src/gpu/GrAtlasTextBlob.h - skia.git - Git at Google

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */

 #ifndef GrAtlasTextBlob_DEFINED
 #define GrAtlasTextBlob_DEFINED

 #include "GrBatchAtlas.h"
 #include "GrBatchFontCache.h"
 #include "GrColor.h"
 #include "SkDescriptor.h"
 #include "SkMaskFilter.h"
 #include "GrMemoryPool.h"
 #include "SkSurfaceProps.h"
 #include "SkTInternalLList.h"

 // With this flag enabled, the GrAtlasTextContext will, as a sanity check, regenerate every blob
 // that comes in to verify the integrity of its cache
 //#define CACHE_SANITY_CHECK // VERY SLOW

 /*
  * A GrAtlasTextBlob contains a fully processed SkTextBlob, suitable for nearly immediate drawing
  * on the GPU.  These are initially created with valid positions and colors, but invalid
  * texture coordinates.  The GrAtlasTextBlob itself has a few Blob-wide properties, and also
  * consists of a number of runs.  Runs inside a blob are flushed individually so they can be
  * reordered.
  *
  * The only thing(aside from a memcopy) required to flush a GrAtlasTextBlob is to ensure that
  * the GrAtlas will not evict anything the Blob needs.
  *
  * Note: This struct should really be named GrCachedAtasTextBlob, but that is too verbose.
  *
  * *WARNING* If you add new fields to this struct, then you may need to to update AssertEqual
  */
 struct GrAtlasTextBlob : public SkRefCnt {
     SK_DECLARE_INTERNAL_LLIST_INTERFACE(GrAtlasTextBlob);

     /*
      * Each Run inside of the blob can have its texture coordinates regenerated if required.
      * To determine if regeneration is necessary, fAtlasGeneration is used.  If there have been
      * any evictions inside of the atlas, then we will simply regenerate Runs.  We could track
      * this at a more fine grained level, but its not clear if this is worth it, as evictions
      * should be fairly rare.
      *
      * One additional point, each run can contain glyphs with any of the three mask formats.
      * We call these SubRuns.  Because a subrun must be a contiguous range, we have to create
      * a new subrun each time the mask format changes in a run.  In theory, a run can have as
      * many SubRuns as it has glyphs, ie if a run alternates between color emoji and A8.  In
      * practice, the vast majority of runs have only a single subrun.
      *
      * Finally, for runs where the entire thing is too large for the GrAtlasTextContext to
      * handle, we have a bit to mark the run as flusahable via rendering as paths.  It is worth
      * pointing. It would be a bit expensive to figure out ahead of time whether or not a run
      * can flush in this manner, so we always allocate vertices for the run, regardless of
      * whether or not it is too large.  The benefit of this strategy is that we can always reuse
      * a blob allocation regardless of viewmatrix changes.  We could store positions for these
      * glyphs.  However, its not clear if this is a win because we'd still have to either go the
      * glyph cache to get the path at flush time, or hold onto the path in the cache, which
      * would greatly increase the memory of these cached items.
      */
     struct Run {
         Run()
             : fColor(GrColor_ILLEGAL)
             , fInitialized(false)
             , fDrawAsPaths(false) {
             fVertexBounds.setLargestInverted();
             // To ensure we always have one subrun, we push back a fresh run here
             fSubRunInfo.push_back();
         }
         struct SubRunInfo {
             SubRunInfo()
                 : fAtlasGeneration(GrBatchAtlas::kInvalidAtlasGeneration)
                 , fVertexStartIndex(0)
                 , fVertexEndIndex(0)
                 , fGlyphStartIndex(0)
                 , fGlyphEndIndex(0)
                 , fDrawAsDistanceFields(false) {}
             SubRunInfo(const SubRunInfo& that)
                 : fBulkUseToken(that.fBulkUseToken)
                 , fStrike(SkSafeRef(that.fStrike.get()))
                 , fAtlasGeneration(that.fAtlasGeneration)
                 , fVertexStartIndex(that.fVertexStartIndex)
                 , fVertexEndIndex(that.fVertexEndIndex)
                 , fGlyphStartIndex(that.fGlyphStartIndex)
                 , fGlyphEndIndex(that.fGlyphEndIndex)
                 , fTextRatio(that.fTextRatio)
                 , fMaskFormat(that.fMaskFormat)
                 , fDrawAsDistanceFields(that.fDrawAsDistanceFields)
                 , fUseLCDText(that.fUseLCDText) {
             }
             // Distance field text cannot draw coloremoji, and so has to fall back.  However,
             // though the distance field text and the coloremoji may share the same run, they
             // will have different descriptors.  If fOverrideDescriptor is non-nullptr, then it
             // will be used in place of the run's descriptor to regen texture coords
             // TODO we could have a descriptor cache, it would reduce the size of these blobs
             // significantly, and then the subrun could just have a refed pointer to the
             // correct descriptor.
             GrBatchAtlas::BulkUseTokenUpdater fBulkUseToken;
             SkAutoTUnref<GrBatchTextStrike> fStrike;
             uint64_t fAtlasGeneration;
             size_t fVertexStartIndex;
             size_t fVertexEndIndex;
             uint32_t fGlyphStartIndex;
             uint32_t fGlyphEndIndex;
             SkScalar fTextRatio; // df property
             GrMaskFormat fMaskFormat;
             bool fDrawAsDistanceFields; // df property
             bool fUseLCDText; // df property
         };

