michael@0: /*
michael@0:  * Copyright 2012 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: #include "SkTypes.h"
michael@0: 
michael@0: #include "SkDWriteGeometrySink.h"
michael@0: #include "SkFloatUtils.h"
michael@0: #include "SkPath.h"
michael@0: 
michael@0: #include <dwrite.h>
michael@0: #include <d2d1.h>
michael@0: 
michael@0: SkDWriteGeometrySink::SkDWriteGeometrySink(SkPath* path) : fRefCount(1), fPath(path) { }
michael@0: 
michael@0: SkDWriteGeometrySink::~SkDWriteGeometrySink() { }
michael@0: 
michael@0: HRESULT STDMETHODCALLTYPE SkDWriteGeometrySink::QueryInterface(REFIID iid, void **object) {
michael@0:     if (NULL == object) {
michael@0:         return E_INVALIDARG;
michael@0:     }
michael@0:     if (iid == __uuidof(IUnknown) || iid == __uuidof(IDWriteGeometrySink)) {
michael@0:         *object = static_cast<IDWriteGeometrySink*>(this);
michael@0:         this->AddRef();
michael@0:         return S_OK;
michael@0:     } else {
michael@0:         *object = NULL;
michael@0:         return E_NOINTERFACE;
michael@0:     }
michael@0: }
michael@0: 
michael@0: ULONG STDMETHODCALLTYPE SkDWriteGeometrySink::AddRef(void) {
michael@0:     return static_cast<ULONG>(InterlockedIncrement(&fRefCount));
michael@0: }
michael@0: 
michael@0: ULONG STDMETHODCALLTYPE SkDWriteGeometrySink::Release(void) {
michael@0:     ULONG res = static_cast<ULONG>(InterlockedDecrement(&fRefCount));
michael@0:     if (0 == res) {
michael@0:         delete this;
michael@0:     }
michael@0:     return res;
michael@0: }
michael@0: 
michael@0: void STDMETHODCALLTYPE SkDWriteGeometrySink::SetFillMode(D2D1_FILL_MODE fillMode) {
michael@0:     switch (fillMode) {
michael@0:     case D2D1_FILL_MODE_ALTERNATE:
michael@0:         fPath->setFillType(SkPath::kEvenOdd_FillType);
michael@0:         break;
michael@0:     case D2D1_FILL_MODE_WINDING:
michael@0:         fPath->setFillType(SkPath::kWinding_FillType);
michael@0:         break;
michael@0:     default:
michael@0:         SkDEBUGFAIL("Unknown D2D1_FILL_MODE.");
michael@0:         break;
michael@0:     }
michael@0: }
michael@0: 
michael@0: void STDMETHODCALLTYPE SkDWriteGeometrySink::SetSegmentFlags(D2D1_PATH_SEGMENT vertexFlags) {
michael@0:     if (vertexFlags == D2D1_PATH_SEGMENT_NONE || vertexFlags == D2D1_PATH_SEGMENT_FORCE_ROUND_LINE_JOIN) {
michael@0:         SkDEBUGFAIL("Invalid D2D1_PATH_SEGMENT value.");
michael@0:     }
michael@0: }
michael@0: 
michael@0: void STDMETHODCALLTYPE SkDWriteGeometrySink::BeginFigure(D2D1_POINT_2F startPoint, D2D1_FIGURE_BEGIN figureBegin) {
michael@0:     fPath->moveTo(startPoint.x, startPoint.y);
michael@0:     if (figureBegin == D2D1_FIGURE_BEGIN_HOLLOW) {
michael@0:         SkDEBUGFAIL("Invalid D2D1_FIGURE_BEGIN value.");
michael@0:     }
michael@0: }
michael@0: 
michael@0: void STDMETHODCALLTYPE SkDWriteGeometrySink::AddLines(const D2D1_POINT_2F *points, UINT pointsCount) {
michael@0:     for (const D2D1_POINT_2F *end = &points[pointsCount]; points < end; ++points) {
michael@0:         fPath->lineTo(points->x, points->y);
michael@0:     }
michael@0: }
michael@0: 
michael@0: static bool approximately_equal(float a, float b) {
michael@0:     const SkFloatingPoint<float, 10> lhs(a), rhs(b);
michael@0:     return lhs.AlmostEquals(rhs);
michael@0: }
michael@0: 
michael@0: typedef struct {
michael@0:     float x;
michael@0:     float y;
michael@0: } Cubic[4], Quadratic[3];
michael@0: 
michael@0: static bool check_quadratic(const Cubic& cubic, Quadratic& reduction) {
michael@0:     float dx10 = cubic[1].x - cubic[0].x;
michael@0:     float dx23 = cubic[2].x - cubic[3].x;
michael@0:     float midX = cubic[0].x + dx10 * 3 / 2;
michael@0:     //NOTE: !approximately_equal(midX - cubic[3].x, dx23 * 3 / 2)
michael@0:     //does not work as subnormals get in between the left side and 0.
