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gecko-dev/gfx/thebes/gfxContext.h

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/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* ***** 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 Oracle Corporation code.
*
* The Initial Developer of the Original Code is Oracle Corporation.
* Portions created by the Initial Developer are Copyright (C) 2005
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Stuart Parmenter <pavlov@pavlov.net>
* Vladimir Vukicevic <vladimir@pobox.com>
*
* Alternatively, the contents of this file may be used under the terms of
* either 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 GFX_CONTEXT_H
#define GFX_CONTEXT_H
#include "gfxTypes.h"
#include "gfxASurface.h"
#include "gfxColor.h"
#include "gfxPoint.h"
#include "gfxRect.h"
#include "gfxMatrix.h"
#include "gfxPattern.h"
#include "gfxPath.h"
#include "nsISupportsImpl.h"
typedef struct _cairo cairo_t;
template <typename T> class FallibleTArray;
/**
* This is the main class for doing actual drawing. It is initialized using
* a surface and can be drawn on. It manages various state information like
* a current transformation matrix (CTM), a current path, current color,
* etc.
*
* All drawing happens by creating a path and then stroking or filling it.
* The functions like Rectangle and Arc do not do any drawing themselves.
* When a path is drawn (stroked or filled), it is filled/stroked with a
* pattern set by SetPattern, SetColor or SetSource.
*
* Note that the gfxContext takes coordinates in device pixels,
* as opposed to app units.
*/
class THEBES_API gfxContext {
NS_INLINE_DECL_REFCOUNTING(gfxContext)
public:
/**
* Initialize this context from a surface.
*/
gfxContext(gfxASurface *surface);
~gfxContext();
/**
* Return the surface that this gfxContext was created with
*/
gfxASurface *OriginalSurface();
/**
* Return the current transparency group target, if any, along
* with its device offsets from the top. If no group is
* active, returns the surface the gfxContext was created with,
* and 0,0 in dx,dy.
*/
already_AddRefed<gfxASurface> CurrentSurface(gfxFloat *dx, gfxFloat *dy);
already_AddRefed<gfxASurface> CurrentSurface() {
return CurrentSurface(NULL, NULL);
}
/**
* Return the raw cairo_t object.
* XXX this should go away at some point.
*/
cairo_t *GetCairo() { return mCairo; }
/**
* Returns true if the cairo context is in an error state.
*/
PRBool HasError();
/**
** State
**/
// XXX document exactly what bits are saved
void Save();
void Restore();
/**
** Paths & Drawing
**/
/**
* Stroke the current path using the current settings (such as line
* width and color).
* A path is set up using functions such as Line, Rectangle and Arc.
*
* Does not consume the current path.
*/
void Stroke();
/**
* Fill the current path according to the current settings.
*
* Does not consume the current path.
*/
void Fill();
/**
* Fill the current path according to the current settings and
* with |aOpacity|.
*
* Does not consume the current path.
*/
void FillWithOpacity(gfxFloat aOpacity);
/**
* Forgets the current path.
*/
void NewPath();
/**
* Closes the path, i.e. connects the last drawn point to the first one.
*
* Filling a path will implicitly close it.
*/
void ClosePath();
/**
* Copies the current path and returns the copy.
*/
already_AddRefed<gfxPath> CopyPath() const;
/**
* Appends the given path to the current path.
*/
void AppendPath(gfxPath* path);
/**
* Moves the pen to a new point without drawing a line.
*/
void MoveTo(const gfxPoint& pt);
/**
* Creates a new subpath starting at the current point.
* Equivalent to MoveTo(CurrentPoint()).
*/
void NewSubPath();
/**
* Returns the current point in the current path.
*/
gfxPoint CurrentPoint() const;
/**
* Draws a line from the current point to pt.
*
* @see MoveTo
*/
void LineTo(const gfxPoint& pt);
/**
* Draws a cubic Bézier curve with control points pt1, pt2 and pt3.
*/
void CurveTo(const gfxPoint& pt1, const gfxPoint& pt2, const gfxPoint& pt3);
/**
* Draws a quadratic Bézier curve with control points pt1, pt2 and pt3.
*/
void QuadraticCurveTo(const gfxPoint& pt1, const gfxPoint& pt2);
/**
* Draws a clockwise arc (i.e. a circle segment).
