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- // 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 "base/check.h"
- #include "ui/gfx/geometry/point.h"
- #include "ui/gfx/geometry/rect.h"
- #include "ui/gfx/geometry/vector2d.h"
- namespace chrome_pdf {
- 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;
- gfx::Rect PaintAggregator::InternalPaintUpdate::GetScrollDamage() const {
- // Should only be scrolling in one direction at a time.
- DCHECK(!(scroll_delta.x() && scroll_delta.y()));
- gfx::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 gfx::IntersectRects(scroll_rect, 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;
- gfx::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<PaintReadyRect>& ready,
- const std::vector<gfx::Rect>& pending) {
- update_.ready_rects.insert(update_.ready_rects.end(), ready.begin(),
- ready.end());
- update_.paint_rects = pending;
- }
- std::vector<PaintReadyRect> PaintAggregator::GetReadyRects() const {
- return update_.ready_rects;
- }
- void PaintAggregator::InvalidateRect(const gfx::Rect& rect) {
- InvalidateRectInternal(rect, true);
- }
- void PaintAggregator::ScrollRect(const gfx::Rect& clip_rect,
- const gfx::Vector2d& 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 == gfx::Vector2d()) {
- update_.scroll_rect = gfx::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<gfx::Rect> leftover_rects;
- for (size_t i = 0; i < update_.paint_rects.size(); ++i) {
- if (!update_.scroll_rect.Intersects(update_.paint_rects[i]))
- continue;
- gfx::Rect intersection =
- gfx::IntersectRects(update_.paint_rects[i], update_.scroll_rect);
- gfx::Rect rect = update_.paint_rects[i];
- while (!rect.IsEmpty()) {
- gfx::Rect leftover = gfx::SubtractRects(rect, 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.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.set_rect(ScrollPaintRect(update_rect.rect(), amount));
- }
- if (update_.synthesized_scroll_damage_rect_) {
- InvalidateRect(update_.GetScrollDamage());
- }
- }
- gfx::Rect PaintAggregator::ScrollPaintRect(const gfx::Rect& paint_rect,
- const gfx::Vector2d& amount) const {
- gfx::Rect result = paint_rect + amount;
- result.Intersect(update_.scroll_rect);
- return result;
- }
- void PaintAggregator::InvalidateScrollRect() {
- gfx::Rect scroll_rect = update_.scroll_rect;
- update_.scroll_rect = gfx::Rect();
- update_.scroll_delta = gfx::Vector2d();
- InvalidateRect(scroll_rect);
- }
- void PaintAggregator::InvalidateRectInternal(const gfx::Rect& rect_old,
- bool check_scroll) {
- gfx::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 gfx::Rect& existing_rect = update_.ready_rects[i].rect();
- if (rect.Intersects(existing_rect)) {
- // Re-invalidate in case the union intersects other paint rects.
- rect.Union(existing_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 gfx::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.
- gfx::Rect combined_rect = gfx::UnionRects(rect, existing_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);
- }
- }
- } // namespace chrome_pdf
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