| // 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 <stddef.h> |
| #include <stdint.h> |
| |
| #include <algorithm> |
| |
| #include "base/check.h" |
| |
| namespace { |
| |
| bool IsNegative(int32_t num) { |
| return num < 0; |
| } |
| |
| } // namespace |
| |
| // ---------------------------------------------------------------------------- |
| // 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() = default; |
| |
| PaintAggregator::PaintUpdate::PaintUpdate(const PaintUpdate& that) = default; |
| |
| PaintAggregator::PaintUpdate::~PaintUpdate() = default; |
| |
| PaintAggregator::InternalPaintUpdate::InternalPaintUpdate() |
| : synthesized_scroll_damage_rect_(false) {} |
| |
| PaintAggregator::InternalPaintUpdate::~InternalPaintUpdate() = default; |
| |
| 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() = default; |
| |
| 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); |
| ret.paint_rects.insert(ret.paint_rects.end(), update_.paint_rects.begin(), |
| update_.paint_rects.end()); |
| |
| 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; |
| } |
| |
| // If we scroll in a reverse direction to the direction we originally scrolled |
| // and there were invalidations that happened in-between we may end up |
| // incorrectly clipping the invalidated rects (see crbug.com/488390). This bug |
| // doesn't exist in the original implementation |
| // (ppapi/utility/graphics/paint_aggregator.cc) which uses a different method |
| // of handling invalidations that occur after a scroll. The problem is that |
| // when we scroll the invalidated region, we clip it to the scroll rect. This |
| // can cause us to lose information about what the invalidated region was if |
| // it gets scrolled back into view. We either need to not do this clipping or |
| // disallow combining scrolls that occur in different directions with |
| // invalidations that happen in-between. This code really needs some tests... |
| if (!update_.paint_rects.empty()) { |
| if (IsNegative(amount.x()) != IsNegative(update_.scroll_delta.x()) || |
| IsNegative(amount.y()) != IsNegative(update_.scroll_delta.y())) { |
| 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 (const auto& leftover_rect : leftover_rects) |
| InvalidateRectInternal(leftover_rect, false); |
| |
| for (auto& update_rect : update_.ready_rects) { |
| if (update_.scroll_rect.Contains(update_rect.rect)) |
| update_rect.rect = ScrollPaintRect(update_rect.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); |
| } |
| } |