outline_font.cpp

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/*
 * This program source code file is part of KICAD, a free EDA CAD application.
 *
 * Copyright (C) 2021 Ola Rinta-Koski <[email protected]>
 * Copyright (C) 2021-2022 Kicad Developers, see AUTHORS.txt for contributors.
 *
 * Outline font class
 *
 * This program 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; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program 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 this program; if not, you may find one here:
 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 * or you may search the http://www.gnu.org website for the version 2 license,
 * or you may write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
 */
 
#include <limits>
#include <pgm_base.h>
#include <settings/settings_manager.h>
#include <harfbuzz/hb.h>
#include <harfbuzz/hb-ft.h>
#include <bezier_curves.h>
#include <geometry/shape_poly_set.h>
#include <eda_text.h>
#include <font/fontconfig.h>
#include <font/outline_font.h>
#include FT_GLYPH_H
#include FT_BBOX_H
#include <trigo.h>
#include <font/fontconfig.h>
#include <convert_basic_shapes_to_polygon.h>
 
using namespace KIFONT;
 
 
FT_Library OUTLINE_FONT::m_freeType = nullptr;
 
OUTLINE_FONT::OUTLINE_FONT() :
 m_face(NULL),
 m_faceSize( 16 ),
 m_fakeBold( false ),
 m_fakeItal( false )
{
 if( !m_freeType )
 FT_Init_FreeType( &m_freeType );
}
 
 
wxString OUTLINE_FONT::FreeTypeVersion()
{
 if( !m_freeType )
 FT_Init_FreeType( &m_freeType );
 
 FT_Int major = 0;
 FT_Int minor = 0;
 FT_Int patch = 0;
 FT_Library_Version( m_freeType, &major, &minor, &patch );
 
 return wxString::Format( "%d.%d.%d", major, minor, patch );
}
 
 
wxString OUTLINE_FONT::HarfBuzzVersion()
{
 return wxString::FromUTF8( HB_VERSION_STRING );
}
 
 
wxString OUTLINE_FONT::FontConfigVersion()
{
 return fontconfig::FONTCONFIG::Version();
}
 
 
wxString OUTLINE_FONT::FontLibraryVersion()
{
 return wxString::Format( "FreeType %s HarfBuzz %s", FreeTypeVersion(), HarfBuzzVersion() );
}
 
 
OUTLINE_FONT* OUTLINE_FONT::LoadFont( const wxString& aFontName, bool aBold, bool aItalic )
{
 OUTLINE_FONT* font = new OUTLINE_FONT();
 
 wxString fontFile;
 using fc = fontconfig::FONTCONFIG;
 
 fc::FF_RESULT retval = Fontconfig()->FindFont( aFontName, fontFile, aBold, aItalic );
 
 if( retval == fc::FF_RESULT::FF_MISSING_BOLD || retval == fc::FF_RESULT::FF_MISSING_BOLD_ITAL )
 font->SetFakeBold();
 
 if( retval == fc::FF_RESULT::FF_MISSING_ITAL || retval == fc::FF_RESULT::FF_MISSING_BOLD_ITAL )
 font->SetFakeItal();
 
 if( retval != fc::FF_RESULT::FF_ERROR )
 (void) font->loadFace( fontFile );
 
 font->m_fontName = aFontName; // Keep asked-for name, even if we substituted.
 font->m_fontFileName = fontFile;
 
 return font;
}
 
 
FT_Error OUTLINE_FONT::loadFace( const wxString& aFontFileName )
{
 // TODO: check that going from wxString to char* with UTF-8
 // conversion for filename makes sense on any/all platforms
 FT_Error e = FT_New_Face( m_freeType, aFontFileName.mb_str( wxConvUTF8 ), 0, &m_face );
 
 if( !e )
 {
 FT_Select_Charmap( m_face, FT_Encoding::FT_ENCODING_UNICODE );
 // params:
 // m_face = handle to face object
 // 0 = char width in 1/64th of points ( 0 = same as char height )
 // faceSize() = char height in 1/64th of points
 // GLYPH_RESOLUTION = horizontal device resolution (288dpi, 4x default)
 // 0 = vertical device resolution ( 0 = same as horizontal )
 FT_Set_Char_Size( m_face, 0, faceSize(), GLYPH_RESOLUTION, 0 );
 }
 
