michael@0: 
michael@0: /*
michael@0:  * Copyright 2006 The Android Open Source Project
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: 
michael@0: #include "SkCornerPathEffect.h"
michael@0: #include "SkPath.h"
michael@0: #include "SkPoint.h"
michael@0: #include "SkReadBuffer.h"
michael@0: #include "SkWriteBuffer.h"
michael@0: 
michael@0: SkCornerPathEffect::SkCornerPathEffect(SkScalar radius) : fRadius(radius) {}
michael@0: SkCornerPathEffect::~SkCornerPathEffect() {}
michael@0: 
michael@0: static bool ComputeStep(const SkPoint& a, const SkPoint& b, SkScalar radius,
michael@0:                         SkPoint* step) {
michael@0:     SkScalar dist = SkPoint::Distance(a, b);
michael@0: 
michael@0:     step->set(b.fX - a.fX, b.fY - a.fY);
michael@0: 
michael@0:     if (dist <= radius * 2) {
michael@0:         step->scale(SK_ScalarHalf);
michael@0:         return false;
michael@0:     } else {
michael@0:         step->scale(SkScalarDiv(radius, dist));
michael@0:         return true;
michael@0:     }
michael@0: }
michael@0: 
michael@0: bool SkCornerPathEffect::filterPath(SkPath* dst, const SkPath& src,
michael@0:                                     SkStrokeRec*, const SkRect*) const {
michael@0:     if (0 == fRadius) {
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     SkPath::Iter    iter(src, false);
michael@0:     SkPath::Verb    verb, prevVerb = (SkPath::Verb)-1;
michael@0:     SkPoint         pts[4];
michael@0: 
michael@0:     bool        closed;
michael@0:     SkPoint     moveTo, lastCorner;
michael@0:     SkVector    firstStep, step;
michael@0:     bool        prevIsValid = true;
michael@0: 
michael@0:     // to avoid warnings
michael@0:     moveTo.set(0, 0);
michael@0:     firstStep.set(0, 0);
michael@0:     lastCorner.set(0, 0);
michael@0: 
michael@0:     for (;;) {
michael@0:         switch (verb = iter.next(pts, false)) {
michael@0:             case SkPath::kMove_Verb:
michael@0:                     // close out the previous (open) contour
michael@0:                 if (SkPath::kLine_Verb == prevVerb) {
michael@0:                     dst->lineTo(lastCorner);
michael@0:                 }
michael@0:                 closed = iter.isClosedContour();
michael@0:                 if (closed) {
michael@0:                     moveTo = pts[0];
michael@0:                     prevIsValid = false;
michael@0:                 } else {
michael@0:                     dst->moveTo(pts[0]);
michael@0:                     prevIsValid = true;
michael@0:                 }
michael@0:                 break;
michael@0:             case SkPath::kLine_Verb: {
michael@0:                 bool drawSegment = ComputeStep(pts[0], pts[1], fRadius, &step);
michael@0:                 // prev corner
michael@0:                 if (!prevIsValid) {
michael@0:                     dst->moveTo(moveTo + step);
michael@0:                     prevIsValid = true;
michael@0:                 } else {
michael@0:                     dst->quadTo(pts[0].fX, pts[0].fY, pts[0].fX + step.fX,
michael@0:                                 pts[0].fY + step.fY);
michael@0:                 }
michael@0:                 if (drawSegment) {
michael@0:                     dst->lineTo(pts[1].fX - step.fX, pts[1].fY - step.fY);
michael@0:                 }
michael@0:                 lastCorner = pts[1];
michael@0:                 prevIsValid = true;
michael@0:                 break;
michael@0:             }
michael@0:             case SkPath::kQuad_Verb:
michael@0:                 // TBD - just replicate the curve for now
michael@0:                 if (!prevIsValid) {
michael@0:                     dst->moveTo(pts[0]);
michael@0:                     prevIsValid = true;
michael@0:                 }
michael@0:                 dst->quadTo(pts[1], pts[2]);
michael@0:                 lastCorner = pts[2];
michael@0:                 firstStep.set(0, 0);
michael@0:                 break;
michael@0:             case SkPath::kCubic_Verb:
michael@0:                 if (!prevIsValid) {
michael@0:                     dst->moveTo(pts[0]);
michael@0:                     prevIsValid = true;
michael@0:                 }
michael@0:                 // TBD - just replicate the curve for now
michael@0:                 dst->cubicTo(pts[1], pts[2], pts[3]);
michael@0:                 lastCorner = pts[3];
michael@0:                 firstStep.set(0, 0);
michael@0:                 break;
michael@0:             case SkPath::kClose_Verb:
michael@0:                 if (firstStep.fX || firstStep.fY) {
michael@0:                     dst->quadTo(lastCorner.fX, lastCorner.fY,
michael@0:                                 lastCorner.fX + firstStep.fX,
michael@0:                                 lastCorner.fY + firstStep.fY);
michael@0:                     }
michael@0:                 dst->close();
michael@0:                 break;
michael@0:             case SkPath::kConic_Verb:
michael@0:                 SkASSERT(0);
michael@0:                 break;
michael@0:             case SkPath::kDone_Verb:
michael@0:                 goto DONE;
michael@0:         }
michael@0: 
michael@0:         if (SkPath::kMove_Verb == prevVerb) {
michael@0:             firstStep = step;
michael@0:         }
michael@0:         prevVerb = verb;
michael@0:     }
michael@0: DONE:
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: void SkCornerPathEffect::flatten(SkWriteBuffer& buffer) const {
michael@0:     this->INHERITED::flatten(buffer);
michael@0:     buffer.writeScalar(fRadius);
michael@0: }
michael@0: 
michael@0: SkCornerPathEffect::SkCornerPathEffect(SkReadBuffer& buffer) {
michael@0:     fRadius = buffer.readScalar();
michael@0: }