The Tor Browser: layout/base/nsCSSRenderingBorders.cpp@6474c204b198 (annotated)

layout/base/nsCSSRenderingBorders.cpp@6474c204b198 (annotated)

layout/base/nsCSSRenderingBorders.cpp

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 // vim:cindent:ts=2:et:sw=2:
 /* 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/. */
 #include "nsStyleConsts.h"
 #include "nsCSSColorUtils.h"
 #include "GeckoProfiler.h"
 #include "nsExpirationTracker.h"
 #include "RoundedRect.h"
 #include "nsClassHashtable.h"
 #include "nsStyleStruct.h"
 #include "gfxContext.h"
 #include "nsCSSRenderingBorders.h"
 #include "mozilla/gfx/2D.h"
 #include "gfx2DGlue.h"
 #include "gfxGradientCache.h"
 #include <algorithm>
 using namespace mozilla;
 using namespace mozilla::gfx;
 /**
  * nsCSSRendering::PaintBorder
  * nsCSSRendering::PaintOutline
  *   -> DrawBorders
  *
  * DrawBorders
  *   -> Ability to use specialized approach?
  *      |- Draw using specialized function
  *   |- separate corners?
  *   |- dashed side mask
  *   |
  *   -> can border be drawn in 1 pass? (e.g., solid border same color all around)
  *      |- DrawBorderSides with all 4 sides
  *   -> more than 1 pass?
  *      |- for each corner
  *         |- clip to DoCornerClipSubPath
  *         |- for each side adjacent to corner
  *            |- clip to DoSideClipSubPath
  *            |- DrawBorderSides with one side
  *      |- for each side
  *         |- DoSideClipWithoutCornersSubPath
  *         |- DrawDashedSide || DrawBorderSides with one side
  */
 static void ComputeBorderCornerDimensions(const gfxRect& aOuterRect,
                                           const gfxRect& aInnerRect,
                                           const gfxCornerSizes& aRadii,
                                           gfxCornerSizes *aDimsResult);
 // given a side index, get the previous and next side index
 #define NEXT_SIDE(_s) mozilla::css::Side(((_s) + 1) & 3)
 #define PREV_SIDE(_s) mozilla::css::Side(((_s) + 3) & 3)
 // from the given base color and the background color, turn
 // color into a color for the given border pattern style
 static gfxRGBA MakeBorderColor(const gfxRGBA& aColor,
                                const gfxRGBA& aBackgroundColor,
                                BorderColorStyle aBorderColorStyle);
 // Given a line index (an index starting from the outside of the
 // border going inwards) and an array of line styles, calculate the
 // color that that stripe of the border should be rendered in.
 static gfxRGBA ComputeColorForLine(uint32_t aLineIndex,
                                    const BorderColorStyle* aBorderColorStyle,
                                    uint32_t aBorderColorStyleCount,
                                    nscolor aBorderColor,
                                    nscolor aBackgroundColor);
 static gfxRGBA ComputeCompositeColorForLine(uint32_t aLineIndex,
                                             const nsBorderColors* aBorderColors);
 // little helper function to check if the array of 4 floats given are
 // equal to the given value
 static bool
 CheckFourFloatsEqual(const gfxFloat *vals, gfxFloat k)
 {
   return (vals[0] == k &&
           vals[1] == k &&
           vals[2] == k &&
           vals[3] == k);
 }
 static bool
 IsZeroSize(const gfxSize& sz) {
   return sz.width == 0.0 || sz.height == 0.0;
 }
 static bool
 AllCornersZeroSize(const gfxCornerSizes& corners) {
   return IsZeroSize(corners[NS_CORNER_TOP_LEFT]) &&
     IsZeroSize(corners[NS_CORNER_TOP_RIGHT]) &&
     IsZeroSize(corners[NS_CORNER_BOTTOM_RIGHT]) &&
     IsZeroSize(corners[NS_CORNER_BOTTOM_LEFT]);
 }
 typedef enum {
   // Normal solid square corner.  Will be rectangular, the size of the
   // adjacent sides.  If the corner has a border radius, the corner
   // will always be solid, since we don't do dotted/dashed etc.
   CORNER_NORMAL,
   // Paint the corner in whatever style is not dotted/dashed of the
   // adjacent corners.
   CORNER_SOLID,
   // Paint the corner as a dot, the size of the bigger of the adjacent
   // sides.
   CORNER_DOT
 } CornerStyle;
 nsCSSBorderRenderer::nsCSSBorderRenderer(int32_t aAppUnitsPerPixel,
                                          gfxContext* aDestContext,
                                          gfxRect& aOuterRect,
                                          const uint8_t* aBorderStyles,
                                          const gfxFloat* aBorderWidths,
                                          gfxCornerSizes& aBorderRadii,
                                          const nscolor* aBorderColors,
                                          nsBorderColors* const* aCompositeColors,
                                          int aSkipSides,
                                          nscolor aBackgroundColor)
   : mContext(aDestContext),
     mOuterRect(aOuterRect),
     mBorderStyles(aBorderStyles),
     mBorderWidths(aBorderWidths),
     mBorderRadii(aBorderRadii),
     mBorderColors(aBorderColors),
     mCompositeColors(aCompositeColors),
     mAUPP(aAppUnitsPerPixel),
     mSkipSides(aSkipSides),
     mBackgroundColor(aBackgroundColor)
 {
   if (!mCompositeColors) {
     static nsBorderColors * const noColors[4] = { nullptr };
     mCompositeColors = &noColors[0];
   }
   mInnerRect = mOuterRect;
   mInnerRect.Deflate(
       gfxMargin(mBorderStyles[0] != NS_STYLE_BORDER_STYLE_NONE ? mBorderWidths[0] : 0,
                 mBorderStyles[1] != NS_STYLE_BORDER_STYLE_NONE ? mBorderWidths[1] : 0,
                 mBorderStyles[2] != NS_STYLE_BORDER_STYLE_NONE ? mBorderWidths[2] : 0,
                 mBorderStyles[3] != NS_STYLE_BORDER_STYLE_NONE ? mBorderWidths[3] : 0));
   ComputeBorderCornerDimensions(mOuterRect, mInnerRect, mBorderRadii, &mBorderCornerDimensions);
   mOneUnitBorder = CheckFourFloatsEqual(mBorderWidths, 1.0);
   mNoBorderRadius = AllCornersZeroSize(mBorderRadii);
   mAvoidStroke = false;
 }
 /* static */ void
 nsCSSBorderRenderer::ComputeInnerRadii(const gfxCornerSizes& aRadii,
                                        const gfxFloat *aBorderSizes,
                                        gfxCornerSizes *aInnerRadiiRet)
 {
   gfxCornerSizes& iRadii = *aInnerRadiiRet;
   iRadii[C_TL].width = std::max(0.0, aRadii[C_TL].width - aBorderSizes[NS_SIDE_LEFT]);
   iRadii[C_TL].height = std::max(0.0, aRadii[C_TL].height - aBorderSizes[NS_SIDE_TOP]);
   iRadii[C_TR].width = std::max(0.0, aRadii[C_TR].width - aBorderSizes[NS_SIDE_RIGHT]);
   iRadii[C_TR].height = std::max(0.0, aRadii[C_TR].height - aBorderSizes[NS_SIDE_TOP]);
   iRadii[C_BR].width = std::max(0.0, aRadii[C_BR].width - aBorderSizes[NS_SIDE_RIGHT]);
   iRadii[C_BR].height = std::max(0.0, aRadii[C_BR].height - aBorderSizes[NS_SIDE_BOTTOM]);
   iRadii[C_BL].width = std::max(0.0, aRadii[C_BL].width - aBorderSizes[NS_SIDE_LEFT]);
   iRadii[C_BL].height = std::max(0.0, aRadii[C_BL].height - aBorderSizes[NS_SIDE_BOTTOM]);
 }
 /* static */ void
 nsCSSBorderRenderer::ComputeOuterRadii(const gfxCornerSizes& aRadii,
                                        const gfxFloat *aBorderSizes,
                                        gfxCornerSizes *aOuterRadiiRet)
 {
   gfxCornerSizes& oRadii = *aOuterRadiiRet;
   // default all corners to sharp corners
   oRadii = gfxCornerSizes(0.0);
   // round the edges that have radii > 0.0 to start with
   if (aRadii[C_TL].width > 0.0 && aRadii[C_TL].height > 0.0) {
     oRadii[C_TL].width = std::max(0.0, aRadii[C_TL].width + aBorderSizes[NS_SIDE_LEFT]);
     oRadii[C_TL].height = std::max(0.0, aRadii[C_TL].height + aBorderSizes[NS_SIDE_TOP]);
   }
   if (aRadii[C_TR].width > 0.0 && aRadii[C_TR].height > 0.0) {
     oRadii[C_TR].width = std::max(0.0, aRadii[C_TR].width + aBorderSizes[NS_SIDE_RIGHT]);
     oRadii[C_TR].height = std::max(0.0, aRadii[C_TR].height + aBorderSizes[NS_SIDE_TOP]);
   }
   if (aRadii[C_BR].width > 0.0 && aRadii[C_BR].height > 0.0) {
     oRadii[C_BR].width = std::max(0.0, aRadii[C_BR].width + aBorderSizes[NS_SIDE_RIGHT]);
     oRadii[C_BR].height = std::max(0.0, aRadii[C_BR].height + aBorderSizes[NS_SIDE_BOTTOM]);
   }
   if (aRadii[C_BL].width > 0.0 && aRadii[C_BL].height > 0.0) {
     oRadii[C_BL].width = std::max(0.0, aRadii[C_BL].width + aBorderSizes[NS_SIDE_LEFT]);
     oRadii[C_BL].height = std::max(0.0, aRadii[C_BL].height + aBorderSizes[NS_SIDE_BOTTOM]);
   }
 }
 /*static*/ void
 ComputeBorderCornerDimensions(const gfxRect& aOuterRect,
                               const gfxRect& aInnerRect,
                               const gfxCornerSizes& aRadii,
                               gfxCornerSizes *aDimsRet)
 {
   gfxFloat leftWidth = aInnerRect.X() - aOuterRect.X();
   gfxFloat topWidth = aInnerRect.Y() - aOuterRect.Y();
   gfxFloat rightWidth = aOuterRect.Width() - aInnerRect.Width() - leftWidth;
   gfxFloat bottomWidth = aOuterRect.Height() - aInnerRect.Height() - topWidth;
   if (AllCornersZeroSize(aRadii)) {
     // These will always be in pixel units from CSS
     (*aDimsRet)[C_TL] = gfxSize(leftWidth, topWidth);
     (*aDimsRet)[C_TR] = gfxSize(rightWidth, topWidth);
     (*aDimsRet)[C_BR] = gfxSize(rightWidth, bottomWidth);
     (*aDimsRet)[C_BL] = gfxSize(leftWidth, bottomWidth);
   } else {
     // Always round up to whole pixels for the corners; it's safe to
     // make the corners bigger than necessary, and this way we ensure
     // that we avoid seams.