 return e;
}
 
 
double OUTLINE_FONT::ComputeOverbarVerticalPosition( double aGlyphHeight ) const
{
 // The overbar on actual text is positioned above the bounding box of the glyphs. However,
 // that's expensive to calculate so we use an estimation here (as this is only used for
 // calculating bounding boxes).
 return aGlyphHeight * m_outlineFontSizeCompensation;
}
 
 
double OUTLINE_FONT::ComputeUnderlineVerticalPosition( double aGlyphHeight ) const
{
 return aGlyphHeight * m_underlineOffsetScaler;
}
 
 
double OUTLINE_FONT::GetInterline( double aGlyphHeight, double aLineSpacing ) const
{
 double pitch = INTERLINE_PITCH_RATIO;
 
 if( GetFace()->units_per_EM )
 pitch = GetFace()->height / GetFace()->units_per_EM;
 
 double interline = aLineSpacing * aGlyphHeight * pitch * m_outlineFontSizeCompensation;
 
 // FONT TODO this hack is an attempt to fix interline spacing by eyeballing it
 static constexpr double interlineHackMultiplier = 1.2;
 interline *= interlineHackMultiplier;
 
 return interline;
}
 
 
static bool contourIsFilled( const CONTOUR& c )
{
 switch( c.m_Orientation )
 {
 case FT_ORIENTATION_TRUETYPE: return c.m_Winding == 1;
 case FT_ORIENTATION_POSTSCRIPT: return c.m_Winding == -1;
 default: return false;
 }
}
 
 
static bool contourIsHole( const CONTOUR& c )
{
 return !contourIsFilled( c );
}
 
 
BOX2I OUTLINE_FONT::getBoundingBox( const std::vector<std::unique_ptr<GLYPH>>& aGlyphs ) const
{
 int minX = INT_MAX;
 int minY = INT_MAX;
 int maxX = INT_MIN;
 int maxY = INT_MIN;
 
 for( const std::unique_ptr<KIFONT::GLYPH>& glyph : aGlyphs )
 {
 BOX2D bbox = glyph->BoundingBox();
 bbox.Normalize();
 
 if( minX > bbox.GetX() )
 minX = bbox.GetX();
 
 if( minY > bbox.GetY() )
 minY = bbox.GetY();
 
 if( maxX < bbox.GetRight() )
 maxX = bbox.GetRight();
 
 if( maxY < bbox.GetBottom() )
 maxY = bbox.GetBottom();
 }
 
 BOX2I ret;
 ret.SetOrigin( minX, minY );
 ret.SetEnd( maxX, maxY );
 return ret;
}
 
 
void OUTLINE_FONT::GetLinesAsGlyphs( std::vector<std::unique_ptr<GLYPH>>* aGlyphs,
 const wxString& aText, const VECTOR2I& aPosition,
 const TEXT_ATTRIBUTES& aAttrs ) const
{
 wxArrayString strings;
 std::vector<VECTOR2I> positions;
 std::vector<VECTOR2I> extents;
 TEXT_STYLE_FLAGS textStyle = 0;
 
 if( aAttrs.m_Italic )
 textStyle |= TEXT_STYLE::ITALIC;
 
 getLinePositions( aText, aPosition, strings, positions, extents, aAttrs );
 
 for( size_t i = 0; i < strings.GetCount(); i++ )
 {
 (void) drawMarkup( nullptr, aGlyphs, strings.Item( i ), positions[i], aAttrs.m_Size,
 aAttrs.m_Angle, aAttrs.m_Mirrored, aPosition, textStyle );
 }
}
 
 
VECTOR2I OUTLINE_FONT::GetTextAsGlyphs( BOX2I* aBBox, std::vector<std::unique_ptr<GLYPH>>* aGlyphs,
 const wxString& aText, const VECTOR2I& aSize,
 const VECTOR2I& aPosition, const EDA_ANGLE& aAngle,
 bool aMirror, const VECTOR2I& aOrigin,
 TEXT_STYLE_FLAGS aTextStyle ) const
{
 // HarfBuzz needs further processing to split tab-delimited text into text runs.
 
 constexpr double TAB_WIDTH = 4 * 0.6;
 
