(svn r25465) -Codechange: add the concept of a layouting engine for text

2 files changed, 470 insertions, 0 deletions

diff --git a/src/gfx_layout.cpp b/src/gfx_layout.cpp
new file mode 100644
index 000000000..caa06fc29
--- /dev/null
+++ b/src/gfx_layout.cpp
@@ -0,0 +1,361 @@
+/* $Id$ */
+
+/*
+ * This file is part of OpenTTD.
+ * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
+ * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/** @file gfx_layout.cpp Handling of laying out text. */
+
+#include "stdafx.h"
+#include "gfx_layout.h"
+#include "string_func.h"
+
+#include "table/control_codes.h"
+
+/**
+ * Construct a new font.
+ * @param size   The font size to use for this font.
+ * @param colour The colour to draw this font in.
+ */
+Font::Font(FontSize size, TextColour colour) :
+		fc(FontCache::Get(size)), colour(colour)
+{
+	assert(size < FS_END);
+}
+
+/*** Paragraph layout ***/
+
+/**
+ * Create the visual run.
+ * @param font       The font to use for this run.
+ * @param chars      The characters to use for this run.
+ * @param char_count The number of characters in this run.
+ * @param x          The initial x position for this run.
+ */
+ParagraphLayout::VisualRun::VisualRun(Font *font, const WChar *chars, int char_count, int x) :
+		font(font), glyph_count(char_count)
+{
+	this->glyphs = MallocT<GlyphID>(this->glyph_count);
+
+	/* Positions contains the location of the begin of each of the glyphs, and the end of the last one. */
+	this->positions = MallocT<float>(this->glyph_count * 2 + 2);
+	this->positions[0] = x;
+	this->positions[1] = 0;
+
+	for (int i = 0; i < this->glyph_count; i++) {
+		this->glyphs[i] = font->fc->MapCharToGlyph(chars[i]);
+		this->positions[2 * i + 2] = this->positions[2 * i] + font->fc->GetGlyphWidth(this->glyphs[i]);
+		this->positions[2 * i + 3] = 0;
+	}
+}
+
+/** Free all data. */
+ParagraphLayout::VisualRun::~VisualRun()
+{
+	free(this->positions);
+	free(this->glyphs);
+}
+
+/**
+ * Get the font associated with this run.
+ * @return The font.
+ */
+Font *ParagraphLayout::VisualRun::getFont() const
+{
+	return this->font;
+}
+
+/**
+ * Get the number of glyhps in this run.
+ * @return The number of glyphs.
+ */
+int ParagraphLayout::VisualRun::getGlyphCount() const
+{
+	return this->glyph_count;
+}
+
+/**
+ * Get the glyhps of this run.
+ * @return The glyphs.
+ */
+const GlyphID *ParagraphLayout::VisualRun::getGlyphs() const
+{
+	return this->glyphs;
+}
+
+/**
+ * Get the positions of this run.
+ * @return The positions.
+ */
+float *ParagraphLayout::VisualRun::getPositions() const
+{
+	return this->positions;
+}
+
+/**
+ * Get the height of this font.
+ * @return The height of the font.
+ */
+int ParagraphLayout::VisualRun::getLeading() const
+{
+	return this->getFont()->fc->GetHeight();
+}
+
+/**
+ * Get the height of the line.
+ * @return The maximum height of the line.
+ */
+int ParagraphLayout::Line::getLeading() const
+{
+	int leading = 0;
+	for (const VisualRun * const *run = this->Begin(); run != this->End(); run++) {
+		leading = max(leading, (*run)->getLeading());
+	}
+
+	return leading;
+}
+
+/**
+ * Get the width of this line.
+ * @return The width of the line.
+ */
+int ParagraphLayout::Line::getWidth() const
+{
+	if (this->Length() == 0) return 0;
+
+	/*
+	 * The last X position of a run contains is the end of that run.