     (*aDimsRet)[C_TL] = gfxSize(ceil(std::max(leftWidth, aRadii[C_TL].width)),
                                 ceil(std::max(topWidth, aRadii[C_TL].height)));
     (*aDimsRet)[C_TR] = gfxSize(ceil(std::max(rightWidth, aRadii[C_TR].width)),
                                 ceil(std::max(topWidth, aRadii[C_TR].height)));
     (*aDimsRet)[C_BR] = gfxSize(ceil(std::max(rightWidth, aRadii[C_BR].width)),
                                 ceil(std::max(bottomWidth, aRadii[C_BR].height)));
     (*aDimsRet)[C_BL] = gfxSize(ceil(std::max(leftWidth, aRadii[C_BL].width)),
                                 ceil(std::max(bottomWidth, aRadii[C_BL].height)));
   }
 }
 bool
 nsCSSBorderRenderer::AreBorderSideFinalStylesSame(uint8_t aSides)
 {
   NS_ASSERTION(aSides != 0 && (aSides & ~SIDE_BITS_ALL) == 0,
                "AreBorderSidesSame: invalid whichSides!");
   /* First check if the specified styles and colors are the same for all sides */
   int firstStyle = 0;
   NS_FOR_CSS_SIDES (i) {
     if (firstStyle == i) {
       if (((1 << i) & aSides) == 0)
         firstStyle++;
       continue;
     }
     if (((1 << i) & aSides) == 0) {
       continue;
     }
     if (mBorderStyles[firstStyle] != mBorderStyles[i] ||
         mBorderColors[firstStyle] != mBorderColors[i] ||
         !nsBorderColors::Equal(mCompositeColors[firstStyle],
                                mCompositeColors[i]))
       return false;
   }
   /* Then if it's one of the two-tone styles and we're not
    * just comparing the TL or BR sides */
   switch (mBorderStyles[firstStyle]) {
     case NS_STYLE_BORDER_STYLE_GROOVE:
     case NS_STYLE_BORDER_STYLE_RIDGE:
     case NS_STYLE_BORDER_STYLE_INSET:
     case NS_STYLE_BORDER_STYLE_OUTSET:
       return ((aSides & ~(SIDE_BIT_TOP | SIDE_BIT_LEFT)) == 0 ||
               (aSides & ~(SIDE_BIT_BOTTOM | SIDE_BIT_RIGHT)) == 0);
   }
   return true;
 }
 bool
 nsCSSBorderRenderer::IsSolidCornerStyle(uint8_t aStyle, mozilla::css::Corner aCorner)
 {
   switch (aStyle) {
     case NS_STYLE_BORDER_STYLE_DOTTED:
     case NS_STYLE_BORDER_STYLE_DASHED:
     case NS_STYLE_BORDER_STYLE_SOLID:
       return true;
     case NS_STYLE_BORDER_STYLE_INSET:
     case NS_STYLE_BORDER_STYLE_OUTSET:
       return (aCorner == NS_CORNER_TOP_LEFT || aCorner == NS_CORNER_BOTTOM_RIGHT);
     case NS_STYLE_BORDER_STYLE_GROOVE:
     case NS_STYLE_BORDER_STYLE_RIDGE:
       return mOneUnitBorder && (aCorner == NS_CORNER_TOP_LEFT || aCorner == NS_CORNER_BOTTOM_RIGHT);
     case NS_STYLE_BORDER_STYLE_DOUBLE:
       return mOneUnitBorder;
     default:
       return false;
   }
 }
 BorderColorStyle
 nsCSSBorderRenderer::BorderColorStyleForSolidCorner(uint8_t aStyle, mozilla::css::Corner aCorner)
 {
   // note that this function assumes that the corner is already solid,
   // as per the earlier function
   switch (aStyle) {
     case NS_STYLE_BORDER_STYLE_DOTTED:
     case NS_STYLE_BORDER_STYLE_DASHED:
     case NS_STYLE_BORDER_STYLE_SOLID:
     case NS_STYLE_BORDER_STYLE_DOUBLE:
       return BorderColorStyleSolid;
     case NS_STYLE_BORDER_STYLE_INSET:
     case NS_STYLE_BORDER_STYLE_GROOVE:
       if (aCorner == NS_CORNER_TOP_LEFT)
         return BorderColorStyleDark;
       else if (aCorner == NS_CORNER_BOTTOM_RIGHT)
         return BorderColorStyleLight;
       break;
     case NS_STYLE_BORDER_STYLE_OUTSET:
     case NS_STYLE_BORDER_STYLE_RIDGE:
       if (aCorner == NS_CORNER_TOP_LEFT)
         return BorderColorStyleLight;
       else if (aCorner == NS_CORNER_BOTTOM_RIGHT)
         return BorderColorStyleDark;
       break;
   }
   return BorderColorStyleNone;
 }
 void
 nsCSSBorderRenderer::DoCornerSubPath(mozilla::css::Corner aCorner)
 {
   gfxPoint offset(0.0, 0.0);
   if (aCorner == C_TR || aCorner == C_BR)
     offset.x = mOuterRect.Width() - mBorderCornerDimensions[aCorner].width;
   if (aCorner == C_BR || aCorner == C_BL)
     offset.y = mOuterRect.Height() - mBorderCornerDimensions[aCorner].height;
   mContext->Rectangle(gfxRect(mOuterRect.TopLeft() + offset,
                               mBorderCornerDimensions[aCorner]));
 }
 void
 nsCSSBorderRenderer::DoSideClipWithoutCornersSubPath(mozilla::css::Side aSide)
 {
   gfxPoint offset(0.0, 0.0);
   // The offset from the outside rect to the start of this side's
   // box.  For the top and bottom sides, the height of the box
   // must be the border height; the x start must take into account
   // the corner size (which may be bigger than the right or left
   // side's width).  The same applies to the right and left sides.
   if (aSide == NS_SIDE_TOP) {
     offset.x = mBorderCornerDimensions[C_TL].width;
   } else if (aSide == NS_SIDE_RIGHT) {
     offset.x = mOuterRect.Width() - mBorderWidths[NS_SIDE_RIGHT];
     offset.y = mBorderCornerDimensions[C_TR].height;
   } else if (aSide == NS_SIDE_BOTTOM) {
     offset.x = mBorderCornerDimensions[C_BL].width;
     offset.y = mOuterRect.Height() - mBorderWidths[NS_SIDE_BOTTOM];
   } else if (aSide == NS_SIDE_LEFT) {
     offset.y = mBorderCornerDimensions[C_TL].height;
   }
   // The sum of the width & height of the corners adjacent to the
   // side.  This relies on the relationship between side indexing and
   // corner indexing; that is, 0 == SIDE_TOP and 0 == CORNER_TOP_LEFT,
   // with both proceeding clockwise.
   gfxSize sideCornerSum = mBorderCornerDimensions[mozilla::css::Corner(aSide)]
                         + mBorderCornerDimensions[mozilla::css::Corner(NEXT_SIDE(aSide))];
   gfxRect rect(mOuterRect.TopLeft() + offset,
                mOuterRect.Size() - sideCornerSum);
   if (aSide == NS_SIDE_TOP || aSide == NS_SIDE_BOTTOM)
     rect.height = mBorderWidths[aSide];
   else
     rect.width = mBorderWidths[aSide];
   mContext->Rectangle(rect);
 }
 // The side border type and the adjacent border types are
 // examined and one of the different types of clipping (listed
 // below) is selected.
 typedef enum {
   // clip to the trapezoid formed by the corners of the
   // inner and outer rectangles for the given side
   SIDE_CLIP_TRAPEZOID,
   // clip to the trapezoid formed by the outer rectangle
   // corners and the center of the region, making sure
   // that diagonal lines all go directly from the outside
   // corner to the inside corner, but that they then continue on
   // to the middle.
   //
   // This is needed for correctly clipping rounded borders,
   // which might extend past the SIDE_CLIP_TRAPEZOID trap.
   SIDE_CLIP_TRAPEZOID_FULL,
   // clip to the rectangle formed by the given side; a specific
   // overlap algorithm is used; see the function for details.
   // this is currently used for dashing.
   SIDE_CLIP_RECTANGLE
 } SideClipType;
 // Given three points, p0, p1, and midPoint, move p1 further in to the
 // rectangle (of which aMidPoint is the center) so that it reaches the
 // closer of the horizontal or vertical lines intersecting the midpoint,
 // while maintaing the slope of the line.  If p0 and p1 are the same,
 // just move p1 to midPoint (since there's no slope to maintain).
 // FIXME: Extending only to the midpoint isn't actually sufficient for
 // boxes with asymmetric radii.
 static void
 MaybeMoveToMidPoint(gfxPoint& aP0, gfxPoint& aP1, const gfxPoint& aMidPoint)
 {
   gfxPoint ps = aP1 - aP0;
   if (ps.x == 0.0) {
     if (ps.y == 0.0) {
       aP1 = aMidPoint;
     } else {
       aP1.y = aMidPoint.y;
     }
   } else {
     if (ps.y == 0.0) {
       aP1.x = aMidPoint.x;
     } else {
       gfxFloat k = std::min((aMidPoint.x - aP0.x) / ps.x,
                           (aMidPoint.y - aP0.y) / ps.y);
       aP1 = aP0 + ps * k;
     }
   }
 }
 void
 nsCSSBorderRenderer::DoSideClipSubPath(mozilla::css::Side aSide)
 {
   // the clip proceeds clockwise from the top left corner;
   // so "start" in each case is the start of the region from that side.
