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      1 /*
      2  * Copyright 2015 Google Inc.
      3  *
      4  * Use of this source code is governed by a BSD-style license that can be
      5  * found in the LICENSE file.
      6  */
      7 
      8 #ifndef GrTextContext_DEFINED
      9 #define GrTextContext_DEFINED
     10 
     11 #include "GrDistanceFieldAdjustTable.h"
     12 #include "GrGeometryProcessor.h"
     13 #include "GrTextTarget.h"
     14 #include "SkGlyphRun.h"
     15 
     16 #if GR_TEST_UTILS
     17 #include "GrDrawOpTest.h"
     18 #endif
     19 
     20 class GrDrawOp;
     21 class GrRecordingContext;
     22 class GrTextBlobCache;
     23 class SkGlyph;
     24 class GrTextBlob;
     25 
     26 /*
     27  * Renders text using some kind of an atlas, ie BitmapText or DistanceField text
     28  */
     29 class GrTextContext {
     30 public:
     31     struct Options {
     32         /**
     33          * Below this size (in device space) distance field text will not be used. Negative means
     34          * use a default value.
     35          */
     36         SkScalar fMinDistanceFieldFontSize = -1.f;
     37         /**
     38          * Above this size (in device space) distance field text will not be used and glyphs will
     39          * be rendered from outline as individual paths. Negative means use a default value.
     40          */
     41         SkScalar fMaxDistanceFieldFontSize = -1.f;
     42         /** Forces all distance field vertices to use 3 components, not just when in perspective. */
     43         bool fDistanceFieldVerticesAlwaysHaveW = false;
     44     };
     45 
     46     static std::unique_ptr<GrTextContext> Make(const Options& options);
     47 
     48     void drawGlyphRunList(GrRecordingContext*, GrTextTarget*, const GrClip&,
     49                           const SkMatrix& viewMatrix, const SkSurfaceProps&, const SkGlyphRunList&);
     50 
     51     std::unique_ptr<GrDrawOp> createOp_TestingOnly(GrRecordingContext*,
     52                                                    GrTextContext*,
     53                                                    GrRenderTargetContext*,
     54                                                    const SkPaint&, const SkFont&,
     55                                                    const SkMatrix& viewMatrix,
     56                                                    const char* text,
     57                                                    int x,
     58                                                    int y);
     59 
     60     static void SanitizeOptions(Options* options);
     61     static bool CanDrawAsDistanceFields(const SkPaint&, const SkFont&, const SkMatrix& viewMatrix,
     62                                         const SkSurfaceProps& props,
     63                                         bool contextSupportsDistanceFieldText,
     64                                         const Options& options);
     65 
     66     static SkFont InitDistanceFieldFont(const SkFont& font,
     67                                         const SkMatrix& viewMatrix,
     68                                         const Options& options,
     69                                         SkScalar* textRatio);
     70 
     71     static SkPaint InitDistanceFieldPaint(const SkPaint& paint);
     72 
     73     static std::pair<SkScalar, SkScalar> InitDistanceFieldMinMaxScale(SkScalar textSize,
     74                                                                       const SkMatrix& viewMatrix,
     75                                                                       const Options& options);
     76 
     77 private:
     78     GrTextContext(const Options& options);
     79 
     80     // sets up the descriptor on the blob and returns a detached cache.  Client must attach
     81     static SkColor ComputeCanonicalColor(const SkPaint&, bool lcd);
     82     // Determines if we need to use fake gamma (and contrast boost):
     83     static SkScalerContextFlags ComputeScalerContextFlags(const GrColorSpaceInfo&);
     84 
     85     const GrDistanceFieldAdjustTable* dfAdjustTable() const { return fDistanceAdjustTable.get(); }
     86 
     87     sk_sp<const GrDistanceFieldAdjustTable> fDistanceAdjustTable;
     88 
     89     Options fOptions;
     90 
     91 #if GR_TEST_UTILS
     92     static const SkScalerContextFlags kTextBlobOpScalerContextFlags =
     93             SkScalerContextFlags::kFakeGammaAndBoostContrast;
     94     GR_DRAW_OP_TEST_FRIEND(GrAtlasTextOp);
     95 #endif
     96 };
     97 
     98 #endif  // GrTextContext_DEFINED
     99