The Tor Browser: gfx/thebes/gfxContext.h@b8a032363ba2 (annotated)

gfx/thebes/gfxContext.h@b8a032363ba2 (annotated)

gfx/thebes/gfxContext.h

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
  * This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #ifndef GFX_CONTEXT_H
 #define GFX_CONTEXT_H
 #include "gfxTypes.h"
 #include "gfxASurface.h"
 #include "gfxPoint.h"
 #include "gfxRect.h"
 #include "gfxMatrix.h"
 #include "gfxPattern.h"
 #include "gfxPath.h"
 #include "nsTArray.h"
 #include "nsAutoPtr.h"
 #include "mozilla/gfx/2D.h"
 typedef struct _cairo cairo_t;
 struct GlyphBufferAzure;
 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 gfxContext {
     NS_INLINE_DECL_REFCOUNTING(gfxContext)
 public:
     /**
      * Initialize this context from a surface.
      */
     gfxContext(gfxASurface *surface);
     /**
      * Initialize this context from a DrawTarget.
      * Strips any transform from aTarget.
      * aTarget will be flushed in the gfxContext's destructor.
      */
     gfxContext(mozilla::gfx::DrawTarget *aTarget,
                const mozilla::gfx::Point& aDeviceOffset = mozilla::gfx::Point());
     ~gfxContext();
     /**
      * Create a new gfxContext wrapping aTarget and preserving aTarget's
      * transform. Note that the transform is moved from aTarget to the resulting
      * gfxContext, aTarget will no longer have its transform.
      */
     static already_AddRefed<gfxContext> ContextForDrawTarget(mozilla::gfx::DrawTarget* aTarget);
     /**
      * 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(nullptr, nullptr);
     }
     /**
      * Return the raw cairo_t object.
      * XXX this should go away at some point.
      */
     cairo_t *GetCairo();
     mozilla::gfx::DrawTarget *GetDrawTarget() { return mDT; }
     /**
      * Returns true if the cairo context is in an error state.
      */
     bool 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();
     /**
      * Appends the given path to the current path.
      */
     void SetPath(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();
     /**
      * 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, bool snapToPixels = false);
     void SnappedRectangle(const gfxRect& rect) { return Rectangle(rect, true); }
     /**
      * 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, uint32_t 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 false,
      * then it's drawn counterclockwise.
      */
     void RoundedRectangle(const gfxRect& rect,
                           const gfxCornerSizes& corners,
                           bool draw_clockwise = 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);
     /**
      * As "Multiply", but also nudges any entries in the resulting matrix that
      * are close to an integer to that integer, to correct for
      * compounded rounding errors.
      */
     void MultiplyAndNudgeToIntegers(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 true, and the rect will
      * be in device coordinates (already transformed by the CTM).  If it
      * fails, the method will return false, and the rect will not be
      * changed.
      *
      * If ignoreScale is 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.
      */
     bool UserToDevicePixelSnapped(gfxRect& rect, bool ignoreScale = false) const;
     /**
      * Takes the given point and tries to align it to device pixels.  If
      * this succeeds, the method will return true, and the point will
      * be in device coordinates (already transformed by the CTM).  If it
      * fails, the method will return false, and the point will not be
      * changed.
      *
      * If ignoreScale is 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.
      */
     bool UserToDevicePixelSnapped(gfxPoint& pt, bool ignoreScale = 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 false if there is something other than a color
      *         set as the current source (pattern, surface, etc)
      */
     bool 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));
     void Mask(mozilla::gfx::SourceSurface *surface, const mozilla::gfx::Point& offset = mozilla::gfx::Point());
     /**
      ** 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 nullptr 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,