   //
   // the final path will be formed like:
   // s0 ------- e0
   // |         /
   // s1 ----- e1
   //
   // that is, the second point will always be on the inside
   gfxPoint start[2];
   gfxPoint end[2];
 #define IS_DASHED_OR_DOTTED(_s)  ((_s) == NS_STYLE_BORDER_STYLE_DASHED || (_s) == NS_STYLE_BORDER_STYLE_DOTTED)
   bool isDashed      = IS_DASHED_OR_DOTTED(mBorderStyles[aSide]);
   bool startIsDashed = IS_DASHED_OR_DOTTED(mBorderStyles[PREV_SIDE(aSide)]);
   bool endIsDashed   = IS_DASHED_OR_DOTTED(mBorderStyles[NEXT_SIDE(aSide)]);
 #undef IS_DASHED_OR_DOTTED
   SideClipType startType = SIDE_CLIP_TRAPEZOID;
   SideClipType endType = SIDE_CLIP_TRAPEZOID;
   if (!IsZeroSize(mBorderRadii[mozilla::css::Corner(aSide)]))
     startType = SIDE_CLIP_TRAPEZOID_FULL;
   else if (startIsDashed && isDashed)
     startType = SIDE_CLIP_RECTANGLE;
   if (!IsZeroSize(mBorderRadii[mozilla::css::Corner(NEXT_SIDE(aSide))]))
     endType = SIDE_CLIP_TRAPEZOID_FULL;
   else if (endIsDashed && isDashed)
     endType = SIDE_CLIP_RECTANGLE;
   gfxPoint midPoint = mInnerRect.Center();
   start[0] = mOuterRect.CCWCorner(aSide);
   start[1] = mInnerRect.CCWCorner(aSide);
   end[0] = mOuterRect.CWCorner(aSide);
   end[1] = mInnerRect.CWCorner(aSide);
   if (startType == SIDE_CLIP_TRAPEZOID_FULL) {
     MaybeMoveToMidPoint(start[0], start[1], midPoint);
   } else if (startType == SIDE_CLIP_RECTANGLE) {
     if (aSide == NS_SIDE_TOP || aSide == NS_SIDE_BOTTOM)
       start[1] = gfxPoint(mOuterRect.CCWCorner(aSide).x, mInnerRect.CCWCorner(aSide).y);
     else
       start[1] = gfxPoint(mInnerRect.CCWCorner(aSide).x, mOuterRect.CCWCorner(aSide).y);
   }
   if (endType == SIDE_CLIP_TRAPEZOID_FULL) {
     MaybeMoveToMidPoint(end[0], end[1], midPoint);
   } else if (endType == SIDE_CLIP_RECTANGLE) {
     if (aSide == NS_SIDE_TOP || aSide == NS_SIDE_BOTTOM)
       end[0] = gfxPoint(mInnerRect.CWCorner(aSide).x, mOuterRect.CWCorner(aSide).y);
     else
       end[0] = gfxPoint(mOuterRect.CWCorner(aSide).x, mInnerRect.CWCorner(aSide).y);
   }
   mContext->MoveTo(start[0]);
   mContext->LineTo(end[0]);
   mContext->LineTo(end[1]);
   mContext->LineTo(start[1]);
   mContext->ClosePath();
 }
 void
 nsCSSBorderRenderer::FillSolidBorder(const gfxRect& aOuterRect,
                                      const gfxRect& aInnerRect,
                                      const gfxCornerSizes& aBorderRadii,
                                      const gfxFloat *aBorderSizes,
                                      int aSides,
                                      const gfxRGBA& aColor)
 {
   mContext->SetColor(aColor);
   // Note that this function is allowed to draw more than just the
   // requested sides.
   // If we have a border radius, do full rounded rectangles
   // and fill, regardless of what sides we're asked to draw.
   if (!AllCornersZeroSize(aBorderRadii)) {
     gfxCornerSizes innerRadii;
     ComputeInnerRadii(aBorderRadii, aBorderSizes, &innerRadii);
     mContext->NewPath();
     // do the outer border
     mContext->RoundedRectangle(aOuterRect, aBorderRadii, true);
     // then do the inner border CCW
     mContext->RoundedRectangle(aInnerRect, innerRadii, false);
     mContext->Fill();
     return;
   }
   // If we're asked to draw all sides of an equal-sized border,
   // stroking is fastest.  This is a fairly common path, but partial
   // sides is probably second in the list -- there are a bunch of
   // common border styles, such as inset and outset, that are
   // top-left/bottom-right split.
   if (aSides == SIDE_BITS_ALL &&
       CheckFourFloatsEqual(aBorderSizes, aBorderSizes[0]) &&
       !mAvoidStroke)
   {
     gfxRect r(aOuterRect);
     r.Deflate(aBorderSizes[0] / 2.0);
     mContext->SetLineWidth(aBorderSizes[0]);
     mContext->NewPath();
     mContext->Rectangle(r);
     mContext->Stroke();
     return;
   }
   // Otherwise, we have unequal sized borders or we're only
   // drawing some sides; create rectangles for each side
   // and fill them.
   gfxRect r[4];
   // compute base rects for each side
   if (aSides & SIDE_BIT_TOP) {
     r[NS_SIDE_TOP] =
         gfxRect(aOuterRect.X(), aOuterRect.Y(),
                 aOuterRect.Width(), aBorderSizes[NS_SIDE_TOP]);
   }
   if (aSides & SIDE_BIT_BOTTOM) {
     r[NS_SIDE_BOTTOM] =
         gfxRect(aOuterRect.X(), aOuterRect.YMost() - aBorderSizes[NS_SIDE_BOTTOM],
                 aOuterRect.Width(), aBorderSizes[NS_SIDE_BOTTOM]);
   }
   if (aSides & SIDE_BIT_LEFT) {
     r[NS_SIDE_LEFT] =
         gfxRect(aOuterRect.X(), aOuterRect.Y(),
                 aBorderSizes[NS_SIDE_LEFT], aOuterRect.Height());
   }
   if (aSides & SIDE_BIT_RIGHT) {
     r[NS_SIDE_RIGHT] =
         gfxRect(aOuterRect.XMost() - aBorderSizes[NS_SIDE_RIGHT], aOuterRect.Y(),
                 aBorderSizes[NS_SIDE_RIGHT], aOuterRect.Height());
   }
   // If two sides meet at a corner that we're rendering, then
   // make sure that we adjust one of the sides to avoid overlap.
   // This is especially important in the case of colors with
   // an alpha channel.
   if ((aSides & (SIDE_BIT_TOP | SIDE_BIT_LEFT)) == (SIDE_BIT_TOP | SIDE_BIT_LEFT)) {
     // adjust the left's top down a bit
     r[NS_SIDE_LEFT].y += aBorderSizes[NS_SIDE_TOP];
     r[NS_SIDE_LEFT].height -= aBorderSizes[NS_SIDE_TOP];
   }
   if ((aSides & (SIDE_BIT_TOP | SIDE_BIT_RIGHT)) == (SIDE_BIT_TOP | SIDE_BIT_RIGHT)) {
     // adjust the top's left a bit
     r[NS_SIDE_TOP].width -= aBorderSizes[NS_SIDE_RIGHT];
   }
   if ((aSides & (SIDE_BIT_BOTTOM | SIDE_BIT_RIGHT)) == (SIDE_BIT_BOTTOM | SIDE_BIT_RIGHT)) {
     // adjust the right's bottom a bit
     r[NS_SIDE_RIGHT].height -= aBorderSizes[NS_SIDE_BOTTOM];
   }
   if ((aSides & (SIDE_BIT_BOTTOM | SIDE_BIT_LEFT)) == (SIDE_BIT_BOTTOM | SIDE_BIT_LEFT)) {
     // adjust the bottom's left a bit
     r[NS_SIDE_BOTTOM].x += aBorderSizes[NS_SIDE_LEFT];
     r[NS_SIDE_BOTTOM].width -= aBorderSizes[NS_SIDE_LEFT];
   }
   // Filling these one by one is faster than filling them all at once.