* @param center The center of the circle
* @param radius The radius of the circle
* @param angle1 Starting angle for the segment
* @param angle2 Ending angle
*/
void Arc(const gfxPoint& center, gfxFloat radius,
gfxFloat angle1, gfxFloat angle2);
/**
* Draws a counter-clockwise arc (i.e. a circle segment).
* @param center The center of the circle
* @param radius The radius of the circle
* @param angle1 Starting angle for the segment
* @param angle2 Ending angle
*/
void NegativeArc(const gfxPoint& center, gfxFloat radius,
gfxFloat angle1, gfxFloat angle2);
// path helpers
/**
* Draws a line from start to end.
*/
void Line(const gfxPoint& start, const gfxPoint& end); // XXX snapToPixels option?
/**
* Draws the rectangle given by rect.
* @param snapToPixels ?
*/
void Rectangle(const gfxRect& rect, PRBool snapToPixels = PR_FALSE);
/**
* Draw an ellipse at the center corner with the given dimensions.
* It extends dimensions.width / 2.0 in the horizontal direction
* from the center, and dimensions.height / 2.0 in the vertical
* direction.
*/
void Ellipse(const gfxPoint& center, const gfxSize& dimensions);
/**
* Draw a polygon from the given points
*/
void Polygon(const gfxPoint *points, PRUint32 numPoints);
/*
* Draw a rounded rectangle, with the given outer rect and
* corners. The corners specify the radii of the two axes of an
* ellipse (the horizontal and vertical directions given by the
* width and height, respectively). By default the ellipse is
* drawn in a clockwise direction; if draw_clockwise is PR_FALSE,
* then it's drawn counterclockwise.
*/
void RoundedRectangle(const gfxRect& rect,
const gfxCornerSizes& corners,
PRBool draw_clockwise = PR_TRUE);
/**
** Transformation Matrix manipulation
**/
/**
* Adds a translation to the current matrix. This translation takes place
* before the previously set transformations.
*/
void Translate(const gfxPoint& pt);
/**
* Adds a scale to the current matrix. This scaling takes place before the
* previously set transformations.
*/
void Scale(gfxFloat x, gfxFloat y);
/**
* Adds a rotation around the origin to the current matrix. This rotation
* takes place before the previously set transformations.
*
* @param angle The angle in radians.
*/
void Rotate(gfxFloat angle);
/**
* Post-multiplies 'other' onto the current CTM, i.e. this
* matrix's transformation will take place before the previously set
* transformations.
*/
void Multiply(const gfxMatrix& other);
/**
* Replaces the current transformation matrix with matrix.
*/
void SetMatrix(const gfxMatrix& matrix);
/**
* Sets the transformation matrix to the identity matrix.
*/
void IdentityMatrix();
/**
* Returns the current transformation matrix.
*/
gfxMatrix CurrentMatrix() const;
/**
* Snap components of the current matrix that are close to integers
* to integers. In particular, components that are integral when
* converted to single precision are set to those integers.
*/
void NudgeCurrentMatrixToIntegers();
/**
* Converts a point from device to user coordinates using the inverse
* transformation matrix.
*/
gfxPoint DeviceToUser(const gfxPoint& point) const;
/**
* Converts a size from device to user coordinates. This does not apply
* translation components of the matrix.
*/
gfxSize DeviceToUser(const gfxSize& size) const;
/**
* Converts a rectangle from device to user coordinates; this has the
* same effect as using DeviceToUser on both the rectangle's point and
* size.
*/
gfxRect DeviceToUser(const gfxRect& rect) const;
/**
* Converts a point from user to device coordinates using the transformation
* matrix.
*/
gfxPoint UserToDevice(const gfxPoint& point) const;
/**
* Converts a size from user to device coordinates. This does not apply
* translation components of the matrix.
*/
gfxSize UserToDevice(const gfxSize& size) const;
/**
* Converts a rectangle from user to device coordinates. The
* resulting rectangle is the minimum device-space rectangle that
* encloses the user-space rectangle given.
*/
gfxRect UserToDevice(const gfxRect& rect) const;
/**
* Takes the given rect and tries to align it to device pixels. If
* this succeeds, the method will return PR_TRUE, and the rect will
* be in device coordinates (already transformed by the CTM). If it
* fails, the method will return PR_FALSE, and the rect will not be
* changed.
*
* If ignoreScale is PR_TRUE, then snapping will take place even if
* the CTM has a scale applied. Snapping never takes place if
* there is a rotation in the CTM.
