/* * Copyright 2006 The Android Open Source Project * * Use of this source code is governed by a BSD-style license that can be * found in the LICENSE file. */ #ifndef SkEdge_DEFINED #define SkEdge_DEFINED #include "include/core/SkMath.h" #include "include/core/SkRect.h" #include "include/private/SkTo.h" #include "src/core/SkFDot6.h" #include // This correctly favors the lower-pixel when y0 is on a 1/2 pixel boundary #define SkEdge_Compute_DY(top, y0) (SkLeftShift(top, 6) + 32 - (y0)) struct SkEdge { enum Type { kLine_Type, kQuad_Type, kCubic_Type }; SkEdge* fNext; SkEdge* fPrev; SkFixed fX; SkFixed fDX; int32_t fFirstY; int32_t fLastY; int8_t fCurveCount; // only used by kQuad(+) and kCubic(-) uint8_t fCurveShift; // appled to all Dx/DDx/DDDx except for fCubicDShift exception uint8_t fCubicDShift; // applied to fCDx and fCDy only in cubic int8_t fWinding; // 1 or -1 int setLine(const SkPoint& p0, const SkPoint& p1, const SkIRect* clip, int shiftUp); // call this version if you know you don't have a clip inline int setLine(const SkPoint& p0, const SkPoint& p1, int shiftUp); inline int updateLine(SkFixed ax, SkFixed ay, SkFixed bx, SkFixed by); void chopLineWithClip(const SkIRect& clip); inline bool intersectsClip(const SkIRect& clip) const { SkASSERT(fFirstY < clip.fBottom); return fLastY >= clip.fTop; } #ifdef SK_DEBUG void dump() const { SkDebugf("edge: firstY:%d lastY:%d x:%g dx:%g w:%d\n", fFirstY, fLastY, SkFixedToFloat(fX), SkFixedToFloat(fDX), fWinding); } void validate() const { SkASSERT(fPrev && fNext); SkASSERT(fPrev->fNext == this); SkASSERT(fNext->fPrev == this); SkASSERT(fFirstY <= fLastY); SkASSERT(SkAbs32(fWinding) == 1); } #endif }; struct SkQuadraticEdge : public SkEdge { SkFixed fQx, fQy; SkFixed fQDx, fQDy; SkFixed fQDDx, fQDDy; SkFixed fQLastX, fQLastY; bool setQuadraticWithoutUpdate(const SkPoint pts[3], int shiftUp); int setQuadratic(const SkPoint pts[3], int shiftUp); int updateQuadratic(); }; struct SkCubicEdge : public SkEdge { SkFixed fCx, fCy; SkFixed fCDx, fCDy; SkFixed fCDDx, fCDDy; SkFixed fCDDDx, fCDDDy; SkFixed fCLastX, fCLastY; bool setCubicWithoutUpdate(const SkPoint pts[4], int shiftUp, bool sortY = true); int setCubic(const SkPoint pts[4], int shiftUp); int updateCubic(); }; int SkEdge::setLine(const SkPoint& p0, const SkPoint& p1, int shift) { SkFDot6 x0, y0, x1, y1; { #ifdef SK_RASTERIZE_EVEN_ROUNDING x0 = SkScalarRoundToFDot6(p0.fX, shift); y0 = SkScalarRoundToFDot6(p0.fY, shift); x1 = SkScalarRoundToFDot6(p1.fX, shift); y1 = SkScalarRoundToFDot6(p1.fY, shift); #else float scale = float(1 << (shift + 6)); x0 = int(p0.fX * scale); y0 = int(p0.fY * scale); x1 = int(p1.fX * scale); y1 = int(p1.fY * scale); #endif } int winding = 1; if (y0 > y1) { using std::swap; swap(x0, x1); swap(y0, y1); winding = -1; } int top = SkFDot6Round(y0); int bot = SkFDot6Round(y1); // are we a zero-height line? if (top == bot) { return 0; } SkFixed slope = SkFDot6Div(x1 - x0, y1 - y0); const SkFDot6 dy = SkEdge_Compute_DY(top, y0); fX = SkFDot6ToFixed(x0 + SkFixedMul(slope, dy)); // + SK_Fixed1/2 fDX = slope; fFirstY = top; fLastY = bot - 1; fCurveCount = 0; fWinding = SkToS8(winding); fCurveShift = 0; return 1; } #endif