   for (uint32_t i = 0; i < 4; i++) {
     if (aSides & (1 << i)) {
       mContext->NewPath();
       mContext->Rectangle(r[i], true);
       mContext->Fill();
     }
   }
 }
 gfxRGBA
 MakeBorderColor(const gfxRGBA& aColor, const gfxRGBA& aBackgroundColor, BorderColorStyle aBorderColorStyle)
 {
   nscolor colors[2];
   int k = 0;
   switch (aBorderColorStyle) {
     case BorderColorStyleNone:
       return gfxRGBA(0.0, 0.0, 0.0, 0.0);
     case BorderColorStyleLight:
       k = 1;
       /* fall through */
     case BorderColorStyleDark:
       NS_GetSpecial3DColors(colors, aBackgroundColor.Packed(), aColor.Packed());
       return gfxRGBA(colors[k]);
     case BorderColorStyleSolid:
     default:
       return aColor;
   }
 }
 gfxRGBA
 ComputeColorForLine(uint32_t aLineIndex,
                     const BorderColorStyle* aBorderColorStyle,
                     uint32_t aBorderColorStyleCount,
                     nscolor aBorderColor,
                     nscolor aBackgroundColor)
 {
   NS_ASSERTION(aLineIndex < aBorderColorStyleCount, "Invalid lineIndex given");
   return MakeBorderColor(gfxRGBA(aBorderColor), gfxRGBA(aBackgroundColor), aBorderColorStyle[aLineIndex]);
 }
 gfxRGBA
 ComputeCompositeColorForLine(uint32_t aLineIndex,
                              const nsBorderColors* aBorderColors)
 {
   while (aLineIndex-- && aBorderColors->mNext)
     aBorderColors = aBorderColors->mNext;
   return gfxRGBA(aBorderColors->mColor);
 }
 void
 nsCSSBorderRenderer::DrawBorderSidesCompositeColors(int aSides, const nsBorderColors *aCompositeColors)
 {
   gfxCornerSizes radii = mBorderRadii;
   // the generic composite colors path; each border is 1px in size
   gfxRect soRect = mOuterRect;
   gfxFloat maxBorderWidth = 0;
   NS_FOR_CSS_SIDES (i) {
     maxBorderWidth = std::max(maxBorderWidth, mBorderWidths[i]);
   }
   gfxFloat fakeBorderSizes[4];
   gfxPoint itl = mInnerRect.TopLeft();
   gfxPoint ibr = mInnerRect.BottomRight();
   for (uint32_t i = 0; i < uint32_t(maxBorderWidth); i++) {
     gfxRGBA lineColor = ComputeCompositeColorForLine(i, aCompositeColors);
     gfxRect siRect = soRect;
     siRect.Deflate(1.0);
     // now cap the rects to the real mInnerRect
     gfxPoint tl = siRect.TopLeft();
     gfxPoint br = siRect.BottomRight();
     tl.x = std::min(tl.x, itl.x);
     tl.y = std::min(tl.y, itl.y);
     br.x = std::max(br.x, ibr.x);
     br.y = std::max(br.y, ibr.y);
     siRect = gfxRect(tl.x, tl.y, br.x - tl.x , br.y - tl.y);
     fakeBorderSizes[NS_SIDE_TOP] = siRect.TopLeft().y - soRect.TopLeft().y;
     fakeBorderSizes[NS_SIDE_RIGHT] = soRect.TopRight().x - siRect.TopRight().x;
     fakeBorderSizes[NS_SIDE_BOTTOM] = soRect.BottomRight().y - siRect.BottomRight().y;
     fakeBorderSizes[NS_SIDE_LEFT] = siRect.BottomLeft().x - soRect.BottomLeft().x;
     FillSolidBorder(soRect, siRect, radii, fakeBorderSizes, aSides, lineColor);
     soRect = siRect;
     ComputeInnerRadii(radii, fakeBorderSizes, &radii);
   }
 }
 void
 nsCSSBorderRenderer::DrawBorderSides(int aSides)
 {
   if (aSides == 0 || (aSides & ~SIDE_BITS_ALL) != 0) {
     NS_WARNING("DrawBorderSides: invalid sides!");
     return;
   }
   uint8_t borderRenderStyle = NS_STYLE_BORDER_STYLE_NONE;
   nscolor borderRenderColor;
   const nsBorderColors *compositeColors = nullptr;
   uint32_t borderColorStyleCount = 0;
   BorderColorStyle borderColorStyleTopLeft[3], borderColorStyleBottomRight[3];
   BorderColorStyle *borderColorStyle = nullptr;
   NS_FOR_CSS_SIDES (i) {
     if ((aSides & (1 << i)) == 0)
       continue;
     borderRenderStyle = mBorderStyles[i];
     borderRenderColor = mBorderColors[i];
     compositeColors = mCompositeColors[i];
     break;
   }
   if (borderRenderStyle == NS_STYLE_BORDER_STYLE_NONE ||
       borderRenderStyle == NS_STYLE_BORDER_STYLE_HIDDEN)
     return;
   // -moz-border-colors is a hack; if we have it for a border, then
   // it's always drawn solid, and each color is given 1px.  The last
   // color is used for the remainder of the border's size.  Just
   // hand off to another function to do all that.
   if (compositeColors) {
     DrawBorderSidesCompositeColors(aSides, compositeColors);
     return;
   }
   // We're not doing compositeColors, so we can calculate the
   // borderColorStyle based on the specified style.  The
   // borderColorStyle array goes from the outer to the inner style.
   //
   // If the border width is 1, we need to change the borderRenderStyle
   // a bit to make sure that we get the right colors -- e.g. 'ridge'
   // with a 1px border needs to look like solid, not like 'outset'.
   if (mOneUnitBorder &&
       (borderRenderStyle == NS_STYLE_BORDER_STYLE_RIDGE ||
        borderRenderStyle == NS_STYLE_BORDER_STYLE_GROOVE ||
        borderRenderStyle == NS_STYLE_BORDER_STYLE_DOUBLE))
     borderRenderStyle = NS_STYLE_BORDER_STYLE_SOLID;
   switch (borderRenderStyle) {
     case NS_STYLE_BORDER_STYLE_SOLID:
     case NS_STYLE_BORDER_STYLE_DASHED:
     case NS_STYLE_BORDER_STYLE_DOTTED:
       borderColorStyleTopLeft[0] = BorderColorStyleSolid;
       borderColorStyleBottomRight[0] = BorderColorStyleSolid;
       borderColorStyleCount = 1;
       break;
     case NS_STYLE_BORDER_STYLE_GROOVE:
       borderColorStyleTopLeft[0] = BorderColorStyleDark;
       borderColorStyleTopLeft[1] = BorderColorStyleLight;
       borderColorStyleBottomRight[0] = BorderColorStyleLight;
       borderColorStyleBottomRight[1] = BorderColorStyleDark;
       borderColorStyleCount = 2;
       break;
     case NS_STYLE_BORDER_STYLE_RIDGE:
       borderColorStyleTopLeft[0] = BorderColorStyleLight;
       borderColorStyleTopLeft[1] = BorderColorStyleDark;
       borderColorStyleBottomRight[0] = BorderColorStyleDark;
       borderColorStyleBottomRight[1] = BorderColorStyleLight;
       borderColorStyleCount = 2;
       break;
     case NS_STYLE_BORDER_STYLE_DOUBLE:
       borderColorStyleTopLeft[0] = BorderColorStyleSolid;
       borderColorStyleTopLeft[1] = BorderColorStyleNone;
       borderColorStyleTopLeft[2] = BorderColorStyleSolid;
       borderColorStyleBottomRight[0] = BorderColorStyleSolid;
       borderColorStyleBottomRight[1] = BorderColorStyleNone;
       borderColorStyleBottomRight[2] = BorderColorStyleSolid;
       borderColorStyleCount = 3;
       break;
     case NS_STYLE_BORDER_STYLE_INSET:
       borderColorStyleTopLeft[0] = BorderColorStyleDark;
       borderColorStyleBottomRight[0] = BorderColorStyleLight;
       borderColorStyleCount = 1;
       break;
     case NS_STYLE_BORDER_STYLE_OUTSET:
       borderColorStyleTopLeft[0] = BorderColorStyleLight;
       borderColorStyleBottomRight[0] = BorderColorStyleDark;
       borderColorStyleCount = 1;
       break;
     default:
       NS_NOTREACHED("Unhandled border style!!");
       break;
   }
   // The only way to get to here is by having a
   // borderColorStyleCount < 1 or > 3; this should never happen,
   // since -moz-border-colors doesn't get handled here.
   NS_ASSERTION(borderColorStyleCount > 0 && borderColorStyleCount < 4,
                "Non-border-colors case with borderColorStyleCount < 1 or > 3; what happened?");
   // The caller should never give us anything with a mix
   // of TL/BR if the border style would require a
   // TL/BR split.
   if (aSides & (SIDE_BIT_BOTTOM | SIDE_BIT_RIGHT))
     borderColorStyle = borderColorStyleBottomRight;
   else
     borderColorStyle = borderColorStyleTopLeft;
   // Distribute the border across the available space.
   gfxFloat borderWidths[3][4];
   if (borderColorStyleCount == 1) {
     NS_FOR_CSS_SIDES (i) {
       borderWidths[0][i] = mBorderWidths[i];
     }
   } else if (borderColorStyleCount == 2) {
     // with 2 color styles, any extra pixel goes to the outside
     NS_FOR_CSS_SIDES (i) {
       borderWidths[0][i] = int32_t(mBorderWidths[i]) / 2 + int32_t(mBorderWidths[i]) % 2;
       borderWidths[1][i] = int32_t(mBorderWidths[i]) / 2;
     }
   } else if (borderColorStyleCount == 3) {
     // with 3 color styles, any extra pixel (or lack of extra pixel)
     // goes to the middle
     NS_FOR_CSS_SIDES (i) {
       if (mBorderWidths[i] == 1.0) {
         borderWidths[0][i] = 1.0;
         borderWidths[1][i] = borderWidths[2][i] = 0.0;
       } else {
         int32_t rest = int32_t(mBorderWidths[i]) % 3;
         borderWidths[0][i] = borderWidths[2][i] = borderWidths[1][i] = (int32_t(mBorderWidths[i]) - rest) / 3;
         if (rest == 1) {
           borderWidths[1][i] += 1.0;
         } else if (rest == 2) {
           borderWidths[0][i] += 1.0;
           borderWidths[2][i] += 1.0;
         }
       }
     }
   }
   // make a copy that we can modify
   gfxCornerSizes radii = mBorderRadii;
   gfxRect soRect(mOuterRect);
   gfxRect siRect(mOuterRect);
   for (unsigned int i = 0; i < borderColorStyleCount; i++) {
     // walk siRect inwards at the start of the loop to get the
     // correct inner rect.
     siRect.Deflate(gfxMargin(borderWidths[i][0], borderWidths[i][1],
                              borderWidths[i][2], borderWidths[i][3]));
     if (borderColorStyle[i] != BorderColorStyleNone) {
       gfxRGBA color = ComputeColorForLine(i,
                                           borderColorStyle, borderColorStyleCount,
                                           borderRenderColor, mBackgroundColor);
       FillSolidBorder(soRect, siRect, radii, borderWidths[i], aSides, color);
     }
     ComputeInnerRadii(radii, borderWidths[i], &radii);
     // And now soRect is the same as siRect, for the next line in.
