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gecko-dev/layout/base/nsDisplayList.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: set ts=2 sw=2 et tw=78:
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Novell code.
*
* The Initial Developer of the Original Code is Novell Corporation.
* Portions created by the Initial Developer are Copyright (C) 2006
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* robert@ocallahan.org
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK *****
*/
/*
* structures that represent things to be painted (ordered in z-order),
* used during painting and hit testing
*/
#ifndef NSDISPLAYLIST_H_
#define NSDISPLAYLIST_H_
#include "nsCOMPtr.h"
#include "nsIFrame.h"
#include "nsPoint.h"
#include "nsRect.h"
#include "nsISelection.h"
#include "nsCaret.h"
#include "plarena.h"
#include "nsLayoutUtils.h"
#include <stdlib.h>
class nsIPresShell;
class nsIContent;
class nsRegion;
class nsIRenderingContext;
class nsIDeviceContext;
class nsDisplayTableItem;
/*
* An nsIFrame can have many different visual parts. For example an image frame
* can have a background, border, and outline, the image itself, and a
* translucent selection overlay. In general these parts can be drawn at
* discontiguous z-levels; see CSS2.1 appendix E:
* http://www.w3.org/TR/CSS21/zindex.html
*
* We construct a display list for a frame tree that contains one item
* for each visual part. The display list is itself a tree since some items
* are containers for other items; however, its structure does not match
* the structure of its source frame tree. The display list items are sorted
* by z-order. A display list can be used to paint the frames, to determine
* which frame is the target of a mouse event, and to determine what areas
* need to be repainted when scrolling. The display lists built for each task
* may be different for efficiency; in particular some frames need special
* display list items only for event handling, and do not create these items
* when the display list will be used for painting (the common case). For
* example, when painting we avoid creating nsDisplayBackground items for
* frames that don't display a visible background, but for event handling
* we need those backgrounds because they are not transparent to events.
*
* We could avoid constructing an explicit display list by traversing the
* frame tree multiple times in clever ways. However, reifying the display list
* reduces code complexity and reduces the number of times each frame must be
* traversed to one, which seems to be good for performance. It also means
* we can share code for painting, event handling and scroll analysis.
*
* Display lists are short-lived; content and frame trees cannot change
* between a display list being created and destroyed. Display lists should
* not be created during reflow because the frame tree may be in an
* inconsistent state (e.g., a frame's stored overflow-area may not include
* the bounds of all its children). However, it should be fine to create
* a display list while a reflow is pending, before it starts.
*
* A display list covers the "extended" frame tree; the display list for a frame
* tree containing FRAME/IFRAME elements can include frames from the subdocuments.
*/
#ifdef NS_DEBUG
#define NS_DISPLAY_DECL_NAME(n) virtual const char* Name() { return n; }
#else
#define NS_DISPLAY_DECL_NAME(n)
#endif
/**
* This manages a display list and is passed as a parameter to
* nsIFrame::BuildDisplayList.
* It contains the parameters that don't change from frame to frame and manages
* the display list memory using a PLArena. It also establishes the reference
* coordinate system for all display list items. Some of the parameters are
* available from the prescontext/presshell, but we copy them into the builder
* for faster/more convenient access.
*/
class NS_STACK_CLASS nsDisplayListBuilder {
public:
/**
* @param aReferenceFrame the frame at the root of the subtree; its origin
* is the origin of the reference coordinate system for this display list
* @param aIsForEvents PR_TRUE if we're creating this list in order to
* determine which frame is under the mouse position
* @param aBuildCaret whether or not we should include the caret in any
* display lists that we make.
* @param aMovingFrame a frame whose subtree should be regarded as
* moving; moving frames are not allowed to clip or cover (during
* OptimizeVisibility) non-moving frames. E.g. when we're constructing
* a display list to see what should be repainted during a scroll
* operation, we specify the scrolled frame as the moving frame.
*/
nsDisplayListBuilder(nsIFrame* aReferenceFrame, PRBool aIsForEvents,
PRBool aBuildCaret);
~nsDisplayListBuilder();
/**
* @return PR_TRUE if the display is being built in order to determine which
* frame is under the mouse position.
*/
PRBool IsForEventDelivery() { return mEventDelivery; }
/**
* @return PR_TRUE if "painting is suppressed" during page load and we
* should paint only the background of the document.
*/
PRBool IsBackgroundOnly() { return mIsBackgroundOnly; }
/**
* Set to PR_TRUE if painting should be suppressed during page load.
* Set to PR_FALSE if painting should not be suppressed.
*/
void SetBackgroundOnly(PRBool aIsBackgroundOnly) { mIsBackgroundOnly = aIsBackgroundOnly; }
/**
* @return PR_TRUE if the currently active BuildDisplayList call is being
* applied to a frame at the root of a pseudo stacking context. A pseudo
* stacking context is either a real stacking context or basically what
* CSS2.1 appendix E refers to with "treat the element as if it created
* a new stacking context
*/
PRBool IsAtRootOfPseudoStackingContext() { return mIsAtRootOfPseudoStackingContext; }
/**
* Indicate that we'll use this display list to analyze the effects
* of aMovingFrame moving by aMoveDelta. The move has already been
* applied to the frame tree.
*/
void SetMovingFrame(nsIFrame* aMovingFrame, const nsPoint& aMoveDelta) {
mMovingFrame = aMovingFrame;
mMoveDelta = aMoveDelta;
}
/**
* @return PR_TRUE if we are doing analysis of moving frames
*/
PRBool HasMovingFrames() { return mMovingFrame != nsnull; }
/**
* @return the frame that was moved
*/
nsIFrame* GetRootMovingFrame() { return mMovingFrame; }
/**
* @return the amount by which mMovingFrame was moved.
* Only valid when GetRootMovingFrame() returns non-null.
*/
const nsPoint& GetMoveDelta() { return mMoveDelta; }
/**
* @return PR_TRUE if aFrame is, or is a descendant of, the hypothetical
* moving frame
*/
PRBool IsMovingFrame(nsIFrame* aFrame) {
return aFrame == mMovingFrame || (mMovingFrame &&
nsLayoutUtils::IsProperAncestorFrameCrossDoc(mMovingFrame, aFrame, mReferenceFrame));
}
/**
* @return the selection that painting should be restricted to (or nsnull
* in the normal unrestricted case)
*/
nsISelection* GetBoundingSelection() { return mBoundingSelection; }
/**
* @return the root of the display list's frame (sub)tree, whose origin
* establishes the coordinate system for the display list
*/
nsIFrame* ReferenceFrame() { return mReferenceFrame; }
/**
* @return a point pt such that adding pt to a coordinate relative to aFrame
* makes it relative to ReferenceFrame(), i.e., returns
* aFrame->GetOffsetTo(ReferenceFrame()). It may be optimized to be faster
* than aFrame->GetOffsetTo(ReferenceFrame()) (but currently isn't).
