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gecko/layout/base/nsLayoutUtils.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** 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 Mozilla.org code.
*
* The Initial Developer of the Original Code is
* Boris Zbarsky <bzbarsky@mit.edu>.
* Portions created by the Initial Developer are Copyright (C) 2002
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Boris Zbarsky <bzbarsky@mit.edu> (original author)
* L. David Baron <dbaron@dbaron.org>, Mozilla Corporation
* Mats Palmgren <mats.palmgren@bredband.net>
*
* 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 ***** */
#ifndef nsLayoutUtils_h__
#define nsLayoutUtils_h__
class nsIFormControlFrame;
class nsPresContext;
class nsIContent;
class nsIAtom;
class nsIScrollableView;
class nsIScrollableFrame;
class nsIDOMEvent;
class nsRegion;
class nsDisplayListBuilder;
class nsIFontMetrics;
#include "prtypes.h"
#include "nsStyleContext.h"
#include "nsAutoPtr.h"
#include "nsStyleSet.h"
#include "nsIView.h"
#include "nsIFrame.h"
class nsBlockFrame;
/**
* nsLayoutUtils is a namespace class used for various helper
* functions that are useful in multiple places in layout. The goal
* is not to define multiple copies of the same static helper.
*/
class nsLayoutUtils
{
public:
/**
* GetBeforeFrame returns the :before frame of the given frame, if
* one exists. This is typically O(1). The frame passed in must be
* the first-in-flow.
*
* @param aFrame the frame whose :before is wanted
* @return the :before frame or nsnull if there isn't one
*/
static nsIFrame* GetBeforeFrame(nsIFrame* aFrame);
/**
* GetAfterFrame returns the :after frame of the given frame, if one
* exists. This will walk the in-flow chain to the last-in-flow if
* needed. This function is typically O(N) in the number of child
* frames, following in-flows, etc.
*
* @param aFrame the frame whose :after is wanted
* @return the :after frame or nsnull if there isn't one
*/
static nsIFrame* GetAfterFrame(nsIFrame* aFrame);
/**
* Given a frame, search up the frame tree until we find an
* ancestor that (or the frame itself) is of type aFrameType, if any.
*
* @param aFrame the frame to start at
* @param aFrameType the frame type to look for
* @return a frame of the given type or nsnull if no
* such ancestor exists
*/
static nsIFrame* GetClosestFrameOfType(nsIFrame* aFrame, nsIAtom* aFrameType);
/**
* Given a frame, search up the frame tree until we find an
* ancestor that (or the frame itself) is a "Page" frame, if any.
*
* @param aFrame the frame to start at
* @return a frame of type nsGkAtoms::pageFrame or nsnull if no
* such ancestor exists
*/
static nsIFrame* GetPageFrame(nsIFrame* aFrame)
{
return GetClosestFrameOfType(aFrame, nsGkAtoms::pageFrame);
}
/**
* IsGeneratedContentFor returns PR_TRUE if aFrame is generated
* content of type aPseudoElement for aContent
*
* @param aContent the content node we're looking at. If this is
* null, then we just assume that aFrame has the right content
* pointer.
* @param aFrame the frame we're looking at
* @param aPseudoElement the pseudo type we're interested in
* @return whether aFrame is the generated aPseudoElement frame for aContent
*/
static PRBool IsGeneratedContentFor(nsIContent* aContent, nsIFrame* aFrame,
nsIAtom* aPseudoElement);
/**
* CompareTreePosition determines whether aContent1 comes before or
* after aContent2 in a preorder traversal of the content tree.
*
* @param aCommonAncestor either null, or a common ancestor of
* aContent1 and aContent2. Actually this is
* only a hint; if it's not an ancestor of
* aContent1 or aContent2, this function will
* still work, but it will be slower than
* normal.
