layout/forms/nsSelectsAreaFrame.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6 #include "nsSelectsAreaFrame.h"
   7
   8 #include "mozilla/PresShell.h"
   9 #include "nsIContent.h"
  10 #include "nsListControlFrame.h"
  11 #include "nsDisplayList.h"
  12 #include "WritingModes.h"
  13
  14 using namespace mozilla;
  15
  16 nsContainerFrame* NS_NewSelectsAreaFrame(PresShell* aShell,
  17                                          ComputedStyle* aStyle) {
  18   nsSelectsAreaFrame* it =
  19       new (aShell) nsSelectsAreaFrame(aStyle, aShell->GetPresContext());
  20
  21   // We need NS_BLOCK_STATIC_BFC to ensure that the options inside the select
  22   // aren't expanded by right floats outside the select.
  23   it->AddStateBits(NS_BLOCK_STATIC_BFC);
  24
  25   return it;
  26 }
  27
  28 NS_IMPL_FRAMEARENA_HELPERS(nsSelectsAreaFrame)
  29
  30 static nsListControlFrame* GetEnclosingListFrame(nsIFrame* aSelectsAreaFrame) {
  31   nsIFrame* frame = aSelectsAreaFrame->GetParent();
  32   while (frame) {
  33     if (frame->IsListControlFrame())
  34       return static_cast<nsListControlFrame*>(frame);
  35     frame = frame->GetParent();
  36   }
  37   return nullptr;
  38 }
  39
  40 void nsSelectsAreaFrame::Reflow(nsPresContext* aPresContext,
  41                                 ReflowOutput& aDesiredSize,
  42                                 const ReflowInput& aReflowInput,
  43                                 nsReflowStatus& aStatus) {
  44   MOZ_ASSERT(aStatus.IsEmpty(), "Caller should pass a fresh reflow status!");
  45
  46   nsListControlFrame* list = GetEnclosingListFrame(this);
  47   NS_ASSERTION(list,
  48                "Must have an nsListControlFrame!  Frame constructor is "
  49                "broken");
  50
  51   nsBlockFrame::Reflow(aPresContext, aDesiredSize, aReflowInput, aStatus);
  52
  53   // Check whether we need to suppress scrollbar updates.  We want to do
  54   // that if we're in a possible first pass and our block size of a row
  55   // has changed.
  56   if (list->MightNeedSecondPass()) {
  57     nscoord newBSizeOfARow = list->CalcBSizeOfARow();
  58     // We'll need a second pass if our block size of a row changed.  For
  59     // comboboxes, we'll also need it if our block size changed.  If
  60     // we're going to do a second pass, suppress scrollbar updates for
  61     // this pass.
  62     if (newBSizeOfARow != mBSizeOfARow) {
  63       mBSizeOfARow = newBSizeOfARow;
  64       list->SetSuppressScrollbarUpdate(true);
  65     }
  66   }
  67 }
  68
  69 namespace mozilla {
  70 /**
  71  * This wrapper class lets us redirect mouse hits from the child frame of
  72  * an option element to the element's own frame.
  73  * REVIEW: This is what nsSelectsAreaFrame::GetFrameForPoint used to do
  74  */
  75 class nsDisplayOptionEventGrabber : public nsDisplayWrapList {
  76  public:
  77   nsDisplayOptionEventGrabber(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame,
  78                               nsDisplayItem* aItem)
  79       : nsDisplayWrapList(aBuilder, aFrame, aItem) {}
  80   nsDisplayOptionEventGrabber(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame,
  81                               nsDisplayList* aList)
  82       : nsDisplayWrapList(aBuilder, aFrame, aList) {}
  83   virtual void HitTest(nsDisplayListBuilder* aBuilder, const nsRect& aRect,
  84                        HitTestState* aState,
  85                        nsTArray<nsIFrame*>* aOutFrames) override;
  86   virtual bool ShouldFlattenAway(nsDisplayListBuilder* aBuilder) override {
  87     return false;
  88   }
  89   void Paint(nsDisplayListBuilder* aBuilder, gfxContext* aCtx) override {
  90     GetChildren()->Paint(aBuilder, aCtx,
  91                          mFrame->PresContext()->AppUnitsPerDevPixel());
  92   }
  93   NS_DISPLAY_DECL_NAME("OptionEventGrabber", TYPE_OPTION_EVENT_GRABBER)
  94 };
  95
  96 void nsDisplayOptionEventGrabber::HitTest(nsDisplayListBuilder* aBuilder,
  97                                           const nsRect& aRect,