 VECTOR2I position = aPosition;
 wxString textRun;
 
 if( aBBox )
 {
 aBBox->SetOrigin( aPosition );
 aBBox->SetEnd( aPosition );
 }
 
 for( wxUniChar c : aText )
 {
 // Handle tabs as locked to the nearest 4th column (in space-widths).
 if( c == '\t' )
 {
 if( !textRun.IsEmpty() )
 {
 position = getTextAsGlyphs( aBBox, aGlyphs, textRun, aSize, position, aAngle,
 aMirror, aOrigin, aTextStyle );
 textRun.clear();
 }
 
 int tabWidth = KiROUND( aSize.x * TAB_WIDTH );
 int currentIntrusion = ( position.x - aOrigin.x ) % tabWidth;
 
 position.x += tabWidth - currentIntrusion;
 }
 else
 {
 textRun += c;
 }
 }
 
 if( !textRun.IsEmpty() )
 {
 position = getTextAsGlyphs( aBBox, aGlyphs, textRun, aSize, position, aAngle, aMirror,
 aOrigin, aTextStyle );
 }
 
 return position;
}
 
 
double OUTLINE_FONT::getOverbarOffset( int ascender, int height, int thickness ) const
{
 double thicknessRatio = abs( (double) thickness ) / (double) height;
 double ascenderRatio = (double) ascender / (double) height;
 
 if( thicknessRatio < 0.05 )
 return 0.04;
 else if( ascenderRatio < 0.78 )
 return 0.00;
 else if( ascenderRatio < 0.80 )
 return -0.03;
 else
 return -0.06;
}
 
 
VECTOR2I OUTLINE_FONT::getTextAsGlyphs( BOX2I* aBBox, std::vector<std::unique_ptr<GLYPH>>* aGlyphs,
 const wxString& aText, const VECTOR2I& aSize,
 const VECTOR2I& aPosition, const EDA_ANGLE& aAngle,
 bool aMirror, const VECTOR2I& aOrigin,
 TEXT_STYLE_FLAGS aTextStyle ) const
{
 VECTOR2D glyphSize = aSize;
 FT_Face face = m_face;
 double scaler = faceSize();
 
 if( IsSubscript( aTextStyle ) || IsSuperscript( aTextStyle ) )
 {
 scaler = subscriptSize();
 }
 
 // set glyph resolution so that FT_Load_Glyph() results are good enough for decomposing
 FT_Set_Char_Size( face, 0, scaler, GLYPH_RESOLUTION, 0 );
 
 hb_buffer_t* buf = hb_buffer_create();
 hb_buffer_add_utf8( buf, UTF8( aText ).c_str(), -1, 0, -1 );
 hb_buffer_guess_segment_properties( buf ); // guess direction, script, and language based on
 // contents
 
 unsigned int glyphCount;
 hb_glyph_info_t* glyphInfo = hb_buffer_get_glyph_infos( buf, &glyphCount );
 hb_glyph_position_t* glyphPos = hb_buffer_get_glyph_positions( buf, &glyphCount );
 
 hb_font_t* referencedFont = hb_ft_font_create_referenced( face );
 hb_ft_font_set_funcs( referencedFont );
 hb_shape( referencedFont, buf, nullptr, 0 );
 
 VECTOR2D scaleFactor( glyphSize.x / faceSize(), -glyphSize.y / faceSize() );
 scaleFactor = scaleFactor * m_outlineFontSizeCompensation;
 
 VECTOR2I cursor( 0, 0 );
 
 for( unsigned int i = 0; i < glyphCount; i++ )
 {
 // Don't process glyphs that were already included in a previous cluster
 if( i > 0 && glyphInfo[i].cluster == glyphInfo[i-1].cluster )
 continue;
 
 if( aGlyphs )
 {
 if( m_fakeItal )
 {
 FT_Matrix matrix;
 // Create a 12 degree slant
 const float angle = ( -M_PI * 12 ) / 180.0f;
 matrix.xx = (FT_Fixed) ( cos( angle ) * 0x10000L );
 matrix.xy = (FT_Fixed) ( -sin( angle ) * 0x10000L );
 matrix.yx = (FT_Fixed) ( 0 * 0x10000L ); // Don't rotate in the y direction
 matrix.yy = (FT_Fixed) ( 1 * 0x10000L );
 
 FT_Set_Transform(face, &matrix,0);
 }
 
 FT_Load_Glyph( face, glyphInfo[i].codepoint, FT_LOAD_NO_BITMAP );
 
 if( m_fakeBold )
 FT_Outline_Embolden( &face->glyph->outline, 1 << 6 );
 
