skia2/include/core/SkFontMetrics.h

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/*
* Copyright 2018 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkFontMetrics_DEFINED
#define SkFontMetrics_DEFINED
#include "SkScalar.h"
struct SK_API SkFontMetrics {
/** \enum SkPaint::FontMetrics::FontMetricsFlags
FontMetricsFlags are set in fFlags when underline and strikeout metrics are valid;
the underline or strikeout metric may be valid and zero.
Fonts with embedded bitmaps may not have valid underline or strikeout metrics.
*/
enum FontMetricsFlags {
kUnderlineThicknessIsValid_Flag = 1 << 0, //!< set if fUnderlineThickness is valid
kUnderlinePositionIsValid_Flag = 1 << 1, //!< set if fUnderlinePosition is valid
kStrikeoutThicknessIsValid_Flag = 1 << 2, //!< set if fStrikeoutThickness is valid
kStrikeoutPositionIsValid_Flag = 1 << 3, //!< set if fStrikeoutPosition is valid
};
uint32_t fFlags; //!< is set to FontMetricsFlags when metrics are valid
SkScalar fTop; //!< extent above baseline
SkScalar fAscent; //!< distance to reserve above baseline
SkScalar fDescent; //!< distance to reserve below baseline
SkScalar fBottom; //!< extent below baseline
SkScalar fLeading; //!< distance to add between lines
SkScalar fAvgCharWidth; //!< average character width
SkScalar fMaxCharWidth; //!< maximum character width
SkScalar fXMin; //!< minimum x
SkScalar fXMax; //!< maximum x
SkScalar fXHeight; //!< height of lower-case 'x'
SkScalar fCapHeight; //!< height of an upper-case letter
SkScalar fUnderlineThickness; //!< underline thickness
SkScalar fUnderlinePosition; //!< underline position relative to baseline
SkScalar fStrikeoutThickness; //!< strikeout thickness
SkScalar fStrikeoutPosition; //!< strikeout position relative to baseline
/** Returns true if SkPaint::FontMetrics has a valid underline thickness, and sets
thickness to that value. If the underline thickness is not valid,
return false, and ignore thickness.
@param thickness storage for underline width
@return true if font specifies underline width
*/
bool hasUnderlineThickness(SkScalar* thickness) const {
if (SkToBool(fFlags & kUnderlineThicknessIsValid_Flag)) {
*thickness = fUnderlineThickness;
return true;
}
return false;
}
/** Returns true if SkPaint::FontMetrics has a valid underline position, and sets
position to that value. If the underline position is not valid,
return false, and ignore position.
@param position storage for underline position
@return true if font specifies underline position
*/
bool hasUnderlinePosition(SkScalar* position) const {
if (SkToBool(fFlags & kUnderlinePositionIsValid_Flag)) {
*position = fUnderlinePosition;
return true;
}
return false;
}
/** Returns true if SkPaint::FontMetrics has a valid strikeout thickness, and sets
thickness to that value. If the underline thickness is not valid,
return false, and ignore thickness.
@param thickness storage for strikeout width
@return true if font specifies strikeout width
*/
bool hasStrikeoutThickness(SkScalar* thickness) const {
if (SkToBool(fFlags & kStrikeoutThicknessIsValid_Flag)) {
*thickness = fStrikeoutThickness;
return true;
}
return false;
}
/** Returns true if SkPaint::FontMetrics has a valid strikeout position, and sets
position to that value. If the underline position is not valid,
return false, and ignore position.
@param position storage for strikeout position
@return true if font specifies strikeout position
*/
bool hasStrikeoutPosition(SkScalar* position) const {
if (SkToBool(fFlags & kStrikeoutPositionIsValid_Flag)) {
*position = fStrikeoutPosition;
return true;
}
return false;
}
};
#endif