     soRect = siRect;
   }
 }
 void
 nsCSSBorderRenderer::DrawDashedSide(mozilla::css::Side aSide)
 {
   gfxFloat dashWidth;
   gfxFloat dash[2];
   uint8_t style = mBorderStyles[aSide];
   gfxFloat borderWidth = mBorderWidths[aSide];
   nscolor borderColor = mBorderColors[aSide];
   if (borderWidth == 0.0)
     return;
   if (style == NS_STYLE_BORDER_STYLE_NONE ||
       style == NS_STYLE_BORDER_STYLE_HIDDEN)
     return;
   if (style == NS_STYLE_BORDER_STYLE_DASHED) {
     dashWidth = gfxFloat(borderWidth * DOT_LENGTH * DASH_LENGTH);
     dash[0] = dashWidth;
     dash[1] = dashWidth;
     mContext->SetLineCap(gfxContext::LINE_CAP_BUTT);
   } else if (style == NS_STYLE_BORDER_STYLE_DOTTED) {
     dashWidth = gfxFloat(borderWidth * DOT_LENGTH);
     if (borderWidth > 2.0) {
       dash[0] = 0.0;
       dash[1] = dashWidth * 2.0;
       mContext->SetLineCap(gfxContext::LINE_CAP_ROUND);
     } else {
       dash[0] = dashWidth;
       dash[1] = dashWidth;
     }
   } else {
     SF("DrawDashedSide: style: %d!!\n", style);
     NS_ERROR("DrawDashedSide called with style other than DASHED or DOTTED; someone's not playing nice");
     return;
   }
   SF("dash: %f %f\n", dash[0], dash[1]);
   mContext->SetDash(dash, 2, 0.0);
   gfxPoint start = mOuterRect.CCWCorner(aSide);
   gfxPoint end = mOuterRect.CWCorner(aSide);
   if (aSide == NS_SIDE_TOP) {
     start.x += mBorderCornerDimensions[C_TL].width;
     end.x -= mBorderCornerDimensions[C_TR].width;
     start.y += borderWidth / 2.0;
     end.y += borderWidth / 2.0;
   } else if (aSide == NS_SIDE_RIGHT) {
     start.x -= borderWidth / 2.0;
     end.x -= borderWidth / 2.0;
     start.y += mBorderCornerDimensions[C_TR].height;
     end.y -= mBorderCornerDimensions[C_BR].height;
   } else if (aSide == NS_SIDE_BOTTOM) {
     start.x -= mBorderCornerDimensions[C_BR].width;
     end.x += mBorderCornerDimensions[C_BL].width;
     start.y -= borderWidth / 2.0;
     end.y -= borderWidth / 2.0;
   } else if (aSide == NS_SIDE_LEFT) {
     start.x += borderWidth / 2.0;
     end.x += borderWidth / 2.0;
     start.y -= mBorderCornerDimensions[C_BL].height;
     end.y += mBorderCornerDimensions[C_TL].height;
   }
   mContext->NewPath();
   mContext->MoveTo(start);
   mContext->LineTo(end);
   mContext->SetLineWidth(borderWidth);
   mContext->SetColor(gfxRGBA(borderColor));
   //mContext->SetColor(gfxRGBA(1.0, 0.0, 0.0, 1.0));
   mContext->Stroke();
 }
 void
 nsCSSBorderRenderer::SetupStrokeStyle(mozilla::css::Side aSide)
 {
   mContext->SetColor(gfxRGBA(mBorderColors[aSide]));
   mContext->SetLineWidth(mBorderWidths[aSide]);
 }
 bool
 nsCSSBorderRenderer::AllBordersSameWidth()
 {
   if (mBorderWidths[0] == mBorderWidths[1] &&
       mBorderWidths[0] == mBorderWidths[2] &&
       mBorderWidths[0] == mBorderWidths[3])
   {
     return true;
   }
   return false;
 }
 bool
 nsCSSBorderRenderer::AllBordersSolid(bool *aHasCompositeColors)
 {
   *aHasCompositeColors = false;
   NS_FOR_CSS_SIDES(i) {
     if (mCompositeColors[i] != nullptr) {
       *aHasCompositeColors = true;
     }
     if (mBorderStyles[i] == NS_STYLE_BORDER_STYLE_SOLID ||
         mBorderStyles[i] == NS_STYLE_BORDER_STYLE_NONE ||
         mBorderStyles[i] == NS_STYLE_BORDER_STYLE_HIDDEN)
     {
       continue;
     }
     return false;
   }
   return true;
 }
 bool IsVisible(int aStyle)
 {
   if (aStyle != NS_STYLE_BORDER_STYLE_NONE &&
       aStyle != NS_STYLE_BORDER_STYLE_HIDDEN) {
         return true;
   }
   return false;
 }
 already_AddRefed<gfxPattern>
 nsCSSBorderRenderer::CreateCornerGradient(mozilla::css::Corner aCorner,
                                           const gfxRGBA &aFirstColor,
                                           const gfxRGBA &aSecondColor)
 {
   typedef struct { gfxFloat a, b; } twoFloats;
   const twoFloats gradientCoeff[4] = { { -1, +1 },
                                        { -1, -1 },
                                        { +1, -1 },
                                        { +1, +1 } };
   // Sides which form the 'width' and 'height' for the calculation of the angle
   // for our gradient.
   const int cornerWidth[4] = { 3, 1, 1, 3 };
   const int cornerHeight[4] = { 0, 0, 2, 2 };
   gfxPoint cornerOrigin = mOuterRect.AtCorner(aCorner);
   gfxPoint pat1, pat2;
   pat1.x = cornerOrigin.x +
     mBorderWidths[cornerHeight[aCorner]] * gradientCoeff[aCorner].a;
   pat1.y = cornerOrigin.y +
     mBorderWidths[cornerWidth[aCorner]]  * gradientCoeff[aCorner].b;
   pat2.x = cornerOrigin.x -
     mBorderWidths[cornerHeight[aCorner]] * gradientCoeff[aCorner].a;
   pat2.y = cornerOrigin.y -
     mBorderWidths[cornerWidth[aCorner]]  * gradientCoeff[aCorner].b;
   float gradientOffset;
   if (mContext->IsCairo() &&
       (mContext->OriginalSurface()->GetType() == gfxSurfaceType::D2D ||
        mContext->OriginalSurface()->GetType() == gfxSurfaceType::Quartz))
   {
     // On quarz this doesn't do exactly the right thing, but it does do what
     // most other browsers do and doing the 'right' thing seems to be
     // hard with the quartz cairo backend.
     gradientOffset = 0;
   } else {
     // When cairo/Azure does the gradient drawing this gives us pretty nice behavior!
     gradientOffset = 0.25 / sqrt(pow(mBorderWidths[cornerHeight[aCorner]], 2) +
                                  pow(mBorderWidths[cornerHeight[aCorner]], 2));
   }
   nsRefPtr<gfxPattern> pattern = new gfxPattern(pat1.x, pat1.y, pat2.x, pat2.y);
   pattern->AddColorStop(0.5 - gradientOffset, gfxRGBA(aFirstColor));
   pattern->AddColorStop(0.5 + gradientOffset, gfxRGBA(aSecondColor));
   return pattern.forget();
 }
 TemporaryRef<GradientStops>
 nsCSSBorderRenderer::CreateCornerGradient(mozilla::css::Corner aCorner,
                                           const gfxRGBA &aFirstColor,
                                           const gfxRGBA &aSecondColor,
                                           DrawTarget *aDT,
                                           Point &aPoint1,
                                           Point &aPoint2)
 {
   typedef struct { gfxFloat a, b; } twoFloats;
   const twoFloats gradientCoeff[4] = { { -1, +1 },
                                        { -1, -1 },
                                        { +1, -1 },
                                        { +1, +1 } };
   // Sides which form the 'width' and 'height' for the calculation of the angle
   // for our gradient.
   const int cornerWidth[4] = { 3, 1, 1, 3 };
   const int cornerHeight[4] = { 0, 0, 2, 2 };
   gfxPoint cornerOrigin = mOuterRect.AtCorner(aCorner);
   gfxPoint pat1, pat2;
   pat1.x = cornerOrigin.x +
     mBorderWidths[cornerHeight[aCorner]] * gradientCoeff[aCorner].a;
   pat1.y = cornerOrigin.y +
     mBorderWidths[cornerWidth[aCorner]]  * gradientCoeff[aCorner].b;
   pat2.x = cornerOrigin.x -
     mBorderWidths[cornerHeight[aCorner]] * gradientCoeff[aCorner].a;
   pat2.y = cornerOrigin.y -
     mBorderWidths[cornerWidth[aCorner]]  * gradientCoeff[aCorner].b;
   aPoint1 = Point(pat1.x, pat1.y);
   aPoint2 = Point(pat2.x, pat2.y);
   Color firstColor = ToColor(aFirstColor);
   Color secondColor = ToColor(aSecondColor);
   nsTArray<gfx::GradientStop> rawStops(2);
   rawStops.SetLength(2);
   // This is only guaranteed to give correct (and in some cases more correct)
   // rendering with the Direct2D Azure and Quartz Cairo backends. For other
   // cairo backends it could create un-antialiased border corner transitions
   // since that at least used to be pixman's behaviour for hard stops.
   rawStops[0].color = firstColor;
   rawStops[0].offset = 0.5;
   rawStops[1].color = secondColor;
   rawStops[1].offset = 0.5;
   RefPtr<GradientStops> gs =
     gfxGradientCache::GetGradientStops(aDT, rawStops, ExtendMode::CLAMP);
   if (!gs) {
     // Having two corners, both with reversed color stops is pretty common
     // for certain border types. Let's optimize it!
     rawStops[0].color = secondColor;
     rawStops[1].color = firstColor;
     Point tmp = aPoint1;
     aPoint1 = aPoint2;
     aPoint2 = tmp;
     gs = gfxGradientCache::GetOrCreateGradientStops(aDT, rawStops, ExtendMode::CLAMP);
   }
   return gs;
 }
 typedef struct { gfxFloat a, b; } twoFloats;
 void
 nsCSSBorderRenderer::DrawSingleWidthSolidBorder()
 {
   // Easy enough to deal with.
