1 files changed, 263 insertions, 0 deletions
diff --git a/xfa_test/pdf/paint_aggregator.cc b/xfa_test/pdf/paint_aggregator.cc
new file mode 100644
index 0000000000..549cab6d09
--- /dev/null
+++ b/xfa_test/pdf/paint_aggregator.cc
@@ -0,0 +1,263 @@
+// Copyright (c) 2010 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 "pdf/paint_aggregator.h"
+
+#include <algorithm>
+
+#include "base/logging.h"
+
+// ----------------------------------------------------------------------------
+// ALGORITHM NOTES
+//
+// We attempt to maintain a scroll rect in the presence of invalidations that
+// are contained within the scroll rect.  If an invalidation crosses a scroll
+// rect, then we just treat the scroll rect as an invalidation rect.
+//
+// For invalidations performed prior to scrolling and contained within the
+// scroll rect, we offset the invalidation rects to account for the fact that
+// the consumer will perform scrolling before painting.
+//
+// We only support scrolling along one axis at a time.  A diagonal scroll will
+// therefore be treated as an invalidation.
+// ----------------------------------------------------------------------------
+
+PaintAggregator::PaintUpdate::PaintUpdate() {
+}
+
+PaintAggregator::PaintUpdate::~PaintUpdate() {
+}
+
+PaintAggregator::InternalPaintUpdate::InternalPaintUpdate() :
+    synthesized_scroll_damage_rect_(false) {
+}
+
+PaintAggregator::InternalPaintUpdate::~InternalPaintUpdate() {
+}
+
+pp::Rect PaintAggregator::InternalPaintUpdate::GetScrollDamage() const {
+  // Should only be scrolling in one direction at a time.
+  DCHECK(!(scroll_delta.x() && scroll_delta.y()));
+
+  pp::Rect damaged_rect;
+
+  // Compute the region we will expose by scrolling, and paint that into a
+  // shared memory section.
+  if (scroll_delta.x()) {
+    int32_t dx = scroll_delta.x();
+    damaged_rect.set_y(scroll_rect.y());
+    damaged_rect.set_height(scroll_rect.height());
+    if (dx > 0) {
+      damaged_rect.set_x(scroll_rect.x());
+      damaged_rect.set_width(dx);
+    } else {
+      damaged_rect.set_x(scroll_rect.right() + dx);
+      damaged_rect.set_width(-dx);
+    }
+  } else {
+    int32_t dy = scroll_delta.y();
+    damaged_rect.set_x(scroll_rect.x());
+    damaged_rect.set_width(scroll_rect.width());
+    if (dy > 0) {
+      damaged_rect.set_y(scroll_rect.y());
+      damaged_rect.set_height(dy);
+    } else {
+      damaged_rect.set_y(scroll_rect.bottom() + dy);
+      damaged_rect.set_height(-dy);
+    }
+  }
+
+  // In case the scroll offset exceeds the width/height of the scroll rect
+  return scroll_rect.Intersect(damaged_rect);
+}
+
+PaintAggregator::PaintAggregator() {
+}
+
+bool PaintAggregator::HasPendingUpdate() const {
+  return !update_.scroll_rect.IsEmpty() || !update_.paint_rects.empty();
+}
+
+void PaintAggregator::ClearPendingUpdate() {
+  update_ = InternalPaintUpdate();
+}
+
+PaintAggregator::PaintUpdate PaintAggregator::GetPendingUpdate() {
+  // Convert the internal paint update to the external one, which includes a
+  // bit more precomputed info for the caller.
+  PaintUpdate ret;
+  ret.scroll_delta = update_.scroll_delta;
+  ret.scroll_rect = update_.scroll_rect;
+  ret.has_scroll = ret.scroll_delta.x() != 0 || ret.scroll_delta.y() != 0;
+
+  // Include the scroll damage (if any) in the paint rects.
+  // Code invalidates damaged rect here, it pick it up from the list of paint
+  // rects in the next block.
+  if (ret.has_scroll  && !update_.synthesized_scroll_damage_rect_) {
+    update_.synthesized_scroll_damage_rect_ = true;
+    pp::Rect scroll_damage = update_.GetScrollDamage();
+    InvalidateRectInternal(scroll_damage, false);
+  }
+
+  ret.paint_rects.reserve(update_.paint_rects.size() + 1);
+  for (size_t i = 0; i < update_.paint_rects.size(); i++)
+    ret.paint_rects.push_back(update_.paint_rects[i]);
+
+  return ret;
+}
+
+void PaintAggregator::SetIntermediateResults(
+    const std::vector<ReadyRect>& ready,
+    const std::vector<pp::Rect>& pending) {
+  update_.ready_rects.insert(
+      update_.ready_rects.end(), ready.begin(), ready.end());
+  update_.paint_rects = pending;
+}
+
+std::vector<PaintAggregator::ReadyRect> PaintAggregator::GetReadyRects() const {
+  return update_.ready_rects;
+}
+
+void PaintAggregator::InvalidateRect(const pp::Rect& rect) {
+  InvalidateRectInternal(rect, true);
+}
+
+void PaintAggregator::ScrollRect(const pp::Rect& clip_rect,
+                                 const pp::Point& amount) {
+  // We only support scrolling along one axis at a time.
+  if (amount.x() != 0 && amount.y() != 0) {
+    InvalidateRect(clip_rect);
+    return;
+  }
+
+  // We can only scroll one rect at a time.