* @return < 0 if aContent1 is before aContent2
* > 0 if aContent1 is after aContent2,
* 0 otherwise (meaning they're the same, or they're in
* different documents)
*/
static PRInt32 CompareTreePosition(nsIContent* aContent1,
nsIContent* aContent2,
nsIContent* aCommonAncestor = nsnull)
{
return DoCompareTreePosition(aContent1, aContent2, -1, 1, aCommonAncestor);
}
/*
* More generic version of |CompareTreePosition|. |aIf1Ancestor|
* gives the value to return when 1 is an ancestor of 2, and likewise
* for |aIf2Ancestor|. Passing (-1, 1) gives preorder traversal
* order, and (1, -1) gives postorder traversal order.
*/
static PRInt32 DoCompareTreePosition(nsIContent* aContent1,
nsIContent* aContent2,
PRInt32 aIf1Ancestor,
PRInt32 aIf2Ancestor,
nsIContent* aCommonAncestor = nsnull);
/**
* CompareTreePosition determines whether aFrame1 comes before or
* after aFrame2 in a preorder traversal of the frame tree, where out
* of flow frames are treated as children of their placeholders. This is
* basically the same ordering as DoCompareTreePosition(nsIContent*) except
* that it handles anonymous content properly and there are subtleties with
* continuations.
*
* @param aCommonAncestor either null, or a common ancestor of
* aContent1 and aContent2. Actually this is
* only a hint; if it's not an ancestor of
* aContent1 or aContent2, this function will
* still work, but it will be slower than
* normal.
* @return < 0 if aContent1 is before aContent2
* > 0 if aContent1 is after aContent2,
* 0 otherwise (meaning they're the same, or they're in
* different frame trees)
*/
static PRInt32 CompareTreePosition(nsIFrame* aFrame1,
nsIFrame* aFrame2,
nsIFrame* aCommonAncestor = nsnull)
{
return DoCompareTreePosition(aFrame1, aFrame2, -1, 1, aCommonAncestor);
}
/*
* More generic version of |CompareTreePosition|. |aIf1Ancestor|
* gives the value to return when 1 is an ancestor of 2, and likewise
* for |aIf2Ancestor|. Passing (-1, 1) gives preorder traversal
* order, and (1, -1) gives postorder traversal order.
*/
static PRInt32 DoCompareTreePosition(nsIFrame* aFrame1,
nsIFrame* aFrame2,
PRInt32 aIf1Ancestor,
PRInt32 aIf2Ancestor,
nsIFrame* aCommonAncestor = nsnull);
/**
* GetLastSibling simply finds the last sibling of aFrame, or returns nsnull if
* aFrame is null.
*/
static nsIFrame* GetLastSibling(nsIFrame* aFrame);
/**
* FindSiblingViewFor locates the child of aParentView that aFrame's
* view should be inserted 'above' (i.e., before in sibling view
* order). This is the first child view of aParentView whose
* corresponding content is before aFrame's content (view siblings
* are in reverse content order).
*/
static nsIView* FindSiblingViewFor(nsIView* aParentView, nsIFrame* aFrame);
/**
* Get the parent of aFrame. If aFrame is the root frame for a document,
* and the document has a parent document in the same view hierarchy, then
* we try to return the subdocumentframe in the parent document.
*/
static nsIFrame* GetCrossDocParentFrame(nsIFrame* aFrame);
/**
* IsProperAncestorFrame checks whether aAncestorFrame is an ancestor
* of aFrame and not equal to aFrame.
* @param aCommonAncestor nsnull, or a common ancestor of aFrame and
* aAncestorFrame. If non-null, this can bound the search and speed up
* the function
*/
static PRBool IsProperAncestorFrame(nsIFrame* aAncestorFrame, nsIFrame* aFrame,
nsIFrame* aCommonAncestor = nsnull);
/**
* Like IsProperAncestorFrame, but looks across document boundaries.
