Bug 285038. Support offscreen rendering API in nsIViewManager and provide MOZ_FORCE_PAINT_AFTER_ONLOAD environment variable hack to dump loaded documents to image files. r+sr=bzbarsky

layout/base/nsDocumentViewer.cpp

@@ -111,6 +111,7 @@
 #ifdef MOZ_XUL
 #include "nsIXULDocument.h"
 #endif
+#include "nsPrintfCString.h"
 
 #include "nsIClipboardHelper.h"
 
@@ -359,6 +360,8 @@ private:
   nsresult GetPopupLinkNode(nsIDOMNode** aNode);
   nsresult GetPopupImageNode(nsIImageLoadingContent** aNode);
 
+  void DumpContentToPPM(const char* aFileName);
+
   void PrepareToStartLoad(void);
 
   nsresult SyncParentSubDocMap();
@@ -845,6 +848,107 @@ DocumentViewerImpl::InitInternal(nsIWidget* aParentWidget,
   return rv;
 }
 
+void
+DocumentViewerImpl::DumpContentToPPM(const char* aFileName)
+{
+  mDocument->FlushPendingNotifications(Flush_Display);
+
+  nsIScrollableView* scrollableView;
+  mViewManager->GetRootScrollableView(&scrollableView);
+  nsIView* view;
+  if (scrollableView) {
+    scrollableView->GetScrolledView(view);
+  } else {
+    mViewManager->GetRootView(view);
+  }
+  nsRect r = view->GetBounds() - view->GetPosition();
+  float p2t = mPresContext->PixelsToTwips();
+  // Limit the bitmap size to 5000x5000
+  nscoord twipLimit = NSIntPixelsToTwips(5000, p2t);
+  if (r.height > twipLimit)
+    r.height = twipLimit;
+  if (r.width > twipLimit)
+    r.width = twipLimit;
+
+  const char* status;
+
+  if (r.IsEmpty()) {
+    status = "EMPTY";
+  } else {
+    nsCOMPtr<nsIRenderingContext> context;
+    nsresult rv = mViewManager->RenderOffscreen(view, r,
+                                                PR_FALSE, NS_RGB(255, 255, 255),
+                                                getter_AddRefs(context));
+
+    if (NS_FAILED(rv)) {
+      status = "FAILEDRENDER";
+    } else {
+      nsIDrawingSurface* surface;
+      context->GetDrawingSurface(&surface);
+      if (!surface) {
+        status = "NOSURFACE";
+      } else {
+        float t2p = mPresContext->TwipsToPixels();
+        PRUint32 width = NSTwipsToIntPixels(view->GetBounds().width, t2p);
+        PRUint32 height = NSTwipsToIntPixels(view->GetBounds().height, t2p);
+
+        PRUint8* data;
+        PRInt32 rowLen, rowSpan;
+        rv = surface->Lock(0, 0, width, height, (void**)&data, &rowSpan, &rowLen,
+                           NS_LOCK_SURFACE_READ_ONLY);
+        if (NS_FAILED(rv)) {
+          status = "FAILEDLOCK";
+        } else {
+          PRUint32 bytesPerPix = rowLen/width;
+          nsPixelFormat format;
+          surface->GetPixelFormat(&format);
+
+          PRUint8* buf = new PRUint8[3*width];
+          if (buf) {
+            FILE* f = fopen(aFileName, "wb");
+            if (f) {
+              fprintf(f, "P6\n%d\n%d\n255\n", width, height);
+              for (PRUint32 i = 0; i < height; ++i) {
+                PRUint8* src = data + i*rowSpan;
+                PRUint8* dest = buf;
+                for (PRUint32 j = 0; j < width; ++j) {
+                  /* v is the pixel value */
+#ifdef IS_BIG_ENDIAN
+                  PRUint32 v = (src[0] << 24) | (src[1] << 16) || (src[2] << 8) | src[3];
+                  v >>= (32 - 8*bytesPerPix);
+#else
+                  PRUint32 v = src[0] | (src[1] << 8) | (src[2] << 16) | (src[3] << 24);
+#endif
+                  dest[0] = ((v & format.mRedMask) >> format.mRedShift) << (8 - format.mRedCount);
+                  dest[1] = ((v & format.mGreenMask) >> format.mGreenShift) << (8 - format.mGreenCount);
+                  dest[2] = ((v & format.mBlueMask) >> format.mBlueShift) << (8 - format.mBlueCount);
+                  src += bytesPerPix;
+                  dest += 3;
+                }
+                fwrite(buf, 3, width, f);
+              }
+              fclose(f);
+              status = "OK";
+            }
+            
+            delete[] buf;
+          }
+          surface->Unlock();
+        }
+        context->DestroyDrawingSurface(surface);
+      }
+    }
+  }
+
+  nsIURI *uri = mDocument->GetDocumentURI();
+  nsCAutoString spec;
+  if (uri) {
+    uri->GetAsciiSpec(spec);
+  }
+  printf("GECKO: PAINT FORCED AFTER ONLOAD: %s %s (%s)\n", spec.get(), aFileName, status);
+  fflush(stdout);
+}
+
 //
 // LoadComplete(aStatus)
 //
@@ -912,15 +1016,13 @@ DocumentViewerImpl::LoadComplete(nsresult aStatus)
 
