layout/generic/nsHTMLCanvasFrame.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  *   Vladimir Vukicevic <vladimir@pobox.com>
  19  * Portions created by the Initial Developer are Copyright (C) 2004
  20  * the Initial Developer. All Rights Reserved.
  21  *
  22  * Contributor(s):
  23  *    Vladimir Vukicevic <vladimir@pobox.com> (original author)
  24  *
  25  * Alternatively, the contents of this file may be used under the terms of
  26  * either of the GNU General Public License Version 2 or later (the "GPL"),
  27  * or 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 /* rendering object for the HTML <canvas> element */
  40
  41 #include "nsHTMLParts.h"
  42 #include "nsCOMPtr.h"
  43 #include "nsIServiceManager.h"
  44 #include "nsGkAtoms.h"
  45
  46 #include "nsHTMLCanvasFrame.h"
  47 #include "nsICanvasElement.h"
  48 #include "nsDisplayList.h"
  49
  50 #include "nsTransform2D.h"
  51
  52
  53 class nsDisplayItemCanvas : public nsDisplayItem {
  54 public:
  55   nsDisplayItemCanvas(nsIFrame* aFrame)
  56     : nsDisplayItem(aFrame)
  57   {
  58     MOZ_COUNT_CTOR(nsDisplayItemCanvas);
  59   }
  60 #ifdef NS_BUILD_REFCNT_LOGGING
  61   virtual ~nsDisplayItemCanvas() {
  62     MOZ_COUNT_DTOR(nsDisplayItemCanvas);
  63   }
  64 #endif
  65
  66   NS_DISPLAY_DECL_NAME("nsDisplayItemCanvas")
  67
  68   virtual void Paint(nsDisplayListBuilder* aBuilder, nsIRenderingContext* aCtx,
  69                      const nsRect& aDirtyRect) {
  70     nsHTMLCanvasFrame* f = static_cast<nsHTMLCanvasFrame*>(GetUnderlyingFrame());
  71     f->PaintCanvas(*aCtx, aDirtyRect, aBuilder->ToReferenceFrame(f));
  72   }
  73
  74   virtual PRBool IsOpaque(nsDisplayListBuilder* aBuilder) {
  75     nsIFrame* f = GetUnderlyingFrame();
  76     nsCOMPtr<nsICanvasElement> canvas(do_QueryInterface(f->GetContent()));
  77     return canvas->GetIsOpaque();
  78   }
  79
  80   virtual nsRect GetBounds(nsDisplayListBuilder* aBuilder) {
  81     nsHTMLCanvasFrame* f = static_cast<nsHTMLCanvasFrame*>(GetUnderlyingFrame());
  82     return f->GetInnerArea() + aBuilder->ToReferenceFrame(f);
  83   }
  84 };
  85
  86
  87 nsIFrame*
  88 NS_NewHTMLCanvasFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
  89 {
  90   return new (aPresShell) nsHTMLCanvasFrame(aContext);
  91 }
  92
  93 nsHTMLCanvasFrame::~nsHTMLCanvasFrame()
  94 {
  95 }
  96
  97 nsIntSize
  98 nsHTMLCanvasFrame::GetCanvasSize()
  99 {
 100   PRUint32 w, h;
 101   nsresult rv;
 102   nsCOMPtr<nsICanvasElement> canvas(do_QueryInterface(GetContent()));
 103   if (canvas) {
 104     rv = canvas->GetSize(&w, &h);
 105   } else {
 106     rv = NS_ERROR_NULL_POINTER;
 107   }
 108
 109   if (NS_FAILED(rv)) {
 110     NS_NOTREACHED("couldn't get canvas size");
 111     h = w = 1;
 112   }
 113
 114   return nsIntSize(w, h);
 115 }
 116
 117 /* virtual */ nscoord
 118 nsHTMLCanvasFrame::GetMinWidth(nsIRenderingContext *aRenderingContext)
 119 {
 120   // XXX The caller doesn't account for constraints of the height,
 121   // min-height, and max-height properties.
 122   nscoord result = nsPresContext::CSSPixelsToAppUnits(GetCanvasSize().width);
 123   DISPLAY_MIN_WIDTH(this, result);
 124   return result;
 125 }
 126
 127 /* virtual */ nscoord
 128 nsHTMLCanvasFrame::GetPrefWidth(nsIRenderingContext *aRenderingContext)
 129 {
 130   // XXX The caller doesn't account for constraints of the height,
 131   // min-height, and max-height properties.