*/
static PRBool IsProperAncestorFrameCrossDoc(nsIFrame* aAncestorFrame, nsIFrame* aFrame,
nsIFrame* aCommonAncestor = nsnull);
/**
* GetFrameFor returns the root frame for a view
* @param aView is the view to return the root frame for
* @return the root frame for the view
*/
static nsIFrame* GetFrameFor(nsIView *aView)
{ return static_cast<nsIFrame*>(aView->GetClientData()); }
/**
* GetScrollableFrameFor returns the scrollable frame for a scrollable view
* @param aScrollableView is the scrollable view to return the
* scrollable frame for.
* @return the scrollable frame for the scrollable view
*/
static nsIScrollableFrame* GetScrollableFrameFor(nsIScrollableView *aScrollableView);
/**
* GetScrollableFrameFor returns the scrollable frame for a scrolled frame
*/
static nsIScrollableFrame* GetScrollableFrameFor(nsIFrame *aScrolledFrame);
static nsPresContext::ScrollbarStyles
ScrollbarStylesOfView(nsIScrollableView *aScrollableView);
/**
* GetNearestScrollingView locates the first ancestor of aView (or
* aView itself) that is scrollable. It does *not* count an
* 'overflow' style of 'hidden' as scrollable, even though a scrolling
* view is present. Thus, the direction of the scroll is needed as
* an argument.
*
* @param aView the view we're looking at
* @param aDirection Whether it's for horizontal or vertical scrolling.
* @return the nearest scrollable view or nsnull if not found
*/
enum Direction { eHorizontal, eVertical, eEither };
static nsIScrollableView* GetNearestScrollingView(nsIView* aView,
Direction aDirection);
/**
* HasPseudoStyle returns PR_TRUE if aContent (whose primary style
* context is aStyleContext) has the aPseudoElement pseudo-style
* attached to it; returns PR_FALSE otherwise.
*
* @param aContent the content node we're looking at
* @param aStyleContext aContent's style context
* @param aPseudoElement the name of the pseudo style we care about
* @param aPresContext the presentation context
* @return whether aContent has aPseudoElement style attached to it
*/
static PRBool HasPseudoStyle(nsIContent* aContent,
nsStyleContext* aStyleContext,
nsIAtom* aPseudoElement,
nsPresContext* aPresContext)
{
NS_PRECONDITION(aPresContext, "Must have a prescontext");
NS_PRECONDITION(aPseudoElement, "Must have a pseudo name");
nsRefPtr<nsStyleContext> pseudoContext;
if (aContent) {
pseudoContext = aPresContext->StyleSet()->
ProbePseudoStyleFor(aContent, aPseudoElement, aStyleContext);
}
return pseudoContext != nsnull;
}
/**
* If this frame is a placeholder for a float, then return the float,
* otherwise return nsnull.
*/
static nsIFrame* GetFloatFromPlaceholder(nsIFrame* aPossiblePlaceholder);
// Combine aNewBreakType with aOrigBreakType, but limit the break types
// to NS_STYLE_CLEAR_LEFT, RIGHT, LEFT_AND_RIGHT.
static PRUint8 CombineBreakType(PRUint8 aOrigBreakType, PRUint8 aNewBreakType);
/**
* @return PR_TRUE if aFrame is the CSS initial containing block for
* its pres-shell
*/
static PRBool IsInitialContainingBlock(nsIFrame* aFrame);
/**
* Get the coordinates of a given DOM mouse event, relative to a given
* frame. Works only for DOM events generated by nsGUIEvents.
* @param aDOMEvent the event
* @param aFrame the frame to make coordinates relative to
* @return the point, or (NS_UNCONSTRAINEDSIZE, NS_UNCONSTRAINEDSIZE) if
* for some reason the coordinates for the mouse are not known (e.g.,
* the event is not a GUI event).
*/
static nsPoint GetDOMEventCoordinatesRelativeTo(nsIDOMEvent* aDOMEvent,
nsIFrame* aFrame);
/**
* Get the coordinates of a given native mouse event, relative to a given
* frame.