         SubRunInfo& push_back() {
             // Forward glyph / vertex information to seed the new sub run
             SubRunInfo& newSubRun = fSubRunInfo.push_back();
             SubRunInfo& prevSubRun = fSubRunInfo.fromBack(1);

             newSubRun.fGlyphStartIndex = prevSubRun.fGlyphEndIndex;
             newSubRun.fGlyphEndIndex = prevSubRun.fGlyphEndIndex;

             newSubRun.fVertexStartIndex = prevSubRun.fVertexEndIndex;
             newSubRun.fVertexEndIndex = prevSubRun.fVertexEndIndex;
             return newSubRun;
         }
         static const int kMinSubRuns = 1;
         SkAutoTUnref<SkTypeface> fTypeface;
         SkRect fVertexBounds;
         SkSTArray<kMinSubRuns, SubRunInfo> fSubRunInfo;
         SkAutoDescriptor fDescriptor;
         SkAutoTDelete<SkAutoDescriptor> fOverrideDescriptor; // df properties
         GrColor fColor;
         bool fInitialized;
         bool fDrawAsPaths;
     };

     struct BigGlyph {
         BigGlyph(const SkPath& path, SkScalar vx, SkScalar vy, SkScalar scale, bool applyVM)
             : fPath(path)
             , fVx(vx)
             , fVy(vy)
             , fScale(scale)
             , fApplyVM(applyVM) {}
         SkPath fPath;
         SkScalar fVx;
         SkScalar fVy;
         SkScalar fScale;
         bool fApplyVM;
     };

     struct Key {
         Key() {
             sk_bzero(this, sizeof(Key));
         }
         uint32_t fUniqueID;
         // Color may affect the gamma of the mask we generate, but in a fairly limited way.
         // Each color is assigned to on of a fixed number of buckets based on its
         // luminance. For each luminance bucket there is a "canonical color" that
         // represents the bucket.  This functionality is currently only supported for A8
         SkColor fCanonicalColor;
         SkPaint::Style fStyle;
         SkPixelGeometry fPixelGeometry;
         bool fHasBlur;

         bool operator==(const Key& other) const {
             return 0 == memcmp(this, &other, sizeof(Key));
         }
     };

     struct StrokeInfo {
         SkScalar fFrameWidth;
         SkScalar fMiterLimit;
         SkPaint::Join fJoin;
     };

     enum TextType {
         kHasDistanceField_TextType = 0x1,
         kHasBitmap_TextType = 0x2,
     };

     // all glyph / vertex offsets are into these pools.
     unsigned char* fVertices;
     GrGlyph** fGlyphs;
     Run* fRuns;
     GrMemoryPool* fPool;
     SkMaskFilter::BlurRec fBlurRec;
     StrokeInfo fStrokeInfo;
     SkTArray<BigGlyph> fBigGlyphs;
     Key fKey;
     SkMatrix fViewMatrix;
     GrColor fPaintColor;
     SkScalar fX;
     SkScalar fY;