+	 * Since there is no left-to-right support, taking this value of
+	 * the last run gives us the end of the line and thus the width.
+	 */
+	const VisualRun *run = this->getVisualRun(this->countRuns() - 1);
+	return run->getPositions()[run->getGlyphCount() * 2];
+}
+
+/**
+ * Get the number of runs in this line.
+ * @return The number of runs.
+ */
+int ParagraphLayout::Line::countRuns() const
+{
+	return this->Length();
+}
+
+/**
+ * Get a specific visual run.
+ * @return The visual run.
+ */
+ParagraphLayout::VisualRun *ParagraphLayout::Line::getVisualRun(int run) const
+{
+	return *this->Get(run);
+}
+
+/**
+ * Create a new paragraph layouter.
+ * @param buffer The characters of the paragraph.
+ * @param length The length of the paragraph.
+ * @param runs   The font mapping of this paragraph.
+ */
+ParagraphLayout::ParagraphLayout(WChar *buffer, int length, FontMap &runs) : buffer_begin(buffer), buffer(buffer), runs(runs)
+{
+	assert(runs.End()[-1].first == length);
+}
+
+/**
+ * Construct a new line with a maximum width.
+ * @param max_width The maximum width of the string.
+ * @return A Line, or NULL when at the end of the paragraph.
+ */
+ParagraphLayout::Line *ParagraphLayout::nextLine(int max_width)
+{
+	/* Simple idea:
+	 *  - split a line at a newline character, or at a space where we can break a line.
+	 *  - split for a visual run whenever a new line happens, or the font changes.
+	 */
+	if (this->buffer == NULL|| *this->buffer == '\0') return NULL;
+
+	Line *l = new Line();
+
+	const WChar *begin = this->buffer;
+	WChar *last_space;
+	const WChar *last_char = begin;
+	int width = 0;
+
+	int offset = this->buffer - this->buffer_begin;
+	FontMap::iterator iter = runs.Begin();
+	while (iter->first <= offset) {
+		iter++;
+		assert(iter != runs.End());
+	}
+
+	const FontCache *fc = iter->second->fc;
+	const WChar *next_run = this->buffer_begin + iter->first + 1;
+
+	for (;;) {
+		WChar c = *this->buffer++;
+
+		if (c == '\0') {
+			this->buffer = NULL;
+			break;
+		}
+		if (c == '\n') break;
+
+		if (this->buffer == next_run) {
+			*l->Append() = new VisualRun(iter->second, begin, this->buffer - begin, l->getWidth());
+			iter++;
+			assert(iter != runs.End());
+
+			next_run = this->buffer_begin + iter->first + 1;
+			begin = this->buffer;
+		}
+
+		if (IsWhitespace(c)) last_space = this->buffer;
+
+		last_char = this->buffer;
+
+		if (IsPrintable(c) && !IsTextDirectionChar(c)) {
+			int char_width = GetCharacterWidth(fc->GetSize(), c);
+			width += char_width;
+			if (width > max_width) {
+				/* The string is longer than maximum width so we need to decide
+				 * what to do with it. */
+				if (width == char_width) {
+					/* The character is wider than allowed width; don't know
+					 * what to do with this case... bail out! */
+					this->buffer = NULL;
+					return l;
+				}
+
+				if (last_space == NULL) {
+					/* No space has been found. Just terminate at our current
+					 * location. This usually happens for languages that do not
+					 * require spaces in strings, like Chinese, Japanese and
+					 * Korean. For other languages terminating mid-word might
+					 * not be the best, but terminating the whole string instead
+					 * of continuing the word at the next line is worse. */
+					this->buffer--;
+					last_char = this->buffer;
+				} else {
+					/* A space is found; perfect place to terminate */
+					this->buffer = last_space;
+					last_char = last_space - 1;
+				}
+				break;
+			}
+		}
+	}
+
+	if (last_char - begin != 0) {
+		*l->Append() = new VisualRun(iter->second, begin, last_char - begin, l->getWidth());
+	}
+	return l;
+}
+
+/**
+ * Appand a wide character to the internal buffer.
