qgsfonttextureatlasgenerator.h

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/***************************************************************************
  qgsfonttextureatlasgenerator.h
  --------------------------------------
  Date                 : September 2025
  Copyright            : (C) 2025 by Nyall Dawson
  Email                : nyall dot dawson at gmail dot com
 ***************************************************************************
 *                                                                         *
 *   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.                                   *
 *                                                                         *
 ***************************************************************************/
 
#ifndef QGSFONTTEXTUREATLASGENERATOR_H
#define QGSFONTTEXTUREATLASGENERATOR_H
 
#include <vector>
 
#include "qgis_3d.h"
#include "qgstextformat.h"
 
#include <QImage>
#include <QRect>

class QgsCharTextureRect;
 

class _3D_EXPORT QgsFontTextureAtlas
{
  public:
    QgsFontTextureAtlas();
    ~QgsFontTextureAtlas();
 
    QgsFontTextureAtlas( const QgsFontTextureAtlas &other );
    QgsFontTextureAtlas &operator=( const QgsFontTextureAtlas &other );

    bool isValid() const { return mAtlasSize.isValid(); }

    QSize atlasSize() const { return mAtlasSize; }
 
#ifndef SIP_RUN
    QRect rect( const QString &grapheme ) const;
#else

    QRect rect( const QString &grapheme ) const;
    //%MethodCode
    const QRect res = sipCpp->rect( *a0 );
    if ( res.isNull() )
    {
      PyErr_SetString( PyExc_KeyError, QStringLiteral( "No rectangle for character %1 exists." ).arg( *a0 ).toUtf8().constData() );
      sipIsErr = 1;
    }
    else
    {
      return sipConvertFromNewType( new QRect( res ), sipType_QRect, Py_None );
    }
    //%End
#endif

    int graphemeCount( const QString &string ) const;

    int totalWidth( const QString &string ) const;

    QPoint pixelOffsetForGrapheme( const QString &string, int graphemeIndex ) const;

    QRect textureRectForGrapheme( const QString &string, int graphemeIndex ) const;

    QImage renderAtlasTexture() const;

    QImage renderDebugTexture() const;

    int count() const;
 
#ifdef SIP_RUN
    int __len__() const;
    % Docstring
        Returns the number of textures in the atlas.
      % End
        //%MethodCode
        sipRes
      = sipCpp->count();
    //% End
#endif
 
  private:
    struct GraphemeMetric
    {
        GraphemeMetric( int horizontalAdvance = 0, const QString &grapheme = QString() )
          : horizontalAdvance( horizontalAdvance )
          , grapheme( grapheme )
        {}
 
        int horizontalAdvance = 0;
        QString grapheme;
    };
 
    struct StringMetrics
    {
        int totalWidth = 0;
        QVector< GraphemeMetric > graphemeMetrics;
    };
 
    QgsTextFormat mFormat;
    std::vector< QgsCharTextureRect > mRects;
    QSize mAtlasSize;
    QHash< QString, int > mGraphemeIndices;
    QMap< QString, StringMetrics > mStringMetrics;
    int mTexturePaddingPixels = 0;
 
    friend class QgsFontTextureAtlasGenerator;
};

class _3D_EXPORT QgsFontTextureAtlasGenerator
{
  public:

    static QgsFontTextureAtlas create( const QgsTextFormat &format, const QStringList &strings );
};
 
#endif // QGSFONTTEXTUREATLASGENERATOR_H