     // We can reuse distance field text, but only if the new viewmatrix would not result in
     // a mip change.  Because there can be multiple runs in a blob, we track the overall
     // maximum minimum scale, and minimum maximum scale, we can support before we need to regen
     SkScalar fMaxMinScale;
     SkScalar fMinMaxScale;
     int fRunCount;
     uint8_t fTextType;

     GrAtlasTextBlob()
         : fMaxMinScale(-SK_ScalarMax)
         , fMinMaxScale(SK_ScalarMax)
         , fTextType(0) {}

     ~GrAtlasTextBlob() override {
         for (int i = 0; i < fRunCount; i++) {
             fRuns[i].~Run();
         }
     }

     static const Key& GetKey(const GrAtlasTextBlob& blob) {
         return blob.fKey;
     }

     static uint32_t Hash(const Key& key) {
         return SkChecksum::Murmur3(&key, sizeof(Key));
     }

     void operator delete(void* p) {
         GrAtlasTextBlob* blob = reinterpret_cast<GrAtlasTextBlob*>(p);
         blob->fPool->release(p);
     }
     void* operator new(size_t) {
         SkFAIL("All blobs are created by placement new.");
         return sk_malloc_throw(0);
     }

     void* operator new(size_t, void* p) { return p; }
     void operator delete(void* target, void* placement) {
         ::operator delete(target, placement);
     }

     bool hasDistanceField() const { return SkToBool(fTextType & kHasDistanceField_TextType); }
     bool hasBitmap() const { return SkToBool(fTextType & kHasBitmap_TextType); }
     void setHasDistanceField() { fTextType |= kHasDistanceField_TextType; }
     void setHasBitmap() { fTextType |= kHasBitmap_TextType; }

 #ifdef CACHE_SANITY_CHECK
     static void AssertEqual(const GrAtlasTextBlob&, const GrAtlasTextBlob&);
     size_t fSize;
 #endif
 };

 #endif
	/*
	* Copyright 2015 Google Inc.
	*
	* Use of this source code is governed by a BSD-style license that can be
	* found in the LICENSE file.
	*/

	#ifndef GrAtlasTextBlob_DEFINED
	#define GrAtlasTextBlob_DEFINED

	#include "GrBatchAtlas.h"
	#include "GrBatchFontCache.h"
	#include "GrColor.h"
	#include "SkDescriptor.h"
	#include "SkMaskFilter.h"
	#include "GrMemoryPool.h"
	#include "SkSurfaceProps.h"
	#include "SkTInternalLList.h"

	// With this flag enabled, the GrAtlasTextContext will, as a sanity check, regenerate every blob
	// that comes in to verify the integrity of its cache
	//#define CACHE_SANITY_CHECK // VERY SLOW

	/*
	* A GrAtlasTextBlob contains a fully processed SkTextBlob, suitable for nearly immediate drawing
	* on the GPU. These are initially created with valid positions and colors, but invalid
	* texture coordinates. The GrAtlasTextBlob itself has a few Blob-wide properties, and also
	* consists of a number of runs. Runs inside a blob are flushed individually so they can be
	* reordered.
	*
	* The only thing(aside from a memcopy) required to flush a GrAtlasTextBlob is to ensure that
	* the GrAtlas will not evict anything the Blob needs.
	*
	* Note: This struct should really be named GrCachedAtasTextBlob, but that is too verbose.
	*
	* WARNING If you add new fields to this struct, then you may need to to update AssertEqual
	*/
	struct GrAtlasTextBlob : public SkRefCnt {
	SK_DECLARE_INTERNAL_LLIST_INTERFACE(GrAtlasTextBlob);