   static PRBool forcePaint
     = PR_GetEnv("MOZ_FORCE_PAINT_AFTER_ONLOAD") != nsnull;
+  static PRUint32 index = 0;
   if (forcePaint) {
-    mDocument->FlushPendingNotifications(Flush_Display);
-    nsIURI *uri = mDocument->GetDocumentURI();
-    nsCAutoString spec;
-    if (uri) {
-      uri->GetSpec(spec);
-    }
-    printf("GECKO: PAINT FORCED AFTER ONLOAD: %s\n", spec.get());
-    fflush(stdout);
+    nsCAutoString name(PR_GetEnv("MOZ_FORCE_PAINT_AFTER_ONLOAD"));
+    name.AppendLiteral("-");
+    ++index;
+    name.AppendInt(index);
+    DumpContentToPPM(name.get());
   }
 
 #ifdef NS_PRINTING

view/public/nsIViewManager.h

@@ -449,6 +449,27 @@ public:
    //XXXbz how is this different from UpdateView(NS_VMREFRESH_IMMEDIATE)?
   NS_IMETHOD Display(nsIView *aView, nscoord aX, nscoord aY, const nsRect& aClipRect) = 0;
 
+  /**
+   * Dump the specified view into a new offscreen rendering context.
+   * The view is treated as the display root and is not clipped by
+   * ancestor views, nor is ancestor or sibling content displayed even
+   * if it overlaps the view.
+   * @param aRect is the region to capture into the offscreen buffer, in the view's
+   * coordinate system
+   * @param aUntrusted set to PR_TRUE if the contents may be passed to malicious
+   * agents. E.g. we might choose not to paint the contents of sensitive widgets
+   * such as the file name in a file upload widget, and we might choose not
+   * to paint themes.
+   * @param aBackgroundColor a background color to render onto
+   * @param aRenderedContext gets set to a rendering context whose offscreen
+   * buffer can be locked to get the data. The buffer's size will be aRect's size.
+   * In all cases the caller must clean it up by calling
+   * cx->DestroyDrawingSurface(cx->GetDrawingSurface()).
+   */
+  NS_IMETHOD RenderOffscreen(nsIView* aView, nsRect aRect, PRBool aUntrusted,
+                             nscolor aBackgroundColor,
+                             nsIRenderingContext** aRenderedContext) = 0;
+
   /**
    * Add a listener to the view manager's composite listener list.
    * @param aListener - new listener

view/src/nsView.cpp

@@ -856,15 +856,20 @@ PRBool nsIView::ExternalIsRoot() const
   return nsIView::IsRoot();
 }
 
-// Returns PR_TRUE iff we found a placeholder parent edge on the way
-static PRBool ApplyClipRect(const nsView* aView, nsRect* aRect, PRBool aFollowPlaceholders)
+/**
+ * @param aStopAtView clipping from ancestors of this view will not be applied
+ * @return PR_TRUE iff we found a placeholder parent edge on the way up the view tree
+ * from aView to aStopAtView
+ */
+static PRBool ApplyClipRect(const nsView* aView, nsRect* aRect, PRBool aFollowPlaceholders,
+                            nsIView* aStopAtView)
 {
   // this records the offset from the origin of the current aView
   // to the origin of the initial aView
   nsPoint offset(0, 0);
   PRBool lastViewIsFloating = aView->GetFloating();
   PRBool foundPlaceholders = PR_FALSE;
-  while (PR_TRUE) {
+  while (aView != aStopAtView) {
     const nsView* parentView = aView->GetParent();
     nsPoint offsetFromParent = aView->GetPosition();
 
@@ -874,7 +879,7 @@ static PRBool ApplyClipRect(const nsView* aView, nsRect* aRect, PRBool aFollowPl
       if (aFollowPlaceholders) {
         // correct offsetFromParent to account for the fact that we're
         // switching parentView to ZParent
-        // Note tha the common case is that parentView is an ancestor of
+        // Note that the common case is that parentView is an ancestor of
         // ZParent.
         const nsView* zParentChain;
         for (zParentChain = zParent;
@@ -934,12 +939,12 @@ static PRBool ApplyClipRect(const nsView* aView, nsRect* aRect, PRBool aFollowPl
   return foundPlaceholders;
 }
 
