| // Copyright 2019 Google LLC. |
| #ifndef Metrics_DEFINED |
| #define Metrics_DEFINED |
| |
| #include <map> |
| #include "modules/skparagraph/include/TextStyle.h" |
| |
| namespace skia { |
| namespace textlayout { |
| class StyleMetrics { |
| public: |
| StyleMetrics(const TextStyle* style) : text_style(style) {} |
| |
| StyleMetrics(const TextStyle* style, SkFontMetrics& metrics) |
| : text_style(style), font_metrics(metrics) {} |
| |
| const TextStyle* text_style; |
| |
| // SkFontMetrics contains the following metrics: |
| // |
| // * Top distance to reserve above baseline |
| // * Ascent distance to reserve below baseline |
| // * Descent extent below baseline |
| // * Bottom extent below baseline |
| // * Leading distance to add between lines |
| // * AvgCharWidth average character width |
| // * MaxCharWidth maximum character width |
| // * XMin minimum x |
| // * XMax maximum x |
| // * XHeight height of lower-case 'x' |
| // * CapHeight height of an upper-case letter |
| // * UnderlineThickness underline thickness |
| // * UnderlinePosition underline position relative to baseline |
| // * StrikeoutThickness strikeout thickness |
| // * StrikeoutPosition strikeout position relative to baseline |
| SkFontMetrics font_metrics; |
| }; |
| |
| class LineMetrics { |
| public: |
| LineMetrics() { } |
| |
| LineMetrics(size_t start, |
| size_t end, |
| size_t end_excluding_whitespace, |
| size_t end_including_newline, |
| bool hard_break) |
| : fStartIndex(start) |
| , fEndIndex(end) |
| , fEndExcludingWhitespaces(end_excluding_whitespace) |
| , fEndIncludingNewline(end_including_newline) |
| , fHardBreak(hard_break) {} |
| // The following fields are used in the layout process itself. |
| |
| // The indexes in the text buffer the line begins and ends. |
| size_t fStartIndex = 0; |
| size_t fEndIndex = 0; |
| size_t fEndExcludingWhitespaces = 0; |
| size_t fEndIncludingNewline = 0; |
| bool fHardBreak = false; |
| |
| // The following fields are tracked after or during layout to provide to |
| // the user as well as for computing bounding boxes. |
| |
| // The final computed ascent and descent for the line. This can be impacted by |
| // the strut, height, scaling, as well as outlying runs that are very tall. |
| // |
| // The top edge is `baseline - ascent` and the bottom edge is `baseline + |
| // descent`. Ascent and descent are provided as positive numbers. Raw numbers |
| // for specific runs of text can be obtained in run_metrics_map. These values |
| // are the cumulative metrics for the entire line. |
| double fAscent = SK_ScalarMax; |
| double fDescent = SK_ScalarMin; |
| double fUnscaledAscent = SK_ScalarMax; |
| // Total height of the paragraph including the current line. |
| // |
| // The height of the current line is `round(ascent + descent)`. |
| double fHeight = 0.0; |
| // Width of the line. |
| double fWidth = 0.0; |
| // The left edge of the line. The right edge can be obtained with `left + |
| // width` |
| double fLeft = 0.0; |
| // The y position of the baseline for this line from the top of the paragraph. |
| double fBaseline = 0.0; |
| // Zero indexed line number |
| size_t fLineNumber = 0; |
| |
| // Mapping between text index ranges and the FontMetrics associated with |
| // them. The first run will be keyed under start_index. The metrics here |
| // are before layout and are the base values we calculate from. |
| std::map<size_t, StyleMetrics> fLineMetrics; |
| }; |
| |
| } // namespace textlayout |
| } // namespace skia |
| |
| #endif // Metrics_DEFINED |