src/gpu/GrStyle.h - skia - Git at Google

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */

 #ifndef GrStyle_DEFINED
 #define GrStyle_DEFINED

 #include "GrTypes.h"
 #include "SkPathEffect.h"
 #include "SkStrokeRec.h"
 #include "SkTemplates.h"

 /**
  * Represents the various ways that a GrShape can be styled. It has fill/stroking information
  * as well as an optional path effect. If the path effect represents dashing, the dashing
  * information is extracted from the path effect and stored explicitly.
  *
  * This will replace GrStrokeInfo as GrShape is deployed.
  */
 class GrStyle {
 public:
     /**
      * A style object that represents a fill with no path effect.
      * TODO: constexpr with C++14
      */
     static const GrStyle& SimpleFill() {
         static const GrStyle kFill(SkStrokeRec::kFill_InitStyle);
         return kFill;
         }

     /**
      * A style object that represents a hairline stroke with no path effect.
      * TODO: constexpr with C++14
      */
     static const GrStyle& SimpleHairline() {
         static const GrStyle kHairline(SkStrokeRec::kHairline_InitStyle);
         return kHairline;
     }

     enum class Apply {
         kPathEffectOnly,
         kPathEffectAndStrokeRec
     };

     /**
      * Optional flags for computing keys that may remove unnecessary variation in the key due to
      * style settings that don't affect particular classes of geometry.
      */
     enum KeyFlags {
         // The shape being styled has no open contours.
         kClosed_KeyFlag = 0x1,
         // The shape being styled doesn't have any joins and so isn't affected by join type.
         kNoJoins_KeyFlag = 0x2
     };

     /**
      * Computes the key length for a GrStyle. The return will be negative if it cannot be turned
      * into a key. This occurs when there is a path effect that is not a dash. The key can
      * either reflect just the path effect (if one) or the path effect and the strokerec. Note
      * that a simple fill has a zero sized key.
      */
     static int KeySize(const GrStyle&, Apply, uint32_t flags = 0);

     /**
      * Writes a unique key for the style into the provided buffer. This function assumes the buffer
      * has room for at least KeySize() values. It assumes that KeySize() returns a non-negative
      * value for the combination of GrStyle, Apply and flags params. This is written so that the key
      * for just dash application followed by the key for the remaining SkStrokeRec is the same as
      * the key for applying dashing and SkStrokeRec all at once.
      */
     static void WriteKey(uint32_t*, const GrStyle&, Apply, SkScalar scale, uint32_t flags = 0);

     GrStyle() : GrStyle(SkStrokeRec::kFill_InitStyle) {}

     explicit GrStyle(SkStrokeRec::InitStyle initStyle) : fStrokeRec(initStyle) {}

     GrStyle(const SkStrokeRec& strokeRec, sk_sp<SkPathEffect> pe) : fStrokeRec(strokeRec) {
         this->initPathEffect(std::move(pe));
     }

     GrStyle(const GrStyle& that) = default;

     explicit GrStyle(const SkPaint& paint) : fStrokeRec(paint) {
         this->initPathEffect(paint.refPathEffect());
     }

     explicit GrStyle(const SkPaint& paint, SkPaint::Style overrideStyle)
             : fStrokeRec(paint, overrideStyle) {
         this->initPathEffect(paint.refPathEffect());
     }

     GrStyle& operator=(const GrStyle& that) {
         fPathEffect = that.fPathEffect;
         fDashInfo = that.fDashInfo;
         fStrokeRec = that.fStrokeRec;
         return *this;
     }

     void resetToInitStyle(SkStrokeRec::InitStyle fillOrHairline) {
         fDashInfo.reset();
         fPathEffect.reset(nullptr);
         if (SkStrokeRec::kFill_InitStyle == fillOrHairline) {
             fStrokeRec.setFillStyle();
         } else {
             fStrokeRec.setHairlineStyle();
         }
     }

     /** Is this style a fill with no path effect? */
     bool isSimpleFill() const { return fStrokeRec.isFillStyle() && !fPathEffect; }

     /** Is this style a hairline with no path effect? */
     bool isSimpleHairline() const { return fStrokeRec.isHairlineStyle() && !fPathEffect; }

