layout/svg/SVGViewFrame.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
   7 // Keep in (case-insensitive) order:
   8 #include "mozilla/PresShell.h"
   9 #include "mozilla/SVGOuterSVGFrame.h"
  10 #include "mozilla/SVGUtils.h"
  11 #include "mozilla/dom/SVGSVGElement.h"
  12 #include "mozilla/dom/SVGViewElement.h"
  13 #include "nsIFrame.h"
  14 #include "nsGkAtoms.h"
  15
  16 using namespace mozilla::dom;
  17
  18 nsIFrame* NS_NewSVGViewFrame(mozilla::PresShell* aPresShell,
  19                              mozilla::ComputedStyle* aStyle);
  20
  21 namespace mozilla {
  22
  23 /**
  24  * While views are not directly rendered in SVG they can be linked to
  25  * and thereby override attributes of an <svg> element via a fragment
  26  * identifier. The SVGViewFrame class passes on any attribute changes
  27  * the view receives to the overridden <svg> element (if there is one).
  28  **/
  29 class SVGViewFrame final : public nsIFrame {
  30   friend nsIFrame* ::NS_NewSVGViewFrame(mozilla::PresShell* aPresShell,
  31                                         ComputedStyle* aStyle);
  32
  33  protected:
  34   explicit SVGViewFrame(ComputedStyle* aStyle, nsPresContext* aPresContext)
  35       : nsIFrame(aStyle, aPresContext, kClassID) {
  36     AddStateBits(NS_FRAME_SVG_LAYOUT | NS_FRAME_IS_NONDISPLAY);
  37   }
  38
  39  public:
  40   NS_DECL_FRAMEARENA_HELPERS(SVGViewFrame)
  41
  42 #ifdef DEBUG
  43   void Init(nsIContent* aContent, nsContainerFrame* aParent,
  44             nsIFrame* aPrevInFlow) override;
  45 #endif
  46
  47 #ifdef DEBUG_FRAME_DUMP
  48   nsresult GetFrameName(nsAString& aResult) const override {
  49     return MakeFrameName(u"SVGView"_ns, aResult);
  50   }
  51 #endif
  52
  53   nsresult AttributeChanged(int32_t aNameSpaceID, nsAtom* aAttribute,
  54                             int32_t aModType) override;
  55
  56   bool ComputeCustomOverflow(OverflowAreas& aOverflowAreas) override {
  57     // We don't maintain a ink overflow rect
  58     return false;
  59   }
  60 };
  61
  62 }  // namespace mozilla
  63
  64 nsIFrame* NS_NewSVGViewFrame(mozilla::PresShell* aPresShell,
  65                              mozilla::ComputedStyle* aStyle) {
  66   return new (aPresShell)
  67       mozilla::SVGViewFrame(aStyle, aPresShell->GetPresContext());
  68 }
  69
  70 namespace mozilla {
  71
  72 NS_IMPL_FRAMEARENA_HELPERS(SVGViewFrame)
  73
  74 #ifdef DEBUG
  75 void SVGViewFrame::Init(nsIContent* aContent, nsContainerFrame* aParent,
  76                         nsIFrame* aPrevInFlow) {
  77   NS_ASSERTION(aContent->IsSVGElement(nsGkAtoms::view),
  78                "Content is not an SVG view");
  79
  80   nsIFrame::Init(aContent, aParent, aPrevInFlow);
  81 }
  82 #endif /* DEBUG */
  83
  84 nsresult SVGViewFrame::AttributeChanged(int32_t aNameSpaceID,
  85                                         nsAtom* aAttribute, int32_t aModType) {
  86   // Ignore zoomAndPan as it does not cause the <svg> element to re-render
  87
  88   if (aNameSpaceID == kNameSpaceID_None &&
  89       (aAttribute == nsGkAtoms::preserveAspectRatio ||
  90        aAttribute == nsGkAtoms::viewBox)) {
  91     SVGOuterSVGFrame* outerSVGFrame = SVGUtils::GetOuterSVGFrame(this);
  92     NS_ASSERTION(outerSVGFrame->GetContent()->IsSVGElement(nsGkAtoms::svg),
  93                  "Expecting an <svg> element");
  94
  95     SVGSVGElement* svgElement =
  96         static_cast<SVGSVGElement*>(outerSVGFrame->GetContent());
  97
  98     nsAutoString viewID;
  99     mContent->AsElement()->GetAttr(nsGkAtoms::id, viewID);
 100
 101     if (svgElement->IsOverriddenBy(viewID)) {
 102       // We're the view that's providing overrides, so pretend that the frame
 103       // we're overriding was updated.
 104       outerSVGFrame->AttributeChanged(aNameSpaceID, aAttribute, aModType);
 105     }
 106   }
 107
 108   return nsIFrame::AttributeChanged(aNameSpaceID, aAttribute, aModType);
 109 }
 110
 111 }  // namespace mozilla