*/
nsPoint ToReferenceFrame(const nsIFrame* aFrame) {
return aFrame->GetOffsetTo(ReferenceFrame());
}
/**
* When building the display list, the scrollframe aFrame will be "ignored"
* for the purposes of clipping, and its scrollbars will be hidden. We use
* this to allow RenderOffscreen to render a whole document without beign
* clipped by the viewport or drawing the viewport scrollbars.
*/
void SetIgnoreScrollFrame(nsIFrame* aFrame) { mIgnoreScrollFrame = aFrame; }
/**
* Get the scrollframe to ignore, if any.
*/
nsIFrame* GetIgnoreScrollFrame() { return mIgnoreScrollFrame; }
/**
* Calling this setter makes us ignore all dirty rects and include all
* descendant frames in the display list, wherever they may be positioned.
*/
void SetPaintAllFrames() { mPaintAllFrames = PR_TRUE; }
PRBool GetPaintAllFrames() { return mPaintAllFrames; }
/**
* Allows callers to selectively override the regular paint suppression checks,
* so that methods like GetFrameForPoint work when painting is suppressed.
*/
void IgnorePaintSuppression() { mIsBackgroundOnly = PR_FALSE; }
/**
* Display the caret if needed.
*/
nsresult DisplayCaret(nsIFrame* aFrame, const nsRect& aDirtyRect,
const nsDisplayListSet& aLists) {
nsIFrame* frame = GetCaretFrame();
if (aFrame != frame) {
return NS_OK;
}
return frame->DisplayCaret(this, aDirtyRect, aLists);
}
/**
* Get the frame that the caret is supposed to draw in.
* If the caret is currently invisible, this will be null.
*/
nsIFrame* GetCaretFrame() {
return CurrentPresShellState()->mCaretFrame;
}
/**
* Get the caret associated with the current presshell.
*/
nsCaret* GetCaret();
/**
* Notify the display list builder that we're entering a presshell.
* aReferenceFrame should be a frame in the new presshell and aDirtyRect
* should be the current dirty rect in aReferenceFrame's coordinate space.
*/
void EnterPresShell(nsIFrame* aReferenceFrame, const nsRect& aDirtyRect);
/**
* Notify the display list builder that we're leaving a presshell.
*/
void LeavePresShell(nsIFrame* aReferenceFrame, const nsRect& aDirtyRect);
/**
* Mark aFrames and its (next) siblings to be displayed if they
* intersect aDirtyRect (which is relative to aDirtyFrame). If the
* frame(s) have placeholders that might not be displayed, we mark the
* placeholders and their ancestors to ensure that display list construction
* descends into them anyway. nsDisplayListBuilder will take care of
* unmarking them when it is destroyed.
*/
void MarkFramesForDisplayList(nsIFrame* aDirtyFrame, nsIFrame* aFrames,
const nsRect& aDirtyRect);
/**
* Allocate memory in our arena. It will only be freed when this display list
* builder is destroyed. This memory holds nsDisplayItems. nsDisplayItem
* destructors are called as soon as the item is no longer used.
*/
void* Allocate(size_t aSize);
/**
* A helper class to temporarily set the value of
* mIsAtRootOfPseudoStackingContext.
*/
class AutoIsRootSetter;
friend class AutoIsRootSetter;
class AutoIsRootSetter {
public:
AutoIsRootSetter(nsDisplayListBuilder* aBuilder, PRBool aIsRoot)
: mBuilder(aBuilder), mOldValue(aBuilder->mIsAtRootOfPseudoStackingContext) {
aBuilder->mIsAtRootOfPseudoStackingContext = aIsRoot;
}
~AutoIsRootSetter() {
mBuilder->mIsAtRootOfPseudoStackingContext = mOldValue;
}
private:
nsDisplayListBuilder* mBuilder;
PRPackedBool mOldValue;
};
// Helpers for tables
nsDisplayTableItem* GetCurrentTableItem() { return mCurrentTableItem; }
void SetCurrentTableItem(nsDisplayTableItem* aTableItem) { mCurrentTableItem = aTableItem; }
private:
// This class is only used on stack, so we don't have to worry about leaking
// it. Don't let us be heap-allocated!
void* operator new(size_t sz) CPP_THROW_NEW;
struct PresShellState {
nsIPresShell* mPresShell;
nsIFrame* mCaretFrame;
PRUint32 mFirstFrameMarkedForDisplay;
};
PresShellState* CurrentPresShellState() {
NS_ASSERTION(mPresShellStates.Length() > 0,
"Someone forgot to enter a presshell");
return &mPresShellStates[mPresShellStates.Length() - 1];
}
nsIFrame* mReferenceFrame;
nsIFrame* mMovingFrame;
nsIFrame* mIgnoreScrollFrame;
nsPoint mMoveDelta; // only valid when mMovingFrame is non-null
PLArenaPool mPool;
nsCOMPtr<nsISelection> mBoundingSelection;
nsAutoTArray<PresShellState,8> mPresShellStates;
nsAutoTArray<nsIFrame*,100> mFramesMarkedForDisplay;
nsDisplayTableItem* mCurrentTableItem;
PRPackedBool mBuildCaret;
PRPackedBool mEventDelivery;
PRPackedBool mIsBackgroundOnly;
PRPackedBool mIsAtRootOfPseudoStackingContext;
PRPackedBool mPaintAllFrames;
};
class nsDisplayItem;
class nsDisplayList;
/**
* nsDisplayItems are put in singly-linked lists rooted in an nsDisplayList.
* nsDisplayItemLink holds the link. The lists are linked from lowest to
* highest in z-order.
*/
class nsDisplayItemLink {
// This is never instantiated directly, so no need to count constructors and
// destructors.
protected:
nsDisplayItemLink() : mAbove(nsnull) {}
nsDisplayItem* mAbove;
friend class nsDisplayList;
};
/**
* This is the unit of rendering and event testing. Each instance of this
* class represents an entity that can be drawn on the screen, e.g., a
* frame's CSS background, or a frame's text string.
*
* nsDisplayListItems can be containers --- i.e., they can perform hit testing
* and painting by recursively traversing a list of child items.
*
* These are arena-allocated during display list construction. A typical
* subclass would just have a frame pointer, so its object would be just three
* pointers (vtable, next-item, frame).
*
* Display items belong to a list at all times (except temporarily as they
* move from one list to another).