   mContext->SetLineWidth(1);
   gfxRect rect = mOuterRect;
   rect.Deflate(0.5);
   const twoFloats cornerAdjusts[4] = { { +0.5,  0   },
                                        {    0, +0.5 },
                                        { -0.5,  0   },
                                        {    0, -0.5 } };
   NS_FOR_CSS_SIDES(side) {
     gfxPoint firstCorner = rect.CCWCorner(side);
     firstCorner.x += cornerAdjusts[side].a;
     firstCorner.y += cornerAdjusts[side].b;
     gfxPoint secondCorner = rect.CWCorner(side);
     secondCorner.x += cornerAdjusts[side].a;
     secondCorner.y += cornerAdjusts[side].b;
     mContext->SetColor(gfxRGBA(mBorderColors[side]));
     mContext->NewPath();
     mContext->MoveTo(firstCorner);
     mContext->LineTo(secondCorner);
     mContext->Stroke();
   }
 }
 void
 nsCSSBorderRenderer::DrawNoCompositeColorSolidBorder()
 {
   const gfxFloat alpha = 0.55191497064665766025;
   const twoFloats cornerMults[4] = { { -1,  0 },
                                       {  0, -1 },
                                       { +1,  0 },
                                       {  0, +1 } };
   const twoFloats centerAdjusts[4] = { { 0, +0.5 },
                                         { -0.5, 0 },
                                         { 0, -0.5 },
                                         { +0.5, 0 } };
   gfxPoint pc, pci, p0, p1, p2, p3, pd, p3i;
   gfxCornerSizes innerRadii;
   ComputeInnerRadii(mBorderRadii, mBorderWidths, &innerRadii);
   gfxRect strokeRect = mOuterRect;
   strokeRect.Deflate(gfxMargin(mBorderWidths[0] / 2.0, mBorderWidths[1] / 2.0,
                                mBorderWidths[2] / 2.0, mBorderWidths[3] / 2.0));
   NS_FOR_CSS_CORNERS(i) {
       // the corner index -- either 1 2 3 0 (cw) or 0 3 2 1 (ccw)
     mozilla::css::Corner c = mozilla::css::Corner((i+1) % 4);
     mozilla::css::Corner prevCorner = mozilla::css::Corner(i);
     // i+2 and i+3 respectively.  These are used to index into the corner
     // multiplier table, and were deduced by calculating out the long form
     // of each corner and finding a pattern in the signs and values.
     int i1 = (i+1) % 4;
     int i2 = (i+2) % 4;
     int i3 = (i+3) % 4;
     pc = mOuterRect.AtCorner(c);
     pci = mInnerRect.AtCorner(c);
     mContext->SetLineWidth(mBorderWidths[i]);
     nscolor firstColor, secondColor;
     if (IsVisible(mBorderStyles[i]) && IsVisible(mBorderStyles[i1])) {
       firstColor = mBorderColors[i];
       secondColor = mBorderColors[i1];
     } else if (IsVisible(mBorderStyles[i])) {
       firstColor = mBorderColors[i];
       secondColor = mBorderColors[i];
     } else {
       firstColor = mBorderColors[i1];
       secondColor = mBorderColors[i1];
     }
     mContext->NewPath();
     gfxPoint strokeStart, strokeEnd;
     strokeStart.x = mOuterRect.AtCorner(prevCorner).x +
       mBorderCornerDimensions[prevCorner].width * cornerMults[i2].a;
     strokeStart.y = mOuterRect.AtCorner(prevCorner).y +
       mBorderCornerDimensions[prevCorner].height * cornerMults[i2].b;
     strokeEnd.x = pc.x + mBorderCornerDimensions[c].width * cornerMults[i].a;
     strokeEnd.y = pc.y + mBorderCornerDimensions[c].height * cornerMults[i].b;
     strokeStart.x += centerAdjusts[i].a * mBorderWidths[i];
     strokeStart.y += centerAdjusts[i].b * mBorderWidths[i];
     strokeEnd.x += centerAdjusts[i].a * mBorderWidths[i];
     strokeEnd.y += centerAdjusts[i].b * mBorderWidths[i];
     mContext->MoveTo(strokeStart);
     mContext->LineTo(strokeEnd);
     mContext->SetColor(gfxRGBA(mBorderColors[i]));
     mContext->Stroke();
     if (firstColor != secondColor) {
       nsRefPtr<gfxPattern> pattern =
         CreateCornerGradient(c, firstColor, secondColor);
       mContext->SetPattern(pattern);
     } else {
       mContext->SetColor(firstColor);
     }
     if (mBorderRadii[c].width > 0 && mBorderRadii[c].height > 0) {
       p0.x = pc.x + cornerMults[i].a * mBorderRadii[c].width;
       p0.y = pc.y + cornerMults[i].b * mBorderRadii[c].height;
       p3.x = pc.x + cornerMults[i3].a * mBorderRadii[c].width;
       p3.y = pc.y + cornerMults[i3].b * mBorderRadii[c].height;
       p1.x = p0.x + alpha * cornerMults[i2].a * mBorderRadii[c].width;
       p1.y = p0.y + alpha * cornerMults[i2].b * mBorderRadii[c].height;
       p2.x = p3.x - alpha * cornerMults[i3].a * mBorderRadii[c].width;
       p2.y = p3.y - alpha * cornerMults[i3].b * mBorderRadii[c].height;
       mContext->NewPath();
       gfxPoint cornerStart;
       cornerStart.x = pc.x + cornerMults[i].a * mBorderCornerDimensions[c].width;
       cornerStart.y = pc.y + cornerMults[i].b * mBorderCornerDimensions[c].height;
       mContext->MoveTo(cornerStart);
       mContext->LineTo(p0);
       mContext->CurveTo(p1, p2, p3);
       gfxPoint outerCornerEnd;
       outerCornerEnd.x = pc.x + cornerMults[i3].a * mBorderCornerDimensions[c].width;
       outerCornerEnd.y = pc.y + cornerMults[i3].b * mBorderCornerDimensions[c].height;
       mContext->LineTo(outerCornerEnd);
       p0.x = pci.x + cornerMults[i].a * innerRadii[c].width;
       p0.y = pci.y + cornerMults[i].b * innerRadii[c].height;
       p3i.x = pci.x + cornerMults[i3].a * innerRadii[c].width;
       p3i.y = pci.y + cornerMults[i3].b * innerRadii[c].height;
       p1.x = p0.x + alpha * cornerMults[i2].a * innerRadii[c].width;
       p1.y = p0.y + alpha * cornerMults[i2].b * innerRadii[c].height;
       p2.x = p3i.x - alpha * cornerMults[i3].a * innerRadii[c].width;
       p2.y = p3i.y - alpha * cornerMults[i3].b * innerRadii[c].height;
       mContext->LineTo(p3i);
       mContext->CurveTo(p2, p1, p0);
       mContext->ClosePath();
       mContext->Fill();
     } else {
       gfxPoint c1, c2, c3, c4;
       c1.x = pc.x + cornerMults[i].a * mBorderCornerDimensions[c].width;
       c1.y = pc.y + cornerMults[i].b * mBorderCornerDimensions[c].height;
       c2 = pc;
       c3.x = pc.x + cornerMults[i3].a * mBorderCornerDimensions[c].width;
       c3.y = pc.y + cornerMults[i3].b * mBorderCornerDimensions[c].height;
       mContext->NewPath();
       mContext->MoveTo(c1);
       mContext->LineTo(c2);
       mContext->LineTo(c3);
       mContext->LineTo(pci);
       mContext->ClosePath();
       mContext->Fill();
     }
   }
 }
 void
 nsCSSBorderRenderer::DrawNoCompositeColorSolidBorderAzure()
 {
   DrawTarget *dt = mContext->GetDrawTarget();
   const gfxFloat alpha = 0.55191497064665766025;
   const twoFloats cornerMults[4] = { { -1,  0 },
                                      {  0, -1 },
                                      { +1,  0 },
                                      {  0, +1 } };
   const twoFloats centerAdjusts[4] = { { 0, +0.5 },
                                        { -0.5, 0 },
                                        { 0, -0.5 },
                                        { +0.5, 0 } };
   Point pc, pci, p0, p1, p2, p3, pd, p3i;
   gfxCornerSizes innerRadii;
   ComputeInnerRadii(mBorderRadii, mBorderWidths, &innerRadii);
   gfxRect strokeRect = mOuterRect;
   strokeRect.Deflate(gfxMargin(mBorderWidths[0] / 2.0, mBorderWidths[1] / 2.0,
                                mBorderWidths[2] / 2.0, mBorderWidths[3] / 2.0));
   ColorPattern colorPat(Color(0, 0, 0, 0));
   LinearGradientPattern gradPat(Point(), Point(), nullptr);
   NS_FOR_CSS_CORNERS(i) {
       // the corner index -- either 1 2 3 0 (cw) or 0 3 2 1 (ccw)
     mozilla::css::Corner c = mozilla::css::Corner((i+1) % 4);
     mozilla::css::Corner prevCorner = mozilla::css::Corner(i);
     // i+2 and i+3 respectively.  These are used to index into the corner
     // multiplier table, and were deduced by calculating out the long form
     // of each corner and finding a pattern in the signs and values.
