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add Text metrics helper
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Jeremie Roy
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60e51ea707
commit
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2 changed files with 370 additions and 0 deletions
303
examples/common/font/text_metrics.cpp
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303
examples/common/font/text_metrics.cpp
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/*
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* Copyright 2013 Jeremie Roy. All rights reserved.
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* License: http://www.opensource.org/licenses/BSD-2-Clause
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*/
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#include "text_metrics.h"
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#include <wchar.h> // wcslen
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#include "utf8.h"
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TextMetrics::TextMetrics(FontManager* _fontManager): m_fontManager(_fontManager), m_width(0), m_height(0), m_x(0), m_lineHeight(0), m_lineGap(0)
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{
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}
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void TextMetrics::appendText(FontHandle _fontHandle, const char* _string)
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{
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GlyphInfo glyph;
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const FontInfo& font = m_fontManager->getFontInfo(_fontHandle);
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if(font.lineGap > m_lineGap)
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{
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m_lineGap = font.lineGap;
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}
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if( (font.ascender - font.descender) > m_lineHeight)
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{
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m_height -= m_lineHeight;
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m_lineHeight = font.ascender - font.descender;
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m_height += m_lineHeight;
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}
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CodePoint codepoint = 0;
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uint32_t state = 0;
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for (; *_string; ++_string)
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{
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if (!utf8_decode(&state, (uint32_t*)&codepoint, *_string) )
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{
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if (m_fontManager->getGlyphInfo(_fontHandle, codepoint, glyph) )
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{
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if (codepoint == L'\n')
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{
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m_height += m_lineGap + font.ascender - font.descender;
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m_lineGap = font.lineGap;
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m_lineHeight = font.ascender - font.descender;
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m_x = 0;
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break;
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}
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//TODO handle kerning
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m_x += glyph.advance_x;
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if(m_x > m_width)
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{
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m_width = m_x;
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}
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}
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else
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{
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BX_CHECK(false, "Glyph not found");
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}
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}
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}
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BX_CHECK(state == UTF8_ACCEPT, "The string is not well-formed");
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}
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void TextMetrics::appendText(FontHandle _fontHandle, const wchar_t* _string)
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{
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GlyphInfo glyph;
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const FontInfo& font = m_fontManager->getFontInfo(_fontHandle);
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if(font.lineGap > m_lineGap)
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{
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m_lineGap = font.lineGap;
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}
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if( (font.ascender - font.descender) > m_lineHeight)
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{
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m_height -= m_lineHeight;
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m_lineHeight = font.ascender - font.descender;
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m_height += m_lineHeight;
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}
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for (uint32_t ii = 0, end = wcslen(_string); ii < end; ++ii)
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{
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uint32_t codepoint = _string[ii];
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if (m_fontManager->getGlyphInfo(_fontHandle, codepoint, glyph) )
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{
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if (codepoint == L'\n')
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{
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m_height += m_lineGap + font.ascender - font.descender;
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m_lineGap = font.lineGap;
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m_lineHeight = font.ascender - font.descender;
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m_x = 0;
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break;
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}
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//TODO handle kerning
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m_x += glyph.advance_x;
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if(m_x > m_width)
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{
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m_width = m_x;
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}
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}
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else
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{
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BX_CHECK(false, "Glyph not found");
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}
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}
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}
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TextLineMetrics::TextLineMetrics(FontManager* _fontManager, FontHandle _fontHandle )
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{
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const FontInfo& font = _fontManager->getFontInfo(_fontHandle);
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m_lineHeight = font.ascender - font.descender + font.lineGap;
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}
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uint32_t TextLineMetrics::getLineCount(const char* _string) const
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{
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CodePoint codepoint = 0;
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uint32_t state = 0;
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uint32_t lineCount = 1;
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for (; *_string; ++_string)
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{
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if(utf8_decode(&state, (uint32_t*)&codepoint, *_string) == UTF8_ACCEPT)
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{
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if(codepoint == L'\n')
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{
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++lineCount;
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}
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}
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}
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BX_CHECK(state == UTF8_ACCEPT, "The string is not well-formed");
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return lineCount;
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}
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uint32_t TextLineMetrics::getLineCount(const wchar_t* _string) const
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{
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uint32_t lineCount = 1;
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for ( ;*_string != L'\0'; ++_string)
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{
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if(*_string == L'\n')
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{
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++lineCount;
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}
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}
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return lineCount;
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}
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void TextLineMetrics::getSubText(const char* _string, uint32_t _firstLine, uint32_t _lastLine, const char*& _begin, const char*& _end)
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{
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CodePoint codepoint = 0;
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uint32_t state = 0;
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// y is bottom of a text line
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uint32_t currentLine = 0;
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while(*_string && (currentLine < _firstLine))
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{
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for (; *_string; ++_string)
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{
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if(utf8_decode(&state, (uint32_t*)&codepoint, *_string) == UTF8_ACCEPT)
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{
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if(codepoint == L'\n')
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{
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++currentLine;
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++_string;
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break;
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}
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}
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}
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}
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BX_CHECK(state == UTF8_ACCEPT, "The string is not well-formed");
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_begin = _string;
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while((*_string) && (currentLine < _lastLine) )
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{
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for (; *_string; ++_string)
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{
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if(utf8_decode(&state, (uint32_t*)&codepoint, *_string) == UTF8_ACCEPT)
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{
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if(codepoint == L'\n')
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{
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++currentLine;
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++_string;
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break;
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}
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}
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}
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}
