accessible/src/msaa/nsTextAccessibleWrap.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* ***** BEGIN LICENSE BLOCK *****
   3  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   4  *
   5  * The contents of this file are subject to the Mozilla Public License Version
   6  * 1.1 (the "License"); you may not use this file except in compliance with
   7  * the License. You may obtain a copy of the License at
   8  * http://www.mozilla.org/MPL/
   9  *
  10  * Software distributed under the License is distributed on an "AS IS" basis,
  11  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  12  * for the specific language governing rights and limitations under the
  13  * License.
  14  *
  15  * The Original Code is mozilla.org code.
  16  *
  17  * The Initial Developer of the Original Code is
  18  * Netscape Corp.
  19  * Portions created by the Initial Developer are Copyright (C) 2003
  20  * the Initial Developer. All Rights Reserved.
  21  *
  22  * Contributor(s):
  23  *   Aaron Leventhal
  24  *
  25  * Alternatively, the contents of this file may be used under the terms of
  26  * either the GNU General Public License Version 2 or later (the "GPL"), or
  27  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  28  * in which case the provisions of the GPL or the LGPL are applicable instead
  29  * of those above. If you wish to allow use of your version of this file only
  30  * under the terms of either the GPL or the LGPL, and not to allow others to
  31  * use your version of this file under the terms of the MPL, indicate your
  32  * decision by deleting the provisions above and replace them with the notice
  33  * and other provisions required by the GPL or the LGPL. If you do not delete
  34  * the provisions above, a recipient may use your version of this file under
  35  * the terms of any one of the MPL, the GPL or the LGPL.
  36  *
  37  * ***** END LICENSE BLOCK ***** */
  38
  39 // NOTE: alphabetically ordered
  40 #include "nsTextAccessibleWrap.h"
  41 #include "ISimpleDOMText_i.c"
  42 #include "nsIAccessibleDocument.h"
  43 #include "nsIFontMetrics.h"
  44 #include "nsIFrame.h"
  45 #include "nsPresContext.h"
  46 #include "nsIPresShell.h"
  47 #include "nsIRenderingContext.h"
  48 #include "nsIWidget.h"
  49 #include "nsIComponentManager.h"
  50
  51 // --------------------------------------------------------
  52 // nsTextAccessibleWrap Accessible
  53 // --------------------------------------------------------
  54
  55 nsTextAccessibleWrap::nsTextAccessibleWrap(nsIDOMNode* aDOMNode, nsIWeakReference* aShell):
  56 nsTextAccessible(aDOMNode, aShell)
  57 {
  58 }
  59
  60 STDMETHODIMP_(ULONG) nsTextAccessibleWrap::AddRef()
  61 {
  62   return nsAccessNode::AddRef();
  63 }
  64
  65 STDMETHODIMP_(ULONG) nsTextAccessibleWrap::Release()
  66 {
  67   return nsAccessNode::Release();
  68 }
  69
  70 STDMETHODIMP nsTextAccessibleWrap::QueryInterface(REFIID iid, void** ppv)
  71 {
  72   *ppv = nsnull;
  73
  74   if (IID_IUnknown == iid || IID_ISimpleDOMText == iid)
  75     *ppv = static_cast<ISimpleDOMText*>(this);
  76
  77   if (nsnull == *ppv)
  78     return nsAccessibleWrap::QueryInterface(iid, ppv);
  79
  80   (reinterpret_cast<IUnknown*>(*ppv))->AddRef();
  81   return S_OK;
  82 }
  83
  84 STDMETHODIMP nsTextAccessibleWrap::get_domText(
  85     /* [retval][out] */ BSTR __RPC_FAR *aDomText)
  86 {
  87 __try {
  88   *aDomText = NULL;
  89
  90   if (!mDOMNode) {
  91     return E_FAIL; // Node already shut down
  92   }
  93   nsAutoString nodeValue;
  94
  95   mDOMNode->GetNodeValue(nodeValue);
  96   if (nodeValue.IsEmpty())
  97     return S_FALSE;
  98
  99   *aDomText = ::SysAllocStringLen(nodeValue.get(), nodeValue.Length());
