SkFontStyleSet Class Reference

#include <SkFontMgr.h>

Inheritance diagram for SkFontStyleSet:

Public Member Functions
virtual int	count ()=0
virtual void	getStyle (int index, SkFontStyle *, SkString *style)=0
virtual sk_sp< SkTypeface >	createTypeface (int index)=0
virtual sk_sp< SkTypeface >	matchStyle (const SkFontStyle &pattern)=0
Public Member Functions inherited from SkRefCntBase
	SkRefCntBase ()
virtual	~SkRefCntBase ()
bool	unique () const
void	ref () const
void	unref () const

Static Public Member Functions
static sk_sp< SkFontStyleSet >	CreateEmpty ()

Protected Member Functions
sk_sp< SkTypeface >	matchStyleCSS3 (const SkFontStyle &pattern)

Detailed Description

Definition at line 23 of file SkFontMgr.h.

Member Function Documentation

count()

virtual int SkFontStyleSet::count ( )

pure virtual

Implemented in flutter::AssetManagerFontStyleSet, OneFontStyleSet, skia::textlayout::TypefaceFontStyleSet, SkEmptyFontStyleSet, SkFontStyleSet_Custom, SkFontStyleSet_FCI, SkFontStyleSet_Fuchsia, and txt::TypefaceFontStyleSet.

CreateEmpty()

sk_sp< SkFontStyleSet > SkFontStyleSet::CreateEmpty ( )

static

Definition at line 35 of file SkFontMgr.cpp.

                                                  {
    return sk_sp<SkFontStyleSet>(new SkEmptyFontStyleSet);
}

createTypeface()

virtual sk_sp< SkTypeface > SkFontStyleSet::createTypeface ( int  index )

pure virtual

Implemented in flutter::AssetManagerFontStyleSet, OneFontStyleSet, skia::textlayout::TypefaceFontStyleSet, SkEmptyFontStyleSet, SkFontStyleSet_Custom, SkFontStyleSet_FCI, SkFontStyleSet_Fuchsia, and txt::TypefaceFontStyleSet.

getStyle()

virtual void SkFontStyleSet::getStyle ( int  index, SkFontStyle *  , SkString *  style  )

pure virtual

Implemented in skia::textlayout::TypefaceFontStyleSet, flutter::AssetManagerFontStyleSet, SkFontStyleSet_FCI, SkFontStyleSet_Custom, txt::TypefaceFontStyleSet, SkFontStyleSet_Fuchsia, SkEmptyFontStyleSet, and OneFontStyleSet.

matchStyle()

virtual sk_sp< SkTypeface > SkFontStyleSet::matchStyle ( const SkFontStyle &  pattern )

pure virtual

Implemented in OneFontStyleSet, SkEmptyFontStyleSet, flutter::AssetManagerFontStyleSet, skia::textlayout::TypefaceFontStyleSet, SkFontStyleSet_Custom, SkFontStyleSet_FCI, SkFontStyleSet_Fuchsia, and txt::TypefaceFontStyleSet.

matchStyleCSS3()

sk_sp< SkTypeface > SkFontStyleSet::matchStyleCSS3 ( const SkFontStyle &  pattern )

protected

Width has the greatest priority. If the value of pattern.width is 5 (normal) or less, narrower width values are checked first, then wider values. If the value of pattern.width is greater than 5 (normal), wider values are checked first, followed by narrower values.

Italic/Oblique has the next highest priority. If italic requested and there is some italic font, use it. If oblique requested and there is some oblique font, use it. If italic requested and there is some oblique font, use it. If oblique requested and there is some italic font, use it.

Exact match. If pattern.weight < 400, weights below pattern.weight are checked in descending order followed by weights above pattern.weight in ascending order until a match is found. If pattern.weight > 500, weights above pattern.weight are checked in ascending order followed by weights below pattern.weight in descending order until a match is found. If pattern.weight is 400, 500 is checked first and then the rule for pattern.weight < 400 is used. If pattern.weight is 500, 400 is checked first and then the rule for pattern.weight < 400 is used.

Definition at line 184 of file SkFontMgr.cpp.

                                                                           {
    int count = this->count();
    if (0 == count) {
        return nullptr;
    }
 
    struct Score {
        int score;
        int index;
        Score& operator +=(int rhs) { this->score += rhs; return *this; }
        Score& operator <<=(int rhs) { this->score <<= rhs; return *this; }
        bool operator <(const Score& that) { return this->score < that.score; }
    };
 
    Score maxScore = { 0, 0 };
    for (int i = 0; i < count; ++i) {
        SkFontStyle current;
        this->getStyle(i, &current, nullptr);
        Score currentScore = { 0, i };
 
        // CSS stretch / SkFontStyle::Width
        // Takes priority over everything else.
        if (pattern.width() <= SkFontStyle::kNormal_Width) {
            if (current.width() <= pattern.width()) {
                currentScore += 10 - pattern.width() + current.width();
            } else {
                currentScore += 10 - current.width();
            }
        } else {
            if (current.width() > pattern.width()) {
                currentScore += 10 + pattern.width() - current.width();
            } else {
                currentScore += current.width();
            }
        }
        currentScore <<= 8;
 
        // CSS style (normal, italic, oblique) / SkFontStyle::Slant (upright, italic, oblique)
        // Takes priority over all valid weights.
        static_assert(SkFontStyle::kUpright_Slant == 0 &&
                      SkFontStyle::kItalic_Slant  == 1 &&
                      SkFontStyle::kOblique_Slant == 2,
                      "SkFontStyle::Slant values not as required.");
        SkASSERT(0 <= pattern.slant() && pattern.slant() <= 2 &&
                 0 <= current.slant() && current.slant() <= 2);
        static const int score[3][3] = {
            /*               Upright Italic Oblique  [current]*/
            /*   Upright */ {   3   ,  1   ,   2   },
            /*   Italic  */ {   1   ,  3   ,   2   },
            /*   Oblique */ {   1   ,  2   ,   3   },
            /* [pattern] */
        };
        currentScore += score[pattern.slant()][current.slant()];
        currentScore <<= 8;
 
        // Synthetics (weight, style) [no stretch synthetic?]
 
        // CSS weight / SkFontStyle::Weight
        // The 'closer' to the target weight, the higher the score.
        // 1000 is the 'heaviest' recognized weight
        if (pattern.weight() == current.weight()) {
            currentScore += 1000;
        // less than 400 prefer lighter weights
        } else if (pattern.weight() < 400) {
            if (current.weight() <= pattern.weight()) {
                currentScore += 1000 - pattern.weight() + current.weight();
            } else {
                currentScore += 1000 - current.weight();
            }
        // between 400 and 500 prefer heavier up to 500, then lighter weights
        } else if (pattern.weight() <= 500) {
            if (current.weight() >= pattern.weight() && current.weight() <= 500) {
                currentScore += 1000 + pattern.weight() - current.weight();
            } else if (current.weight() <= pattern.weight()) {
                currentScore += 500 + current.weight();
            } else {
                currentScore += 1000 - current.weight();
            }
        // greater than 500 prefer heavier weights
        } else if (pattern.weight() > 500) {
            if (current.weight() > pattern.weight()) {
                currentScore += 1000 + pattern.weight() - current.weight();
            } else {
                currentScore += current.weight();
            }
        }
 
        if (maxScore < currentScore) {
            maxScore = currentScore;
        }
    }
 
    return this->createTypeface(maxScore.index);
}

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The documentation for this class was generated from the following files:

• third_party/skia/include/core/SkFontMgr.h
• third_party/skia/src/core/SkFontMgr.cpp