	/*
	* Each Run inside of the blob can have its texture coordinates regenerated if required.
	* To determine if regeneration is necessary, fAtlasGeneration is used. If there have been
	* any evictions inside of the atlas, then we will simply regenerate Runs. We could track
	* this at a more fine grained level, but its not clear if this is worth it, as evictions
	* should be fairly rare.
	*
	* One additional point, each run can contain glyphs with any of the three mask formats.
	* We call these SubRuns. Because a subrun must be a contiguous range, we have to create
	* a new subrun each time the mask format changes in a run. In theory, a run can have as
	* many SubRuns as it has glyphs, ie if a run alternates between color emoji and A8. In
	* practice, the vast majority of runs have only a single subrun.
	*
	* Finally, for runs where the entire thing is too large for the GrAtlasTextContext to
	* handle, we have a bit to mark the run as flusahable via rendering as paths. It is worth
	* pointing. It would be a bit expensive to figure out ahead of time whether or not a run
	* can flush in this manner, so we always allocate vertices for the run, regardless of
	* whether or not it is too large. The benefit of this strategy is that we can always reuse
	* a blob allocation regardless of viewmatrix changes. We could store positions for these
	* glyphs. However, its not clear if this is a win because we'd still have to either go the
	* glyph cache to get the path at flush time, or hold onto the path in the cache, which
	* would greatly increase the memory of these cached items.
	*/
	struct Run {
	Run()
	: fColor(GrColor_ILLEGAL)
	, fInitialized(false)
	, fDrawAsPaths(false) {
	fVertexBounds.setLargestInverted();
	// To ensure we always have one subrun, we push back a fresh run here
	fSubRunInfo.push_back();
	}
	struct SubRunInfo {
	SubRunInfo()
	: fAtlasGeneration(GrBatchAtlas::kInvalidAtlasGeneration)
	, fVertexStartIndex(0)
	, fVertexEndIndex(0)
	, fGlyphStartIndex(0)
	, fGlyphEndIndex(0)
	, fDrawAsDistanceFields(false) {}
	SubRunInfo(const SubRunInfo& that)
	: fBulkUseToken(that.fBulkUseToken)
	, fStrike(SkSafeRef(that.fStrike.get()))
	, fAtlasGeneration(that.fAtlasGeneration)
	, fVertexStartIndex(that.fVertexStartIndex)
	, fVertexEndIndex(that.fVertexEndIndex)
	, fGlyphStartIndex(that.fGlyphStartIndex)
	, fGlyphEndIndex(that.fGlyphEndIndex)
	, fTextRatio(that.fTextRatio)
	, fMaskFormat(that.fMaskFormat)
	, fDrawAsDistanceFields(that.fDrawAsDistanceFields)
	, fUseLCDText(that.fUseLCDText) {
	}
	// Distance field text cannot draw coloremoji, and so has to fall back. However,
	// though the distance field text and the coloremoji may share the same run, they
	// will have different descriptors. If fOverrideDescriptor is non-nullptr, then it
	// will be used in place of the run's descriptor to regen texture coords
	// TODO we could have a descriptor cache, it would reduce the size of these blobs
	// significantly, and then the subrun could just have a refed pointer to the
	// correct descriptor.
	GrBatchAtlas::BulkUseTokenUpdater fBulkUseToken;
	SkAutoTUnref<GrBatchTextStrike> fStrike;
	uint64_t fAtlasGeneration;
	size_t fVertexStartIndex;
	size_t fVertexEndIndex;
	uint32_t fGlyphStartIndex;
	uint32_t fGlyphEndIndex;
	SkScalar fTextRatio; // df property
	GrMaskFormat fMaskFormat;
	bool fDrawAsDistanceFields; // df property
	bool fUseLCDText; // df property
	};

	SubRunInfo& push_back() {
	// Forward glyph / vertex information to seed the new sub run
	SubRunInfo& newSubRun = fSubRunInfo.push_back();
	SubRunInfo& prevSubRun = fSubRunInfo.fromBack(1);

	newSubRun.fGlyphStartIndex = prevSubRun.fGlyphEndIndex;
	newSubRun.fGlyphEndIndex = prevSubRun.fGlyphEndIndex;