*/
PRBool UserToDevicePixelSnapped(gfxRect& rect, PRBool ignoreScale = PR_FALSE) const;
/**
* Takes the given point and tries to align it to device pixels. If
* this succeeds, the method will return PR_TRUE, and the point will
* be in device coordinates (already transformed by the CTM). If it
* fails, the method will return PR_FALSE, and the point will not be
* changed.
*
* If ignoreScale is PR_TRUE, then snapping will take place even if
* the CTM has a scale applied. Snapping never takes place if
* there is a rotation in the CTM.
*/
PRBool UserToDevicePixelSnapped(gfxPoint& pt, PRBool ignoreScale = PR_FALSE) const;
/**
* Attempts to pixel snap the rectangle, add it to the current
* path, and to set pattern as the current painting source. This
* should be used for drawing filled pixel-snapped rectangles (like
* images), because the CTM at the time of the SetPattern call needs
* to have a snapped translation, or you get smeared images.
*/
void PixelSnappedRectangleAndSetPattern(const gfxRect& rect, gfxPattern *pattern);
/**
** Painting sources
**/
/**
* Set a solid color to use for drawing. This color is in the device color space
* and is not transformed.
*/
void SetDeviceColor(const gfxRGBA& c);
/**
* Gets the current color. It's returned in the device color space.
* returns PR_FALSE if there is something other than a color
* set as the current source (pattern, surface, etc)
*/
PRBool GetDeviceColor(gfxRGBA& c);
/**
* Set a solid color in the sRGB color space to use for drawing.
* If CMS is not enabled, the color is treated as a device-space color
* and this call is identical to SetDeviceColor().
*/
void SetColor(const gfxRGBA& c);
/**
* Uses a surface for drawing. This is a shorthand for creating a
* pattern and setting it.
*
* @param offset from the source surface, to use only part of it.
* May need to make it negative.
*/
void SetSource(gfxASurface *surface, const gfxPoint& offset = gfxPoint(0.0, 0.0));
/**
* Uses a pattern for drawing.
*/
void SetPattern(gfxPattern *pattern);
/**
* Get the source pattern (solid color, normal pattern, surface, etc)
*/
already_AddRefed<gfxPattern> GetPattern();
/**
** Painting
**/
/**
* Paints the current source surface/pattern everywhere in the current
* clip region.
*/
void Paint(gfxFloat alpha = 1.0);
/**
** Painting with a Mask
**/
/**
* Like Paint, except that it only draws the source where pattern is
* non-transparent.
*/
void Mask(gfxPattern *pattern);
/**
* Shorthand for creating a pattern and calling the pattern-taking
* variant of Mask.
*/
void Mask(gfxASurface *surface, const gfxPoint& offset = gfxPoint(0.0, 0.0));
/**
** Shortcuts
**/
/**
* Creates a new path with a rectangle from 0,0 to size.w,size.h
* and calls cairo_fill.
*/
void DrawSurface(gfxASurface *surface, const gfxSize& size);
/**
** Line Properties
**/
typedef enum {
gfxLineSolid,
gfxLineDashed,
gfxLineDotted
} gfxLineType;
void SetDash(gfxLineType ltype);
void SetDash(gfxFloat *dashes, int ndash, gfxFloat offset);
// Return true if dashing is set, false if it's not enabled or the
// context is in an error state. |offset| can be NULL to mean
// "don't care".
bool CurrentDash(FallibleTArray<gfxFloat>& dashes, gfxFloat* offset) const;
// Returns 0.0 if dashing isn't enabled.
gfxFloat CurrentDashOffset() const;
/**
* Sets the line width that's used for line drawing.
*/
void SetLineWidth(gfxFloat width);
/**
* Returns the currently set line width.
*
* @see SetLineWidth
*/
gfxFloat CurrentLineWidth() const;
enum GraphicsLineCap {
LINE_CAP_BUTT,
LINE_CAP_ROUND,
LINE_CAP_SQUARE
};
/**
* Sets the line caps, i.e. how line endings are drawn.
*/
void SetLineCap(GraphicsLineCap cap);
GraphicsLineCap CurrentLineCap() const;
enum GraphicsLineJoin {
LINE_JOIN_MITER,
LINE_JOIN_ROUND,
LINE_JOIN_BEVEL
};
/**
* Sets the line join, i.e. how the connection between two lines is
* drawn.