+  if (!update_.scroll_rect.IsEmpty() && update_.scroll_rect != clip_rect) {
+    InvalidateRect(clip_rect);
+    return;
+  }
+
+  // Again, we only support scrolling along one axis at a time.  Make sure this
+  // update doesn't scroll on a different axis than any existing one.
+  if ((amount.x() && update_.scroll_delta.y()) ||
+      (amount.y() && update_.scroll_delta.x())) {
+    InvalidateRect(clip_rect);
+    return;
+  }
+
+  // The scroll rect is new or isn't changing (though the scroll amount may
+  // be changing).
+  update_.scroll_rect = clip_rect;
+  update_.scroll_delta += amount;
+
+  // We might have just wiped out a pre-existing scroll.
+  if (update_.scroll_delta == pp::Point()) {
+    update_.scroll_rect = pp::Rect();
+    return;
+  }
+
+  // Adjust any paint rects that intersect the scroll. For the portion of the
+  // paint that is inside the scroll area, move it by the scroll amount and
+  // replace the existing paint with it. For the portion (if any) that is
+  // outside the scroll, just invalidate it.
+  std::vector<pp::Rect> leftover_rects;
+  for (size_t i = 0; i < update_.paint_rects.size(); ++i) {
+    if (!update_.scroll_rect.Intersects(update_.paint_rects[i]))
+      continue;
+
+    pp::Rect intersection =
+        update_.paint_rects[i].Intersect(update_.scroll_rect);
+    pp::Rect rect = update_.paint_rects[i];
+    while (!rect.IsEmpty()) {
+      pp::Rect leftover = rect.Subtract(intersection);
+      if (leftover.IsEmpty())
+        break;
+      // Don't want to call InvalidateRectInternal now since it'll modify
+      // update_.paint_rects, so keep track of this and do it below.
+      leftover_rects.push_back(leftover);
+      rect = rect.Subtract(leftover);
+    }
+
+    update_.paint_rects[i] = ScrollPaintRect(intersection, amount);
+
+    // The rect may have been scrolled out of view.
+    if (update_.paint_rects[i].IsEmpty()) {
+      update_.paint_rects.erase(update_.paint_rects.begin() + i);
+      i--;
+    }
+  }
+
+  for (size_t i = 0; i < leftover_rects.size(); ++i)
+    InvalidateRectInternal(leftover_rects[i], false);
+
+  for (size_t i = 0; i < update_.ready_rects.size(); ++i) {
+    if (update_.scroll_rect.Contains(update_.ready_rects[i].rect)) {
+      update_.ready_rects[i].rect =
+          ScrollPaintRect(update_.ready_rects[i].rect, amount);
+    }
+  }
+
+  if (update_.synthesized_scroll_damage_rect_) {
+    pp::Rect damage = update_.GetScrollDamage();
+    InvalidateRect(damage);
+  }
+}
+
+pp::Rect PaintAggregator::ScrollPaintRect(const pp::Rect& paint_rect,
+                                          const pp::Point& amount) const {
+  pp::Rect result = paint_rect;
+  result.Offset(amount);
+  result = update_.scroll_rect.Intersect(result);
+  return result;
+}
+
+void PaintAggregator::InvalidateScrollRect() {
+  pp::Rect scroll_rect = update_.scroll_rect;
+  update_.scroll_rect = pp::Rect();
+  update_.scroll_delta = pp::Point();
+  InvalidateRect(scroll_rect);
+}
+
+void PaintAggregator::InvalidateRectInternal(const pp::Rect& rect_old,
+                                             bool check_scroll) {
+  pp::Rect rect = rect_old;
+  // Check if any rects that are ready to be painted overlap.
+  for (size_t i = 0; i < update_.ready_rects.size(); ++i) {
+    const pp::Rect& existing_rect = update_.ready_rects[i].rect;
+    if (rect.Intersects(existing_rect)) {
+      // Re-invalidate in case the union intersects other paint rects.
+      rect = existing_rect.Union(rect);
+      update_.ready_rects.erase(update_.ready_rects.begin() + i);
+      break;
+    }
+  }
+
+  bool add_paint = true;
+
+  // Combine overlapping paints using smallest bounding box.
+  for (size_t i = 0; i < update_.paint_rects.size(); ++i) {
+    const pp::Rect& existing_rect = update_.paint_rects[i];
+    if (existing_rect.Contains(rect))  // Optimize out redundancy.
+      add_paint = false;
+    if (rect.Intersects(existing_rect) || rect.SharesEdgeWith(existing_rect)) {
+      // Re-invalidate in case the union intersects other paint rects.
+      pp::Rect combined_rect = existing_rect.Union(rect);
+      update_.paint_rects.erase(update_.paint_rects.begin() + i);
+      InvalidateRectInternal(combined_rect, check_scroll);
+      add_paint = false;
+    }
+  }
+
+  if (add_paint) {
+    // Add a non-overlapping paint.
+    update_.paint_rects.push_back(rect);
+  }
+
+  // If the new paint overlaps with a scroll, then also invalidate the rect in
+  // its new position.
+  if (check_scroll &&
+      !update_.scroll_rect.IsEmpty() &&
+      update_.scroll_rect.Intersects(rect)) {
+    InvalidateRectInternal(ScrollPaintRect(rect, update_.scroll_delta), false);
+  }
+}