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BX_CHECK(state == UTF8_ACCEPT, "The string is not well-formed");
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_end = _string;
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}
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void TextLineMetrics::getSubText(const wchar_t* _string, uint32_t _firstLine, uint32_t _lastLine, const wchar_t*& _begin, const wchar_t*& _end)
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{
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uint32_t currentLine = 0;
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while((*_string != L'\0') && (currentLine < _firstLine))
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{
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for ( ;*_string != L'\0'; ++_string)
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{
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if(*_string == L'\n')
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{
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++currentLine;
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++_string;
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break;
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}
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}
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}
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_begin = _string;
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while((*_string != L'\0') && (currentLine < _lastLine) )
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{
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for ( ;*_string != L'\0'; ++_string)
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{
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if(*_string == L'\n')
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{
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++currentLine;
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++_string;
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break;
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}
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}
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}
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_end = _string;
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}
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void TextLineMetrics::getVisibleText(const char* _string, float _top, float _bottom, const char*& _begin, const char*& _end)
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{
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CodePoint codepoint = 0;
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uint32_t state = 0;
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// y is bottom of a text line
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float y = m_lineHeight;
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while(*_string && (y < _top))
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{
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for (; *_string; ++_string)
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{
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if(utf8_decode(&state, (uint32_t*)&codepoint, *_string) == UTF8_ACCEPT)
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{
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if(codepoint == L'\n')
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{
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y += m_lineHeight;
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++_string;
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break;
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}
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}
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}
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}
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BX_CHECK(state == UTF8_ACCEPT, "The string is not well-formed");
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_begin = _string;
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// y is now top of a text line
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y -= m_lineHeight;
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while((*_string) && (y < _bottom) )
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{
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for (; *_string; ++_string)
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{
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if(utf8_decode(&state, (uint32_t*)&codepoint, *_string) == UTF8_ACCEPT)
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{
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if(codepoint == L'\n')
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{
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y += m_lineHeight;
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++_string;
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break;
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}
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}
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}
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}
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BX_CHECK(state == UTF8_ACCEPT, "The string is not well-formed");
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_end = _string;
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}
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void TextLineMetrics::getVisibleText(const wchar_t* _string, float _top, float _bottom, const wchar_t*& _begin, const wchar_t*& _end)
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{
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// y is bottom of a text line
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float y = m_lineHeight;
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const wchar_t* _textEnd = _string + wcslen(_string);
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while(y < _top)
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{
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for (const wchar_t* _current = _string; _current < _textEnd; ++_current)
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{
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if(*_current == L'\n')
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{
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y += m_lineHeight;
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++_string;
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break;
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}
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}
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}
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_begin = _string;
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// y is now top of a text line
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y -= m_lineHeight;
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while(y < _bottom )
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{
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for (const wchar_t* _current = _string; _current < _textEnd; ++_current)
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{
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if(*_current == L'\n')
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{
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y += m_lineHeight;
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++_string;
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break;
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}
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}
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}
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_end = _string;
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}
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67
examples/common/font/text_metrics.h
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67
examples/common/font/text_metrics.h
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@ -0,0 +1,67 @@
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/*
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* Copyright 2013 Jeremie Roy. All rights reserved.
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* License: http://www.opensource.org/licenses/BSD-2-Clause
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*/
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#ifndef __TEXT_METRICS_H__
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#define __TEXT_METRICS_H__
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#include "font_manager.h"
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class TextMetrics
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{
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public:
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TextMetrics(FontManager* _fontManager);
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/// Append an ASCII/utf-8 string to the metrics helper
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void appendText(FontHandle _fontHandle, const char* _string);
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/// Append a wide char string to the metrics helper
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void appendText(FontHandle _fontHandle, const wchar_t* _string);
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/// return the width of the measured text
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float getWidth() const { return m_width; }
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/// return the height of the measured text
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float getHeight() const { return m_height; }
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private:
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FontManager* m_fontManager;
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float m_width;
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float m_height;
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float m_x;
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float m_lineHeight;
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float m_lineGap;
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};
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/// Compute text crop area for text using a single font
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class TextLineMetrics
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{
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public:
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TextLineMetrics(FontManager* _fontManager, FontHandle _fontHandle);
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/// Return the height of a line of text using the given font
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float getLineHeight() const { return m_lineHeight; }
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/// Return the number of text line in the given text
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uint32_t getLineCount(const char* _string) const;
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/// Return the number of text line in the given text
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uint32_t getLineCount(const wchar_t* _string) const;
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/// Return the first and last character visible in the [_firstLine, _lastLine[ range
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void getSubText(const char* _string, uint32_t _firstLine, uint32_t _lastLine, const char*& _begin, const char*& _end);
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/// Return the first and last character visible in the [_firstLine, _lastLine[ range
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void getSubText(const wchar_t* _string, uint32_t _firstLine, uint32_t _lastLine, const wchar_t*& _begin, const wchar_t*& _end);
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/// Return the first and last character visible in the [_top, _bottom] range,
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void getVisibleText(const char* _string, float _top, float _bottom, const char*& _begin, const char*& _end);
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/// Return the first and last character visible in the [_top, _bottom] range,
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void getVisibleText(const wchar_t* _string, float _top, float _bottom, const wchar_t*& _begin, const wchar_t*& _end);
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private:
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FontManager* m_fontManager;
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float m_lineHeight;
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};
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#endif // __TEXT_METRICS_H__
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