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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 "base/logging.h"
#include "chrome/common/transport_dib.h"
#include "skia/ext/platform_canvas.h"
#include "skia/include/SkBitmap.h"
#include "skia/include/SkCanvas.h"
BackingStore::BackingStore(const gfx::Size& size)
: size_(size) {
if (!canvas_.initialize(size.width(), size.height(), true))
SK_CRASH();
}
BackingStore::~BackingStore() {
}
void BackingStore::PaintRect(base::ProcessHandle process,
TransportDIB* bitmap,
const gfx::Rect& bitmap_rect) {
SkBitmap skbitmap;
skbitmap.setConfig(SkBitmap::kARGB_8888_Config, bitmap_rect.width(),
bitmap_rect.height(), 4 * bitmap_rect.width());
skbitmap.setPixels(bitmap->memory());
canvas_.drawBitmap(skbitmap, bitmap_rect.x(), bitmap_rect.y());
}
void BackingStore::ScrollRect(base::ProcessHandle process,
TransportDIB* bitmap,
const gfx::Rect& bitmap_rect,
int dx, int dy,
const gfx::Rect& clip_rect,
const gfx::Size& view_size) {
// WARNING: this is temporary code until a real solution is found for Mac and
// Linux.
//
// On Windows, there's a ScrollDC call which performs horiz and vertical
// scrolling
//
// clip_rect: MSDN says "The only bits that will be painted are the
// bits that remain inside this rectangle after the scroll operation has been
// completed."
//
// The Windows code always sets the whole backing store as the source of the
// scroll. Thus, we only have to worry about pixels which will end up inside
// the clipping rectangle. (Note that the clipping rectangle is not
// translated by the scroll.)
// We only support scrolling in one direction at a time.
DCHECK(dx == 0 || dy == 0);
// We assume |clip_rect| is contained within the backing store.
DCHECK(clip_rect.bottom() <= canvas_.getDevice()->height());
DCHECK(clip_rect.right() <= canvas_.getDevice()->width());
const SkBitmap &backing_bitmap = canvas_.getDevice()->accessBitmap(true);
const int stride = backing_bitmap.rowBytes();
uint8_t* x = static_cast<uint8_t*>(backing_bitmap.getPixels());
if (dx) {
// Horizontal scroll. According to msdn, positive values of |dx| scroll
// left, but in practice this seems reversed. TODO(port): figure this
// out. For now just reverse the sign.
dx *= -1;
// This is the number of bytes to move per line at 4 bytes per pixel.
const int len = (clip_rect.width() - abs(dx)) * 4;
// Move |x| to the first pixel of the first row.
x += clip_rect.y() * stride;
x += clip_rect.x() * 4;
// If we are scrolling left, move |x| to the |dx|^th pixel.
if (dx < 0) {
x -= dx * 4;
}
for (int i = clip_rect.y(); i < clip_rect.bottom(); ++i) {
// Note that overlapping regions requires memmove, not memcpy.
memmove(x, x + dx * 4, len);
x += stride;
}
} else {
// Vertical scroll. According to msdn, positive values of |dy| scroll down,
// but in practice this seems reversed. TODO(port): figure this out. For now
// just reverse the sign.
dy *= -1;
const int len = clip_rect.width() * 4;
// For down scrolls, we copy bottom-up (in screen coordinates).
// For up scrolls, we copy top-down.
if (dy > 0) {
// Move |x| to the first pixel of this row.
x += clip_rect.x() * 4;
for (int i = clip_rect.y(); i < clip_rect.height() - dy; ++i) {
memcpy(x, x + stride * dy, len);
x += stride;
}
} else {
// Move |x| to the first pixel of the last row of the clip rect.
x += clip_rect.x() * 4;
x += (clip_rect.bottom() - 1) * stride;
for (int i = clip_rect.y(); i < clip_rect.height() + dy; ++i) {
memcpy(x, x + stride * dy, len);
x -= stride;
}
}
}
// Now paint the new bitmap data.
PaintRect(process, bitmap, bitmap_rect);
return;
}
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