*/
class nsDisplayItem : public nsDisplayItemLink {
public:
// This is never instantiated directly (it has pure virtual methods), so no
// need to count constructors and destructors.
nsDisplayItem(nsIFrame* aFrame) : mFrame(aFrame) {}
virtual ~nsDisplayItem() {}
void* operator new(size_t aSize,
nsDisplayListBuilder* aBuilder) CPP_THROW_NEW {
return aBuilder->Allocate(aSize);
}
/**
* It's useful to be able to dynamically check the type of certain items.
* For items whose type never gets checked, TYPE_GENERIC will suffice.
*/
enum Type {
TYPE_GENERIC,
TYPE_OUTLINE,
TYPE_CLIP,
TYPE_OPACITY,
#ifdef MOZ_SVG
TYPE_SVG_EFFECTS,
#endif
TYPE_WRAPLIST,
TYPE_TRANSFORM
};
struct HitTestState {
~HitTestState() {
NS_ASSERTION(mItemBuffer.Length() == 0,
"mItemBuffer should have been cleared");
}
nsAutoTArray<nsDisplayItem*, 100> mItemBuffer;
};
/**
* Some consecutive items should be rendered together as a unit, e.g.,
* outlines for the same element. For this, we need a way for items to
* identify their type.
*/
virtual Type GetType() { return TYPE_GENERIC; }
/**
* This is called after we've constructed a display list for event handling.
* When this is called, we've already ensured that aPt is in the item's bounds.
*
* @param aState must point to a HitTestState. If you don't have one,
* just create one with the default constructor and pass it in.
* @return the frame that the point is considered over, or nsnull if
* this is not over any frame
*/
virtual nsIFrame* HitTest(nsDisplayListBuilder* aBuilder, nsPoint aPt,
HitTestState* aState) { return nsnull; }
/**
* @return the frame that this display item is based on. This is used to sort
* items by z-index and content order and for some other uses. For some items
* that wrap item lists, this could return nsnull because there is no single
* underlying frame; for leaf items it will never return nsnull.
*/
inline nsIFrame* GetUnderlyingFrame() { return mFrame; }
/**
* The default bounds is the frame border rect.
* @return a rectangle relative to aBuilder->ReferenceFrame() that
* contains the area drawn by this display item
*/
virtual nsRect GetBounds(nsDisplayListBuilder* aBuilder) {
nsIFrame* f = GetUnderlyingFrame();
return nsRect(aBuilder->ToReferenceFrame(f), f->GetSize());
}
/**
* @return PR_TRUE if the item is definitely opaque --- i.e., paints
* every pixel within its bounds opaquely
*/
virtual PRBool IsOpaque(nsDisplayListBuilder* aBuilder) { return PR_FALSE; }
/**
* @return PR_TRUE if the item is guaranteed to paint every pixel in its
* bounds with the same (possibly translucent) color
*/
virtual PRBool IsUniform(nsDisplayListBuilder* aBuilder) { return PR_FALSE; }
/**
* @return PR_FALSE if the painting performed by the item is invariant
* when frame aFrame is moved relative to aBuilder->GetRootMovingFrame().
* This can only be called when aBuilder->IsMovingFrame(mFrame) is true.
* It return PR_TRUE for all wrapped lists.
*/
virtual PRBool IsVaryingRelativeToMovingFrame(nsDisplayListBuilder* aBuilder)
{ return PR_FALSE; }
/**
* Actually paint this item to some rendering context.
* @param aDirtyRect relative to aBuilder->ReferenceFrame()
*/
virtual void Paint(nsDisplayListBuilder* aBuilder, nsIRenderingContext* aCtx,
const nsRect& aDirtyRect) {}
/**
* Only to be (re)implemented by items that contain child display lists.
* Do not reimplement for leaf items.
* The default implementation calls GetBounds() and IsOpaque().
* On entry, aVisibleRegion contains the region (relative to ReferenceFrame())
* which may be visible. If the display item opaquely covers an area, it
* can remove that area from aVisibleRegion before returning.
* @return PR_TRUE if the item is visible, PR_FALSE if no part of the item
* is visible
*/
virtual PRBool OptimizeVisibility(nsDisplayListBuilder* aBuilder,
nsRegion* aVisibleRegion);
/**
* Try to merge with the other item (which is below us in the display
* list). This gets used by nsDisplayClip to coalesce clipping operations
* (optimization), by nsDisplayOpacity to merge rendering for the same
* content element into a single opacity group (correctness), and will be
* used by nsDisplayOutline to merge multiple outlines for the same element
* (also for correctness).
* @return PR_TRUE if the merge was successful and the other item should be deleted
*/
virtual PRBool TryMerge(nsDisplayListBuilder* aBuilder, nsDisplayItem* aItem) {
return PR_FALSE;
}
/**
* If this is a leaf item we return null, otherwise we return the wrapped
* list.
*/
virtual nsDisplayList* GetList() { return nsnull; }
#ifdef NS_DEBUG
/**
* For debugging and stuff
*/
virtual const char* Name() = 0;
#endif
nsDisplayItem* GetAbove() { return mAbove; }
protected:
friend class nsDisplayList;
nsDisplayItem() {
mAbove = nsnull;
}
static PRBool ComputeVisibilityFromBounds(nsIFrame* aFrame,
const nsRect& aRect, nsRegion& aCovered, PRBool aIsOpaque);
nsIFrame* mFrame;
};
/**
* Manages a singly-linked list of display list items.
*
* mSentinel is the sentinel list value, the first value in the null-terminated
* linked list of items. mTop is the last item in the list (whose 'above'
* pointer is null). This class has no virtual methods. So list objects are just
* two pointers.
*
* Stepping upward through this list is very fast. Stepping downward is very
* slow so we don't support it. The methods that need to step downward
* (HitTest(), OptimizeVisibility()) internally build a temporary array of all
* the items while they do the downward traversal, so overall they're still
* linear time. We have optimized for efficient AppendToTop() of both
* items and lists, with minimal codesize. AppendToBottom() is efficient too.
*/
class nsDisplayList {
public:
/**
* Create an empty list.
*/
nsDisplayList() { mTop = &mSentinel; mSentinel.mAbove = nsnull; }
~nsDisplayList() {
if (mSentinel.mAbove) {
NS_WARNING("Nonempty list left over?");
}
DeleteAll();
}
/**
* Append an item to the top of the list. The item must not currently
* be in a list and cannot be null.
*/
void AppendToTop(nsDisplayItem* aItem) {
NS_ASSERTION(aItem, "No item to append!");
NS_ASSERTION(!aItem->mAbove, "Already in a list!");
mTop->mAbove = aItem;
mTop = aItem;
}
/**
* Append a new item to the top of the list. If the item is null we return
* NS_ERROR_OUT_OF_MEMORY. The intended usage is AppendNewToTop(new ...);
*/
nsresult AppendNewToTop(nsDisplayItem* aItem) {
if (!aItem)
return NS_ERROR_OUT_OF_MEMORY;
AppendToTop(aItem);
return NS_OK;
}
/**
* Append a new item to the bottom of the list. If the item is null we return
* NS_ERROR_OUT_OF_MEMORY. The intended usage is AppendNewToBottom(new ...);
*/
nsresult AppendNewToBottom(nsDisplayItem* aItem) {
if (!aItem)
return NS_ERROR_OUT_OF_MEMORY;
AppendToBottom(aItem);
return NS_OK;
}
/**
* Append a new item to the bottom of the list. The item must be non-null
* and not already in a list.
