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
  11 namespace mozilla {
  12 namespace a11y {
  13
  14 /* LocalAccessible for supporting images
  15  * supports:
  16  * - gets name, role
  17  * - support basic state
  18  */
  19 class ImageAccessible : public LinkableAccessible {
  20  public:
  21   ImageAccessible(nsIContent* aContent, DocAccessible* aDoc);
  22
  23   // LocalAccessible
  24   virtual a11y::role NativeRole() const override;
  25   virtual uint64_t NativeState() const override;
  26   virtual already_AddRefed<nsIPersistentProperties> NativeAttributes() override;
  27
  28   // ActionAccessible
  29   virtual uint8_t ActionCount() const override;
  30   virtual void ActionNameAt(uint8_t aIndex, nsAString& aName) override;
  31   virtual bool DoAction(uint8_t aIndex) const override;
  32
  33   // ImageAccessible
  34   nsIntPoint Position(uint32_t aCoordType);
  35   nsIntSize Size();
  36
  37  protected:
  38   virtual ~ImageAccessible();
  39
  40   // LocalAccessible
  41   virtual ENameValueFlag NativeName(nsString& aName) const override;
  42
  43  private:
  44   /**
  45    * Return whether the element has a longdesc URI.
  46    */
  47   bool HasLongDesc() const {
  48     nsCOMPtr<nsIURI> uri = GetLongDescURI();
  49     return uri;
  50   }
  51
  52   /**
  53    * Return an URI for showlongdesc action if any.
  54    */
  55   already_AddRefed<nsIURI> GetLongDescURI() const;
  56
  57   /**
  58    * Used by ActionNameAt and DoAction to ensure the index for opening the
  59    * longdesc URL is valid.
  60    * It is always assumed that the highest possible index opens the longdesc.
  61    * This doesn't check that there is actually a longdesc, just that the index
  62    * would be correct if there was one.
  63    *
  64    * @param aIndex  The 0-based index to be tested.
  65    *
  66    * @returns  true if index is valid for longdesc action.
  67    */
  68   inline bool IsLongDescIndex(uint8_t aIndex) const;
  69 };
  70
  71 ////////////////////////////////////////////////////////////////////////////////
  72 // LocalAccessible downcasting method
  73
  74 inline ImageAccessible* LocalAccessible::AsImage() {
  75   return IsImage() ? static_cast<ImageAccessible*>(this) : nullptr;
  76 }
  77
  78 }  // namespace a11y
  79 }  // namespace mozilla
  80
  81 #endif