     SkPathEffect* pathEffect() const { return fPathEffect.get(); }
     sk_sp<SkPathEffect> refPathEffect() const { return fPathEffect; }

     bool hasPathEffect() const { return SkToBool(fPathEffect.get()); }

     bool hasNonDashPathEffect() const { return fPathEffect.get() && !this->isDashed(); }

     bool isDashed() const { return SkPathEffect::kDash_DashType == fDashInfo.fType; }
     SkScalar dashPhase() const {
         SkASSERT(this->isDashed());
         return fDashInfo.fPhase;
     }
     int dashIntervalCnt() const {
         SkASSERT(this->isDashed());
         return fDashInfo.fIntervals.count();
     }
     const SkScalar* dashIntervals() const {
         SkASSERT(this->isDashed());
         return fDashInfo.fIntervals.get();
     }

     const SkStrokeRec& strokeRec() const { return fStrokeRec; }

     /** Hairline or fill styles without path effects make no alterations to a geometry. */
     bool applies() const {
         return this->pathEffect() || (!fStrokeRec.isFillStyle() && !fStrokeRec.isHairlineStyle());
     }

     static SkScalar MatrixToScaleFactor(const SkMatrix& matrix) {
         // getMaxScale will return -1 if the matrix has perspective. In that case we can use a scale
         // factor of 1. This isn't necessarily a good choice and in the future we might consider
         // taking a bounds here for the perspective case.
         return SkScalarAbs(matrix.getMaxScale());
     }
     /**
      * Applies just the path effect and returns remaining stroke information. This will fail if
      * there is no path effect. dst may or may not have been overwritten on failure. Scale controls
      * geometric approximations made by the path effect. It is typically computed from the view
      * matrix.
      */
     bool SK_WARN_UNUSED_RESULT applyPathEffectToPath(SkPath* dst, SkStrokeRec* remainingStoke,
                                                      const SkPath& src, SkScalar scale) const;

     /**
      * If this succeeds then the result path should be filled or hairlined as indicated by the
      * returned SkStrokeRec::InitStyle value. Will fail if there is no path effect and the
      * strokerec doesn't change the geometry. When this fails the outputs may or may not have
      * been overwritten. Scale controls geometric approximations made by the path effect and
      * stroker. It is typically computed from the view matrix.
      */
     bool SK_WARN_UNUSED_RESULT applyToPath(SkPath* dst, SkStrokeRec::InitStyle* fillOrHairline,
                                            const SkPath& src, SkScalar scale) const;

     /** Given bounds of a path compute the bounds of path with the style applied. */
     void adjustBounds(SkRect* dst, const SkRect& src) const {
         if (this->pathEffect()) {
             this->pathEffect()->computeFastBounds(dst, src);
             // This may not be the correct SkStrokeRec to use. skbug.com/5299
             // It happens to work for dashing.
             SkScalar radius = fStrokeRec.getInflationRadius();
             dst->outset(radius, radius);
         } else {
             SkScalar radius = fStrokeRec.getInflationRadius();
             *dst = src.makeOutset(radius, radius);
         }
     }

 private:
     void initPathEffect(sk_sp<SkPathEffect> pe);

     struct DashInfo {
         DashInfo() : fType(SkPathEffect::kNone_DashType) {}
         DashInfo(const DashInfo& that) { *this = that; }
         DashInfo& operator=(const DashInfo& that) {
             fType = that.fType;
             fPhase = that.fPhase;
             fIntervals.reset(that.fIntervals.count());
             sk_careful_memcpy(fIntervals.get(), that.fIntervals.get(),
                               sizeof(SkScalar) * that.fIntervals.count());
             return *this;
         }
         void reset() {
             fType = SkPathEffect::kNone_DashType;
             fIntervals.reset(0);
         }
         SkPathEffect::DashType      fType;
         SkScalar                    fPhase;
         SkAutoSTArray<4, SkScalar>  fIntervals;
     };

     bool applyPathEffect(SkPath* dst, SkStrokeRec* strokeRec, const SkPath& src) const;

     SkStrokeRec         fStrokeRec;
     sk_sp<SkPathEffect> fPathEffect;
     DashInfo            fDashInfo;
 };

