i = rect.height() - 1; i >= 0; --i) {
         fast_dword_fill(dst, color.value(), rect.width());
@@ -73,7 +73,7 @@ void Painter::fill_rect_with_gradient(const Rect& a_rect, Color gradient_start,
     int x_offset = clipped_rect.x() - rect.x();
 
     RGBA32* dst = m_target->scanline(clipped_rect.top()) + clipped_rect.left();
-    const unsigned dst_skip = m_target->width();
+    const size_t dst_skip = m_target->pitch() / sizeof(RGBA32);
 
     float increment = (1.0/((rect.width())/255.0));
 
@@ -153,7 +153,7 @@ void Painter::draw_bitmap(const Point& p, const CharacterBitmap& bitmap, Color c
     const int first_column = clipped_rect.left() - rect.left();
     const int last_column = clipped_rect.right() - rect.left();
     RGBA32* dst = m_target->scanline(clipped_rect.y()) + clipped_rect.x();
-    const size_t dst_skip = m_target->width();
+    const size_t dst_skip = m_target->pitch() / sizeof(RGBA32);
     const char* bitmap_row = &bitmap.bits()[first_row * bitmap.width() + first_column];
     const size_t bitmap_skip = bitmap.width();
 
@@ -179,7 +179,7 @@ void Painter::draw_bitmap(const Point& p, const GlyphBitmap& bitmap, Color color
     const int first_column = clipped_rect.left() - dst_rect.left();
     const int last_column = clipped_rect.right() - dst_rect.left();
     RGBA32* dst = m_target->scanline(clipped_rect.y()) + clipped_rect.x();
-    const size_t dst_skip = m_target->width();
+    const size_t dst_skip = m_target->pitch() / sizeof(RGBA32);
 
     for (int row = first_row; row <= last_row; ++row) {
         for (int j = 0; j <= (last_column - first_column); ++j) {
@@ -213,8 +213,8 @@ void Painter::blit_with_opacity(const Point& position, const GraphicsBitmap& sou
     const int last_column = clipped_rect.right() - dst_rect.left();
     RGBA32* dst = m_target->scanline(clipped_rect.y()) + clipped_rect.x();
     const RGBA32* src = source.scanline(src_rect.top() + first_row) + src_rect.left() + first_column;
-    const size_t dst_skip = m_target->width();
-    const unsigned src_skip = source.width();
+    const size_t dst_skip = m_target->pitch() / sizeof(RGBA32);
+    const unsigned src_skip = source.pitch() / sizeof(RGBA32);
 
     for (int row = first_row; row <= last_row; ++row) {
         for (int x = 0; x <= (last_column - first_column); ++x) {
@@ -241,8 +241,8 @@ void Painter::blit_dimmed(const Point& position, const GraphicsBitmap& source, c
     const int last_column = clipped_rect.right() - dst_rect.left();
     RGBA32* dst = m_target->scanline(clipped_rect.y()) + clipped_rect.x();
     const RGBA32* src = source.scanline(src_rect.top() + first_row) + src_rect.left() + first_column;
-    const size_t dst_skip = m_target->width();
-    const unsigned src_skip = source.width();
+    const size_t dst_skip = m_target->pitch() / sizeof(RGBA32);
+    const size_t src_skip = source.pitch() / sizeof(RGBA32);
 
     for (int row = first_row; row <= last_row; ++row) {
         for (int x = 0; x <= (last_column - first_column); ++x) {
@@ -274,8 +274,8 @@ void Painter::blit_with_alpha(const Point& position, const GraphicsBitmap& sourc
     const int last_column = clipped_rect.right() - dst_rect.left();
     RGBA32* dst = m_target->scanline(clipped_rect.y()) + clipped_rect.x();
     const RGBA32* src = source.scanline(src_rect.top() + first_row) + src_rect.left() + first_column;
-    const size_t dst_skip = m_target->width();
-    const unsigned src_skip = source.width();
+    const size_t dst_skip = m_target->pitch() / sizeof(RGBA32);
+    const size_t src_skip = source.pitch() / sizeof(RGBA32);
 
     for (int row = first_row; row <= last_row; ++row) {
         for (int x = 0; x <= (last_column - first_column); ++x) {
@@ -309,8 +309,8 @@ void Painter::blit(const Point& position, const GraphicsBitmap& source, const Re
     const int first_column = clipped_rect.left() - dst_rect.left();
     RGBA32* dst = m_target->scanline(clipped_rect.y()) + clipped_rect.x();
     const RGBA32* src = source.scanline(src_rect.top() + first_row) + src_rect.left() + first_column;
-    const size_t dst_skip = m_target->width();
-    const unsigned src_skip = source.width();
+    const size_t dst_skip = m_target->pitch() / sizeof(RGBA32);
+    const size_t src_skip = source.pitch() / sizeof(RGBA32);
 
     for (int row = first_row; row <= last_row; ++row) {
         fast_dword_copy(dst, src, clipped_rect.width());