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// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "chrome/browser/renderer_host/backing_store.h"
#include "chrome/browser/renderer_host/render_widget_host.h"
#include "chrome/common/win_util.h"
#if defined(OS_WIN)
#include "base/gfx/gdi_util.h"
#endif
namespace {
typedef OwningMRUCache<RenderWidgetHost*, BackingStore*> BackingStoreCache;
static BackingStoreCache* cache = NULL;
// Returns the size of the backing store cache.
// TODO(iyengar) Make this dynamic, i.e. based on the available resources
// on the machine.
static int GetBackingStoreCacheSize() {
const int kMaxSize = 5;
return kMaxSize;
}
// Creates the backing store for the host based on the dimensions passed in.
// Removes the existing backing store if there is one.
BackingStore* CreateBackingStore(RenderWidgetHost* host,
const gfx::Rect& backing_store_rect) {
BackingStoreManager::RemoveBackingStore(host);
BackingStore* backing_store = new BackingStore(backing_store_rect.size());
int backing_store_cache_size = GetBackingStoreCacheSize();
if (backing_store_cache_size > 0) {
if (!cache)
cache = new BackingStoreCache(backing_store_cache_size);
cache->Put(host, backing_store);
}
return backing_store;
}
} // namespace
#if defined(OS_WIN)
// BackingStore (Windows) ------------------------------------------------------
BackingStore::BackingStore(const gfx::Size& size)
: size_(size),
backing_store_dib_(NULL),
original_bitmap_(NULL) {
HDC screen_dc = ::GetDC(NULL);
hdc_ = CreateCompatibleDC(screen_dc);
ReleaseDC(NULL, screen_dc);
}
BackingStore::~BackingStore() {
DCHECK(hdc_);
DeleteDC(hdc_);
if (backing_store_dib_) {
DeleteObject(backing_store_dib_);
backing_store_dib_ = NULL;
}
}
bool BackingStore::PaintRect(base::ProcessHandle process,
HANDLE bitmap_section,
const gfx::Rect& bitmap_rect) {
// The bitmap received is valid only in the renderer process.
HANDLE valid_bitmap =
win_util::GetSectionFromProcess(bitmap_section, process, false);
if (!valid_bitmap)
return false;
if (!backing_store_dib_) {
backing_store_dib_ = CreateDIB(hdc_, size_.width(), size_.height(), true,
NULL);
DCHECK(backing_store_dib_ != NULL);
original_bitmap_ = SelectObject(hdc_, backing_store_dib_);
}
// TODO(darin): protect against integer overflow
DWORD size = 4 * bitmap_rect.width() * bitmap_rect.height();
void* backing_store_data = MapViewOfFile(valid_bitmap, FILE_MAP_READ, 0, 0,
size);
// These values are shared with gfx::PlatformDevice
BITMAPINFOHEADER hdr;
gfx::CreateBitmapHeader(bitmap_rect.width(), bitmap_rect.height(), &hdr);
// Account for a bitmap_rect that exceeds the bounds of our view
gfx::Rect view_rect(0, 0, size_.width(), size_.height());
gfx::Rect paint_rect = view_rect.Intersect(bitmap_rect);
StretchDIBits(hdc_,
paint_rect.x(),
paint_rect.y(),
paint_rect.width(),
paint_rect.height(),
0, 0, // source x,y
paint_rect.width(),
paint_rect.height(),
backing_store_data,
reinterpret_cast<BITMAPINFO*>(&hdr),
DIB_RGB_COLORS,
SRCCOPY);
UnmapViewOfFile(backing_store_data);
CloseHandle(valid_bitmap);
return true;
}
void BackingStore::ScrollRect(base::ProcessHandle process,
HANDLE bitmap, const gfx::Rect& bitmap_rect,
int dx, int dy,
const gfx::Rect& clip_rect,
const gfx::Size& view_size) {
RECT damaged_rect, r = clip_rect.ToRECT();
ScrollDC(hdc_, dx, dy, NULL, &r, NULL, &damaged_rect);
// TODO(darin): this doesn't work if dx and dy are both non-zero!
DCHECK(dx == 0 || dy == 0);
// We expect that damaged_rect should equal bitmap_rect.
DCHECK(gfx::Rect(damaged_rect) == bitmap_rect);
PaintRect(process, bitmap, bitmap_rect);
}
HANDLE BackingStore::CreateDIB(HDC dc,
int width, int height,
bool use_system_color_depth,
HANDLE section) {
BITMAPINFOHEADER hdr;
if (use_system_color_depth) {
HDC screen_dc = ::GetDC(NULL);
int color_depth = GetDeviceCaps(screen_dc, BITSPIXEL);
::ReleaseDC(NULL, screen_dc);
// Color depths less than 16 bpp require a palette to be specified in the
// BITMAPINFO structure passed to CreateDIBSection. Instead of creating
// the palette, we specify the desired color depth as 16 which allows the
// OS to come up with an approximation. Tested this with 8bpp.
if (color_depth < 16)
color_depth = 16;
gfx::CreateBitmapHeaderWithColorDepth(width, height, color_depth, &hdr);
} else {
gfx::CreateBitmapHeader(width, height, &hdr);
}
void* data = NULL;
HANDLE dib =
CreateDIBSection(hdc_, reinterpret_cast<BITMAPINFO*>(&hdr),
0, &data, section, 0);
return dib;
}
#elif defined(OS_LINUX)
// BackingStore (Linux) --------------------------------------------------------
#elif defined(OS_MAC)
// BackingStore (Mac) ----------------------------------------------------------
#endif
// BackingStoreManager ---------------------------------------------------------
// static
BackingStore* BackingStoreManager::GetBackingStore(
RenderWidgetHost* host,
const gfx::Size& desired_size) {
BackingStore* backing_store = Lookup(host);
if (backing_store) {
// If we already have a backing store, then make sure it is the correct
// size.
if (backing_store->size() == desired_size)
return backing_store;
backing_store = NULL;
}
return backing_store;
}
// static
BackingStore* BackingStoreManager::PrepareBackingStore(
RenderWidgetHost* host,
const gfx::Rect& backing_store_rect,
HANDLE process_handle,
HANDLE bitmap_section,
const gfx::Rect& bitmap_rect,
bool* needs_full_paint) {
BackingStore* backing_store = GetBackingStore(host,
backing_store_rect.size());
if (!backing_store) {
// We need to get Webkit to generate a new paint here, as we
// don't have a previous snapshot.
if (bitmap_rect != backing_store_rect) {
DCHECK(needs_full_paint != NULL);
*needs_full_paint = true;
}
backing_store = CreateBackingStore(host, backing_store_rect);
}
DCHECK(backing_store != NULL);
backing_store->PaintRect(process_handle, bitmap_section, bitmap_rect);
return backing_store;
}
// static
BackingStore* BackingStoreManager::Lookup(RenderWidgetHost* host) {
if (cache) {
BackingStoreCache::iterator it = cache->Peek(host);
if (it != cache->end())
return it->second;
}
return NULL;
}
// static
void BackingStoreManager::RemoveBackingStore(RenderWidgetHost* host) {
if (!cache)
return;
BackingStoreCache::iterator it = cache->Peek(host);
if (it == cache->end())
return;
cache->Erase(it);
if (cache->empty()) {
delete cache;
cache = NULL;
}
}
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