*/
void SetLineJoin(GraphicsLineJoin join);
GraphicsLineJoin CurrentLineJoin() const;
void SetMiterLimit(gfxFloat limit);
gfxFloat CurrentMiterLimit() const;
/**
** Fill Properties
**/
enum FillRule {
FILL_RULE_WINDING,
FILL_RULE_EVEN_ODD
};
void SetFillRule(FillRule rule);
FillRule CurrentFillRule() const;
/**
** Operators and Rendering control
**/
// define enum for operators (clear, src, dst, etc)
enum GraphicsOperator {
OPERATOR_CLEAR,
OPERATOR_SOURCE,
OPERATOR_OVER,
OPERATOR_IN,
OPERATOR_OUT,
OPERATOR_ATOP,
OPERATOR_DEST,
OPERATOR_DEST_OVER,
OPERATOR_DEST_IN,
OPERATOR_DEST_OUT,
OPERATOR_DEST_ATOP,
OPERATOR_XOR,
OPERATOR_ADD,
OPERATOR_SATURATE
};
/**
* Sets the operator used for all further drawing. The operator affects
* how drawing something will modify the destination. For example, the
* OVER operator will do alpha blending of source and destination, while
* SOURCE will replace the destination with the source.
*
* Note that if the flag FLAG_SIMPLIFY_OPERATORS is set on this
* gfxContext, the actual operator set might change for optimization
* purposes. Check the comments below around that flag.
*/
void SetOperator(GraphicsOperator op);
GraphicsOperator CurrentOperator() const;
/**
* MODE_ALIASED means that only pixels whose centers are in the drawn area
* should be modified, and they should be modified to take the value drawn
* at the pixel center.
*/
enum AntialiasMode {
MODE_ALIASED,
MODE_COVERAGE
};
void SetAntialiasMode(AntialiasMode mode);
AntialiasMode CurrentAntialiasMode() const;
/**
** Clipping
**/
/**
* Clips all further drawing to the current path.
* This does not consume the current path.
*/
void Clip();
/**
* Undoes any clipping. Further drawings will only be restricted by the
* surface dimensions.
*/
void ResetClip();
/**
* Helper functions that will create a rect path and call Clip().
* Any current path will be destroyed by these functions!
*/
void Clip(const gfxRect& rect); // will clip to a rect
/**
* This will ensure that the surface actually has its clip set.
* Useful if you are doing native drawing.
*/
void UpdateSurfaceClip();
/**
* This will return the current bounds of the clip region in user
* space.
*/
gfxRect GetClipExtents();
/**
* Groups
*/
void PushGroup(gfxASurface::gfxContentType content = gfxASurface::CONTENT_COLOR);
/**
* Like PushGroup, but if the current surface is CONTENT_COLOR and
* content is CONTENT_COLOR_ALPHA, makes the pushed surface CONTENT_COLOR
* instead and copies the contents of the current surface to the pushed
* surface. This is good for pushing opacity groups, since blending the
* group back to the current surface with some alpha applied will give
* the correct results and using an opaque pushed surface gives better
* quality and performance.
* This API really only makes sense if you do a PopGroupToSource and
* immediate Paint with OPERATOR_OVER.
*/
void PushGroupAndCopyBackground(gfxASurface::gfxContentType content = gfxASurface::CONTENT_COLOR);
already_AddRefed<gfxPattern> PopGroup();
void PopGroupToSource();
/**
** Hit Testing - check if given point is in the current path
**/
PRBool PointInFill(const gfxPoint& pt);
PRBool PointInStroke(const gfxPoint& pt);
/**
** Extents - returns user space extent of current path
**/
gfxRect GetUserPathExtent();
gfxRect GetUserFillExtent();
gfxRect GetUserStrokeExtent();
/**
** Obtaining a "flattened" path - path converted to all line segments
**/
already_AddRefed<gfxFlattenedPath> GetFlattenedPath();
/**
** Flags
**/
enum {
/* If this flag is set, operators other than CLEAR, SOURCE, or
* OVER will be converted to OVER before being sent to cairo.
*
* This is most useful with a printing surface, where
* operators such as ADD are used to avoid seams for on-screen
* display, but where such errors aren't noticeable in print.
* This approach is currently used in border rendering.
*
* However, when printing complex renderings such as SVG,
* care should be taken to clear this flag.
*/
FLAG_SIMPLIFY_OPERATORS = (1 << 0),
/**
* When this flag is set, snapping to device pixels is disabled.
