/* * Copyright (C) 2006, 2007, 2008 Apple Inc. All rights reserved. * * Portions are Copyright (C) 1998 Netscape Communications Corporation. * * Other contributors: * Robert O'Callahan * David Baron * Christian Biesinger * Randall Jesup * Roland Mainz * Josh Soref * Boris Zbarsky * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA * * Alternatively, the contents of this file may be used under the terms * of either the Mozilla Public License Version 1.1, found at * http://www.mozilla.org/MPL/ (the "MPL") or the GNU General Public * License Version 2.0, found at http://www.fsf.org/copyleft/gpl.html * (the "GPL"), in which case the provisions of the MPL or the GPL are * applicable instead of those above. If you wish to allow use of your * version of this file only under the terms of one of those two * licenses (the MPL or the GPL) and not to allow others to use your * version of this file under the LGPL, indicate your decision by * deletingthe provisions above and replace them with the notice and * other provisions required by the MPL or the GPL, as the case may be. * If you do not delete the provisions above, a recipient may use your * version of this file under any of the LGPL, the MPL or the GPL. */ #include "third_party/blink/renderer/core/scroll/scroll_alignment.h" #include "third_party/blink/renderer/core/layout/geometry/physical_rect.h" namespace blink { // static ScrollOffset ScrollAlignment::GetScrollOffsetToExpose( const PhysicalRect& scroll_snapport_rect, const PhysicalRect& expose_rect, const mojom::blink::ScrollAlignment& align_x, const mojom::blink::ScrollAlignment& align_y, const ScrollOffset& current_scroll_offset) { // Prevent degenerate cases by giving the visible rect a minimum non-0 size. PhysicalRect non_zero_visible_rect = scroll_snapport_rect; LayoutUnit minimum_layout_unit; minimum_layout_unit.SetRawValue(1); if (non_zero_visible_rect.Width() == LayoutUnit()) non_zero_visible_rect.SetWidth(minimum_layout_unit); if (non_zero_visible_rect.Height() == LayoutUnit()) non_zero_visible_rect.SetHeight(minimum_layout_unit); // Determine the appropriate X behavior. mojom::blink::ScrollAlignment::Behavior scroll_x; PhysicalRect expose_rect_x(expose_rect.X(), non_zero_visible_rect.Y(), expose_rect.Width(), non_zero_visible_rect.Height()); LayoutUnit intersect_width = Intersection(non_zero_visible_rect, expose_rect_x).Width(); if (intersect_width == expose_rect.Width()) { // If the rectangle is fully visible, use the specified visible behavior. // If the rectangle is partially visible, but over a certain threshold, // then treat it as fully visible to avoid unnecessary horizontal scrolling scroll_x = align_x.rect_visible; } else if (intersect_width == non_zero_visible_rect.Width()) { // If the rect is bigger than the visible area, don't bother trying to // center. Other alignments will work. scroll_x = align_x.rect_visible; if (scroll_x == mojom::blink::ScrollAlignment::Behavior::kCenter) scroll_x = mojom::blink::ScrollAlignment::Behavior::kNoScroll; } else if (intersect_width > 0) { // If the rectangle is partially visible, but not above the minimum // threshold, use the specified partial behavior scroll_x = align_x.rect_partial; } else { scroll_x = align_x.rect_hidden; } if (scroll_x == mojom::blink::ScrollAlignment::Behavior::kClosestEdge) { // Closest edge is the right in two cases: // (1) exposeRect to the right of and smaller than nonZeroVisibleRect // (2) exposeRect to the left of and larger than nonZeroVisibleRect if ((expose_rect.Right() > non_zero_visible_rect.Right() && expose_rect.Width() < non_zero_visible_rect.Width()) || (expose_rect.Right() < non_zero_visible_rect.Right() && expose_rect.Width() > non_zero_visible_rect.Width())) { scroll_x = mojom::blink::ScrollAlignment::Behavior::kRight; } } // Determine the appropriate Y behavior. mojom::blink::ScrollAlignment::Behavior scroll_y; PhysicalRect expose_rect_y(non_zero_visible_rect.X(), expose_rect.Y(), non_zero_visible_rect.Width(), expose_rect.Height()); LayoutUnit intersect_height = Intersection(non_zero_visible_rect, expose_rect_y).Height(); if (intersect_height == expose_rect.Height()) { // If the rectangle is fully visible, use the specified visible behavior. scroll_y = align_y.rect_visible; } else if (intersect_height == non_zero_visible_rect.Height()) { // If the rect is bigger than the visible area, don't bother trying to // center. Other alignments will work. scroll_y = align_y.rect_visible; if (scroll_y == mojom::blink::ScrollAlignment::Behavior::kCenter) scroll_y = mojom::blink::ScrollAlignment::Behavior::kNoScroll; } else if (intersect_height > 0) { // If the rectangle is partially visible, use the specified partial behavior scroll_y = align_y.rect_partial; } else { scroll_y = align_y.rect_hidden; } if (scroll_y == mojom::blink::ScrollAlignment::Behavior::kClosestEdge) { // Closest edge is the bottom in two cases: // (1) exposeRect below and smaller than nonZeroVisibleRect // (2) exposeRect above and larger than nonZeroVisibleRect if ((expose_rect.Bottom() > non_zero_visible_rect.Bottom() && expose_rect.Height() < non_zero_visible_rect.Height()) || (expose_rect.Bottom() < non_zero_visible_rect.Bottom() && expose_rect.Height() > non_zero_visible_rect.Height())) { scroll_y = mojom::blink::ScrollAlignment::Behavior::kBottom; } } // We would like calculate the ScrollPosition to move |expose_rect| inside // the scroll_snapport, which is based on the scroll_origin of the scroller. non_zero_visible_rect.Move( -PhysicalOffset::FromFloatSizeRound(current_scroll_offset)); // Given the X behavior, compute the X coordinate. float x; if (scroll_x == mojom::blink::ScrollAlignment::Behavior::kNoScroll) { x = current_scroll_offset.Width(); } else if (scroll_x == mojom::blink::ScrollAlignment::Behavior::kRight) { x = (expose_rect.Right() - non_zero_visible_rect.Right()).ToFloat(); } else if (scroll_x == mojom::blink::ScrollAlignment::Behavior::kCenter) { x = ((expose_rect.X() + expose_rect.Right() - (non_zero_visible_rect.X() + non_zero_visible_rect.Right())) / 2) .ToFloat(); } else { x = (expose_rect.X() - non_zero_visible_rect.X()).ToFloat(); } // Given the Y behavior, compute the Y coordinate. float y; if (scroll_y == mojom::blink::ScrollAlignment::Behavior::kNoScroll) { y = current_scroll_offset.Height(); } else if (scroll_y == mojom::blink::ScrollAlignment::Behavior::kBottom) { y = (expose_rect.Bottom() - non_zero_visible_rect.Bottom()).ToFloat(); } else if (scroll_y == mojom::blink::ScrollAlignment::Behavior::kCenter) { y = ((expose_rect.Y() + expose_rect.Bottom() - (non_zero_visible_rect.Y() + non_zero_visible_rect.Bottom())) / 2) .ToFloat(); } else { y = (expose_rect.Y() - non_zero_visible_rect.Y()).ToFloat(); } return ScrollOffset(x, y); } // static const mojom::blink::ScrollAlignment& ScrollAlignment::CenterIfNeeded() { DEFINE_STATIC_LOCAL(const mojom::blink::ScrollAlignment, g_scroll_align_center_if_needed, (mojom::blink::ScrollAlignment::Behavior::kNoScroll, mojom::blink::ScrollAlignment::Behavior::kCenter, mojom::blink::ScrollAlignment::Behavior::kClosestEdge)); return g_scroll_align_center_if_needed; } // static const mojom::blink::ScrollAlignment& ScrollAlignment::ToEdgeIfNeeded() { DEFINE_STATIC_LOCAL(const mojom::blink::ScrollAlignment, g_scroll_align_to_edge_if_needed, (mojom::blink::ScrollAlignment::Behavior::kNoScroll, mojom::blink::ScrollAlignment::Behavior::kClosestEdge, mojom::blink::ScrollAlignment::Behavior::kClosestEdge)); return g_scroll_align_to_edge_if_needed; } // static const mojom::blink::ScrollAlignment& ScrollAlignment::CenterAlways() { DEFINE_STATIC_LOCAL(const mojom::blink::ScrollAlignment, g_scroll_align_center_always, (mojom::blink::ScrollAlignment::Behavior::kCenter, mojom::blink::ScrollAlignment::Behavior::kCenter, mojom::blink::ScrollAlignment::Behavior::kCenter)); return g_scroll_align_center_always; } // static const mojom::blink::ScrollAlignment& ScrollAlignment::TopAlways() { DEFINE_STATIC_LOCAL(const mojom::blink::ScrollAlignment, g_scroll_align_top_always, (mojom::blink::ScrollAlignment::Behavior::kTop, mojom::blink::ScrollAlignment::Behavior::kTop, mojom::blink::ScrollAlignment::Behavior::kTop)); return g_scroll_align_top_always; } // static const mojom::blink::ScrollAlignment& ScrollAlignment::BottomAlways() { DEFINE_STATIC_LOCAL(const mojom::blink::ScrollAlignment, g_scroll_align_bottom_always, (mojom::blink::ScrollAlignment::Behavior::kBottom, mojom::blink::ScrollAlignment::Behavior::kBottom, mojom::blink::ScrollAlignment::Behavior::kBottom)); return g_scroll_align_bottom_always; } // static const mojom::blink::ScrollAlignment& ScrollAlignment::LeftAlways() { DEFINE_STATIC_LOCAL(const mojom::blink::ScrollAlignment, g_scroll_align_left_always, (mojom::blink::ScrollAlignment::Behavior::kLeft, mojom::blink::ScrollAlignment::Behavior::kLeft, mojom::blink::ScrollAlignment::Behavior::kLeft)); return g_scroll_align_left_always; } // static const mojom::blink::ScrollAlignment& ScrollAlignment::RightAlways() { DEFINE_STATIC_LOCAL(const mojom::blink::ScrollAlignment, g_scroll_align_right_always, (mojom::blink::ScrollAlignment::Behavior::kRight, mojom::blink::ScrollAlignment::Behavior::kRight, mojom::blink::ScrollAlignment::Behavior::kRight)); return g_scroll_align_right_always; } // static mojom::blink::ScrollIntoViewParamsPtr ScrollAlignment::CreateScrollIntoViewParams( const mojom::blink::ScrollAlignment& align_x, const mojom::blink::ScrollAlignment& align_y, mojom::blink::ScrollType scroll_type, bool make_visible_in_visual_viewport, mojom::blink::ScrollBehavior scroll_behavior, bool is_for_scroll_sequence, bool zoom_into_rect) { auto params = mojom::blink::ScrollIntoViewParams::New(); params->align_x = mojom::blink::ScrollAlignment::New(align_x); params->align_y = mojom::blink::ScrollAlignment::New(align_y); params->type = scroll_type; params->make_visible_in_visual_viewport = make_visible_in_visual_viewport; params->behavior = scroll_behavior; params->is_for_scroll_sequence = is_for_scroll_sequence; params->zoom_into_rect = zoom_into_rect; return params; } } // namespace blink