* @param aEvent the event
* @param aFrame the frame to make coordinates relative to
* @return the point, or (NS_UNCONSTRAINEDSIZE, NS_UNCONSTRAINEDSIZE) if
* for some reason the coordinates for the mouse are not known (e.g.,
* the event is not a GUI event).
*/
static nsPoint GetEventCoordinatesRelativeTo(const nsEvent* aEvent,
nsIFrame* aFrame);
/**
* Get the coordinates of a given native mouse event, relative to the nearest
* view for a given frame.
* The "nearest view" is the view returned by nsFrame::GetOffsetFromView.
* XXX this is extremely BOGUS because "nearest view" is a mess; every
* use of this method is really a bug!
* @param aEvent the event
* @param aFrame the frame to make coordinates relative to
* @param aView view to which returned coordinates are relative
* @return the point, or (NS_UNCONSTRAINEDSIZE, NS_UNCONSTRAINEDSIZE) if
* for some reason the coordinates for the mouse are not known (e.g.,
* the event is not a GUI event).
*/
static nsPoint GetEventCoordinatesForNearestView(nsEvent* aEvent,
nsIFrame* aFrame,
nsIView** aView = nsnull);
/**
* Translate from widget coordinates to the view's coordinates
* @param aPresContext the PresContext for the view
* @param aWidget the widget
* @param aPt the point relative to the widget
* @param aView view to which returned coordinates are relative
* @return the point in the view's coordinates
*/
static nsPoint TranslateWidgetToView(nsPresContext* aPresContext,
nsIWidget* aWidget, nsIntPoint aPt,
nsIView* aView);
/**
* Given aFrame, the root frame of a stacking context, find its descendant
* frame under the point aPt that receives a mouse event at that location,
* or nsnull if there is no such frame.
* @param aPt the point, relative to the frame origin
* @param aShouldIgnoreSuppression a boolean to control if the display
* list builder should ignore paint suppression or not
*/
static nsIFrame* GetFrameForPoint(nsIFrame* aFrame, nsPoint aPt,
PRBool aShouldIgnoreSuppression = PR_FALSE);
/**
* Given aFrame, the root frame of a stacking context, paint it and its
* descendants to aRenderingContext.
* @param aRenderingContext a rendering context translated so that (0,0)
* is the origin of aFrame
* @param aDirtyRegion the region that must be painted, in the coordinates
* of aFrame
* @param aBackground paint the dirty area with this color before drawing
* the actual content; pass NS_RGBA(0,0,0,0) to draw no background
*/
static nsresult PaintFrame(nsIRenderingContext* aRenderingContext, nsIFrame* aFrame,
const nsRegion& aDirtyRegion, nscolor aBackground);
/**
* @param aRootFrame the root frame of the tree to be displayed
* @param aMovingFrame a frame that has moved
* @param aPt the amount by which aMovingFrame has moved and the rect will
* be copied
* @param aCopyRect a rectangle that will be copied, relative to aRootFrame
* @param aRepaintRegion a subregion of aCopyRect+aDelta that must be repainted
* after doing the bitblt
*
* Ideally this function would actually have the rect-to-copy as an output
* rather than an input, but for now, scroll bitblitting is limited to
* the whole of a single widget, so we cannot choose the rect.
*
* This function assumes that the caller will do a bitblt copy of aCopyRect
* to aCopyRect+aPt. It computes a region that must be repainted in order
* for the resulting rendering to be correct.
*
* The region consists of:
* a) any visible background-attachment:fixed areas in the after-move display
* list
* b) any visible areas of the before-move display list corresponding to
* frames that will not move (translated by aDelta)
* c) any visible areas of the after-move display list corresponding to
* frames that did not move
* d) except that if the same display list element is visible in b) and c)
* for a frame that did not move and paints a uniform color within its
* bounds, then the intersection of its old and new bounds can be excluded
* when it is processed by b) and c).
*
* We may return a larger region if computing the above region precisely is
* too expensive.