 // contours is a collection of all outlines in the glyph; for example the 'o' glyph
 // generally contains 2 contours, one for the glyph outline and one for the hole
 CONTOURS contours;
 
 OUTLINE_DECOMPOSER decomposer( face->glyph->outline );
 decomposer.OutlineToSegments( &contours );
 
 std::unique_ptr<OUTLINE_GLYPH> glyph = std::make_unique<OUTLINE_GLYPH>();
 std::vector<SHAPE_LINE_CHAIN> holes;
 
 for( CONTOUR& c : contours )
 {
 GLYPH_POINTS points = c.m_Points;
 SHAPE_LINE_CHAIN shape;
 
 for( const VECTOR2D& v : points )
 {
 VECTOR2D pt( v + cursor );
 
 if( IsSubscript( aTextStyle ) )
 pt.y += m_subscriptVerticalOffset * scaler;
 else if( IsSuperscript( aTextStyle ) )
 pt.y += m_superscriptVerticalOffset * scaler;
 
 pt *= scaleFactor;
 pt += aPosition;
 
 if( aMirror )
 pt.x = aOrigin.x - ( pt.x - aOrigin.x );
 
 if( !aAngle.IsZero() )
 RotatePoint( pt, aOrigin, aAngle );
 
 shape.Append( pt.x, pt.y );
 }
 
 shape.SetClosed( true );
 
 if( contourIsHole( c ) )
 holes.push_back( std::move( shape ) );
 else
 glyph->AddOutline( std::move( shape ) );
 }
 
 for( SHAPE_LINE_CHAIN& hole : holes )
 {
 if( hole.PointCount() )
 {
 for( int ii = 0; ii < glyph->OutlineCount(); ++ii )
 {
 if( glyph->Outline( ii ).PointInside( hole.GetPoint( 0 ) ) )
 {
 glyph->AddHole( std::move( hole ), ii );
 break;
 }
 }
 }
 }
 
 // FONT TODO we might not want to do Fracture() here;
 // knockout text (eg. silkscreen labels with a background) will
 // need to do that after the contours have been turned into holes
 // and vice versa
 if( glyph->HasHoles() )
 glyph->Fracture( SHAPE_POLY_SET::PM_FAST ); // FONT TODO verify aFastMode
 
 aGlyphs->push_back( std::move( glyph ) );
 }
 
 hb_glyph_position_t& pos = glyphPos[i];
 cursor.x += ( pos.x_advance * GLYPH_SIZE_SCALER );
 cursor.y += ( pos.y_advance * GLYPH_SIZE_SCALER );
 }
 
 int ascender = abs( face->size->metrics.ascender * GLYPH_SIZE_SCALER );
 int height = abs( face->size->metrics.height * GLYPH_SIZE_SCALER );
 int descender = abs( face->size->metrics.descender * GLYPH_SIZE_SCALER );
 VECTOR2I extents( cursor.x * scaleFactor.x, ( ascender + descender ) * abs( scaleFactor.y ) );
 
 // Font metrics don't include all descenders and diacriticals, so beef them up just a little.
 extents.y *= 1.05;
 
 if( IsOverbar( aTextStyle ) )
 {
 std::vector<std::unique_ptr<GLYPH>> underscoreGlyphs;
 
 getTextAsGlyphs( nullptr, &underscoreGlyphs, wxT( "_" ), aSize, { 0, 0 }, ANGLE_0, false,
 { 0, 0 }, aTextStyle & ~TEXT_STYLE::OVERBAR );
 
 OUTLINE_GLYPH* underscoreGlyph = static_cast<OUTLINE_GLYPH*>( underscoreGlyphs[0].get() );
 BOX2I underscoreBBox;
 
 for( const VECTOR2I& pt : underscoreGlyph->Outline( 0 ).CPoints() )
 underscoreBBox.Merge( pt );
 
 int barThickness = underscoreBBox.GetHeight();
 
 // Shorten the bar a little so its rounded ends don't make it over-long
 double barTrim = barThickness / 2.0;
 double barOffset = getOverbarOffset( ascender, height, barThickness / scaleFactor.y );
 
