accessible/generic/ImageAccessible.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef mozilla_a11y_ImageAccessible_h__
   7 #define mozilla_a11y_ImageAccessible_h__
   8
   9 #include "BaseAccessibles.h"
  10 #include "imgINotificationObserver.h"
  11
  12 namespace mozilla {
  13 namespace a11y {
  14
  15 /* LocalAccessible for supporting images
  16  * supports:
  17  * - gets name, role
  18  * - support basic state
  19  */
  20 class ImageAccessible : public LinkableAccessible,
  21                         public imgINotificationObserver {
  22  public:
  23   ImageAccessible(nsIContent* aContent, DocAccessible* aDoc);
  24
  25   NS_DECL_ISUPPORTS_INHERITED
  26   NS_DECL_IMGINOTIFICATIONOBSERVER
  27
  28   // LocalAccessible
  29   virtual void Shutdown() override;
  30   virtual a11y::role NativeRole() const override;
  31   virtual uint64_t NativeState() const override;
  32   virtual already_AddRefed<AccAttributes> NativeAttributes() override;
  33
  34   // ActionAccessible
  35   virtual uint8_t ActionCount() const override;
  36   virtual void ActionNameAt(uint8_t aIndex, nsAString& aName) override;
  37   virtual bool DoAction(uint8_t aIndex) const override;
  38
  39   // ImageAccessible
  40   LayoutDeviceIntPoint Position(uint32_t aCoordType);
  41   LayoutDeviceIntSize Size();
  42
  43   /**
  44    * Return whether the element has a longdesc URI.
  45    */
  46   bool HasLongDesc() const {
  47     nsCOMPtr<nsIURI> uri = GetLongDescURI();
  48     return uri;
  49   }
  50
  51  protected:
  52   virtual ~ImageAccessible();
  53
  54   // LocalAccessible
  55   virtual ENameValueFlag NativeName(nsString& aName) const override;
  56
  57   virtual void DOMAttributeChanged(int32_t aNameSpaceID, nsAtom* aAttribute,
  58                                    int32_t aModType,
  59                                    const nsAttrValue* aOldValue,
  60                                    uint64_t aOldState) override;
  61
  62  private:
  63   /**
  64    * Return an URI for showlongdesc action if any.
  65    */
  66   already_AddRefed<nsIURI> GetLongDescURI() const;
  67
  68   /**
  69    * Used by ActionNameAt and DoAction to ensure the index for opening the
  70    * longdesc URL is valid.
  71    * It is always assumed that the highest possible index opens the longdesc.
  72    * This doesn't check that there is actually a longdesc, just that the index
  73    * would be correct if there was one.
  74    *
  75    * @param aIndex  The 0-based index to be tested.
  76    *
  77    * @returns  true if index is valid for longdesc action.
  78    */
  79   inline bool IsLongDescIndex(uint8_t aIndex) const;
  80
  81   uint32_t mImageRequestStatus;
  82 };
  83
  84 ////////////////////////////////////////////////////////////////////////////////
  85 // LocalAccessible downcasting method
  86
  87 inline ImageAccessible* LocalAccessible::AsImage() {
  88   return IsImage() ? static_cast<ImageAccessible*>(this) : nullptr;
  89 }
  90
  91 }  // namespace a11y
  92 }  // namespace mozilla
  93
  94 #endif