-nsRect nsView::GetClippedRect()
+nsRect nsView::GetClippedRect(nsIView* aStopAtView)
 {
   nsRect clip = GetDimensions();
-  PRBool foundPlaceholders = ApplyClipRect(this, &clip, PR_FALSE);
+  PRBool foundPlaceholders = ApplyClipRect(this, &clip, PR_FALSE, aStopAtView);
   if (foundPlaceholders && !clip.IsEmpty()) {
-    ApplyClipRect(this, &clip, PR_TRUE);
+    ApplyClipRect(this, &clip, PR_TRUE, aStopAtView);
   }
   return clip;
 }

view/src/nsView.h

@@ -226,8 +226,10 @@ public:
   /**
    * @return the view's dimensions after clipping by ancestors is applied
    * (the rect is relative to the view's origin)
+   * @param aStopAtView do not consider clipping imposed by views above this view
+   * on the ancestor chain
    */
-  nsRect GetClippedRect();
+  nsRect GetClippedRect(nsIView* aStopAtView = nsnull);
 
   // Helper function to get the view that's associated with a widget
   static nsView*  GetViewFor(nsIWidget* aWidget);

view/src/nsViewManager.cpp

@@ -884,7 +884,8 @@ void nsViewManager::Refresh(nsView *aView, nsIRenderingContext *aContext,
   PLArenaPool displayArena;
   PL_INIT_ARENA_POOL(&displayArena, "displayArena", 1024);
   PRBool anyTransparentPixels
-    = BuildRenderingDisplayList(aView, damageRegion, &displayList, displayArena);
+    = BuildRenderingDisplayList(aView, damageRegion, &displayList, displayArena,
+                                PR_FALSE, PR_FALSE);
   PRBool needBlending = PR_FALSE;
   for (PRInt32 i = 0; i < displayList.Count(); i++) {
     DisplayListElement2* element = NS_STATIC_CAST(DisplayListElement2*, displayList.ElementAt(i));
@@ -1288,14 +1289,18 @@ void nsViewManager::AddCoveringWidgetsToOpaqueRegion(nsRegion &aRgn, nsIDeviceCo
 }
 
 PRBool nsViewManager::BuildRenderingDisplayList(nsIView* aRootView,
-  const nsRegion& aRegion, nsVoidArray* aDisplayList, PLArenaPool &aPool)
+  const nsRegion& aRegion, nsVoidArray* aDisplayList, PLArenaPool &aPool,
+  PRBool aIgnoreCoveringWidgets, PRBool aIgnoreOutsideClipping)
 {
   BuildDisplayList(NS_STATIC_CAST(nsView*, aRootView),
-                   aRegion.GetBounds(), PR_FALSE, PR_FALSE, aDisplayList, aPool);
+                   aRegion.GetBounds(), PR_FALSE, aIgnoreOutsideClipping,
+                   aDisplayList, aPool);
 
   nsRegion opaqueRgn;
-  AddCoveringWidgetsToOpaqueRegion(opaqueRgn, mContext,
-                                   NS_STATIC_CAST(nsView*, aRootView));
+  if (!aIgnoreCoveringWidgets) {
+    AddCoveringWidgetsToOpaqueRegion(opaqueRgn, mContext,
+                                     NS_STATIC_CAST(nsView*, aRootView));
+  }
 
   nsRect finalTransparentRect;
   OptimizeDisplayList(aDisplayList, aRegion, finalTransparentRect, opaqueRgn, PR_FALSE);
@@ -2332,9 +2337,11 @@ static PRBool ComputePlaceholderContainment(nsView* aView) {
 
   aRect is the area in aView which we want to build a display list for.
   Set aEventProcesing when the list is required for event processing.
-  Set aCaptured if the event is being captured by the given view.
+  Set aCaptured if the event or painting is being captured by the given view so
+  only views that are descended from the given view are considered.
 */
-void nsViewManager::BuildDisplayList(nsView* aView, const nsRect& aRect, PRBool aEventProcessing,
+void nsViewManager::BuildDisplayList(nsView* aView, const nsRect& aRect,
+                                     PRBool aEventProcessing,
                                      PRBool aCaptured, nsVoidArray* aDisplayList,
                                      PLArenaPool &aPool)
 {
@@ -3325,7 +3332,7 @@ nsViewManager::CreateRenderingContext(nsView &aView)
 
   if (nsnull != win)
     {
-      mContext->CreateRenderingContext(&aView, cx);
+      mContext->CreateRenderingContext(par, cx);
 
       if (nsnull != cx)
         cx->Translate(ax, ay);
@@ -3437,6 +3444,54 @@ NS_IMETHODIMP nsViewManager::GetRootScrollableView(nsIScrollableView **aScrollab
   return NS_OK;
 }
 