     int i1 = (i+1) % 4;
     int i2 = (i+2) % 4;
     int i3 = (i+3) % 4;
     pc = ToPoint(mOuterRect.AtCorner(c));
     pci = ToPoint(mInnerRect.AtCorner(c));
     nscolor firstColor, secondColor;
     if (IsVisible(mBorderStyles[i]) && IsVisible(mBorderStyles[i1])) {
       firstColor = mBorderColors[i];
       secondColor = mBorderColors[i1];
     } else if (IsVisible(mBorderStyles[i])) {
       firstColor = mBorderColors[i];
       secondColor = mBorderColors[i];
     } else {
       firstColor = mBorderColors[i1];
       secondColor = mBorderColors[i1];
     }
     RefPtr<PathBuilder> builder = dt->CreatePathBuilder();
     Point strokeStart, strokeEnd;
     strokeStart.x = mOuterRect.AtCorner(prevCorner).x +
       mBorderCornerDimensions[prevCorner].width * cornerMults[i2].a;
     strokeStart.y = mOuterRect.AtCorner(prevCorner).y +
       mBorderCornerDimensions[prevCorner].height * cornerMults[i2].b;
     strokeEnd.x = pc.x + mBorderCornerDimensions[c].width * cornerMults[i].a;
     strokeEnd.y = pc.y + mBorderCornerDimensions[c].height * cornerMults[i].b;
     strokeStart.x += centerAdjusts[i].a * mBorderWidths[i];
     strokeStart.y += centerAdjusts[i].b * mBorderWidths[i];
     strokeEnd.x += centerAdjusts[i].a * mBorderWidths[i];
     strokeEnd.y += centerAdjusts[i].b * mBorderWidths[i];
     builder->MoveTo(strokeStart);
     builder->LineTo(strokeEnd);
     RefPtr<Path> path = builder->Finish();
     dt->Stroke(path, ColorPattern(Color::FromABGR(mBorderColors[i])), StrokeOptions(mBorderWidths[i]));
     builder = nullptr;
     path = nullptr;
     Pattern *pattern;
     if (firstColor != secondColor) {
       gradPat.mStops = CreateCornerGradient(c, firstColor, secondColor, dt, gradPat.mBegin, gradPat.mEnd);
       pattern = &gradPat;
     } else {
       colorPat.mColor = Color::FromABGR(firstColor);
       pattern = &colorPat;
     }
     builder = dt->CreatePathBuilder();
     if (mBorderRadii[c].width > 0 && mBorderRadii[c].height > 0) {
       p0.x = pc.x + cornerMults[i].a * mBorderRadii[c].width;
       p0.y = pc.y + cornerMults[i].b * mBorderRadii[c].height;
       p3.x = pc.x + cornerMults[i3].a * mBorderRadii[c].width;
       p3.y = pc.y + cornerMults[i3].b * mBorderRadii[c].height;
       p1.x = p0.x + alpha * cornerMults[i2].a * mBorderRadii[c].width;
       p1.y = p0.y + alpha * cornerMults[i2].b * mBorderRadii[c].height;
       p2.x = p3.x - alpha * cornerMults[i3].a * mBorderRadii[c].width;
       p2.y = p3.y - alpha * cornerMults[i3].b * mBorderRadii[c].height;
       Point cornerStart;
       cornerStart.x = pc.x + cornerMults[i].a * mBorderCornerDimensions[c].width;
       cornerStart.y = pc.y + cornerMults[i].b * mBorderCornerDimensions[c].height;
       builder->MoveTo(cornerStart);
       builder->LineTo(p0);
       builder->BezierTo(p1, p2, p3);
       Point outerCornerEnd;
       outerCornerEnd.x = pc.x + cornerMults[i3].a * mBorderCornerDimensions[c].width;
       outerCornerEnd.y = pc.y + cornerMults[i3].b * mBorderCornerDimensions[c].height;
       builder->LineTo(outerCornerEnd);
       p0.x = pci.x + cornerMults[i].a * innerRadii[c].width;
       p0.y = pci.y + cornerMults[i].b * innerRadii[c].height;
       p3i.x = pci.x + cornerMults[i3].a * innerRadii[c].width;
       p3i.y = pci.y + cornerMults[i3].b * innerRadii[c].height;
       p1.x = p0.x + alpha * cornerMults[i2].a * innerRadii[c].width;
       p1.y = p0.y + alpha * cornerMults[i2].b * innerRadii[c].height;
       p2.x = p3i.x - alpha * cornerMults[i3].a * innerRadii[c].width;
       p2.y = p3i.y - alpha * cornerMults[i3].b * innerRadii[c].height;
       builder->LineTo(p3i);
       builder->BezierTo(p2, p1, p0);
       builder->Close();
       path = builder->Finish();
       dt->Fill(path, *pattern);
     } else {
       Point c1, c2, c3, c4;
       c1.x = pc.x + cornerMults[i].a * mBorderCornerDimensions[c].width;
       c1.y = pc.y + cornerMults[i].b * mBorderCornerDimensions[c].height;
       c2 = pc;
       c3.x = pc.x + cornerMults[i3].a * mBorderCornerDimensions[c].width;
       c3.y = pc.y + cornerMults[i3].b * mBorderCornerDimensions[c].height;
       builder->MoveTo(c1);
       builder->LineTo(c2);
       builder->LineTo(c3);
       builder->LineTo(pci);
       builder->Close();
       path = builder->Finish();
       dt->Fill(path, *pattern);
     }
   }
 }
 void
 nsCSSBorderRenderer::DrawRectangularCompositeColors()
 {
   nsBorderColors *currentColors[4];
   mContext->SetLineWidth(1);
   memcpy(currentColors, mCompositeColors, sizeof(nsBorderColors*) * 4);
   gfxRect rect = mOuterRect;
   rect.Deflate(0.5);
   const twoFloats cornerAdjusts[4] = { { +0.5,  0   },
                                         {    0, +0.5 },
                                         { -0.5,  0   },
                                         {    0, -0.5 } };
   for (int i = 0; i < mBorderWidths[0]; i++) {
     NS_FOR_CSS_SIDES(side) {
       int sideNext = (side + 1) % 4;
       gfxPoint firstCorner = rect.CCWCorner(side);
       firstCorner.x += cornerAdjusts[side].a;
       firstCorner.y += cornerAdjusts[side].b;
       gfxPoint secondCorner = rect.CWCorner(side);
       secondCorner.x -= cornerAdjusts[side].a;
       secondCorner.y -= cornerAdjusts[side].b;
       gfxRGBA currentColor =
         currentColors[side] ? gfxRGBA(currentColors[side]->mColor)
                             : gfxRGBA(mBorderColors[side]);
       mContext->SetColor(currentColor);
       mContext->NewPath();
       mContext->MoveTo(firstCorner);
       mContext->LineTo(secondCorner);
       mContext->Stroke();
       mContext->NewPath();
       gfxPoint cornerTopLeft = rect.CWCorner(side);
       cornerTopLeft.x -= 0.5;
       cornerTopLeft.y -= 0.5;
       mContext->Rectangle(gfxRect(cornerTopLeft, gfxSize(1, 1)));
       gfxRGBA nextColor =
         currentColors[sideNext] ? gfxRGBA(currentColors[sideNext]->mColor)
                                 : gfxRGBA(mBorderColors[sideNext]);
       gfxRGBA cornerColor((currentColor.r + nextColor.r) / 2.0,
                           (currentColor.g + nextColor.g) / 2.0,
                           (currentColor.b + nextColor.b) / 2.0,
                           (currentColor.a + nextColor.a) / 2.0);
       mContext->SetColor(cornerColor);
       mContext->Fill();
       if (side != 0) {
         // We'll have to keep side 0 for the color averaging on side 3.
         if (currentColors[side] && currentColors[side]->mNext) {
           currentColors[side] = currentColors[side]->mNext;
         }
       }
     }
     // Now advance the color for side 0.
     if (currentColors[0] && currentColors[0]->mNext) {
       currentColors[0] = currentColors[0]->mNext;
     }
     rect.Deflate(1);
   }
 }
 void
 nsCSSBorderRenderer::DrawBorders()
 {
   bool forceSeparateCorners = false;
   // Examine the border style to figure out if we can draw it in one
   // go or not.
   bool tlBordersSame = AreBorderSideFinalStylesSame(SIDE_BIT_TOP | SIDE_BIT_LEFT);
   bool brBordersSame = AreBorderSideFinalStylesSame(SIDE_BIT_BOTTOM | SIDE_BIT_RIGHT);
   bool allBordersSame = AreBorderSideFinalStylesSame(SIDE_BITS_ALL);
   if (allBordersSame &&
       ((mCompositeColors[0] == nullptr &&
        (mBorderStyles[0] == NS_STYLE_BORDER_STYLE_NONE ||
         mBorderStyles[0] == NS_STYLE_BORDER_STYLE_HIDDEN ||
         mBorderColors[0] == NS_RGBA(0,0,0,0))) ||
        (mCompositeColors[0] &&
         (mCompositeColors[0]->mColor == NS_RGBA(0,0,0,0) &&
          !mCompositeColors[0]->mNext))))
   {
     // All borders are the same style, and the style is either none or hidden, or the color
     // is transparent.
     // This also checks if the first composite color is transparent, and there are
     // no others. It doesn't check if there are subsequent transparent ones, because
     // that would be very silly.
     return;
   }
   gfxMatrix mat = mContext->CurrentMatrix();
   // Clamp the CTM to be pixel-aligned; we do this only
   // for translation-only matrices now, but we could do it
   // if the matrix has just a scale as well.  We should not
   // do it if there's a rotation.
   if (mat.HasNonTranslation()) {
     if (!mat.HasNonAxisAlignedTransform()) {
       // Scale + transform. Avoid stroke fast-paths so that we have a chance
       // of snapping to pixel boundaries.
       mAvoidStroke = true;
     }
   } else {
     mat.x0 = floor(mat.x0 + 0.5);
     mat.y0 = floor(mat.y0 + 0.5);
     mContext->SetMatrix(mat);
     // round mOuterRect and mInnerRect; they're already an integer
     // number of pixels apart and should stay that way after
     // rounding. We don't do this if there's a scale in the current transform
     // since this loses information that might be relevant when we're scaling.
     mOuterRect.Round();
     mInnerRect.Round();
   }
   bool allBordersSameWidth = AllBordersSameWidth();
   if (allBordersSameWidth && mBorderWidths[0] == 0.0) {
     // Some of the allBordersSameWidth codepaths depend on the border
     // width being greater than zero.
     return;
   }
   bool allBordersSolid;
   // First there's a couple of 'special cases' that have specifically optimized
   // drawing paths, when none of these can be used we move on to the generalized
   // border drawing code.
   if (allBordersSame &&
       mCompositeColors[0] == nullptr &&
       allBordersSameWidth &&
       mBorderStyles[0] == NS_STYLE_BORDER_STYLE_SOLID &&
       mNoBorderRadius &&
       !mAvoidStroke)
   {
     // Very simple case.
     SetupStrokeStyle(NS_SIDE_TOP);
     gfxRect rect = mOuterRect;
     rect.Deflate(mBorderWidths[0] / 2.0);
     mContext->NewPath();
     mContext->Rectangle(rect);
     mContext->Stroke();
     return;
   }
   if (allBordersSame &&
       mCompositeColors[0] == nullptr &&
       allBordersSameWidth &&
       mBorderStyles[0] == NS_STYLE_BORDER_STYLE_DOTTED &&
       mBorderWidths[0] < 3 &&
       mNoBorderRadius &&
       !mAvoidStroke)
   {
     // Very simple case. We draw this rectangular dotted borner without
     // antialiasing. The dots should be pixel aligned.
     SetupStrokeStyle(NS_SIDE_TOP);
     gfxFloat dash = mBorderWidths[0];
     mContext->SetDash(&dash, 1, 0.5);
     mContext->SetAntialiasMode(gfxContext::MODE_ALIASED);
     gfxRect rect = mOuterRect;
     rect.Deflate(mBorderWidths[0] / 2.0);
     mContext->NewPath();
     mContext->Rectangle(rect);
     mContext->Stroke();
     return;
   }
   if (allBordersSame &&
       mCompositeColors[0] == nullptr &&
       mBorderStyles[0] == NS_STYLE_BORDER_STYLE_SOLID &&
       !mAvoidStroke &&
       !mNoBorderRadius)
   {
     // Relatively simple case.
