| /* |
| * Copyright (C) 2006, 2007, 2008 Apple Inc. All rights reserved. |
| * |
| * Portions are Copyright (C) 1998 Netscape Communications Corporation. |
| * |
| * Other contributors: |
| * Robert O'Callahan <roc+@cs.cmu.edu> |
| * David Baron <dbaron@dbaron.org> |
| * Christian Biesinger <cbiesinger@web.de> |
| * Randall Jesup <rjesup@wgate.com> |
| * Roland Mainz <roland.mainz@informatik.med.uni-giessen.de> |
| * Josh Soref <timeless@mac.com> |
| * Boris Zbarsky <bzbarsky@mit.edu> |
| * |
| * 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/public/mojom/scroll/scroll_into_view_params.mojom-blink.h" |
| #include "third_party/blink/renderer/bindings/core/v8/v8_scroll_into_view_options.h" |
| #include "third_party/blink/renderer/core/layout/geometry/physical_rect.h" |
| #include "third_party/blink/renderer/core/style/computed_style.h" |
| #include "third_party/blink/renderer/platform/text/writing_mode.h" |
| |
| namespace blink { |
| |
| // static |
| ScrollOffset ScrollAlignment::GetScrollOffsetToExpose( |
| const PhysicalRect& scroll_snapport_rect, |
| const PhysicalRect& expose_rect, |
| const PhysicalBoxStrut& expose_scroll_margin, |
| 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); |
| } |
| |
| // The expose_rect includes the scroll-margin of the element that is being |
| // exposed. |
| // We want to exclude the margin for deciding whether it's already visible, |
| // but include it when calculating the scroll offset that we need to scroll |
| // to in order to achieve the desired alignment. |
| PhysicalRect expose_rect_no_margin = expose_rect; |
| expose_rect_no_margin.Contract(expose_scroll_margin); |
| |
| // Determine the appropriate X behavior. |
| mojom::blink::ScrollAlignment::Behavior scroll_x; |
| PhysicalRect expose_rect_x( |
| expose_rect_no_margin.X(), non_zero_visible_rect.Y(), |
| expose_rect_no_margin.Width(), non_zero_visible_rect.Height()); |
| LayoutUnit intersect_width = |
| Intersection(non_zero_visible_rect, expose_rect_x).Width(); |
| if (intersect_width == expose_rect_no_margin.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()) { |
| // The rect is bigger than the visible area. |
| scroll_x = align_x.rect_visible; |
| } 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_no_margin.Y(), |
| non_zero_visible_rect.Width(), expose_rect_no_margin.Height()); |
| LayoutUnit intersect_height = |
| Intersection(non_zero_visible_rect, expose_rect_y).Height(); |
| if (intersect_height == expose_rect_no_margin.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()) { |
| // The rect is bigger than the visible area. |
| scroll_y = align_y.rect_visible; |
| } 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::FromVector2dFRound(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.x(); |
| } 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.y(); |
| } 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 cross_origin_boundaries) { |
| 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->cross_origin_boundaries = cross_origin_boundaries; |
| return params; |
| } |
| |
| namespace { |
| mojom::blink::ScrollAlignment AlignmentFromOptions( |
| const ScrollIntoViewOptions& options, |
| ScrollOrientation axis, |
| const ComputedStyle& computed_style) { |
| WritingMode writing_mode = computed_style.GetWritingMode(); |
| bool is_ltr = computed_style.IsLeftToRightDirection(); |
| |
| bool is_horizontal_writing_mode = IsHorizontalWritingMode(writing_mode); |
| String alignment = |
| ((axis == kHorizontalScroll && is_horizontal_writing_mode) || |