*/
static nsresult ComputeRepaintRegionForCopy(nsIFrame* aRootFrame,
nsIFrame* aMovingFrame,
nsPoint aDelta,
const nsRect& aCopyRect,
nsRegion* aRepaintRegion);
/**
* Compute the used z-index of aFrame; returns zero for elements to which
* z-index does not apply, and for z-index:auto
*/
static PRInt32 GetZIndex(nsIFrame* aFrame);
/**
* Uses a binary search for find where the cursor falls in the line of text
* It also keeps track of the part of the string that has already been measured
* so it doesn't have to keep measuring the same text over and over
*
* @param "aBaseWidth" contains the width in twips of the portion
* of the text that has already been measured, and aBaseInx contains
* the index of the text that has already been measured.
*
* @param aTextWidth returns the (in twips) the length of the text that falls
* before the cursor aIndex contains the index of the text where the cursor falls
*/
static PRBool
BinarySearchForPosition(nsIRenderingContext* acx,
const PRUnichar* aText,
PRInt32 aBaseWidth,
PRInt32 aBaseInx,
PRInt32 aStartInx,
PRInt32 aEndInx,
PRInt32 aCursorPos,
PRInt32& aIndex,
PRInt32& aTextWidth);
/**
* Get the union of all rects in aFrame and its continuations, relative
* to aFrame's origin. Scrolling is taken into account, but this shouldn't
* matter because it should be impossible to have some continuations scrolled
* differently from others.
*/
static nsRect GetAllInFlowBoundingRect(nsIFrame* aFrame);
/**
* Get the font metrics corresponding to the frame's style data.
* @param aFrame the frame
* @param aFontMetrics the font metrics result
* @return success or failure code
*/
static nsresult GetFontMetricsForFrame(nsIFrame* aFrame,
nsIFontMetrics** aFontMetrics);
/**
* Get the font metrics corresponding to the given style data.
* @param aStyleContext the style data
* @param aFontMetrics the font metrics result
* @return success or failure code
*/
static nsresult GetFontMetricsForStyleContext(nsStyleContext* aStyleContext,
nsIFontMetrics** aFontMetrics);
/**
* Find the immediate child of aParent whose frame subtree contains
* aDescendantFrame. Returns null if aDescendantFrame is not a descendant
* of aParent.
*/
static nsIFrame* FindChildContainingDescendant(nsIFrame* aParent, nsIFrame* aDescendantFrame);
/**
* Find the nearest ancestor that's a block
*/
static nsBlockFrame* FindNearestBlockAncestor(nsIFrame* aFrame);
/**
* If aFrame is an out of flow frame, return its placeholder, otherwise
* return its parent.
*/
static nsIFrame* GetParentOrPlaceholderFor(nsFrameManager* aFrameManager,
nsIFrame* aFrame);
/**
* Find the closest common ancestor of aFrame1 and aFrame2, following
* out of flow frames to their placeholders instead of their parents. Returns
* nsnull if the frames are in different frame trees.
*
* @param aKnownCommonAncestorHint a frame that is believed to be on the
* ancestor chain of both aFrame1 and aFrame2. If null, or a frame that is
* not in fact on both ancestor chains, then this function will still return
* the correct result, but it will be slower.
*/
static nsIFrame*
GetClosestCommonAncestorViaPlaceholders(nsIFrame* aFrame1, nsIFrame* aFrame2,
nsIFrame* aKnownCommonAncestorHint);
/**
* Get a frame's next-in-flow, or, if it doesn't have one, its special sibling.
*/
static nsIFrame*
GetNextContinuationOrSpecialSibling(nsIFrame *aFrame);
/**
* Check whether aFrame is a part of the scrollbar or scrollcorner of
* the root content.
* @param aFrame the checking frame
* @return if TRUE, the frame is a part of the scrollbar or scrollcorner of
* the root content.