*/
void AppendToBottom(nsDisplayItem* aItem) {
NS_ASSERTION(aItem, "No item to append!");
NS_ASSERTION(!aItem->mAbove, "Already in a list!");
aItem->mAbove = mSentinel.mAbove;
mSentinel.mAbove = aItem;
if (mTop == &mSentinel) {
mTop = aItem;
}
}
/**
* Removes all items from aList and appends them to the top of this list
*/
void AppendToTop(nsDisplayList* aList) {
if (aList->mSentinel.mAbove) {
mTop->mAbove = aList->mSentinel.mAbove;
mTop = aList->mTop;
aList->mTop = &aList->mSentinel;
aList->mSentinel.mAbove = nsnull;
}
}
/**
* Removes all items from aList and prepends them to the bottom of this list
*/
void AppendToBottom(nsDisplayList* aList) {
if (aList->mSentinel.mAbove) {
aList->mTop->mAbove = mSentinel.mAbove;
mTop = aList->mTop;
mSentinel.mAbove = aList->mSentinel.mAbove;
aList->mTop = &aList->mSentinel;
aList->mSentinel.mAbove = nsnull;
}
}
/**
* Remove an item from the bottom of the list and return it.
*/
nsDisplayItem* RemoveBottom();
/**
* Remove an item from the bottom of the list and call its destructor.
*/
void DeleteBottom();
/**
* Remove all items from the list and call their destructors.
*/
void DeleteAll();
/**
* @return the item at the top of the list, or null if the list is empty
*/
nsDisplayItem* GetTop() const {
return mTop != &mSentinel ? static_cast<nsDisplayItem*>(mTop) : nsnull;
}
/**
* @return the item at the bottom of the list, or null if the list is empty
*/
nsDisplayItem* GetBottom() const { return mSentinel.mAbove; }
PRBool IsEmpty() const { return mTop == &mSentinel; }
/**
* This is *linear time*!
* @return the number of items in the list
*/
PRUint32 Count() const;
/**
* Stable sort the list by the z-order of GetUnderlyingFrame() on
* each item. 'auto' is counted as zero. Content order is used as the
* secondary order.
* @param aCommonAncestor a common ancestor of all the content elements
* associated with the display items, for speeding up tree order
* checks, or nsnull if not known; it's only a hint, if it is not an
* ancestor of some elements, then we lose performance but not correctness
*/
void SortByZOrder(nsDisplayListBuilder* aBuilder, nsIContent* aCommonAncestor);
/**
* Stable sort the list by the tree order of the content of
* GetUnderlyingFrame() on each item. z-index is ignored.
* @param aCommonAncestor a common ancestor of all the content elements
* associated with the display items, for speeding up tree order
* checks, or nsnull if not known; it's only a hint, if it is not an
* ancestor of some elements, then we lose performance but not correctness
*/
void SortByContentOrder(nsDisplayListBuilder* aBuilder, nsIContent* aCommonAncestor);
/**
* Generic stable sort. Take care, because some of the items might be nsDisplayLists
* themselves.
* aCmp(item1, item2) should return true if item1 <= item2. We sort the items
* into increasing order.
*/
typedef PRBool (* SortLEQ)(nsDisplayItem* aItem1, nsDisplayItem* aItem2,
void* aClosure);
void Sort(nsDisplayListBuilder* aBuilder, SortLEQ aCmp, void* aClosure);
/**
* Optimize the display list for visibility, removing any elements that
* are not visible. We put this logic here so it can be shared by top-level
* painting and also display items that maintain child lists.
*
* @param aVisibleRegion the area that is visible, relative to the
* reference frame; on return, this contains the area visible under the list
*/
void OptimizeVisibility(nsDisplayListBuilder* aBuilder, nsRegion* aVisibleRegion);
/**
* Paint the list to the rendering context. We assume that (0,0) in aCtx
* corresponds to the origin of the reference frame. For best results,
* aCtx's current transform should make (0,0) pixel-aligned. The
* rectangle in aDirtyRect is painted, which *must* be contained in the
* dirty rect used to construct the display list.
*/
void Paint(nsDisplayListBuilder* aBuilder, nsIRenderingContext* aCtx,
const nsRect& aDirtyRect) const;
/**
* Get the bounds. Takes the union of the bounds of all children.
*/
nsRect GetBounds(nsDisplayListBuilder* aBuilder) const;
/**
* Find the topmost display item that returns a non-null frame, and return
* the frame.
*/
nsIFrame* HitTest(nsDisplayListBuilder* aBuilder, nsPoint aPt,
nsDisplayItem::HitTestState* aState) const;
private:
// This class is only used on stack, so we don't have to worry about leaking
// it. Don't let us be heap-allocated!
void* operator new(size_t sz) CPP_THROW_NEW;
// Utility function used to massage the list during OptimizeVisibility.
void FlattenTo(nsTArray<nsDisplayItem*>* aElements);
// Utility function used to massage the list during sorting, to rewrite
// any wrapper items with null GetUnderlyingFrame
void ExplodeAnonymousChildLists(nsDisplayListBuilder* aBuilder);
nsDisplayItemLink mSentinel;
nsDisplayItemLink* mTop;
};
/**
* This is passed as a parameter to nsIFrame::BuildDisplayList. That method
* will put any generated items onto the appropriate list given here. It's
* basically just a collection with one list for each separate stacking layer.
* The lists themselves are external to this object and thus can be shared
* with others. Some of the list pointers may even refer to the same list.