| (axis == kVerticalScroll && !is_horizontal_writing_mode)) |
| ? options.inlinePosition() |
| : options.block(); |
| |
| if (alignment == "center") |
| return ScrollAlignment::CenterAlways(); |
| if (alignment == "nearest") |
| return ScrollAlignment::ToEdgeIfNeeded(); |
| if (alignment == "start") { |
| if (axis == kHorizontalScroll) { |
| switch (writing_mode) { |
| case WritingMode::kHorizontalTb: |
| return is_ltr ? ScrollAlignment::LeftAlways() |
| : ScrollAlignment::RightAlways(); |
| case WritingMode::kVerticalRl: |
| case WritingMode::kSidewaysRl: |
| return ScrollAlignment::RightAlways(); |
| case WritingMode::kVerticalLr: |
| case WritingMode::kSidewaysLr: |
| return ScrollAlignment::LeftAlways(); |
| default: |
| NOTREACHED(); |
| return ScrollAlignment::LeftAlways(); |
| } |
| } else { |
| switch (writing_mode) { |
| case WritingMode::kHorizontalTb: |
| return ScrollAlignment::TopAlways(); |
| case WritingMode::kVerticalRl: |
| case WritingMode::kSidewaysRl: |
| case WritingMode::kVerticalLr: |
| return is_ltr ? ScrollAlignment::TopAlways() |
| : ScrollAlignment::BottomAlways(); |
| case WritingMode::kSidewaysLr: |
| return is_ltr ? ScrollAlignment::BottomAlways() |
| : ScrollAlignment::TopAlways(); |
| default: |
| NOTREACHED(); |
| return ScrollAlignment::TopAlways(); |
| } |
| } |
| } |
| if (alignment == "end") { |
| if (axis == kHorizontalScroll) { |
| switch (writing_mode) { |
| case WritingMode::kHorizontalTb: |
| return is_ltr ? ScrollAlignment::RightAlways() |
| : ScrollAlignment::LeftAlways(); |
| case WritingMode::kVerticalRl: |
| case WritingMode::kSidewaysRl: |
| return ScrollAlignment::LeftAlways(); |
| case WritingMode::kVerticalLr: |
| case WritingMode::kSidewaysLr: |
| return ScrollAlignment::RightAlways(); |
| default: |
| NOTREACHED(); |
| return ScrollAlignment::RightAlways(); |
| } |
| } else { |
| switch (writing_mode) { |
| case WritingMode::kHorizontalTb: |
| return ScrollAlignment::BottomAlways(); |
| case WritingMode::kVerticalRl: |
| case WritingMode::kSidewaysRl: |
| case WritingMode::kVerticalLr: |
| return is_ltr ? ScrollAlignment::BottomAlways() |
| : ScrollAlignment::TopAlways(); |
| case WritingMode::kSidewaysLr: |
| return is_ltr ? ScrollAlignment::TopAlways() |
| : ScrollAlignment::BottomAlways(); |
| default: |
| NOTREACHED(); |
| return ScrollAlignment::BottomAlways(); |
| } |
| } |
| } |
| |
| // Default values |
| if (is_horizontal_writing_mode) { |
| return (axis == kHorizontalScroll) ? ScrollAlignment::ToEdgeIfNeeded() |
| : ScrollAlignment::TopAlways(); |
| } |
| return (axis == kHorizontalScroll) ? ScrollAlignment::LeftAlways() |
| : ScrollAlignment::ToEdgeIfNeeded(); |
| } |
| } // namespace |
| |
| // static |
| mojom::blink::ScrollIntoViewParamsPtr |
| ScrollAlignment::CreateScrollIntoViewParams( |
| const ScrollIntoViewOptions& options, |
| const ComputedStyle& computed_style) { |
| mojom::blink::ScrollBehavior behavior = mojom::blink::ScrollBehavior::kAuto; |
| if (options.behavior() == "smooth") { |
| behavior = mojom::blink::ScrollBehavior::kSmooth; |
| } |
| if (options.behavior() == "instant") { |
| behavior = mojom::blink::ScrollBehavior::kInstant; |
| } |
| |
| auto align_x = |
| AlignmentFromOptions(options, kHorizontalScroll, computed_style); |
| auto align_y = AlignmentFromOptions(options, kVerticalScroll, computed_style); |
| |
| mojom::blink::ScrollIntoViewParamsPtr params = |
| ScrollAlignment::CreateScrollIntoViewParams(align_x, align_y); |
| params->behavior = behavior; |
| return params; |
| } |
| |
| } // namespace blink |