* It simply never does anything.
*/
FLAG_DISABLE_SNAPPING = (1 << 1),
/**
* Disable copying of backgrounds in PushGroupAndCopyBackground.
*/
FLAG_DISABLE_COPY_BACKGROUND = (1 << 2)
};
void SetFlag(PRInt32 aFlag) { mFlags |= aFlag; }
void ClearFlag(PRInt32 aFlag) { mFlags &= ~aFlag; }
PRInt32 GetFlags() const { return mFlags; }
private:
cairo_t *mCairo;
nsRefPtr<gfxASurface> mSurface;
PRInt32 mFlags;
};
/**
* Sentry helper class for functions with multiple return points that need to
* call Save() on a gfxContext and have Restore() called automatically on the
* gfxContext before they return.
*/
class THEBES_API gfxContextAutoSaveRestore
{
public:
gfxContextAutoSaveRestore() : mContext(nsnull) {}
gfxContextAutoSaveRestore(gfxContext *aContext) : mContext(aContext) {
mContext->Save();
}
~gfxContextAutoSaveRestore() {
if (mContext) {
mContext->Restore();
}
}
void SetContext(gfxContext *aContext) {
NS_ASSERTION(!mContext, "Not going to call Restore() on some context!!!");
mContext = aContext;
mContext->Save();
}
void Reset(gfxContext *aContext) {
// Do the equivalent of destroying and re-creating this object.
NS_PRECONDITION(aContext, "must provide a context");
if (mContext) {
mContext->Restore();
}
mContext = aContext;
mContext->Save();
}
private:
gfxContext *mContext;
};
/**
* Sentry helper class for functions with multiple return points that need to
* back up the current path of a context and have it automatically restored
* before they return. This class assumes that the transformation matrix will
* be the same when Save and Restore are called. The calling function must
* ensure that this is the case or the path will be copied incorrectly.
*/
class THEBES_API gfxContextPathAutoSaveRestore
{
public:
gfxContextPathAutoSaveRestore() : mContext(nsnull) {}
gfxContextPathAutoSaveRestore(gfxContext *aContext, PRBool aSave = PR_TRUE) : mContext(aContext)
{
if (aSave)
Save();
}
~gfxContextPathAutoSaveRestore()
{
Restore();
}
void SetContext(gfxContext *aContext, PRBool aSave = PR_TRUE)
{
mContext = aContext;
if (aSave)
Save();
}
/**
* If a path is already saved, does nothing. Else copies the current path
* so that it may be restored.
*/
void Save()
{
if (!mPath && mContext) {
mPath = mContext->CopyPath();
}
}
/**
* If no path is saved, does nothing. Else replaces the context's path with
* a copy of the saved one, and clears the saved path.
*/
void Restore()
{
if (mPath) {
mContext->NewPath();
mContext->AppendPath(mPath);
mPath = nsnull;
}
}
private:
gfxContext *mContext;
nsRefPtr<gfxPath> mPath;
};
/**
* Sentry helper class for functions with multiple return points that need to
* back up the current matrix of a context and have it automatically restored
* before they return.
*/
class THEBES_API gfxContextMatrixAutoSaveRestore
{
public:
gfxContextMatrixAutoSaveRestore(gfxContext *aContext) :
mContext(aContext), mMatrix(aContext->CurrentMatrix())
{
}
~gfxContextMatrixAutoSaveRestore()
{
mContext->SetMatrix(mMatrix);
}
const gfxMatrix& Matrix()
{
return mMatrix;
}
private:
gfxContext *mContext;
gfxMatrix mMatrix;
};
class THEBES_API gfxContextAutoDisableSubpixelAntialiasing {
public:
gfxContextAutoDisableSubpixelAntialiasing(gfxContext *aContext, PRBool aDisable)
{
if (aDisable) {
mSurface = aContext->CurrentSurface();
mSubpixelAntialiasingEnabled = mSurface->GetSubpixelAntialiasingEnabled();
mSurface->SetSubpixelAntialiasingEnabled(PR_FALSE);
}
}
~gfxContextAutoDisableSubpixelAntialiasing()
{
if (mSurface) {
mSurface->SetSubpixelAntialiasingEnabled(mSubpixelAntialiasingEnabled);
}
}
private:
nsRefPtr<gfxASurface> mSurface;
PRPackedBool mSubpixelAntialiasingEnabled;
};
#endif /* GFX_CONTEXT_H */
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