*/
class nsDisplayListSet {
public:
/**
* @return a list where one should place the border and/or background for
* this frame (everything from steps 1 and 2 of CSS 2.1 appendix E)
*/
nsDisplayList* BorderBackground() const { return mBorderBackground; }
/**
* @return a list where one should place the borders and/or backgrounds for
* block-level in-flow descendants (step 4 of CSS 2.1 appendix E)
*/
nsDisplayList* BlockBorderBackgrounds() const { return mBlockBorderBackgrounds; }
/**
* @return a list where one should place descendant floats (step 5 of
* CSS 2.1 appendix E)
*/
nsDisplayList* Floats() const { return mFloats; }
/**
* @return a list where one should place the (pseudo) stacking contexts
* for descendants of this frame (everything from steps 3, 7 and 8
* of CSS 2.1 appendix E)
*/
nsDisplayList* PositionedDescendants() const { return mPositioned; }
/**
* @return a list where one should place the outlines
* for this frame and its descendants (step 9 of CSS 2.1 appendix E)
*/
nsDisplayList* Outlines() const { return mOutlines; }
/**
* @return a list where one should place all other content
*/
nsDisplayList* Content() const { return mContent; }
nsDisplayListSet(nsDisplayList* aBorderBackground,
nsDisplayList* aBlockBorderBackgrounds,
nsDisplayList* aFloats,
nsDisplayList* aContent,
nsDisplayList* aPositionedDescendants,
nsDisplayList* aOutlines) :
mBorderBackground(aBorderBackground),
mBlockBorderBackgrounds(aBlockBorderBackgrounds),
mFloats(aFloats),
mContent(aContent),
mPositioned(aPositionedDescendants),
mOutlines(aOutlines) {
}
/**
* A copy constructor that lets the caller override the BorderBackground
* list.
*/
nsDisplayListSet(const nsDisplayListSet& aLists,
nsDisplayList* aBorderBackground) :
mBorderBackground(aBorderBackground),
mBlockBorderBackgrounds(aLists.BlockBorderBackgrounds()),
mFloats(aLists.Floats()),
mContent(aLists.Content()),
mPositioned(aLists.PositionedDescendants()),
mOutlines(aLists.Outlines()) {
}
/**
* Move all display items in our lists to top of the corresponding lists in the
* destination.
*/
void MoveTo(const nsDisplayListSet& aDestination) const;
private:
// This class is only used on stack, so we don't have to worry about leaking
// it. Don't let us be heap-allocated!
void* operator new(size_t sz) CPP_THROW_NEW;
protected:
nsDisplayList* mBorderBackground;
nsDisplayList* mBlockBorderBackgrounds;
nsDisplayList* mFloats;
nsDisplayList* mContent;
nsDisplayList* mPositioned;
nsDisplayList* mOutlines;
};
/**
* A specialization of nsDisplayListSet where the lists are actually internal
* to the object, and all distinct.
*/
struct nsDisplayListCollection : public nsDisplayListSet {
nsDisplayListCollection() :
nsDisplayListSet(&mLists[0], &mLists[1], &mLists[2], &mLists[3], &mLists[4],
&mLists[5]) {}
nsDisplayListCollection(nsDisplayList* aBorderBackground) :
nsDisplayListSet(aBorderBackground, &mLists[1], &mLists[2], &mLists[3], &mLists[4],
&mLists[5]) {}
/**
* Sort all lists by content order.
*/
void SortAllByContentOrder(nsDisplayListBuilder* aBuilder, nsIContent* aCommonAncestor) {
for (PRInt32 i = 0; i < 6; ++i) {
mLists[i].SortByContentOrder(aBuilder, aCommonAncestor);
}
}
private:
// This class is only used on stack, so we don't have to worry about leaking
// it. Don't let us be heap-allocated!
void* operator new(size_t sz) CPP_THROW_NEW;
nsDisplayList mLists[6];
};
/**
* Use this class to implement not-very-frequently-used display items
* that are not opaque, do not receive events, and are bounded by a frame's
* border-rect.
*
* This should not be used for display items which are created frequently,
* because each item is one or two pointers bigger than an item from a
* custom display item class could be, and fractionally slower. However it does
* save code size. We use this for infrequently-used item types.
*/
class nsDisplayGeneric : public nsDisplayItem {
public:
typedef void (* PaintCallback)(nsIFrame* aFrame, nsIRenderingContext* aCtx,
const nsRect& aDirtyRect, nsPoint aFramePt);
nsDisplayGeneric(nsIFrame* aFrame, PaintCallback aPaint, const char* aName)
: nsDisplayItem(aFrame), mPaint(aPaint)
#ifdef DEBUG
, mName(aName)
#endif
{
MOZ_COUNT_CTOR(nsDisplayGeneric);
}
#ifdef NS_BUILD_REFCNT_LOGGING
virtual ~nsDisplayGeneric() {
MOZ_COUNT_DTOR(nsDisplayGeneric);
}
#endif
virtual void Paint(nsDisplayListBuilder* aBuilder, nsIRenderingContext* aCtx,
const nsRect& aDirtyRect) {
mPaint(mFrame, aCtx, aDirtyRect, aBuilder->ToReferenceFrame(mFrame));
}
NS_DISPLAY_DECL_NAME(mName)
protected:
PaintCallback mPaint;
#ifdef DEBUG
const char* mName;
#endif
};
#if defined(MOZ_REFLOW_PERF_DSP) && defined(MOZ_REFLOW_PERF)
/**
* This class implements painting of reflow counts. Ideally, we would simply
* make all the frame names be those returned by nsIFrameDebug::GetFrameName
* (except that tosses in the content tag name!) and support only one color
* and eliminate this class altogether in favor of nsDisplayGeneric, but for
* the time being we can't pass args to a PaintCallback, so just have a
* separate class to do the right thing. Sadly, this alsmo means we need to
* hack all leaf frame classes to handle this.
*
* XXXbz the color thing is a bit of a mess, but 0 basically means "not set"
* here... I could switch it all to nscolor, but why bother?
