Improve cmd::CopyRegion() performance

Here we replace std::stringstream with a base::buffer (std::vector<uint8_t>)
and pre-allocating the required size.

src/app/CMakeLists.txt

@@ -575,6 +575,7 @@ add_library(app-lib
   transformation.cpp
   ui/layer_frame_comboboxes.cpp
   util/autocrop.cpp
+  util/buffer_region.cpp
   util/create_cel_copy.cpp
   util/expand_cel_canvas.cpp
   util/filetoks.cpp

src/app/cmd/copy_region.cpp

@@ -1,4 +1,5 @@
 // Aseprite
+// Copyright (C) 2019  Igara Studio S.A.
 // Copyright (C) 2001-2016  David Capello
 //
 // This program is distributed under the terms of
@@ -10,10 +11,9 @@
 
 #include "app/cmd/copy_region.h"
 
+#include "app/util/buffer_region.h"
 #include "doc/image.h"
 
-#include <algorithm>
-
 namespace app {
 namespace cmd {
 
@@ -22,7 +22,6 @@ CopyRegion::CopyRegion(Image* dst, const Image* src,
                        const gfx::Point& dstPos,
                        bool alreadyCopied)
   : WithImage(dst)
-  , m_size(0)
   , m_alreadyCopied(alreadyCopied)
 {
   // Create region to save/swap later
@@ -38,16 +37,7 @@ CopyRegion::CopyRegion(Image* dst, const Image* src,
     m_region.createUnion(m_region, gfx::Region(clip.dstBounds()));
   }
 
-  // Save region pixels
-  for (const auto& rc : m_region) {
-    for (int y=0; y<rc.h; ++y) {
-      m_stream.write(
-        (const char*)src->getPixelAddress(rc.x-dstPos.x,
-                                          rc.y-dstPos.y+y),
-        src->getRowStrideSize(rc.w));
-    }
-  }
-  m_size = size_t(m_stream.tellp());
+  save_image_region_in_buffer(m_region, src, dstPos, m_buffer);
 }
 
 void CopyRegion::onExecute()
@@ -69,29 +59,7 @@ void CopyRegion::onRedo()
 void CopyRegion::swap()
 {
   Image* image = this->image();
-
-  // Save current image region in "tmp" stream
-  std::stringstream tmp;
-  for (const auto& rc : m_region)
-    for (int y=0; y<rc.h; ++y)
-      tmp.write(
-        (const char*)image->getPixelAddress(rc.x, rc.y+y),
-        image->getRowStrideSize(rc.w));
-
-  // Restore m_stream into the image
-  m_stream.seekg(0, std::ios_base::beg);
-  for (const auto& rc : m_region) {
-    for (int y=0; y<rc.h; ++y) {
-      m_stream.read(
-        (char*)image->getPixelAddress(rc.x, rc.y+y),
-        image->getRowStrideSize(rc.w));
-    }
-  }
-
-  // TODO use m_stream.swap(tmp) when clang and gcc support it
-  m_stream.str(tmp.str());
-  m_stream.clear();
-
+  swap_image_region_with_buffer(m_region, image, m_buffer);
   image->incrementVersion();
 }
 

src/app/cmd/copy_region.h

@@ -1,4 +1,5 @@
 // Aseprite
+// Copyright (C) 2019  Igara Studio S.A.
 // Copyright (C) 2001-2016  David Capello
 //
 // This program is distributed under the terms of
@@ -10,11 +11,10 @@
 
 #include "app/cmd.h"
 #include "app/cmd/with_image.h"
+#include "base/buffer.h"
 #include "gfx/point.h"
 #include "gfx/region.h"
 
-#include <sstream>
-
 namespace app {
 namespace cmd {
   using namespace doc;
@@ -36,16 +36,15 @@ namespace cmd {
     void onUndo() override;
     void onRedo() override;
     size_t onMemSize() const override {
-      return sizeof(*this) + m_size;
+      return sizeof(*this) + m_buffer.size();
     }
 
   private:
     void swap();
 
-    size_t m_size;
     bool m_alreadyCopied;
     gfx::Region m_region;
-    std::stringstream m_stream;
+    base::buffer m_buffer;
   };
 
 } // namespace cmd

src/app/util/buffer_region.cpp

@@ -0,0 +1,63 @@
+// Aseprite
+// Copyright (C) 2019  Igara Studio S.A.
+//
+// This program is distributed under the terms of
+// the End-User License Agreement for Aseprite.
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/util/buffer_region.h"
+
+#include "doc/image.h"
+#include "gfx/region.h"
+
+#include <algorithm>
+
+namespace app {
+
+void save_image_region_in_buffer(
+  const gfx::Region& region,
+  const doc::Image* image,
+  const gfx::Point& imagePos,
+  base::buffer& buffer)
+{
+  // Calculate buffer size for the region
+  const size_t bytesPerPixel = image->getRowStrideSize(1);
+  size_t reqBytes = 0;
+  for (const auto& rc : region)
+    reqBytes += bytesPerPixel*rc.w*rc.h;
+
+  // Save region pixels
+  buffer.resize(reqBytes);
+  auto it = buffer.begin();
+  for (const auto& rc : region) {
+    for (int y=0; y<rc.h; ++y) {
+      auto p = (const uint8_t*)image->getPixelAddress(rc.x-imagePos.x,
+                                                      rc.y-imagePos.y+y);
+      const size_t rowBytes = bytesPerPixel*rc.w;
+      std::copy(p, p+rowBytes, it);
+      it += rowBytes;
+    }
+  }
+}
+
+void swap_image_region_with_buffer(
+  const gfx::Region& region,
+  doc::Image* image,
+  base::buffer& buffer)
+{
+  const size_t bytesPerPixel = image->getRowStrideSize(1);
+  auto it = buffer.begin();
+  for (const auto& rc : region) {
+    for (int y=0; y<rc.h; ++y) {
+      auto p = (uint8_t*)image->getPixelAddress(rc.x, rc.y+y);
+      const size_t rowBytes = bytesPerPixel*rc.w;
+      std::swap_ranges(it, it+rowBytes, p);
+      it += rowBytes;
+    }
+  }
+}
+
+} // namespace app

src/app/util/buffer_region.h

@@ -0,0 +1,33 @@
+// Aseprite
+// Copyright (C) 2019  Igara Studio S.A.
+//
+// This program is distributed under the terms of
+// the End-User License Agreement for Aseprite.
+
+#ifndef APP_UTIL_BUFFER_REGION_H_INCLUDED
+#define APP_UTIL_BUFFER_REGION_H_INCLUDED
+#pragma once
+
+#include "base/buffer.h"
+#include "gfx/fwd.h"
+
+namespace doc {
+  class Image;
+}
+
+namespace app {
+
+  void save_image_region_in_buffer(
+    const gfx::Region& region,
+    const doc::Image* image,
+    const gfx::Point& imagePos,
+    base::buffer& buffer);
+
+  void swap_image_region_with_buffer(
+    const gfx::Region& region,
+    doc::Image* image,
+    base::buffer& buffer);
+
+} // namespace app
+
+#endif