 #endif
	/*
	* Copyright 2016 Google Inc.
	*
	* Use of this source code is governed by a BSD-style license that can be
	* found in the LICENSE file.
	*/

	#ifndef GrStyle_DEFINED
	#define GrStyle_DEFINED

	#include "GrTypes.h"
	#include "SkPathEffect.h"
	#include "SkStrokeRec.h"
	#include "SkTemplates.h"

	/**
	* Represents the various ways that a GrShape can be styled. It has fill/stroking information
	* as well as an optional path effect. If the path effect represents dashing, the dashing
	* information is extracted from the path effect and stored explicitly.
	*
	* This will replace GrStrokeInfo as GrShape is deployed.
	*/
	class GrStyle {
	public:
	/**
	* A style object that represents a fill with no path effect.
	* TODO: constexpr with C++14
	*/
	static const GrStyle& SimpleFill() {
	static const GrStyle kFill(SkStrokeRec::kFill_InitStyle);
	return kFill;
	}

	/**
	* A style object that represents a hairline stroke with no path effect.
	* TODO: constexpr with C++14
	*/
	static const GrStyle& SimpleHairline() {
	static const GrStyle kHairline(SkStrokeRec::kHairline_InitStyle);
	return kHairline;
	}

	enum class Apply {
	kPathEffectOnly,
	kPathEffectAndStrokeRec
	};

	/**
	* Optional flags for computing keys that may remove unnecessary variation in the key due to
	* style settings that don't affect particular classes of geometry.
	*/
	enum KeyFlags {
	// The shape being styled has no open contours.
	kClosed_KeyFlag = 0x1,
	// The shape being styled doesn't have any joins and so isn't affected by join type.
	kNoJoins_KeyFlag = 0x2
	};

	/**
	* Computes the key length for a GrStyle. The return will be negative if it cannot be turned
	* into a key. This occurs when there is a path effect that is not a dash. The key can
	* either reflect just the path effect (if one) or the path effect and the strokerec. Note
	* that a simple fill has a zero sized key.
	*/
	static int KeySize(const GrStyle&, Apply, uint32_t flags = 0);

	/**
	* Writes a unique key for the style into the provided buffer. This function assumes the buffer
	* has room for at least KeySize() values. It assumes that KeySize() returns a non-negative
	* value for the combination of GrStyle, Apply and flags params. This is written so that the key
	* for just dash application followed by the key for the remaining SkStrokeRec is the same as
	* the key for applying dashing and SkStrokeRec all at once.
	*/
	static void WriteKey(uint32_t*, const GrStyle&, Apply, SkScalar scale, uint32_t flags = 0);

	GrStyle() : GrStyle(SkStrokeRec::kFill_InitStyle) {}

	explicit GrStyle(SkStrokeRec::InitStyle initStyle) : fStrokeRec(initStyle) {}

	GrStyle(const SkStrokeRec& strokeRec, sk_sp<SkPathEffect> pe) : fStrokeRec(strokeRec) {
	this->initPathEffect(std::move(pe));
	}

	GrStyle(const GrStyle& that) = default;

	explicit GrStyle(const SkPaint& paint) : fStrokeRec(paint) {
	this->initPathEffect(paint.refPathEffect());
	}

	explicit GrStyle(const SkPaint& paint, SkPaint::Style overrideStyle)
	: fStrokeRec(paint, overrideStyle) {
	this->initPathEffect(paint.refPathEffect());
	}

	GrStyle& operator=(const GrStyle& that) {
	fPathEffect = that.fPathEffect;
	fDashInfo = that.fDashInfo;
	fStrokeRec = that.fStrokeRec;
	return *this;
	}

	void resetToInitStyle(SkStrokeRec::InitStyle fillOrHairline) {
	fDashInfo.reset();
	fPathEffect.reset(nullptr);
	if (SkStrokeRec::kFill_InitStyle == fillOrHairline) {
	fStrokeRec.setFillStyle();
	} else {
	fStrokeRec.setHairlineStyle();
	}
	}

	/** Is this style a fill with no path effect? */
	bool isSimpleFill() const { return fStrokeRec.isFillStyle() && !fPathEffect; }

	/** Is this style a hairline with no path effect? */
	bool isSimpleHairline() const { return fStrokeRec.isHairlineStyle() && !fPathEffect; }