 132   nscoord result = nsPresContext::CSSPixelsToAppUnits(GetCanvasSize().width);
 133   DISPLAY_PREF_WIDTH(this, result);
 134   return result;
 135 }
 136
 137 /* virtual */ nsSize
 138 nsHTMLCanvasFrame::GetIntrinsicRatio()
 139 {
 140   nsIntSize size(GetCanvasSize());
 141   return nsSize(nsPresContext::CSSPixelsToAppUnits(size.width),
 142                 nsPresContext::CSSPixelsToAppUnits(size.height));
 143 }
 144
 145 /* virtual */ nsSize
 146 nsHTMLCanvasFrame::ComputeSize(nsIRenderingContext *aRenderingContext,
 147                                nsSize aCBSize, nscoord aAvailableWidth,
 148                                nsSize aMargin, nsSize aBorder, nsSize aPadding,
 149                                PRBool aShrinkWrap)
 150 {
 151   nsIntSize size = GetCanvasSize();
 152
 153   IntrinsicSize intrinsicSize;
 154   intrinsicSize.width.SetCoordValue(nsPresContext::CSSPixelsToAppUnits(size.width));
 155   intrinsicSize.height.SetCoordValue(nsPresContext::CSSPixelsToAppUnits(size.height));
 156
 157   nsSize intrinsicRatio = GetIntrinsicRatio(); // won't actually be used
 158
 159   return nsLayoutUtils::ComputeSizeWithIntrinsicDimensions(
 160                             aRenderingContext, this,
 161                             intrinsicSize, intrinsicRatio, aCBSize,
 162                             aMargin, aBorder, aPadding);
 163 }
 164
 165 NS_IMETHODIMP
 166 nsHTMLCanvasFrame::Reflow(nsPresContext*           aPresContext,
 167                           nsHTMLReflowMetrics&     aMetrics,
 168                           const nsHTMLReflowState& aReflowState,
 169                           nsReflowStatus&          aStatus)
 170 {
 171   DO_GLOBAL_REFLOW_COUNT("nsHTMLCanvasFrame");
 172   DISPLAY_REFLOW(aPresContext, this, aReflowState, aMetrics, aStatus);
 173   NS_FRAME_TRACE(NS_FRAME_TRACE_CALLS,
 174                   ("enter nsHTMLCanvasFrame::Reflow: availSize=%d,%d",
 175                   aReflowState.availableWidth, aReflowState.availableHeight));
 176
 177   NS_PRECONDITION(mState & NS_FRAME_IN_REFLOW, "frame is not in reflow");
 178
 179   aStatus = NS_FRAME_COMPLETE;
 180
 181   aMetrics.width = aReflowState.ComputedWidth();
 182   aMetrics.height = aReflowState.ComputedHeight();
 183
 184   // stash this away so we can compute our inner area later
 185   mBorderPadding   = aReflowState.mComputedBorderPadding;
 186
 187   aMetrics.width += mBorderPadding.left + mBorderPadding.right;
 188   aMetrics.height += mBorderPadding.top + mBorderPadding.bottom;
 189
 190   if (GetPrevInFlow()) {
 191     nscoord y = GetContinuationOffset(&aMetrics.width);
 192     aMetrics.height -= y + mBorderPadding.top;
 193     aMetrics.height = PR_MAX(0, aMetrics.height);
 194   }
 195
 196   aMetrics.mOverflowArea.SetRect(0, 0, aMetrics.width, aMetrics.height);
 197   FinishAndStoreOverflow(&aMetrics);
 198
 199   if (mRect.width != aMetrics.width || mRect.height != aMetrics.height) {
 200     Invalidate(nsRect(0, 0, mRect.width, mRect.height));
 201   }
 202
 203   NS_FRAME_TRACE(NS_FRAME_TRACE_CALLS,
 204                   ("exit nsHTMLCanvasFrame::Reflow: size=%d,%d",
 205                   aMetrics.width, aMetrics.height));
 206   NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aMetrics);
 207   return NS_OK;
 208 }
 209
 210 // FIXME taken from nsImageFrame, but then had splittable frame stuff
 211 // removed.  That needs to be fixed.
 212 nsRect
 213 nsHTMLCanvasFrame::GetInnerArea() const
 214 {
 215   nsRect r;
 216   r.x = mBorderPadding.left;
 217   r.y = mBorderPadding.top;
 218   r.width = mRect.width - mBorderPadding.left - mBorderPadding.right;
 219   r.height = mRect.height - mBorderPadding.top - mBorderPadding.bottom;
 220   return r;
 221 }
 222
 223 void
 224 nsHTMLCanvasFrame::PaintCanvas(nsIRenderingContext& aRenderingContext,
 225                                const nsRect& aDirtyRect, nsPoint aPt)
 226 {
 227   nsRect inner = GetInnerArea() + aPt;
 228
 229   nsCOMPtr<nsICanvasElement> canvas(do_QueryInterface(GetContent()));
 230   if (!canvas)
 231     return;
 232
 233   // anything to do?