*/
static PRBool IsViewportScrollbarFrame(nsIFrame* aFrame);
/**
* Return the value of aStyle as an nscoord if it can be determined without
* reference to ancestors or children (e.g. is not a percentage width)
* @param aStyle the style coord
* @param aRenderingContext the rendering context to use for font measurement
* @param aFrame the frame whose style context should be used for font information
* @param aResult the nscoord value of the style coord
* @return TRUE if the unit is eStyleUnit_Coord or eStyleUnit_Chars
*/
static PRBool GetAbsoluteCoord(const nsStyleCoord& aStyle,
nsIRenderingContext* aRenderingContext,
nsIFrame* aFrame,
nscoord& aResult)
{
return GetAbsoluteCoord(aStyle, aRenderingContext,
aFrame->GetStyleContext(), aResult);
}
/**
* Same as above but doesn't need a frame
*/
static PRBool GetAbsoluteCoord(const nsStyleCoord& aStyle,
nsIRenderingContext* aRenderingContext,
nsStyleContext* aStyleContext,
nscoord& aResult);
/**
* Get the contribution of aFrame to its containing block's intrinsic
* width. This considers the child's intrinsic width, its 'width',
* 'min-width', and 'max-width' properties, and its padding, border,
* and margin.
*/
enum IntrinsicWidthType { MIN_WIDTH, PREF_WIDTH };
static nscoord IntrinsicForContainer(nsIRenderingContext* aRenderingContext,
nsIFrame* aFrame,
IntrinsicWidthType aType);
/*
* Convert nsStyleCoord to nscoord when percentages depend on the
* containing block width.
*/
static nscoord ComputeWidthDependentValue(
nsIRenderingContext* aRenderingContext,
nsIFrame* aFrame,
nscoord aContainingBlockWidth,
const nsStyleCoord& aCoord);
/*
* Convert nsStyleCoord to nscoord when percentages depend on the
* containing block width, and enumerated values are for width,
* min-width, or max-width. Returns the content-box width value based
* on aContentEdgeToBoxSizing and aBoxSizingToMarginEdge (which are
* also used for the enumerated values for width. This function does
* not handle 'auto'. It ensures that the result is nonnegative.
*
* @param aRenderingContext Rendering context for font measurement/metrics.
* @param aFrame Frame whose (min-/max-/)width is being computed
* @param aContainingBlockWidth Width of aFrame's containing block.
* @param aContentEdgeToBoxSizing The sum of any left/right padding and
* border that goes inside the rect chosen by -moz-box-sizing.
* @param aBoxSizingToMarginEdge The sum of any left/right padding, border,
* and margin that goes outside the rect chosen by -moz-box-sizing.
* @param aCoord The width value to compute.
*/
static nscoord ComputeWidthValue(
nsIRenderingContext* aRenderingContext,
nsIFrame* aFrame,
nscoord aContainingBlockWidth,
nscoord aContentEdgeToBoxSizing,
nscoord aBoxSizingToMarginEdge,
const nsStyleCoord& aCoord);
/*
* Convert nsStyleCoord to nscoord when percentages depend on the
* containing block height.
*/
static nscoord ComputeHeightDependentValue(
nsIRenderingContext* aRenderingContext,
nsIFrame* aFrame,
nscoord aContainingBlockHeight,
const nsStyleCoord& aCoord);
static nsSize ComputeSizeWithIntrinsicDimensions(
nsIRenderingContext* aRenderingContext,
nsIFrame* aFrame, nsSize aIntrinsicSize, nsSize aCBSize,
nsSize aMargin, nsSize aBorder, nsSize aPadding);
// Implement nsIFrame::GetPrefWidth in terms of nsIFrame::AddInlinePrefWidth
static nscoord PrefWidthFromInline(nsIFrame* aFrame,
nsIRenderingContext* aRenderingContext);
// Implement nsIFrame::GetMinWidth in terms of nsIFrame::AddInlineMinWidth
static nscoord MinWidthFromInline(nsIFrame* aFrame,
nsIRenderingContext* aRenderingContext);
static void DrawString(const nsIFrame* aFrame,
nsIRenderingContext* aContext,
const PRUnichar* aString,
PRInt32 aLength,
nsPoint aPoint);
static nscoord GetStringWidth(const nsIFrame* aFrame,
nsIRenderingContext* aContext,
const PRUnichar* aString,
PRInt32 aLength);
/**
* Derive a baseline of |aFrame| (measured from its top border edge)
* from its first in-flow line box (not descending into anything with
* 'overflow' not 'visible', potentially including aFrame itself).