 100   if (!*aDomText)
 101     return E_OUTOFMEMORY;
 102
 103 } __except(FilterA11yExceptions(::GetExceptionCode(), GetExceptionInformation())) { }
 104
 105   return S_OK;
 106 }
 107
 108 STDMETHODIMP nsTextAccessibleWrap::get_clippedSubstringBounds(
 109     /* [in] */ unsigned int aStartIndex,
 110     /* [in] */ unsigned int aEndIndex,
 111     /* [out] */ int __RPC_FAR *aX,
 112     /* [out] */ int __RPC_FAR *aY,
 113     /* [out] */ int __RPC_FAR *aWidth,
 114     /* [out] */ int __RPC_FAR *aHeight)
 115 {
 116 __try {
 117   *aX = *aY = *aWidth = *aHeight = 0;
 118   nscoord x, y, width, height, docX, docY, docWidth, docHeight;
 119   HRESULT rv = get_unclippedSubstringBounds(aStartIndex, aEndIndex, &x, &y, &width, &height);
 120   if (FAILED(rv)) {
 121     return rv;
 122   }
 123
 124   nsCOMPtr<nsIAccessibleDocument> docAccessible(GetDocAccessible());
 125   nsCOMPtr<nsIAccessible> accessible(do_QueryInterface(docAccessible));
 126   NS_ASSERTION(accessible, "There must always be a doc accessible, but there isn't");
 127
 128   accessible->GetBounds(&docX, &docY, &docWidth, &docHeight);
 129
 130   nsRect unclippedRect(x, y, width, height);
 131   nsRect docRect(docX, docY, docWidth, docHeight);
 132   nsRect clippedRect;
 133
 134   clippedRect.IntersectRect(unclippedRect, docRect);
 135
 136   *aX = clippedRect.x;
 137   *aY = clippedRect.y;
 138   *aWidth = clippedRect.width;
 139   *aHeight = clippedRect.height;
 140 } __except(FilterA11yExceptions(::GetExceptionCode(), GetExceptionInformation())) { }
 141
 142   return S_OK;
 143 }
 144
 145 STDMETHODIMP nsTextAccessibleWrap::get_unclippedSubstringBounds(
 146     /* [in] */ unsigned int aStartIndex,
 147     /* [in] */ unsigned int aEndIndex,
 148     /* [out] */ int __RPC_FAR *aX,
 149     /* [out] */ int __RPC_FAR *aY,
 150     /* [out] */ int __RPC_FAR *aWidth,
 151     /* [out] */ int __RPC_FAR *aHeight)
 152 {
 153 __try {
 154   *aX = *aY = *aWidth = *aHeight = 0;
 155
 156   if (!mDOMNode) {
 157     return E_FAIL; // Node already shut down
 158   }
 159
 160   if (NS_FAILED(GetCharacterExtents(aStartIndex, aEndIndex,
 161                                     aX, aY, aWidth, aHeight))) {
 162     return NS_ERROR_FAILURE;
 163   }
 164 } __except(FilterA11yExceptions(::GetExceptionCode(), GetExceptionInformation())) { }
 165
 166   return S_OK;
 167 }
 168
 169
 170 STDMETHODIMP nsTextAccessibleWrap::scrollToSubstring(
 171     /* [in] */ unsigned int aStartIndex,
 172     /* [in] */ unsigned int aEndIndex)
 173 {
 174 __try {
 175   nsresult rv = nsAccUtils::ScrollSubstringTo(GetFrame(), mDOMNode, aStartIndex,
 176                                               mDOMNode, aEndIndex,
 177                                               nsIAccessibleScrollType::SCROLL_TYPE_ANYWHERE);
 178   if (NS_FAILED(rv))
 179     return E_FAIL;
 180 } __except(FilterA11yExceptions(::GetExceptionCode(), GetExceptionInformation())) { }
 181   return S_OK;
 182 }
 183
 184 nsIFrame* nsTextAccessibleWrap::GetPointFromOffset(nsIFrame *aContainingFrame,
 185                                                    PRInt32 aOffset,
 186                                                    PRBool aPreferNext,
 187                                                    nsPoint& aOutPoint)
 188 {
 189   nsIFrame *textFrame = nsnull;
 190   PRInt32 outOffset;
 191   aContainingFrame->GetChildFrameContainingOffset(aOffset, aPreferNext, &outOffset, &textFrame);
 192   if (!textFrame) {
 193     return nsnull;
 194   }
 195
 196   textFrame->GetPointFromOffset(aOffset, &aOutPoint);
 197   return textFrame;
 198 }
 199
 200 /*
 201  * Given an offset, the x, y, width, and height values are filled appropriately.