michael@0:     if (!approximately_equal(midX, (dx23 * 3 / 2) + cubic[3].x)) {
michael@0:         return false;
michael@0:     }
michael@0:     float dy10 = cubic[1].y - cubic[0].y;
michael@0:     float dy23 = cubic[2].y - cubic[3].y;
michael@0:     float midY = cubic[0].y + dy10 * 3 / 2;
michael@0:     if (!approximately_equal(midY, (dy23 * 3 / 2) + cubic[3].y)) {
michael@0:         return false;
michael@0:     }
michael@0:     reduction[0] = cubic[0];
michael@0:     reduction[1].x = midX;
michael@0:     reduction[1].y = midY;
michael@0:     reduction[2] = cubic[3];
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: void STDMETHODCALLTYPE SkDWriteGeometrySink::AddBeziers(const D2D1_BEZIER_SEGMENT *beziers, UINT beziersCount) {
michael@0:     SkPoint lastPt;
michael@0:     fPath->getLastPt(&lastPt);
michael@0:     D2D1_POINT_2F prevPt = { SkScalarToFloat(lastPt.fX), SkScalarToFloat(lastPt.fY) };
michael@0: 
michael@0:     for (const D2D1_BEZIER_SEGMENT *end = &beziers[beziersCount]; beziers < end; ++beziers) {
michael@0:         Cubic cubic = { { prevPt.x, prevPt.y },
michael@0:                         { beziers->point1.x, beziers->point1.y },
michael@0:                         { beziers->point2.x, beziers->point2.y },
michael@0:                         { beziers->point3.x, beziers->point3.y }, };
michael@0:         Quadratic quadratic;
michael@0:         if (check_quadratic(cubic, quadratic)) {
michael@0:             fPath->quadTo(quadratic[1].x, quadratic[1].y,
michael@0:                           quadratic[2].x, quadratic[2].y);
michael@0:         } else {
michael@0:             fPath->cubicTo(beziers->point1.x, beziers->point1.y,
michael@0:                            beziers->point2.x, beziers->point2.y,
michael@0:                            beziers->point3.x, beziers->point3.y);
michael@0:         }
michael@0:         prevPt = beziers->point3;
michael@0:     }
michael@0: }
michael@0: 
michael@0: void STDMETHODCALLTYPE SkDWriteGeometrySink::EndFigure(D2D1_FIGURE_END figureEnd) {
michael@0:     fPath->close();
michael@0: }
michael@0: 
michael@0: HRESULT SkDWriteGeometrySink::Close() {
michael@0:     return S_OK;
michael@0: }
michael@0: 
michael@0: HRESULT SkDWriteGeometrySink::Create(SkPath* path, IDWriteGeometrySink** geometryToPath) {
michael@0:     *geometryToPath = new SkDWriteGeometrySink(path);
michael@0:     return S_OK;
michael@0: }