*
* Returns true if a baseline was found (and fills in aResult).
* Otherwise returns false.
*/
static PRBool GetFirstLineBaseline(const nsIFrame* aFrame, nscoord* aResult);
/**
* Derive a baseline of |aFrame| (measured from its top border edge)
* from its last in-flow line box (not descending into anything with
* 'overflow' not 'visible', potentially including aFrame itself).
*
* Returns true if a baseline was found (and fills in aResult).
* Otherwise returns false.
*/
static PRBool GetLastLineBaseline(const nsIFrame* aFrame, nscoord* aResult);
/**
* Gets the closest frame (the frame passed in or one of its parents) that
* qualifies as a "layer"; used in DOM0 methods that depends upon that
* definition. This is the nearest frame that is either positioned or scrolled
* (the child of a scroll frame). In Gecko terms, it's approximately
* equivalent to having a view, at least for simple HTML. However, views are
* going away, so this is a cleaner definition.
*/
static nsIFrame* GetClosestLayer(nsIFrame* aFrame);
/**
* Draw a single image.
* @param aRenderingContext Where to draw the image, set up with an
* appropriate scale and transform for drawing in
* app units (aDestRect).
* @param aImage The image.
* @param aDestRect Where to draw the image (app units).
* @param aDirtyRect Draw only within this region (rounded to the
* nearest pixel); the intersection of
* invalidation and clipping.
* @param aSourceRect If null, draw the entire image so it fits in
* aDestRect. If non-null, the subregion of the
* image that should be drawn (in app units, such
* that converting it to CSS pixels yields image
* pixels).
*/
static nsresult DrawImage(nsIRenderingContext* aRenderingContext,
imgIContainer* aImage,
const nsRect& aDestRect,
const nsRect& aDirtyRect,
const nsRect* aSourceRect = nsnull);
/**
* Set the font on aRC based on the style in aSC
*/
static void SetFontFromStyle(nsIRenderingContext* aRC, nsStyleContext* aSC);
/**
* Convert an eStyleUnit_Chars nsStyleCoord to an nscoord.
*
* @param aStyle the style coord
* @param aRenderingContext the rendering context to use for font measurement
* @param aStyleContext the style context to use for font infomation
*/
static nscoord CharsToCoord(const nsStyleCoord& aStyle,
nsIRenderingContext* aRenderingContext,
nsStyleContext* aStyleContext);
/**
* Determine if any style coordinate is nonzero
* @param aCoord the style sides
* @return PR_TRUE unless all the coordinates are 0%, 0 or null.
*/
static PRBool HasNonZeroSide(const nsStyleSides& aSides);
/**
* Determine if a widget is likely to require transparency or translucency.
* @param aFrame the frame of a <window>, <popup> or <menupopup> element.
* @return a value suitable for passing to SetWindowTranslucency
*/
static PRBool FrameHasTransparency(nsIFrame* aFrame);
/**
* Get textrun construction flags determined by a given style; in particular
* some combination of:
* -- TEXT_DISABLE_OPTIONAL_LIGATURES if letter-spacing is in use
* -- TEXT_OPTIMIZE_SPEED if the text-rendering CSS property and font size
* and prefs indicate we should be optimizing for speed over quality
*/
static PRUint32 GetTextRunFlagsForStyle(nsStyleContext* aStyleContext,
const nsStyleText* aStyleText,
const nsStyleFont* aStyleFont);
};
#endif // nsLayoutUtils_h__
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