*/
class nsDisplayReflowCount : public nsDisplayItem {
public:
nsDisplayReflowCount(nsIFrame* aFrame, const char* aFrameName,
PRUint32 aColor = 0)
: nsDisplayItem(aFrame),
mFrameName(aFrameName),
mColor(aColor)
{
MOZ_COUNT_CTOR(nsDisplayReflowCount);
}
#ifdef NS_BUILD_REFCNT_LOGGING
virtual ~nsDisplayReflowCount() {
MOZ_COUNT_DTOR(nsDisplayReflowCount);
}
#endif
virtual void Paint(nsDisplayListBuilder* aBuilder, nsIRenderingContext* aCtx,
const nsRect& aDirtyRect) {
nsPoint pt = aBuilder->ToReferenceFrame(mFrame);
nsIRenderingContext::AutoPushTranslation translate(aCtx, pt.x, pt.y);
mFrame->PresContext()->PresShell()->PaintCount(mFrameName, aCtx,
mFrame->PresContext(),
mFrame, mColor);
}
NS_DISPLAY_DECL_NAME("nsDisplayReflowCount")
protected:
const char* mFrameName;
nscolor mColor;
};
#define DO_GLOBAL_REFLOW_COUNT_DSP(_name) \
PR_BEGIN_MACRO \
if (!aBuilder->IsBackgroundOnly() && !aBuilder->IsForEventDelivery()) { \
nsresult _rv = \
aLists.Outlines()->AppendNewToTop(new (aBuilder) \
nsDisplayReflowCount(this, _name)); \
NS_ENSURE_SUCCESS(_rv, _rv); \
} \
PR_END_MACRO
#define DO_GLOBAL_REFLOW_COUNT_DSP_COLOR(_name, _color) \
PR_BEGIN_MACRO \
if (!aBuilder->IsBackgroundOnly() && !aBuilder->IsForEventDelivery()) { \
nsresult _rv = \
aLists.Outlines()->AppendNewToTop(new (aBuilder) \
nsDisplayReflowCount(this, _name, \
_color)); \
NS_ENSURE_SUCCESS(_rv, _rv); \
} \
PR_END_MACRO
/*
Macro to be used for classes that don't actually implement BuildDisplayList
*/
#define DECL_DO_GLOBAL_REFLOW_COUNT_DSP(_class, _super) \
NS_IMETHOD BuildDisplayList(nsDisplayListBuilder* aBuilder, \
const nsRect& aDirtyRect, \
const nsDisplayListSet& aLists) { \
DO_GLOBAL_REFLOW_COUNT_DSP(#_class); \
return _super::BuildDisplayList(aBuilder, aDirtyRect, aLists); \
}
#else // MOZ_REFLOW_PERF_DSP && MOZ_REFLOW_PERF
#define DO_GLOBAL_REFLOW_COUNT_DSP(_name)
#define DO_GLOBAL_REFLOW_COUNT_DSP_COLOR(_name, _color)
#define DECL_DO_GLOBAL_REFLOW_COUNT_DSP(_class, _super)
#endif // MOZ_REFLOW_PERF_DSP && MOZ_REFLOW_PERF
class nsDisplayCaret : public nsDisplayItem {
public:
nsDisplayCaret(nsIFrame* aCaretFrame, nsCaret *aCaret)
: nsDisplayItem(aCaretFrame), mCaret(aCaret) {
MOZ_COUNT_CTOR(nsDisplayCaret);
}
#ifdef NS_BUILD_REFCNT_LOGGING
virtual ~nsDisplayCaret() {
MOZ_COUNT_DTOR(nsDisplayCaret);
}
#endif
virtual nsRect GetBounds(nsDisplayListBuilder* aBuilder) {
// The caret returns a rect in the coordinates of mFrame.
return mCaret->GetCaretRect() + aBuilder->ToReferenceFrame(mFrame);
}
virtual void Paint(nsDisplayListBuilder* aBuilder, nsIRenderingContext* aCtx,
const nsRect& aDirtyRect);
NS_DISPLAY_DECL_NAME("Caret")
protected:
nsRefPtr<nsCaret> mCaret;
};
/**
* The standard display item to paint the CSS borders of a frame.
*/
class nsDisplayBorder : public nsDisplayItem {
public:
nsDisplayBorder(nsIFrame* aFrame) : nsDisplayItem(aFrame) {
MOZ_COUNT_CTOR(nsDisplayBorder);
}
#ifdef NS_BUILD_REFCNT_LOGGING
virtual ~nsDisplayBorder() {
MOZ_COUNT_DTOR(nsDisplayBorder);
}
#endif
virtual void Paint(nsDisplayListBuilder* aBuilder, nsIRenderingContext* aCtx,
const nsRect& aDirtyRect);
virtual PRBool OptimizeVisibility(nsDisplayListBuilder* aBuilder, nsRegion* aVisibleRegion);
NS_DISPLAY_DECL_NAME("Border")
};
/**
* The standard display item to paint the CSS background of a frame.
*/
class nsDisplayBackground : public nsDisplayItem {
public:
nsDisplayBackground(nsIFrame* aFrame) : nsDisplayItem(aFrame) {
mIsThemed = mFrame->IsThemed();
MOZ_COUNT_CTOR(nsDisplayBackground);
}
#ifdef NS_BUILD_REFCNT_LOGGING
virtual ~nsDisplayBackground() {
MOZ_COUNT_DTOR(nsDisplayBackground);
}
#endif
virtual nsIFrame* HitTest(nsDisplayListBuilder* aBuilder, nsPoint aPt,
HitTestState* aState) { return mFrame; }
virtual PRBool IsOpaque(nsDisplayListBuilder* aBuilder);
virtual PRBool IsVaryingRelativeToMovingFrame(nsDisplayListBuilder* aBuilder);
virtual PRBool IsUniform(nsDisplayListBuilder* aBuilder);
virtual nsRect GetBounds(nsDisplayListBuilder* aBuilder);
virtual void Paint(nsDisplayListBuilder* aBuilder, nsIRenderingContext* aCtx,
const nsRect& aDirtyRect);
NS_DISPLAY_DECL_NAME("Background")
private:
/* Used to cache mFrame->IsThemed() since it isn't a cheap call */
PRPackedBool mIsThemed;
};
/**
* The standard display item to paint the CSS box-shadow of a frame.
*/
class nsDisplayBoxShadow : public nsDisplayItem {
public:
nsDisplayBoxShadow(nsIFrame* aFrame) : nsDisplayItem(aFrame) {
MOZ_COUNT_CTOR(nsDisplayBoxShadow);
}
#ifdef NS_BUILD_REFCNT_LOGGING
virtual ~nsDisplayBoxShadow() {
MOZ_COUNT_DTOR(nsDisplayBoxShadow);
}
#endif
virtual void Paint(nsDisplayListBuilder* aBuilder, nsIRenderingContext* aCtx,
const nsRect& aDirtyRect);
virtual nsRect GetBounds(nsDisplayListBuilder* aBuilder);
NS_DISPLAY_DECL_NAME("BoxShadow")
};
/**
* The standard display item to paint the CSS outline of a frame.
*/
class nsDisplayOutline : public nsDisplayItem {
public:
nsDisplayOutline(nsIFrame* aFrame) : nsDisplayItem(aFrame) {
MOZ_COUNT_CTOR(nsDisplayOutline);
}
#ifdef NS_BUILD_REFCNT_LOGGING
virtual ~nsDisplayOutline() {
MOZ_COUNT_DTOR(nsDisplayOutline);
}
#endif
virtual Type GetType() { return TYPE_OUTLINE; }
virtual nsRect GetBounds(nsDisplayListBuilder* aBuilder);
virtual void Paint(nsDisplayListBuilder* aBuilder, nsIRenderingContext* aCtx,
const nsRect& aDirtyRect);
virtual PRBool OptimizeVisibility(nsDisplayListBuilder* aBuilder, nsRegion* aVisibleRegion);
NS_DISPLAY_DECL_NAME("Outline")
};
/**
* A class that lets you receive events within the frame bounds but never paints.