	newSubRun.fVertexStartIndex = prevSubRun.fVertexEndIndex;
	newSubRun.fVertexEndIndex = prevSubRun.fVertexEndIndex;
	return newSubRun;
	}
	static const int kMinSubRuns = 1;
	SkAutoTUnref<SkTypeface> fTypeface;
	SkRect fVertexBounds;
	SkSTArray<kMinSubRuns, SubRunInfo> fSubRunInfo;
	SkAutoDescriptor fDescriptor;
	SkAutoTDelete<SkAutoDescriptor> fOverrideDescriptor; // df properties
	GrColor fColor;
	bool fInitialized;
	bool fDrawAsPaths;
	};

	struct BigGlyph {
	BigGlyph(const SkPath& path, SkScalar vx, SkScalar vy, SkScalar scale, bool applyVM)
	: fPath(path)
	, fVx(vx)
	, fVy(vy)
	, fScale(scale)
	, fApplyVM(applyVM) {}
	SkPath fPath;
	SkScalar fVx;
	SkScalar fVy;
	SkScalar fScale;
	bool fApplyVM;
	};

	struct Key {
	Key() {
	sk_bzero(this, sizeof(Key));
	}
	uint32_t fUniqueID;
	// Color may affect the gamma of the mask we generate, but in a fairly limited way.
	// Each color is assigned to on of a fixed number of buckets based on its
	// luminance. For each luminance bucket there is a "canonical color" that
	// represents the bucket. This functionality is currently only supported for A8
	SkColor fCanonicalColor;
	SkPaint::Style fStyle;
	SkPixelGeometry fPixelGeometry;
	bool fHasBlur;

	bool operator==(const Key& other) const {
	return 0 == memcmp(this, &other, sizeof(Key));
	}
	};

	struct StrokeInfo {
	SkScalar fFrameWidth;
	SkScalar fMiterLimit;
	SkPaint::Join fJoin;
	};

	enum TextType {
	kHasDistanceField_TextType = 0x1,
	kHasBitmap_TextType = 0x2,
	};

	// all glyph / vertex offsets are into these pools.
	unsigned char* fVertices;
	GrGlyph** fGlyphs;
	Run* fRuns;
	GrMemoryPool* fPool;
	SkMaskFilter::BlurRec fBlurRec;
	StrokeInfo fStrokeInfo;
	SkTArray<BigGlyph> fBigGlyphs;
	Key fKey;
	SkMatrix fViewMatrix;
	GrColor fPaintColor;
	SkScalar fX;
	SkScalar fY;

	// We can reuse distance field text, but only if the new viewmatrix would not result in
	// a mip change. Because there can be multiple runs in a blob, we track the overall
	// maximum minimum scale, and minimum maximum scale, we can support before we need to regen
	SkScalar fMaxMinScale;
	SkScalar fMinMaxScale;
	int fRunCount;
	uint8_t fTextType;

	GrAtlasTextBlob()
	: fMaxMinScale(-SK_ScalarMax)
	, fMinMaxScale(SK_ScalarMax)
	, fTextType(0) {}

	~GrAtlasTextBlob() override {
	for (int i = 0; i < fRunCount; i++) {
	fRuns[i].~Run();
	}
	}

	static const Key& GetKey(const GrAtlasTextBlob& blob) {
	return blob.fKey;
	}

	static uint32_t Hash(const Key& key) {
	return SkChecksum::Murmur3(&key, sizeof(Key));
	}

	void operator delete(void* p) {
	GrAtlasTextBlob* blob = reinterpret_cast<GrAtlasTextBlob*>(p);
	blob->fPool->release(p);
	}
	void* operator new(size_t) {
	SkFAIL("All blobs are created by placement new.");
	return sk_malloc_throw(0);
	}

	void* operator new(size_t, void* p) { return p; }
	void operator delete(void* target, void* placement) {
	::operator delete(target, placement);
	}

	bool hasDistanceField() const { return SkToBool(fTextType & kHasDistanceField_TextType); }
	bool hasBitmap() const { return SkToBool(fTextType & kHasBitmap_TextType); }
	void setHasDistanceField() { fTextType \|= kHasDistanceField_TextType; }
	void setHasBitmap() { fTextType \|= kHasBitmap_TextType; }

	#ifdef CACHE_SANITY_CHECK
	static void AssertEqual(const GrAtlasTextBlob&, const GrAtlasTextBlob&);
	size_t fSize;
	#endif
	};

	#endif