         OPERATOR_MULTIPLY,
         OPERATOR_SCREEN,
         OPERATOR_OVERLAY,
         OPERATOR_DARKEN,
         OPERATOR_LIGHTEN,
         OPERATOR_COLOR_DODGE,
         OPERATOR_COLOR_BURN,
         OPERATOR_HARD_LIGHT,
         OPERATOR_SOFT_LIGHT,
         OPERATOR_DIFFERENCE,
         OPERATOR_EXCLUSION,
         OPERATOR_HUE,
         OPERATOR_SATURATION,
         OPERATOR_COLOR,
         OPERATOR_LUMINOSITY
     };
     /**
      * 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();
     /**
      * Returns true if the given rectangle is fully contained in the current clip.
      * This is conservative; it may return false even when the given rectangle is
      * fully contained by the current clip.
      */
     bool ClipContainsRect(const gfxRect& aRect);
     /**
      * Groups
      */
     void PushGroup(gfxContentType content = gfxContentType::COLOR);
     /**
      * Like PushGroup, but if the current surface is gfxContentType::COLOR and
      * content is gfxContentType::COLOR_ALPHA, makes the pushed surface gfxContentType::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(gfxContentType content = gfxContentType::COLOR);
     already_AddRefed<gfxPattern> PopGroup();
     void PopGroupToSource();
     /**
      ** Hit Testing - check if given point is in the current path
      **/
     bool PointInFill(const gfxPoint& pt);
     bool PointInStroke(const gfxPoint& pt);
     /**
      ** Extents - returns user space extent of current path
      **/
     gfxRect GetUserPathExtent();
     gfxRect GetUserFillExtent();
     gfxRect GetUserStrokeExtent();
     mozilla::gfx::Point GetDeviceOffset() const;
     /**
      ** 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(int32_t aFlag) { mFlags |= aFlag; }
     void ClearFlag(int32_t aFlag) { mFlags &= ~aFlag; }
     int32_t GetFlags() const { return mFlags; }
     bool IsCairo() const { return !mDT; }
     // Work out whether cairo will snap inter-glyph spacing to pixels.
     void GetRoundOffsetsToPixels(bool *aRoundX, bool *aRoundY);
 #ifdef MOZ_DUMP_PAINTING
     /**
      * Debug functions to encode the current surface as a PNG and export it.
      */
     /**
      * Writes a binary PNG file.
      */
     void WriteAsPNG(const char* aFile);
     /**
      * Write as a PNG encoded Data URL to stdout.
      */
     void DumpAsDataURL();
     /**
      * Copy a PNG encoded Data URL to the clipboard.
      */
     void CopyAsDataURL();
 #endif
     static mozilla::gfx::UserDataKey sDontUseAsSourceKey;
 private:
   friend class GeneralPattern;
   friend struct GlyphBufferAzure;
   typedef mozilla::gfx::Matrix Matrix;
   typedef mozilla::gfx::DrawTarget DrawTarget;
   typedef mozilla::gfx::Color Color;
   typedef mozilla::gfx::StrokeOptions StrokeOptions;
   typedef mozilla::gfx::Float Float;
   typedef mozilla::gfx::Rect Rect;
   typedef mozilla::gfx::CompositionOp CompositionOp;
   typedef mozilla::gfx::Path Path;
   typedef mozilla::gfx::PathBuilder PathBuilder;
   typedef mozilla::gfx::SourceSurface SourceSurface;
   struct AzureState {
     AzureState()
       : op(mozilla::gfx::CompositionOp::OP_OVER)
       , opIsClear(false)
       , color(0, 0, 0, 1.0f)
       , clipWasReset(false)
       , fillRule(mozilla::gfx::FillRule::FILL_WINDING)
       , aaMode(mozilla::gfx::AntialiasMode::SUBPIXEL)
       , patternTransformChanged(false)
     {}
     mozilla::gfx::CompositionOp op;
     bool opIsClear;
     Color color;
     nsRefPtr<gfxPattern> pattern;
     nsRefPtr<gfxASurface> sourceSurfCairo;
     mozilla::RefPtr<SourceSurface> sourceSurface;
     mozilla::gfx::Point sourceSurfaceDeviceOffset;
     Matrix surfTransform;
     Matrix transform;
     struct PushedClip {
       mozilla::RefPtr<Path> path;
       Rect rect;
       Matrix transform;
     };
     nsTArray<PushedClip> pushedClips;
     nsTArray<Float> dashPattern;
     bool clipWasReset;
     mozilla::gfx::FillRule fillRule;
     StrokeOptions strokeOptions;
     mozilla::RefPtr<DrawTarget> drawTarget;
     mozilla::RefPtr<DrawTarget> parentTarget;
     mozilla::gfx::AntialiasMode aaMode;
     bool patternTransformChanged;
     Matrix patternTransform;
     // This is used solely for using minimal intermediate surface size.