*/
class nsDisplayEventReceiver : public nsDisplayItem {
public:
nsDisplayEventReceiver(nsIFrame* aFrame) : nsDisplayItem(aFrame) {
MOZ_COUNT_CTOR(nsDisplayEventReceiver);
}
#ifdef NS_BUILD_REFCNT_LOGGING
virtual ~nsDisplayEventReceiver() {
MOZ_COUNT_DTOR(nsDisplayEventReceiver);
}
#endif
virtual nsIFrame* HitTest(nsDisplayListBuilder* aBuilder, nsPoint aPt,
HitTestState* aState) { return mFrame; }
NS_DISPLAY_DECL_NAME("EventReceiver")
};
/**
* A class that lets you wrap a display list as a display item.
*
* GetUnderlyingFrame() is troublesome for wrapped lists because if the wrapped
* list has many items, it's not clear which one has the 'underlying frame'.
* Thus we force the creator to specify what the underlying frame is. The
* underlying frame should be the root of a stacking context, because sorting
* a list containing this item will not get at the children.
*
* In some cases (e.g., clipping) we want to wrap a list but we don't have a
* particular underlying frame that is a stacking context root. In that case
* we allow the frame to be nsnull. Callers to GetUnderlyingFrame must
* detect and handle this case.
*/
class nsDisplayWrapList : public nsDisplayItem {
// This is never instantiated directly, so no need to count constructors and
// destructors.
public:
/**
* Takes all the items from aList and puts them in our list.
*/
nsDisplayWrapList(nsIFrame* aFrame, nsDisplayList* aList);
nsDisplayWrapList(nsIFrame* aFrame, nsDisplayItem* aItem);
virtual ~nsDisplayWrapList();
virtual Type GetType() { return TYPE_WRAPLIST; }
virtual nsIFrame* HitTest(nsDisplayListBuilder* aBuilder, nsPoint aPt,
HitTestState* aState);
virtual nsRect GetBounds(nsDisplayListBuilder* aBuilder);
virtual PRBool IsOpaque(nsDisplayListBuilder* aBuilder);
virtual PRBool IsUniform(nsDisplayListBuilder* aBuilder);
virtual PRBool IsVaryingRelativeToMovingFrame(nsDisplayListBuilder* aBuilder);
virtual void Paint(nsDisplayListBuilder* aBuilder, nsIRenderingContext* aCtx,
const nsRect& aDirtyRect);
virtual PRBool OptimizeVisibility(nsDisplayListBuilder* aBuilder,
nsRegion* aVisibleRegion);
virtual PRBool TryMerge(nsDisplayListBuilder* aBuilder, nsDisplayItem* aItem) {
NS_WARNING("This list should already have been flattened!!!");
return PR_FALSE;
}
NS_DISPLAY_DECL_NAME("WrapList")
virtual nsDisplayList* GetList() { return &mList; }
/**
* This creates a copy of this item, but wrapping aItem instead of
* our existing list. Only gets called if this item returned nsnull
* for GetUnderlyingFrame(). aItem is guaranteed to return non-null from
* GetUnderlyingFrame().
*/
virtual nsDisplayWrapList* WrapWithClone(nsDisplayListBuilder* aBuilder,
nsDisplayItem* aItem) {
NS_NOTREACHED("We never returned nsnull for GetUnderlyingFrame!");
return nsnull;
}
protected:
nsDisplayWrapList() {}
nsDisplayList mList;
};
/**
* We call WrapDisplayList on the in-flow lists: BorderBackground(),
* BlockBorderBackgrounds() and Content().
* We call WrapDisplayItem on each item of Outlines(), PositionedDescendants(),
* and Floats(). This is done to support special wrapping processing for frames
* that may not be in-flow descendants of the current frame.
*/
class nsDisplayWrapper {
public:
// This is never instantiated directly (it has pure virtual methods), so no
// need to count constructors and destructors.
virtual PRBool WrapBorderBackground() { return PR_TRUE; }
virtual nsDisplayItem* WrapList(nsDisplayListBuilder* aBuilder,
nsIFrame* aFrame, nsDisplayList* aList) = 0;
virtual nsDisplayItem* WrapItem(nsDisplayListBuilder* aBuilder,
nsDisplayItem* aItem) = 0;
nsresult WrapLists(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame,
const nsDisplayListSet& aIn, const nsDisplayListSet& aOut);
nsresult WrapListsInPlace(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame,
const nsDisplayListSet& aLists);
protected:
nsDisplayWrapper() {}
};
/**
* The standard display item to paint a stacking context with translucency
* set by the stacking context root frame's 'opacity' style.
*/
class nsDisplayOpacity : public nsDisplayWrapList {
public:
nsDisplayOpacity(nsIFrame* aFrame, nsDisplayList* aList);
#ifdef NS_BUILD_REFCNT_LOGGING
virtual ~nsDisplayOpacity();
#endif
virtual Type GetType() { return TYPE_OPACITY; }
virtual PRBool IsOpaque(nsDisplayListBuilder* aBuilder);
virtual void Paint(nsDisplayListBuilder* aBuilder, nsIRenderingContext* aCtx,
const nsRect& aDirtyRect);
virtual PRBool OptimizeVisibility(nsDisplayListBuilder* aBuilder,
nsRegion* aVisibleRegion);
virtual PRBool TryMerge(nsDisplayListBuilder* aBuilder, nsDisplayItem* aItem);
NS_DISPLAY_DECL_NAME("Opacity")
private:
/**
* We set this to PR_FALSE if we can prove that our children cover our bounds
* completely and opaquely, therefore no alpha channel is required in the
* intermediate surface.
*/
PRPackedBool mNeedAlpha;
};
/**
* nsDisplayClip can clip a list of items, but we take a single item
* initially and then later merge other items into it when we merge
* adjacent matching nsDisplayClips
*/
class nsDisplayClip : public nsDisplayWrapList {
public:
/**
* @param aFrame the frame that should be considered the underlying
* frame for this content, e.g. the frame whose z-index we have.
* @param aClippingFrame the frame that is inducing the clipping.
