com.openhtmltopdf.layout

Class Layer

java.lang.Object

com.openhtmltopdf.layout.Layer

public class Layer
extends Object

All positioned and transformed content as well as content with an overflow value other than visible creates a layer. Layers which define stacking contexts provide the entry for rendering the box tree to an output device. The main purpose of this class is to provide an implementation of Appendix E of the spec, but it also provides additional utility services including page management.

When rendering to a paged output device, the layer is also responsible for laying out absolute content (which is layed out after its containing block has completed layout).

Field Summary

Fields

Modifier and Type	Field and Description
static int	AUTO
static int	NEGATIVE
static short	PAGED_MODE_PRINT
static short	PAGED_MODE_SCREEN
static int	POSITIVE
static int	ZERO

Constructor Summary

Constructors

Constructor and Description
Layer(BlockBox master, CssContext c) Creates the root layer.
Layer(BlockBox master, CssContext c, boolean isolated)
Layer(Layer parent, BlockBox master, CssContext c) Creates a child layer.

Method Summary

Modifier and Type	Method and Description
void	addChild(Layer layer)
void	addFloat(BlockBox floater, BlockFormattingContext bfc)
void	addPage(CssContext c)
void	addPageSequence(BlockBox start)
void	addRunningBlock(BlockBox block)
void	assignPagePaintingPositions(CssContext cssCtx, int mode, int additionalClearance)
void	assignPagePaintingPositions(CssContext cssCtx, short mode)
List<Layer>	collectLayers(int which) Called recusively to collect all descendant layers in a layer tree so they can be painted in correct order.
static PageBox	createPageBox(CssContext c, String pseudoPage)
boolean	crossesPageBreak(LayoutContext c, int top, int bottom) Returns whether the a box with the given top and bottom would cross a page break.
void	detach()
void	ensureHasPage(CssContext c, Box box)
Layer	findRoot()
void	finish(LayoutContext c)
List<Layer>	getChildren() The resulting list should not be modified.
AffineTransform	getCurrentTransformMatrix() The document coordinates current transform, this is cumulative from layer to child layer.
PageBox	getFirstPage(CssContext c, Box box)
PageBox	getFirstPage(CssContext c, int absY) Returns the page box for a Y position.
List<BlockBox>	getFloats()
PageBox	getLastPage()
PageBox	getLastPage(CssContext c, Box box)
BlockBox	getMaster()
int	getMaxPageWidth(CssContext cssCtx, int additionalClearance)
PageBox	getPage(CssContext c, int yOffset) Gets the page box for the given document y offset.
PageBox	getPage(CssContext c, int yOffset, boolean addPages) Differs from getPage(CssContext, int) by allowing the caller to control whether a yOffset past the last page will add pages or just return null.
int	getPageIndex(int yOffset) Returns the zero based index of a page containing yOffset or -1 if yOffset is before the first page or after the last.
List<PageBox>	getPages()
List<PageBox>	getPages(CssContext c, int top, int bottom) Tries to return a list of pages that cover top to bottom.
Dimension	getPaintingDimension(LayoutContext c)
Layer	getParent()
int	getRelativePageCount(RenderingContext c)
int	getRelativePageNo(RenderingContext c)
int	getRelativePageNo(RenderingContext c, int absY)
BlockBox	getRunningBlock(String identifer, PageBox page, PageElementPosition which)
List<Layer>	getSortedLayers(int which)
int	getZIndex()
boolean	hasFixedAncester()
boolean	hasLocalTransform()
boolean	isForDeletion()
boolean	isIsolated()
boolean	isLastPage(PageBox pageBox)
boolean	isRequiresLayout()
boolean	isRootLayer()
boolean	isStackingContext()
boolean	isZIndexAuto()
void	layoutPages(LayoutContext c)
void	positionChildren(LayoutContext c)
void	positionFixedLayer(RenderingContext c)
void	propagateCurrentTransformationMatrix(CssContext c) Recursively propagates the transformation matrix.
void	removeFloat(BlockBox floater) FIXME: Only used when we reset a box, so trying to remove at sometime in the future.
void	removeLastPage()
void	removeRunningBlock(BlockBox block)
void	setForDeletion(boolean forDeletion)
void	setPages(List<PageBox> pages)
void	setRequiresLayout(boolean requiresLayout)
void	setStackingContext(boolean stackingContext)
void	trimEmptyPages(CssContext c, int maxYHeight)
void	trimPageCount(int newPageCount)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

PAGED_MODE_SCREEN

public static final short PAGED_MODE_SCREEN

See Also:

Constant Field Values

PAGED_MODE_PRINT

public static final short PAGED_MODE_PRINT

See Also:

Constant Field Values

POSITIVE

public static final int POSITIVE

See Also:

Constant Field Values

ZERO

public static final int ZERO

See Also:

Constant Field Values

NEGATIVE

public static final int NEGATIVE

See Also:

Constant Field Values

AUTO

public static final int AUTO

See Also:

Constant Field Values

Constructor Detail

Layer

public Layer(BlockBox master,
             CssContext c)

Creates the root layer.

Layer

public Layer(BlockBox master,
             CssContext c,
             boolean isolated)

Layer

public Layer(Layer parent,
             BlockBox master,
             CssContext c)

Creates a child layer.