+ * @param buff        The buffer to append to.
+ * @param buffer_last The end of the buffer.
+ * @param c           The character to add.
+ * @return The number of buffer spaces that were used.
+ */
+size_t Layouter::AppendToBuffer(WChar *buff, const WChar *buffer_last, WChar c)
+{
+	*buff = c;
+	return 1;
+}
+
+/**
+ * Get the actual ParagraphLayout for the given buffer.
+ * @param buff_end The location after the last element in the buffer.
+ * @return The ParagraphLayout instance.
+ */
+ParagraphLayout *Layouter::GetParagraphLayout(WChar *buff_end)
+{
+	return new ParagraphLayout(this->buffer, buff_end - this->buffer, this->fonts);
+}
+
+/**
+ * Create a new layouter.
+ * @param str      The string to create the layout for.
+ * @param maxw     The maximum width.
+ * @param colour   The colour of the font.
+ * @param fontsize The size of font to use.
+ */
+Layouter::Layouter(const char *str, int maxw, TextColour colour, FontSize fontsize)
+{
+	const CharType *buffer_last = lastof(this->buffer);
+	CharType *buff = this->buffer;
+
+	TextColour cur_colour = colour, prev_colour = colour;
+	Font *f = new Font(fontsize, cur_colour);
+
+	/*
+	 * Go through the whole string while adding Font instances to the font map
+	 * whenever the font changes, and convert the wide characters into a format
+	 * usable by ParagraphLayout.
+	 */
+	for (; buff < buffer_last;) {
+		WChar c = Utf8Consume(const_cast<const char **>(&str));
+		if (c == 0) {
+			break;
+		} else if (c >= SCC_BLUE && c <= SCC_BLACK) {
+			prev_colour = cur_colour;
+			cur_colour = (TextColour)(c - SCC_BLUE);
+		} else if (c == SCC_PREVIOUS_COLOUR) { // Revert to the previous colour.
+			Swap(prev_colour, cur_colour);
+		} else if (c == SCC_TINYFONT) {
+			fontsize = FS_SMALL;
+		} else if (c == SCC_BIGFONT) {
+			fontsize = FS_LARGE;
+		} else {
+			buff += AppendToBuffer(buff, buffer_last, c);
+			continue;
+		}
+
+		if (!this->fonts.Contains(buff - this->buffer)) {
+			this->fonts.Insert(buff - this->buffer, f);
+			f = new Font(fontsize, cur_colour);
+		}
+	}
+
+	/* Better safe than sorry. */
+	*buff = '\0';
+
+	if (!this->fonts.Contains(buff - this->buffer)) {
+		this->fonts.Insert(buff - this->buffer, f);
+	}
+	ParagraphLayout *p = GetParagraphLayout(buff);
+
+	/* Copy all lines into a local cache so we can reuse them later on more easily. */
+	ParagraphLayout::Line *l;
+	while ((l = p->nextLine(maxw)) != NULL) {
+		*this->Append() = l;
+	}
+
+	delete p;
+}
+
+/** Free everything we allocated. */
+Layouter::~Layouter()
+{
+	for (FontMap::iterator iter = this->fonts.Begin(); iter != this->fonts.End(); iter++) {
+		delete iter->second;
+	}
+}
+
+/**
+ * Get the boundaries of this paragraph.
+ * @return The boundaries.
+ */
+Dimension Layouter::GetBounds()
+{
+	Dimension d = { 0, 0 };
+	for (ParagraphLayout::Line **l = this->Begin(); l != this->End(); l++) {
+		d.width = max<uint>(d.width, (*l)->getWidth());
+		d.height += (*l)->getLeading();
+	}
+	return d;
+}
diff --git a/src/gfx_layout.h b/src/gfx_layout.h
new file mode 100644
index 000000000..cf4f1f90a
--- /dev/null
+++ b/src/gfx_layout.h
@@ -0,0 +1,109 @@
+/* $Id$ */
+
+/*
+ * This file is part of OpenTTD.
+ * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
+ * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/** @file gfx_layout.h Functions related to laying out the texts. */
+
+#ifndef GFX_LAYOUT_H
+#define GFX_LAYOUT_H
+
+#include "fontcache.h"
+#include "gfx_func.h"
+#include "core/smallmap_type.hpp"
+
+/**
+ * Container with information about a font.
+ */
+class Font {
+public:
+	FontCache *fc;     ///< The font we are using.
+	TextColour colour; ///< The colour this font has to be.
+
+	Font(FontSize size, TextColour colour);
+};
+
+/** Mapping from index to font. */
+typedef SmallMap<int, Font *> FontMap;
+
+/**
+ * Class handling the splitting of a paragraph of text into lines and
+ * visual runs.
+ *
+ * One constructs this class with the text that needs to be split into
+ * lines. Then nextLine is called with the maximum with until NULL is
+ * returned. Each nextLine call creates VisualRuns which contain the
+ * length of text that are to be drawn with the same font. In other
+ * words, the result of this class is a list of sub strings with their
+ * font. The sub strings are then already fully laid out, and only
+ * need actual drawing.
+ *
+ * The positions in a visual run are sequential pairs of X,Y of the
+ * begin of each of the glyphs plus an extra pair to mark the end.
+ *
+ * @note This variant does not handle left-to-right properly. This
+ *       is supported in the one ParagraphLayout coming from ICU.
+ * @note Does not conform to function naming style as it provides a
+ *       fallback for the ICU class.
+ */
+class ParagraphLayout {
+public:
+	/** Visual run contains data about the bit of text with the same font. */
+	class VisualRun {
+		Font *font;       ///< The font used to layout these.
+		GlyphID *glyphs;  ///< The glyphs we're drawing.
+		float *positions; ///< The positions of the glyphs.
+		int glyph_count;  ///< The number of glyphs.
+
+	public:
+		VisualRun(Font *font, const WChar *chars, int glyph_count, int x);
+		~VisualRun();
+		Font *getFont() const;
+		int getGlyphCount() const;
+		const GlyphID *getGlyphs() const;
+		float *getPositions() const;
+		int getLeading() const;
+	};
+
+	/** A single line worth of VisualRuns. */
+	class Line : public AutoDeleteSmallVector<VisualRun *, 4> {
+	public:
+		int getLeading() const;
+		int getWidth() const;
+		int countRuns() const;
+		VisualRun *getVisualRun(int run) const;
+	};
+
+	const WChar *buffer_begin; ///< Begin of the buffer.
+	WChar *buffer;             ///< The current location in the buffer.
+	FontMap &runs;             ///< The fonts we have to use for this paragraph.
+
+	ParagraphLayout(WChar *buffer, int length, FontMap &runs);
+	Line *nextLine(int max_width);
+};
+
+/**
+ * The layouter performs all the layout work.
+ *
+ * It also accounts for the memory allocations and frees.
+ */
+class Layouter : public AutoDeleteSmallVector<ParagraphLayout::Line *, 4> {
+	typedef WChar CharType; ///< The type of character used within the layouter.
+
+	size_t AppendToBuffer(CharType *buff, const CharType *buffer_last, WChar c);
+	ParagraphLayout *GetParagraphLayout(CharType *buff);
+
+	CharType buffer[DRAW_STRING_BUFFER]; ///< Buffer for the text that is going to be drawn.
+	FontMap fonts;                       ///< The fonts needed for drawing.
+
+public:
+	Layouter(const char *str, int maxw = INT32_MAX, TextColour colour = TC_FROMSTRING, FontSize fontsize = FS_NORMAL);
+	~Layouter();
+	Dimension GetBounds();
+};
+
+#endif /* GFX_LAYOUT_H */