*/
nsDisplayClip(nsIFrame* aFrame, nsIFrame* aClippingFrame,
nsDisplayItem* aItem, const nsRect& aRect);
nsDisplayClip(nsIFrame* aFrame, nsIFrame* aClippingFrame,
nsDisplayList* aList, const nsRect& aRect);
#ifdef NS_BUILD_REFCNT_LOGGING
virtual ~nsDisplayClip();
#endif
virtual Type GetType() { return TYPE_CLIP; }
virtual nsRect GetBounds(nsDisplayListBuilder* aBuilder);
virtual void Paint(nsDisplayListBuilder* aBuilder, nsIRenderingContext* aCtx,
const nsRect& aDirtyRect);
virtual PRBool OptimizeVisibility(nsDisplayListBuilder* aBuilder,
nsRegion* aVisibleRegion);
virtual PRBool TryMerge(nsDisplayListBuilder* aBuilder, nsDisplayItem* aItem);
NS_DISPLAY_DECL_NAME("Clip")
nsRect GetClipRect() { return mClip; }
void SetClipRect(const nsRect& aRect) { mClip = aRect; }
nsIFrame* GetClippingFrame() { return mClippingFrame; }
virtual nsDisplayWrapList* WrapWithClone(nsDisplayListBuilder* aBuilder,
nsDisplayItem* aItem);
private:
// The frame that is responsible for the clipping. This may be different
// from mFrame because mFrame represents the content that is being
// clipped, and for example may be used to obtain the z-index of the
// content.
nsIFrame* mClippingFrame;
nsRect mClip;
};
#ifdef MOZ_SVG
/**
* A display item to paint a stacking context with effects
* set by the stacking context root frame's style.
*/
class nsDisplaySVGEffects : public nsDisplayWrapList {
public:
nsDisplaySVGEffects(nsIFrame* aFrame, nsDisplayList* aList);
#ifdef NS_BUILD_REFCNT_LOGGING
virtual ~nsDisplaySVGEffects();
#endif
virtual Type GetType() { return TYPE_SVG_EFFECTS; }
virtual PRBool IsOpaque(nsDisplayListBuilder* aBuilder);
virtual nsIFrame* HitTest(nsDisplayListBuilder* aBuilder, nsPoint aPt,
HitTestState* aState);
virtual nsRect GetBounds(nsDisplayListBuilder* aBuilder) {
return mBounds + aBuilder->ToReferenceFrame(mEffectsFrame);
}
virtual void Paint(nsDisplayListBuilder* aBuilder, nsIRenderingContext* aCtx,
const nsRect& aDirtyRect);
virtual PRBool OptimizeVisibility(nsDisplayListBuilder* aBuilder,
nsRegion* aVisibleRegion);
virtual PRBool TryMerge(nsDisplayListBuilder* aBuilder, nsDisplayItem* aItem);
NS_DISPLAY_DECL_NAME("SVGEffects")
nsIFrame* GetEffectsFrame() { return mEffectsFrame; }
private:
nsIFrame* mEffectsFrame;
// relative to mEffectsFrame
nsRect mBounds;
};
#endif
/* A display item that applies a transformation to all of its descendent
* elements. This wrapper should only be used if there is a transform applied
* to the root element.
* INVARIANT: The wrapped frame is transformed.
* INVARIANT: The wrapped frame is non-null.
*/
class nsDisplayTransform: public nsDisplayItem
{
public:
/* Constructor accepts a display list, empties it, and wraps it up. It also
* ferries the underlying frame to the nsDisplayItem constructor.
*/
nsDisplayTransform(nsIFrame *aFrame, nsDisplayList *aList) :
nsDisplayItem(aFrame), mStoredList(aFrame, aList)
{
MOZ_COUNT_CTOR(nsDisplayTransform);
}
#ifdef NS_BUILD_REFCNT_LOGGING
virtual ~nsDisplayTransform()
{
MOZ_COUNT_DTOR(nsDisplayTransform);
}
#endif
NS_DISPLAY_DECL_NAME("nsDisplayTransform");
virtual Type GetType()
{
return TYPE_TRANSFORM;
}
virtual nsIFrame* HitTest(nsDisplayListBuilder *aBuilder, nsPoint aPt,
HitTestState *aState);
virtual nsRect GetBounds(nsDisplayListBuilder *aBuilder);
virtual PRBool IsOpaque(nsDisplayListBuilder *aBuilder);
virtual PRBool IsUniform(nsDisplayListBuilder *aBuilder);
virtual void Paint(nsDisplayListBuilder *aBuilder,
nsIRenderingContext *aCtx,
const nsRect &aDirtyRect);
virtual PRBool OptimizeVisibility(nsDisplayListBuilder *aBuilder,
nsRegion *aVisibleRegion);
virtual PRBool TryMerge(nsDisplayListBuilder *aBuilder, nsDisplayItem *aItem);
/**
* TransformRect takes in as parameters a rectangle (in aFrame's coordinate
* space) and returns the smallest rectangle (in aFrame's coordinate space)
* containing the transformed image of that rectangle. That is, it takes
* the four corners of the rectangle, transforms them according to the
* matrix associated with the specified frame, then returns the smallest
* rectangle containing the four transformed points.
*
* @param untransformedBounds The rectangle (in app units) to transform.
* @param aFrame The frame whose transformation should be applied. This
* function raises an assertion if aFrame is null or doesn't have a
* transform applied to it.
* @param aOrigin The origin of the transform relative to aFrame's local
* coordinate space.
* @param aBoundsOverride (optional) Rather than using the frame's computed
* bounding rect as frame bounds, use this rectangle instead. Pass
* nsnull (or nothing at all) to use the default.
*/
static nsRect TransformRect(const nsRect &aUntransformedBounds,
const nsIFrame* aFrame,
const nsPoint &aOrigin,
const nsRect* aBoundsOverride = nsnull);
/* UntransformRect is like TransformRect, except that it inverts the
* transform.
*/
static nsRect UntransformRect(const nsRect &aUntransformedBounds,
const nsIFrame* aFrame,
const nsPoint &aOrigin);
/**
* Returns the bounds of a frame as defined for transforms. If
* UNIFIED_CONTINUATIONS is not defined, this is simply the frame's bounding
* rectangle, translated to the origin. Otherwise, returns the smallest
* rectangle containing a frame and all of its continuations. For example,
* if there is a <span> element with several continuations split over
* several lines, this function will return the rectangle containing all of
* those continuations. This rectangle is relative to the origin of the
* frame's local coordinate space.
*
* @param aFrame The frame to get the bounding rect for.
* @return The frame's bounding rect, as described above.
*/
static nsRect GetFrameBoundsForTransform(const nsIFrame* aFrame);
/**
* Given a frame with the -moz-transform property, returns the
* transformation matrix for that frame.
*
* @param aFrame The frame to get the matrix from.
* @param aOrigin Relative to which point this transform should be applied.
* @param aScaleFactor The number of app units per graphics unit.
* @param aBoundsOverride [optional] If this is nsnull (the default), the
* computation will use the value of GetFrameBoundsForTransform(aFrame)
* for the frame's bounding rectangle. Otherwise, it will use the
* value of aBoundsOverride. This is mostly for internal use and in
* most cases you will not need to specify a value.
*/
static gfxMatrix GetResultingTransformMatrix(const nsIFrame* aFrame,
const nsPoint& aOrigin,
float aFactor,
const nsRect* aBoundsOverride = nsnull);
private:
nsDisplayWrapList mStoredList;
};
#endif /*NSDISPLAYLIST_H_*/
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