+NS_IMETHODIMP nsViewManager::RenderOffscreen(nsIView* aView, nsRect aRect,
+                                             PRBool aUntrusted,
+                                             nscolor aBackgroundColor,
+                                             nsIRenderingContext** aRenderedContext)
+{
+  nsView* view = NS_STATIC_CAST(nsView*, aView);
+
+  *aRenderedContext = nsnull;
+
+  NS_ASSERTION(!aUntrusted, "We don't support untrusted yet");
+  if (aUntrusted)
+    return NS_ERROR_NOT_IMPLEMENTED;
+
+  nsCOMPtr<nsIRenderingContext> tmpContext
+    = CreateRenderingContext(*view);
+  if (!tmpContext)
+    return NS_ERROR_FAILURE;
+
+  nsRect bounds(nsPoint(0, 0), aRect.Size());
+  nsIDrawingSurface* surface;
+  nsresult rv
+    = tmpContext->CreateDrawingSurface(bounds, NS_CREATEDRAWINGSURFACE_FOR_PIXEL_ACCESS,
+                                       surface);
+  if (NS_FAILED(rv))
+    return NS_ERROR_FAILURE;
+  nsCOMPtr<nsIRenderingContext> localcx;
+  rv = NewOffscreenContext(mContext, surface, aRect, getter_AddRefs(localcx));
+  if (NS_FAILED(rv)) {
+    tmpContext->DestroyDrawingSurface(surface);
+    return NS_ERROR_FAILURE;
+  }
+  // clipping and translation is set by NewOffscreenContext
+
+  localcx->SetColor(aBackgroundColor);
+  localcx->FillRect(aRect);
+
+  nsAutoVoidArray displayList;
+  PLArenaPool displayArena;
+  PL_INIT_ARENA_POOL(&displayArena, "displayArena", 1024);
+  BuildRenderingDisplayList(view, nsRegion(aRect), &displayList, displayArena,
+                            PR_TRUE, PR_TRUE);
+  RenderViews(view, *localcx, nsRegion(aRect), surface, displayList);
+  PL_FreeArenaPool(&displayArena);
+  PL_FinishArenaPool(&displayArena);
+
+  localcx.swap(*aRenderedContext);
+}
+
 NS_IMETHODIMP nsViewManager::Display(nsIView* aView, nscoord aX, nscoord aY, const nsRect& aClipRect)
 {
   nsView              *view = NS_STATIC_CAST(nsView*, aView);
@@ -3470,7 +3525,8 @@ NS_IMETHODIMP nsViewManager::Display(nsIView* aView, nscoord aX, nscoord aY, con
   nsAutoVoidArray displayList;
   PLArenaPool displayArena;
   PL_INIT_ARENA_POOL(&displayArena, "displayArena", 1024);
-  BuildRenderingDisplayList(view, nsRegion(trect), &displayList, displayArena);
+  BuildRenderingDisplayList(view, nsRegion(trect), &displayList, displayArena,
+                            PR_FALSE, PR_FALSE);
   RenderViews(view, *localcx, nsRegion(trect), PR_FALSE, displayList);
   PL_FreeArenaPool(&displayArena);
   PL_FinishArenaPool(&displayArena);
@@ -3650,7 +3706,8 @@ PRBool nsViewManager::CreateDisplayList(nsView *aView,
     
     // Add POP first because the z-tree is in reverse order
     retval = AddToDisplayList(aView, aResult, bounds, bounds,
-                              POP_FILTER, aX - aOriginX, aY - aOriginY, PR_TRUE, aPool);
+                              POP_FILTER, aX - aOriginX, aY - aOriginY, PR_TRUE, aPool,
+                              aTopView);
     if (retval)
       return retval;
     