     mozilla::gfx::Point deviceOffset;
   };
   // This ensures mPath contains a valid path (in user space!)
   void EnsurePath();
   // This ensures mPathBuilder contains a valid PathBuilder (in user space!)
   void EnsurePathBuilder();
   void FillAzure(mozilla::gfx::Float aOpacity);
   void PushClipsToDT(mozilla::gfx::DrawTarget *aDT);
   CompositionOp GetOp();
   void ChangeTransform(const mozilla::gfx::Matrix &aNewMatrix, bool aUpdatePatternTransform = true);
   Rect GetAzureDeviceSpaceClipBounds();
   Matrix GetDeviceTransform() const;
   Matrix GetDTTransform() const;
   void PushNewDT(gfxContentType content);
   bool mPathIsRect;
   bool mTransformChanged;
   Matrix mPathTransform;
   Rect mRect;
   mozilla::RefPtr<PathBuilder> mPathBuilder;
   mozilla::RefPtr<Path> mPath;
   Matrix mTransform;
   nsTArray<AzureState> mStateStack;
   AzureState &CurrentState() { return mStateStack[mStateStack.Length() - 1]; }
   const AzureState &CurrentState() const { return mStateStack[mStateStack.Length() - 1]; }
   cairo_t *mCairo;
   cairo_t *mRefCairo;
   nsRefPtr<gfxASurface> mSurface;
   int32_t mFlags;
   mozilla::RefPtr<DrawTarget> mDT;
   mozilla::RefPtr<DrawTarget> mOriginalDT;
 };
 /**
  * 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 gfxContextAutoSaveRestore
 {
 public:
   gfxContextAutoSaveRestore() : mContext(nullptr) {}
   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 gfxContextPathAutoSaveRestore
 {
 public:
     gfxContextPathAutoSaveRestore() : mContext(nullptr) {}
     gfxContextPathAutoSaveRestore(gfxContext *aContext, bool aSave = true) : mContext(aContext)
     {
         if (aSave)
             Save();
     }
     ~gfxContextPathAutoSaveRestore()
     {
         Restore();
     }
     void SetContext(gfxContext *aContext, bool aSave = 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->SetPath(mPath);
             mPath = nullptr;
         }
     }
 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 gfxContextMatrixAutoSaveRestore
 {
 public:
     gfxContextMatrixAutoSaveRestore() :
         mContext(nullptr)
     {
     }
     gfxContextMatrixAutoSaveRestore(gfxContext *aContext) :
         mContext(aContext), mMatrix(aContext->CurrentMatrix())
     {
     }
     ~gfxContextMatrixAutoSaveRestore()
     {
         if (mContext) {
             mContext->SetMatrix(mMatrix);
         }
     }
     void SetContext(gfxContext *aContext)
     {
         NS_ASSERTION(!mContext, "Not going to restore the matrix on some context!");
         mContext = aContext;
         mMatrix = aContext->CurrentMatrix();
     }
     void Restore()
     {
         if (mContext) {
             mContext->SetMatrix(mMatrix);
         }
     }
     const gfxMatrix& Matrix()
     {
         MOZ_ASSERT(mContext, "mMatrix doesn't contain a useful matrix");
         return mMatrix;
     }
 private:
     gfxContext *mContext;
     gfxMatrix   mMatrix;
 };
 class gfxContextAutoDisableSubpixelAntialiasing {
 public:
     gfxContextAutoDisableSubpixelAntialiasing(gfxContext *aContext, bool aDisable)
     {
         if (aDisable) {
             if (aContext->IsCairo()) {
                 mSurface = aContext->CurrentSurface();
                 if (!mSurface) {
                   return;
                 }
                 mSubpixelAntialiasingEnabled = mSurface->GetSubpixelAntialiasingEnabled();
                 mSurface->SetSubpixelAntialiasingEnabled(false);
             } else {
                 mDT = aContext->GetDrawTarget();
                 mSubpixelAntialiasingEnabled = mDT->GetPermitSubpixelAA();
                 mDT->SetPermitSubpixelAA(false);
             }
         }
     }
     ~gfxContextAutoDisableSubpixelAntialiasing()
     {
         if (mSurface) {
             mSurface->SetSubpixelAntialiasingEnabled(mSubpixelAntialiasingEnabled);
         } else if (mDT) {
             mDT->SetPermitSubpixelAA(mSubpixelAntialiasingEnabled);
         }
     }
 private:
     nsRefPtr<gfxASurface> mSurface;
     mozilla::RefPtr<mozilla::gfx::DrawTarget> mDT;
     bool mSubpixelAntialiasingEnabled;
 };
 #endif /* GFX_CONTEXT_H */

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gfx/thebes/gfxContext.h@b8a032363ba2 (annotated)

gfx/thebes/gfxContext.h