 VECTOR2I topLeft( aPosition );
 VECTOR2I topRight( aPosition );
 
 topLeft.y += ascender * scaleFactor.y * ( 1.0 + barOffset );
 topRight.y = topLeft.y;
 
 topLeft.x += barTrim;
 topRight.x += extents.x - barTrim;
 
 extents.y *= ( 1.0 + barOffset + barOffset );
 extents.x += barTrim;
 
 if( IsItalic() )
 {
 topLeft.x += aSize.y * ITALIC_TILT;
 topRight.x += aSize.y * ITALIC_TILT;
 extents.x += aSize.y * ITALIC_TILT;
 }
 
 if( aMirror )
 {
 topLeft.x = aOrigin.x - ( topLeft.x - aOrigin.x );
 topRight.x = aOrigin.x - ( topRight.x - aOrigin.x );
 }
 
 if( !aAngle.IsZero() )
 {
 RotatePoint( topLeft, aOrigin, aAngle );
 RotatePoint( topRight, aOrigin, aAngle );
 }
 
 if( aGlyphs )
 {
 int maxError = KiROUND( barThickness / 48 );
 SHAPE_POLY_SET poly;
 
 TransformOvalToPolygon( poly, topLeft, topRight, barThickness, maxError, ERROR_INSIDE );
 
 std::unique_ptr<OUTLINE_GLYPH> overbarGlyph = std::make_unique<OUTLINE_GLYPH>( poly );
 aGlyphs->push_back( std::move( overbarGlyph ) );
 }
 }
 
 hb_buffer_destroy( buf );
 hb_font_destroy( referencedFont );
 
 VECTOR2I cursorDisplacement( cursor.x * scaleFactor.x, -cursor.y * scaleFactor.y );
 
 if( aBBox )
 aBBox->Merge( aPosition + extents );
 
 return VECTOR2I( aPosition.x + cursorDisplacement.x, aPosition.y + cursorDisplacement.y );
}
 
 
#undef OUTLINEFONT_RENDER_AS_PIXELS
#ifdef OUTLINEFONT_RENDER_AS_PIXELS
/*
 * WIP: eeschema (and PDF output?) should use pixel rendering instead of linear segmentation
 */
void OUTLINE_FONT::RenderToOpenGLCanvas( KIGFX::OPENGL_GAL& aGal, const wxString& aString,
 const VECTOR2D& aGlyphSize, const VECTOR2I& aPosition,
 const EDA_ANGLE& aOrientation, bool aIsMirrored ) const
{
 hb_buffer_t* buf = hb_buffer_create();
 hb_buffer_add_utf8( buf, UTF8( aString ).c_str(), -1, 0, -1 );
 hb_buffer_guess_segment_properties( buf ); // guess direction, script, and language based on contents
 
 unsigned int glyphCount;
 hb_glyph_info_t* glyphInfo = hb_buffer_get_glyph_infos( buf, &glyphCount );
 hb_glyph_position_t* glyphPos = hb_buffer_get_glyph_positions( buf, &glyphCount );
 hb_font_t* referencedFont = hb_ft_font_create_referenced( m_face );
 
 hb_ft_font_set_funcs( referencedFont );
 hb_shape( referencedFont, buf, nullptr, 0 );
 
 const double mirror_factor = ( aIsMirrored ? 1 : -1 );
 const double x_scaleFactor = mirror_factor * aGlyphSize.x / mScaler;
 const double y_scaleFactor = aGlyphSize.y / mScaler;
 
 hb_position_t cursor_x = 0;
 hb_position_t cursor_y = 0;
 
 for( unsigned int i = 0; i < glyphCount; i++ )
 {
 hb_glyph_position_t& pos = glyphPos[i];
 int codepoint = glyphInfo[i].codepoint;
 
 FT_Error e = FT_Load_Glyph( m_face, codepoint, FT_LOAD_DEFAULT );
 // TODO handle FT_Load_Glyph error
 
 FT_Glyph glyph;
 e = FT_Get_Glyph( m_face->glyph, &glyph );
 // TODO handle FT_Get_Glyph error
 
 wxPoint pt( aPosition );
 pt.x += ( cursor_x >> 6 ) * x_scaleFactor;
 pt.y += ( cursor_y >> 6 ) * y_scaleFactor;
 
 cursor_x += pos.x_advance;
 cursor_y += pos.y_advance;
 }
 
 hb_buffer_destroy( buf );
}
#endif //OUTLINEFONT_RENDER_AS_PIXELS