 202  */
 203 nsresult nsTextAccessibleWrap::GetCharacterExtents(PRInt32 aStartOffset, PRInt32 aEndOffset,
 204                                                    PRInt32* aX, PRInt32* aY,
 205                                                    PRInt32* aWidth, PRInt32* aHeight)
 206 {
 207   *aX = *aY = *aWidth = *aHeight = 0;
 208   nsPresContext *presContext = GetPresContext();
 209   NS_ENSURE_TRUE(presContext, NS_ERROR_FAILURE);
 210
 211   nsIFrame *frame = GetFrame();
 212   NS_ENSURE_TRUE(frame, NS_ERROR_FAILURE);
 213
 214   nsIWidget *widget = frame->GetWindow();
 215   NS_ENSURE_TRUE(widget, NS_ERROR_FAILURE);
 216
 217   nsPoint startPoint, endPoint;
 218   nsIFrame *startFrame = GetPointFromOffset(frame, aStartOffset, PR_TRUE, startPoint);
 219   nsIFrame *endFrame = GetPointFromOffset(frame, aEndOffset, PR_FALSE, endPoint);
 220   if (!startFrame || !endFrame) {
 221     return E_FAIL;
 222   }
 223
 224   nsRect sum(0, 0, 0, 0);
 225   nsIFrame *iter = startFrame;
 226   nsIFrame *stopLoopFrame = endFrame->GetNextContinuation();
 227   for (; iter != stopLoopFrame; iter = iter->GetNextContinuation()) {
 228     nsRect rect = iter->GetScreenRectExternal();
 229     nscoord start = (iter == startFrame) ? presContext->AppUnitsToDevPixels(startPoint.x) : 0;
 230     nscoord end = (iter == endFrame) ? presContext->AppUnitsToDevPixels(endPoint.x) :
 231                                        rect.width;
 232     rect.x += start;
 233     rect.width = end - start;
 234     sum.UnionRect(sum, rect);
 235   }
 236
 237   *aX      = sum.x;
 238   *aY      = sum.y;
 239   *aWidth  = sum.width;
 240   *aHeight = sum.height;
 241
 242   return NS_OK;
 243 }
 244
 245 STDMETHODIMP nsTextAccessibleWrap::get_fontFamily(
 246     /* [retval][out] */ BSTR __RPC_FAR *aFontFamily)
 247 {
 248 __try {
 249   *aFontFamily = NULL;
 250
 251   nsIFrame *frame = GetFrame();
 252   nsCOMPtr<nsIPresShell> presShell = GetPresShell();
 253   if (!frame || !presShell) {
 254     return E_FAIL;
 255   }
 256
 257   nsCOMPtr<nsIRenderingContext> rc;
 258   presShell->CreateRenderingContext(frame, getter_AddRefs(rc));
 259   if (!rc) {
 260     return E_FAIL;
 261   }
 262
 263   const nsStyleFont *font = frame->GetStyleFont();
 264
 265   const nsStyleVisibility *visibility = frame->GetStyleVisibility();
 266
 267   if (NS_FAILED(rc->SetFont(font->mFont, visibility->mLangGroup))) {
 268     return E_FAIL;
 269   }
 270
 271   nsCOMPtr<nsIDeviceContext> deviceContext;
 272   rc->GetDeviceContext(*getter_AddRefs(deviceContext));
 273   if (!deviceContext) {
 274     return E_FAIL;
 275   }
 276
 277   nsIFontMetrics *fm;
 278   rc->GetFontMetrics(fm);
 279   if (!fm) {
 280     return E_FAIL;
 281   }
 282
 283   nsAutoString fontFamily;
 284   deviceContext->FirstExistingFont(fm->Font(), fontFamily);
 285   if (fontFamily.IsEmpty())
 286     return S_FALSE;
 287
 288   *aFontFamily = ::SysAllocStringLen(fontFamily.get(), fontFamily.Length());
 289   if (!*aFontFamily)
 290     return E_OUTOFMEMORY;
 291
 292 } __except(FilterA11yExceptions(::GetExceptionCode(), GetExceptionInformation())) { }
 293
 294   return S_OK;
 295 }