@@ -3667,7 +3724,8 @@ PRBool nsViewManager::CreateDisplayList(nsView *aView,
 
       // Add POP first because the z-tree is in reverse order
       retval = AddToDisplayList(aView, aResult, bounds, bounds,
-                                POP_CLIP, aX - aOriginX, aY - aOriginY, PR_TRUE, aPool);
+                                POP_CLIP, aX - aOriginX, aY - aOriginY, PR_TRUE, aPool,
+                                aTopView);
 
       if (retval)
         return retval;
@@ -3710,7 +3768,8 @@ PRBool nsViewManager::CreateDisplayList(nsView *aView,
           flags |= VIEW_TRANSPARENT;
         retval = AddToDisplayList(aView, aResult, bounds, irect, flags,
                                   aX - aOriginX, aY - aOriginY,
-                                  aEventProcessing && aTopView == aView, aPool);
+                                  aEventProcessing && aTopView == aView, aPool,
+                                  aTopView);
         // We're forcing AddToDisplayList to pick up the view only
         // during event processing, and only when aView is back at the
         // root of the tree of acceptable views (note that when event
@@ -3735,7 +3794,8 @@ PRBool nsViewManager::CreateDisplayList(nsView *aView,
     bounds.y -= aOriginY;
 
     if (AddToDisplayList(aView, aResult, bounds, bounds, PUSH_CLIP,
-                         aX - aOriginX, aY - aOriginY, PR_TRUE, aPool)) {
+                         aX - aOriginX, aY - aOriginY, PR_TRUE, aPool,
+                         aTopView)) {
       retval = PR_TRUE;
     }
     
@@ -3750,7 +3810,8 @@ PRBool nsViewManager::CreateDisplayList(nsView *aView,
     bounds.y -= aOriginY;
     
     retval = AddToDisplayList(aView, aResult, bounds, bounds,
-                              PUSH_FILTER, aX - aOriginX, aY - aOriginY, PR_TRUE, aPool);
+                              PUSH_FILTER, aX - aOriginX, aY - aOriginY, PR_TRUE, aPool,
+                              aTopView);
     if (retval)
       return retval;
     
@@ -3766,9 +3827,10 @@ PRBool nsViewManager::AddToDisplayList(nsView *aView,
                                        DisplayZTreeNode* &aParent, nsRect &aClipRect,
                                        nsRect& aDirtyRect, PRUint32 aFlags,
                                        nscoord aAbsX, nscoord aAbsY,
-                                       PRBool aAssumeIntersection, PLArenaPool &aPool)
+                                       PRBool aAssumeIntersection, PLArenaPool &aPool,
+                                       nsIView* aStopClippingAtView)
 {
-  nsRect clipRect = aView->GetClippedRect();
+  nsRect clipRect = aView->GetClippedRect(aStopClippingAtView);
   PRBool clipped = clipRect != aView->GetDimensions();
 
   // get clipRect into the coordinate system of aView's parent. aAbsX and

view/src/nsViewManager.h

@@ -231,6 +231,10 @@ public:
 
   NS_IMETHOD Display(nsIView *aView, nscoord aX, nscoord aY, const nsRect& aClipRect);
 
+  NS_IMETHOD RenderOffscreen(nsIView* aView, nsRect aRect, PRBool aUntrusted,
+                             nscolor aBackgroundColor,
+                             nsIRenderingContext** aRenderedContext);
+
   NS_IMETHOD AddCompositeListener(nsICompositeListener *aListener);
   NS_IMETHOD RemoveCompositeListener(nsICompositeListener *aListener);
 
@@ -286,7 +290,8 @@ private:
    */
   void DefaultRefresh(nsView* aView, const nsRect* aRect);
   PRBool BuildRenderingDisplayList(nsIView* aRootView,
-    const nsRegion& aRegion, nsVoidArray* aDisplayList, PLArenaPool &aPool);
+    const nsRegion& aRegion, nsVoidArray* aDisplayList, PLArenaPool &aPool,
+    PRBool aIgnoreCoveringWidgets, PRBool aIgnoreOutsideClipping);
   void RenderViews(nsView *aRootView, nsIRenderingContext& aRC,
                    const nsRegion& aRegion, nsIDrawingSurface* aRCSurface,
                    const nsVoidArray& aDisplayList);
@@ -320,7 +325,8 @@ private:
   PRBool AddToDisplayList(nsView *aView,
                           DisplayZTreeNode* &aParent, nsRect &aClipRect,
                           nsRect& aDirtyRect, PRUint32 aFlags, nscoord aAbsX, nscoord aAbsY,
-                          PRBool aAssumeIntersection, PLArenaPool &aPool);
+                          PRBool aAssumeIntersection, PLArenaPool &aPool,
+                          nsIView* aStopClippingAtView);
   void OptimizeDisplayList(const nsVoidArray* aDisplayList, const nsRegion& aDirtyRegion,
                            nsRect& aFinalTransparentRect, nsRegion& aOpaqueRgn,
                            PRBool aTreatUniformAsOpaque);