Method Detail

propagateCurrentTransformationMatrix

public void propagateCurrentTransformationMatrix(CssContext c)

Recursively propagates the transformation matrix. This must be done after layout of the master box and its children as this method relies on the box width and height for relative units in the transforms and transform origins.

getCurrentTransformMatrix

public AffineTransform getCurrentTransformMatrix()

The document coordinates current transform, this is cumulative from layer to child layer. May be null, if identity transform is in effect. Used to check if a box belonging to this layer sits on a particular page after the transform is applied. This method can only be used after propagateCurrentTransformationMatrix(CssContext) has been called on the root layer.

Returns:

null or affine transform.

hasLocalTransform

public boolean hasLocalTransform()

setForDeletion

public void setForDeletion(boolean forDeletion)

isForDeletion

public boolean isForDeletion()

hasFixedAncester

public boolean hasFixedAncester()

getParent

public Layer getParent()

isStackingContext

public boolean isStackingContext()

setStackingContext

public void setStackingContext(boolean stackingContext)

getZIndex

public int getZIndex()

isZIndexAuto

public boolean isZIndexAuto()

getMaster

public BlockBox getMaster()

addChild

public void addChild(Layer layer)

createPageBox

public static PageBox createPageBox(CssContext c,
                                    String pseudoPage)

removeFloat

public void removeFloat(BlockBox floater)

FIXME: Only used when we reset a box, so trying to remove at sometime in the future.

addFloat

public void addFloat(BlockBox floater,
                     BlockFormattingContext bfc)

collectLayers

public List<Layer> collectLayers(int which)

Called recusively to collect all descendant layers in a layer tree so they can be painted in correct order.

Parameters:

which - NEGATIVE ZERO POSITIVE AUTO corresponding to z-index property.

getSortedLayers

public List<Layer> getSortedLayers(int which)

getPaintingDimension

public Dimension getPaintingDimension(LayoutContext c)

getFloats

public List<BlockBox> getFloats()

positionFixedLayer

public void positionFixedLayer(RenderingContext c)

isRootLayer

public boolean isRootLayer()

positionChildren

public void positionChildren(LayoutContext c)

getChildren

public List<Layer> getChildren()

The resulting list should not be modified.

detach

public void detach()

isRequiresLayout

public boolean isRequiresLayout()

setRequiresLayout

public void setRequiresLayout(boolean requiresLayout)

finish

public void finish(LayoutContext c)

getPages

public List<PageBox> getPages()

setPages

public void setPages(List<PageBox> pages)

isLastPage

public boolean isLastPage(PageBox pageBox)

removeLastPage

public void removeLastPage()

addPage

public void addPage(CssContext c)

getFirstPage

public PageBox getFirstPage(CssContext c,
                            int absY)

Returns the page box for a Y position. If the y position is less than 0 then the first page will be returned if available. Only returns null if there are no pages available.

IMPORTANT: If absY is past the end of the last page, pages will be created as required to include absY and the last page will be returned.

getFirstPage

public PageBox getFirstPage(CssContext c,
                            Box box)

getLastPage

public PageBox getLastPage(CssContext c,
                           Box box)

ensureHasPage

public void ensureHasPage(CssContext c,
                          Box box)

getPages

public List<PageBox> getPages(CssContext c,
                              int top,
                              int bottom)

Tries to return a list of pages that cover top to bottom. If top and bottom are less-than zero returns null.

IMPORTANT: If bottom is past the end of the last page, pages are created until bottom is included.

getPage

public PageBox getPage(CssContext c,
                       int yOffset)

Gets the page box for the given document y offset. If y offset is less-than zero returns null.

IMPORTANT: If y offset is past the end of the last page, pages are created until y offset is included and the last page is returned.

getPage

public PageBox getPage(CssContext c,
                       int yOffset,
                       boolean addPages)

Differs from getPage(CssContext, int) by allowing the caller to control whether a yOffset past the last page will add pages or just return null.

getPageIndex

public int getPageIndex(int yOffset)

Returns the zero based index of a page containing yOffset or -1 if yOffset is before the first page or after the last.

trimEmptyPages

public void trimEmptyPages(CssContext c,
                           int maxYHeight)

trimPageCount

public void trimPageCount(int newPageCount)

assignPagePaintingPositions

public void assignPagePaintingPositions(CssContext cssCtx,
                                        short mode)

assignPagePaintingPositions

public void assignPagePaintingPositions(CssContext cssCtx,
                                        int mode,
                                        int additionalClearance)

getMaxPageWidth

public int getMaxPageWidth(CssContext cssCtx,
                           int additionalClearance)

getLastPage

public PageBox getLastPage()

crossesPageBreak

public boolean crossesPageBreak(LayoutContext c,
                                int top,
                                int bottom)

Returns whether the a box with the given top and bottom would cross a page break.

Requirements: top is >= 0.

Important: This method will take into account any float: bottom content when used in in-flow content. For example, if the top/bottom pair overlaps the footnote area, returns true. It also takes into account space set aside for paginated table header/footer.

See CssContext.isInFloatBottom() LayoutContext.getExtraSpaceBottom()

findRoot

public Layer findRoot()

addRunningBlock

public void addRunningBlock(BlockBox block)

removeRunningBlock

public void removeRunningBlock(BlockBox block)

getRunningBlock

public BlockBox getRunningBlock(String identifer,
                                PageBox page,
                                PageElementPosition which)

layoutPages

public void layoutPages(LayoutContext c)

addPageSequence

public void addPageSequence(BlockBox start)

getRelativePageNo

public int getRelativePageNo(RenderingContext c,
                             int absY)

getRelativePageNo

public int getRelativePageNo(RenderingContext c)

getRelativePageCount

public int getRelativePageCount(RenderingContext c)

isIsolated

public boolean isIsolated()