 234   if (inner.width == 0 || inner.height == 0)
 235     return;
 236
 237   nsIntSize canvasSize = GetCanvasSize();
 238   nsSize sizeAppUnits(PresContext()->DevPixelsToAppUnits(canvasSize.width),
 239                       PresContext()->DevPixelsToAppUnits(canvasSize.height));
 240
 241   // XXXvlad clip to aDirtyRect!
 242
 243   if (inner.Size() != sizeAppUnits)
 244   {
 245     float sx = inner.width / (float) sizeAppUnits.width;
 246     float sy = inner.height / (float) sizeAppUnits.height;
 247
 248     aRenderingContext.PushState();
 249     aRenderingContext.Translate(inner.x, inner.y);
 250     aRenderingContext.Scale(sx, sy);
 251
 252     canvas->RenderContexts(aRenderingContext.ThebesContext());
 253
 254     aRenderingContext.PopState();
 255   } else {
 256     //nsIRenderingContext::AutoPushTranslation(&aRenderingContext, px, py);
 257
 258     aRenderingContext.PushState();
 259     aRenderingContext.Translate(inner.x, inner.y);
 260
 261     canvas->RenderContexts(aRenderingContext.ThebesContext());
 262
 263     aRenderingContext.PopState();
 264   }
 265 }
 266
 267 NS_IMETHODIMP
 268 nsHTMLCanvasFrame::BuildDisplayList(nsDisplayListBuilder*   aBuilder,
 269                                     const nsRect&           aDirtyRect,
 270                                     const nsDisplayListSet& aLists)
 271 {
 272   if (!IsVisibleForPainting(aBuilder))
 273     return NS_OK;
 274
 275   nsresult rv = DisplayBorderBackgroundOutline(aBuilder, aLists);
 276   NS_ENSURE_SUCCESS(rv, rv);
 277
 278   rv = aLists.Content()->AppendNewToTop(new (aBuilder)
 279          nsDisplayItemCanvas(this));
 280   NS_ENSURE_SUCCESS(rv, rv);
 281
 282   return DisplaySelectionOverlay(aBuilder, aLists,
 283                                  nsISelectionDisplay::DISPLAY_IMAGES);
 284 }
 285
 286 NS_IMETHODIMP
 287 nsHTMLCanvasFrame::GetContentForEvent(nsPresContext* aPresContext,
 288                                       nsEvent* aEvent,
 289                                       nsIContent** aContent)
 290 {
 291   NS_ENSURE_ARG_POINTER(aContent);
 292   *aContent = GetContent();
 293   NS_IF_ADDREF(*aContent);
 294   return NS_OK;
 295 }
 296
 297 nsIAtom*
 298 nsHTMLCanvasFrame::GetType() const
 299 {
 300   return nsGkAtoms::HTMLCanvasFrame;
 301 }
 302
 303 // get the offset into the content area of the image where aImg starts if it is a continuation.
 304 // from nsImageFrame
 305 nscoord
 306 nsHTMLCanvasFrame::GetContinuationOffset(nscoord* aWidth) const
 307 {
 308   nscoord offset = 0;
 309   if (aWidth) {
 310     *aWidth = 0;
 311   }
 312
 313   if (GetPrevInFlow()) {
 314     for (nsIFrame* prevInFlow = GetPrevInFlow() ; prevInFlow; prevInFlow = prevInFlow->GetPrevInFlow()) {
 315       nsRect rect = prevInFlow->GetRect();
 316       if (aWidth) {
 317         *aWidth = rect.width;
 318       }
 319       offset += rect.height;
 320     }
 321     offset -= mBorderPadding.top;
 322     offset = PR_MAX(0, offset);
 323   }
 324   return offset;
 325 }
 326
 327 #ifdef ACCESSIBILITY
 328 NS_IMETHODIMP
 329 nsHTMLCanvasFrame::GetAccessible(nsIAccessible** aAccessible)
 330 {
 331   return NS_ERROR_FAILURE;
 332 }
 333 #endif
 334
 335 #ifdef DEBUG
 336 NS_IMETHODIMP
 337 nsHTMLCanvasFrame::GetFrameName(nsAString& aResult) const
 338 {
 339   return MakeFrameName(NS_LITERAL_STRING("HTMLCanvas"), aResult);
 340 }
 341
 342 NS_IMETHODIMP
 343 nsHTMLCanvasFrame::List(FILE* out, PRInt32 aIndent) const
 344 {
 345   IndentBy(out, aIndent);
 346   ListTag(out);
 347   fputs("\n", out);
 348   return NS_OK;
 349 }
 350 #endif
 351