  98                                           HitTestState* aState,
  99                                           nsTArray<nsIFrame*>* aOutFrames) {
 100   nsTArray<nsIFrame*> outFrames;
 101   mList.HitTest(aBuilder, aRect, aState, &outFrames);
 102
 103   for (uint32_t i = 0; i < outFrames.Length(); i++) {
 104     nsIFrame* selectedFrame = outFrames.ElementAt(i);
 105     while (selectedFrame &&
 106            !(selectedFrame->GetContent() &&
 107              selectedFrame->GetContent()->IsHTMLElement(nsGkAtoms::option))) {
 108       selectedFrame = selectedFrame->GetParent();
 109     }
 110     if (selectedFrame) {
 111       aOutFrames->AppendElement(selectedFrame);
 112     } else {
 113       // keep the original result, which could be this frame
 114       aOutFrames->AppendElement(outFrames.ElementAt(i));
 115     }
 116   }
 117 }
 118
 119 class nsOptionEventGrabberWrapper : public nsDisplayItemWrapper {
 120  public:
 121   nsOptionEventGrabberWrapper() = default;
 122   virtual nsDisplayItem* WrapList(nsDisplayListBuilder* aBuilder,
 123                                   nsIFrame* aFrame,
 124                                   nsDisplayList* aList) override {
 125     return MakeDisplayItem<nsDisplayOptionEventGrabber>(aBuilder, aFrame,
 126                                                         aList);
 127   }
 128   virtual nsDisplayItem* WrapItem(nsDisplayListBuilder* aBuilder,
 129                                   nsDisplayItem* aItem) override {
 130     return MakeDisplayItem<nsDisplayOptionEventGrabber>(aBuilder,
 131                                                         aItem->Frame(), aItem);
 132   }
 133 };
 134
 135 class nsDisplayListFocus : public nsPaintedDisplayItem {
 136  public:
 137   nsDisplayListFocus(nsDisplayListBuilder* aBuilder, nsSelectsAreaFrame* aFrame)
 138       : nsPaintedDisplayItem(aBuilder, aFrame) {
 139     MOZ_COUNT_CTOR(nsDisplayListFocus);
 140   }
 141   MOZ_COUNTED_DTOR_OVERRIDE(nsDisplayListFocus)
 142
 143   virtual nsRect GetBounds(nsDisplayListBuilder* aBuilder,
 144                            bool* aSnap) const override {
 145     *aSnap = false;
 146     // override bounds because the list item focus ring may extend outside
 147     // the nsSelectsAreaFrame
 148     nsListControlFrame* listFrame = GetEnclosingListFrame(Frame());
 149     return listFrame->InkOverflowRectRelativeToSelf() +
 150            listFrame->GetOffsetToCrossDoc(Frame()) + ToReferenceFrame();
 151   }
 152   virtual void Paint(nsDisplayListBuilder* aBuilder,
 153                      gfxContext* aCtx) override {
 154     nsListControlFrame* listFrame = GetEnclosingListFrame(Frame());
 155     // listFrame must be non-null or we wouldn't get called.
 156     listFrame->PaintFocus(
 157         aCtx->GetDrawTarget(),
 158         listFrame->GetOffsetToCrossDoc(Frame()) + ToReferenceFrame());
 159   }
 160   NS_DISPLAY_DECL_NAME("ListFocus", TYPE_LIST_FOCUS)
 161 };
 162
 163 }  // namespace mozilla
 164
 165 void nsSelectsAreaFrame::BuildDisplayList(nsDisplayListBuilder* aBuilder,
 166                                           const nsDisplayListSet& aLists) {
 167   if (!aBuilder->IsForEventDelivery()) {
 168     BuildDisplayListInternal(aBuilder, aLists);
 169     return;
 170   }
 171
 172   nsDisplayListCollection set(aBuilder);
 173   BuildDisplayListInternal(aBuilder, set);
 174
 175   nsOptionEventGrabberWrapper wrapper;
 176   wrapper.WrapLists(aBuilder, this, set, aLists);
 177 }
 178
 179 void nsSelectsAreaFrame::BuildDisplayListInternal(
 180     nsDisplayListBuilder* aBuilder, const nsDisplayListSet& aLists) {
 181   nsBlockFrame::BuildDisplayList(aBuilder, aLists);
 182
 183   nsListControlFrame* listFrame = GetEnclosingListFrame(this);
 184   if (listFrame && listFrame->IsFocused()) {
 185     // we can't just associate the display item with the list frame,
 186     // because then the list's scrollframe won't clip it (the scrollframe
 187     // only clips contained descendants).
 188     aLists.Outlines()->AppendNewToTop<nsDisplayListFocus>(aBuilder, this);
 189   }
 190 }