	SkPathEffect* pathEffect() const { return fPathEffect.get(); }
	sk_sp<SkPathEffect> refPathEffect() const { return fPathEffect; }

	bool hasPathEffect() const { return SkToBool(fPathEffect.get()); }

	bool hasNonDashPathEffect() const { return fPathEffect.get() && !this->isDashed(); }

	bool isDashed() const { return SkPathEffect::kDash_DashType == fDashInfo.fType; }
	SkScalar dashPhase() const {
	SkASSERT(this->isDashed());
	return fDashInfo.fPhase;
	}
	int dashIntervalCnt() const {
	SkASSERT(this->isDashed());
	return fDashInfo.fIntervals.count();
	}
	const SkScalar* dashIntervals() const {
	SkASSERT(this->isDashed());
	return fDashInfo.fIntervals.get();
	}

	const SkStrokeRec& strokeRec() const { return fStrokeRec; }

	/** Hairline or fill styles without path effects make no alterations to a geometry. */
	bool applies() const {
	return this->pathEffect() \|\| (!fStrokeRec.isFillStyle() && !fStrokeRec.isHairlineStyle());
	}

	static SkScalar MatrixToScaleFactor(const SkMatrix& matrix) {
	// getMaxScale will return -1 if the matrix has perspective. In that case we can use a scale
	// factor of 1. This isn't necessarily a good choice and in the future we might consider
	// taking a bounds here for the perspective case.
	return SkScalarAbs(matrix.getMaxScale());
	}
	/**
	* Applies just the path effect and returns remaining stroke information. This will fail if
	* there is no path effect. dst may or may not have been overwritten on failure. Scale controls
	* geometric approximations made by the path effect. It is typically computed from the view
	* matrix.
	*/
	bool SK_WARN_UNUSED_RESULT applyPathEffectToPath(SkPath* dst, SkStrokeRec* remainingStoke,
	const SkPath& src, SkScalar scale) const;

	/**
	* If this succeeds then the result path should be filled or hairlined as indicated by the
	* returned SkStrokeRec::InitStyle value. Will fail if there is no path effect and the
	* strokerec doesn't change the geometry. When this fails the outputs may or may not have
	* been overwritten. Scale controls geometric approximations made by the path effect and
	* stroker. It is typically computed from the view matrix.
	*/
	bool SK_WARN_UNUSED_RESULT applyToPath(SkPath* dst, SkStrokeRec::InitStyle* fillOrHairline,
	const SkPath& src, SkScalar scale) const;

	/** Given bounds of a path compute the bounds of path with the style applied. */
	void adjustBounds(SkRect* dst, const SkRect& src) const {
	if (this->pathEffect()) {
	this->pathEffect()->computeFastBounds(dst, src);
	// This may not be the correct SkStrokeRec to use. skbug.com/5299
	// It happens to work for dashing.
	SkScalar radius = fStrokeRec.getInflationRadius();
	dst->outset(radius, radius);
	} else {
	SkScalar radius = fStrokeRec.getInflationRadius();
	*dst = src.makeOutset(radius, radius);
	}
	}

	private:
	void initPathEffect(sk_sp<SkPathEffect> pe);

	struct DashInfo {
	DashInfo() : fType(SkPathEffect::kNone_DashType) {}
	DashInfo(const DashInfo& that) { *this = that; }
	DashInfo& operator=(const DashInfo& that) {
	fType = that.fType;
	fPhase = that.fPhase;
	fIntervals.reset(that.fIntervals.count());
	sk_careful_memcpy(fIntervals.get(), that.fIntervals.get(),
	sizeof(SkScalar) * that.fIntervals.count());
	return *this;
	}
	void reset() {
	fType = SkPathEffect::kNone_DashType;
	fIntervals.reset(0);
	}
	SkPathEffect::DashType fType;
	SkScalar fPhase;
	SkAutoSTArray<4, SkScalar> fIntervals;
	};

	bool applyPathEffect(SkPath* dst, SkStrokeRec* strokeRec, const SkPath& src) const;

	SkStrokeRec fStrokeRec;
	sk_sp<SkPathEffect> fPathEffect;
	DashInfo fDashInfo;
	};

	#endif