     SetupStrokeStyle(NS_SIDE_TOP);
     RoundedRect borderInnerRect(mOuterRect, mBorderRadii);
     borderInnerRect.Deflate(mBorderWidths[NS_SIDE_TOP],
                       mBorderWidths[NS_SIDE_BOTTOM],
                       mBorderWidths[NS_SIDE_LEFT],
                       mBorderWidths[NS_SIDE_RIGHT]);
     // Instead of stroking we just use two paths: an inner and an outer.
     // This allows us to draw borders that we couldn't when stroking. For example,
     // borders with a border width >= the border radius. (i.e. when there are
     // square corners on the inside)
     //
     // Further, this approach can be more efficient because the backend
     // doesn't need to compute an offset curve to stroke the path. We know that
     // the rounded parts are elipses we can offset exactly and can just compute
     // a new cubic approximation.
     mContext->NewPath();
     mContext->RoundedRectangle(mOuterRect, mBorderRadii, true);
     mContext->RoundedRectangle(borderInnerRect.rect, borderInnerRect.corners, false);
     mContext->Fill();
     return;
   }
   bool hasCompositeColors;
   allBordersSolid = AllBordersSolid(&hasCompositeColors);
   // This leaves the border corners non-interpolated for single width borders.
   // Doing this is slightly faster and shouldn't be a problem visually.
   if (allBordersSolid &&
       allBordersSameWidth &&
       mCompositeColors[0] == nullptr &&
       mBorderWidths[0] == 1 &&
       mNoBorderRadius &&
       !mAvoidStroke)
   {
     DrawSingleWidthSolidBorder();
     return;
   }
   if (allBordersSolid && !hasCompositeColors &&
       !mAvoidStroke)
   {
     if (mContext->IsCairo()) {
       DrawNoCompositeColorSolidBorder();
     } else {
       DrawNoCompositeColorSolidBorderAzure();
     }
     return;
   }
   if (allBordersSolid &&
       allBordersSameWidth &&
       mNoBorderRadius &&
       !mAvoidStroke)
   {
     // Easy enough to deal with.
     DrawRectangularCompositeColors();
     return;
   }
   // If we have composite colors -and- border radius,
   // then use separate corners so we get OPERATOR_ADD for the corners.
   // Otherwise, we'll get artifacts as we draw stacked 1px-wide curves.
   if (allBordersSame && mCompositeColors[0] != nullptr && !mNoBorderRadius)
     forceSeparateCorners = true;
   S(" mOuterRect: "), S(mOuterRect), SN();
   S(" mInnerRect: "), S(mInnerRect), SN();
   SF(" mBorderColors: 0x%08x 0x%08x 0x%08x 0x%08x\n", mBorderColors[0], mBorderColors[1], mBorderColors[2], mBorderColors[3]);
   // if conditioning the outside rect failed, then bail -- the outside
   // rect is supposed to enclose the entire border
   mOuterRect.Condition();
   if (mOuterRect.IsEmpty())
     return;
   mInnerRect.Condition();
   int dashedSides = 0;
   NS_FOR_CSS_SIDES(i) {
     uint8_t style = mBorderStyles[i];
     if (style == NS_STYLE_BORDER_STYLE_DASHED ||
         style == NS_STYLE_BORDER_STYLE_DOTTED)
     {
       // pretend that all borders aren't the same; we need to draw
       // things separately for dashed/dotting
       allBordersSame = false;
       dashedSides |= (1 << i);
     }
   }
   SF(" allBordersSame: %d dashedSides: 0x%02x\n", allBordersSame, dashedSides);
   if (allBordersSame && !forceSeparateCorners) {
     /* Draw everything in one go */
     DrawBorderSides(SIDE_BITS_ALL);
     SN("---------------- (1)");
   } else {
     PROFILER_LABEL("nsCSSBorderRenderer", "DrawBorders::multipass");
     /* We have more than one pass to go.  Draw the corners separately from the sides. */
     /*
      * If we have a 1px-wide border, the corners are going to be
      * negligible, so don't bother doing anything fancy.  Just extend
      * the top and bottom borders to the right 1px and the left border
      * to the bottom 1px.  We do this by twiddling the corner dimensions,
      * which causes the right to happen later on.  Only do this if we have
      * a 1.0 unit border all around and no border radius.
      */
     NS_FOR_CSS_CORNERS(corner) {
       const mozilla::css::Side sides[2] = { mozilla::css::Side(corner), PREV_SIDE(corner) };
       if (!IsZeroSize(mBorderRadii[corner]))
         continue;
       if (mBorderWidths[sides[0]] == 1.0 && mBorderWidths[sides[1]] == 1.0) {
         if (corner == NS_CORNER_TOP_LEFT || corner == NS_CORNER_TOP_RIGHT)
           mBorderCornerDimensions[corner].width = 0.0;
         else
           mBorderCornerDimensions[corner].height = 0.0;
       }
     }
     // First, the corners
     NS_FOR_CSS_CORNERS(corner) {
       // if there's no corner, don't do all this work for it
       if (IsZeroSize(mBorderCornerDimensions[corner]))
         continue;
       const int sides[2] = { corner, PREV_SIDE(corner) };
       int sideBits = (1 << sides[0]) | (1 << sides[1]);
       bool simpleCornerStyle = mCompositeColors[sides[0]] == nullptr &&
                                  mCompositeColors[sides[1]] == nullptr &&
                                  AreBorderSideFinalStylesSame(sideBits);
       // If we don't have anything complex going on in this corner,
       // then we can just fill the corner with a solid color, and avoid
       // the potentially expensive clip.
       if (simpleCornerStyle &&
           IsZeroSize(mBorderRadii[corner]) &&
           IsSolidCornerStyle(mBorderStyles[sides[0]], corner))
       {
         mContext->NewPath();
         DoCornerSubPath(corner);
         mContext->SetColor(MakeBorderColor(mBorderColors[sides[0]],
                                            mBackgroundColor,
                                            BorderColorStyleForSolidCorner(mBorderStyles[sides[0]], corner)));
         mContext->Fill();
         continue;
       }
       mContext->Save();
       // clip to the corner
       mContext->NewPath();
       DoCornerSubPath(corner);
       mContext->Clip();
       if (simpleCornerStyle) {
         // we don't need a group for this corner, the sides are the same,
         // but we weren't able to render just a solid block for the corner.
         DrawBorderSides(sideBits);
       } else {
         // Sides are different.  We could draw using OPERATOR_ADD to
         // get correct color blending behaviour at the seam.  We'd need
         // to do it in an offscreen surface to ensure that we're
         // always compositing on transparent black.  If the colors
         // don't have transparency and the current destination surface
         // has an alpha channel, we could just clear the region and
         // avoid the temporary, but that situation doesn't happen all
         // that often in practice (we double buffer to no-alpha
         // surfaces). We choose just to seam though, as the performance
         // advantages outway the modest easthetic improvement.
         for (int cornerSide = 0; cornerSide < 2; cornerSide++) {
           mozilla::css::Side side = mozilla::css::Side(sides[cornerSide]);
           uint8_t style = mBorderStyles[side];
           SF("corner: %d cornerSide: %d side: %d style: %d\n", corner, cornerSide, side, style);
           mContext->Save();
           mContext->NewPath();
           DoSideClipSubPath(side);
           mContext->Clip();
           DrawBorderSides(1 << side);
           mContext->Restore();
         }
       }
       mContext->Restore();
       SN();
     }
     // in the case of a single-unit border, we already munged the
     // corners up above; so we can just draw the top left and bottom
     // right sides separately, if they're the same.
     //
     // We need to check for mNoBorderRadius, because when there is
     // one, FillSolidBorder always draws the full rounded rectangle
     // and expects there to be a clip in place.
     int alreadyDrawnSides = 0;
     if (mOneUnitBorder &&
         mNoBorderRadius &&
         (dashedSides & (SIDE_BIT_TOP | SIDE_BIT_LEFT)) == 0)
     {
       if (tlBordersSame) {
         DrawBorderSides(SIDE_BIT_TOP | SIDE_BIT_LEFT);
         alreadyDrawnSides |= (SIDE_BIT_TOP | SIDE_BIT_LEFT);
       }
       if (brBordersSame && (dashedSides & (SIDE_BIT_BOTTOM | SIDE_BIT_RIGHT)) == 0) {
         DrawBorderSides(SIDE_BIT_BOTTOM | SIDE_BIT_RIGHT);
         alreadyDrawnSides |= (SIDE_BIT_BOTTOM | SIDE_BIT_RIGHT);
       }
     }
     // We're done with the corners, now draw the sides.
     NS_FOR_CSS_SIDES (side) {
       // if we drew it above, skip it
       if (alreadyDrawnSides & (1 << side))
         continue;
       // If there's no border on this side, skip it
       if (mBorderWidths[side] == 0.0 ||
           mBorderStyles[side] == NS_STYLE_BORDER_STYLE_HIDDEN ||
           mBorderStyles[side] == NS_STYLE_BORDER_STYLE_NONE)
         continue;
       if (dashedSides & (1 << side)) {
         // Dashed sides will always draw just the part ignoring the
         // corners for the side, so no need to clip.
         DrawDashedSide (side);
         SN("---------------- (d)");
         continue;
       }
       // Undashed sides will currently draw the entire side,
       // including parts that would normally be covered by a corner,
       // so we need to clip.
       //
       // XXX Optimization -- it would be good to make this work like
       // DrawDashedSide, and have a DrawOneSide function that just
       // draws one side and not the corners, because then we can
       // avoid the potentially expensive clip.
       mContext->Save();
       mContext->NewPath();
       DoSideClipWithoutCornersSubPath(side);
       mContext->Clip();
       DrawBorderSides(1 << side);
       mContext->Restore();
       SN("---------------- (*)");
     }
   }
 }

The Tor Browser / annotate

layout/base/nsCSSRenderingBorders.cpp@6474c204b198 (annotated)

layout/base/nsCSSRenderingBorders.cpp