improved documentation of the text layout code (9bca55b5) · Commits · github_fork / Clip

core/graphics/text_layout.cc

+24 −7

Original line number	Diff line number	Diff line
		@@ -59,16 +59,13 @@ Status text_layout_hrun(
		}

		Status text_layout_hline(
		const std::string& text_logical,
		const TextDirection base_text_direction,
		const TextLine& text_line,
		const TextDirection text_direction_base,
		const FontInfo& font_info,
		double font_size,
		double dpi,
		std::vector<GlyphSpan>* glyph_spans,
		Rectangle* bbox) {
		TextLine text_line;
		text_analyze_bidi_line(text_logical, base_text_direction, &text_line);

		double line_top = 0.0;
		double line_bottom = 0.0;
		double line_length = 0;
		@@ -92,7 +89,7 @@ Status text_layout_hline(
		}

		for (auto& gi : span_glyphs) {
		switch (base_text_direction) {
		switch (text_direction_base) {
		case TextDirection::LTR:
		gi.x += line_length;
		break;
		@@ -116,7 +113,7 @@ Status text_layout_hline(
		}

		double line_left = 0.0;
		switch (base_text_direction) {
		switch (text_direction_base) {
		case TextDirection::LTR:
		line_left = 0;
		break;
		@@ -134,6 +131,26 @@ Status text_layout_hline(
		return OK;
		}

		Status text_layout_hline(
		const std::string& text_logical,
		const TextDirection base_text_direction,
		const FontInfo& font_info,
		double font_size,
		double dpi,
		std::vector<GlyphSpan>* glyph_spans,
		Rectangle* bbox) {
		TextLine text_line;
		text_analyze_bidi_line(text_logical, base_text_direction, &text_line);

		return text_layout_hline(
		text_line,
		base_text_direction,
		font_info,
		font_size,
		dpi,
		glyph_spans,
		bbox);
		}

		Status text_measure_span(
		const std::string& text,

core/graphics/text_layout.h

+29 −9

Original line number	Diff line number	Diff line
		@@ -40,6 +40,10 @@ struct TextLine {
		std::vector<TextDirection> text_directions;
		};

		/**
		* The output of the text layout stack is a list of glyph placements. The
		* coordinates are absolute screen positions
		*/
		struct GlyphPlacement {
		FontRef font;
		uint32_t codepoint;
		@@ -53,28 +57,44 @@ struct GlyphSpan {
		};

		/**
		* Measure the size of a horizontal span of text where (0, 0) is the baseline of
		* the first glyph
		* Layout a horizontal line of text. The input text must be provided in UTF-8
		* encoding and in logical character order. The `text_direction_base` argument
		* controls the base writing direction of the line
		*/
		Status text_measure_span(
		const std::string& text,
		const FontInfo& font_info,
		Status text_layout_hline(
		const TextLine& line,
		TextDirection base_direction,
		const FontInfo& font,
		double font_size,
		double dpi,
		Rectangle* rect);
		std::vector<GlyphSpan>* spans,
		Rectangle* bbox);

		/**
		* Layout a horizontal line of text
		* Layout a horizontal line of text. The input text must be provided in UTF-8
		* encoding and in logical character order. The `text_direction_base` argument
		* controls the base writing direction of the line
		*/
		Status text_layout_hline(
		const std::string& text,
		TextDirection direction,
		const std::string& text_logical,
		TextDirection base_direction,
		const FontInfo& font,
		double font_size,
		double dpi,
		std::vector<GlyphSpan>* spans,
		Rectangle* bbox);

		/**
		* Measure the size of a horizontal span of text where (0, 0) is the baseline of
		* the first glyph
		*/
		Status text_measure_span(
		const std::string& text,
		const FontInfo& font_info,
		double font_size,
		double dpi,
		Rectangle* rect);

		} // namespace text
		} // namespace fviz

core/graphics/text_shaper.h

+3 −21

Original line number	Diff line number	Diff line
		@@ -30,10 +30,9 @@ struct GlyphInfo {
		double metrics_descender;
		};

		using GlyphRun = std::vector<GlyphInfo>;

		/**
		* Shape a "run" of text with a given font
		* Shape a "run" of text with a given font and a given text direction. The
		* text must be provided as a UTF-8 string in logical character order.
		*/
		Status text_shape_run(
		const std::string& text,
		@@ -44,7 +43,7 @@ Status text_shape_run(
		std::vector<GlyphInfo>* glyphs);

		/**
		* Shape a "run" of text with font fallback.
		* Shape a "run" of UTF-8 text in logical character order with font fallback
		*/
		Status text_shape_run_with_font_fallback(
		const std::string& text,
		@@ -54,23 +53,6 @@ Status text_shape_run_with_font_fallback(
		double dpi,
		std::vector<GlyphInfo>* glyphs);

		/**
		* "Shape" a non-breakable span of text. Input is a UTF8 string in logical order
		* and the intended text rendering direction. Output is a "glyph run", i.e. a
		* list of glyphs in the order in which they should be displayed. Note that this
		* method performs bidi reordering to 'visual' order, so the output of this
		* method is not suitable for line breaking. If line breaking is desired, it
		* must be handled by a mechanism higher up in the stack that only calls `text_shape`
		* for non-breakable spans of text (i.e. words).
		*/
		Status text_shape(
		const std::string& text,
		TextDirection text_direction,
		FontRef font,
		double font_size,
		double dpi,
		std::vector<GlyphInfo>* glyphs);

		} // namespace text
		} // namespace fviz

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