qgstextrenderer.h

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/***************************************************************************
  qgstextrenderer.h
  -----------------
   begin                : September 2015
   copyright            : (C) 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 QGSTEXTRENDERER_H
#define QGSTEXTRENDERER_H
 
#include "qgis_sip.h"
#include "qgis_core.h"
#include "qgstextblock.h"
#include "qgsrendercontext.h"
#include "qgstextformat.h"
 
#include <QPicture>
 
class QgsTextDocument;
 
class CORE_EXPORT QgsTextRenderer
{
  public:
 
    enum DrawMode
    {
      Rect = 0, 
      Point, 
      Label, 
    };
 
    enum TextPart
    {
      Text = 0, 
      Buffer, 
      Background, 
      Shadow, 
    };
 
    enum HAlignment
    {
      AlignLeft = 0, 
      AlignCenter, 
      AlignRight, 
      AlignJustify, 
    };
 
    static HAlignment convertQtHAlignment( Qt::Alignment alignment );
 
    enum VAlignment
    {
      AlignTop = 0, 
      AlignVCenter, 
      AlignBottom, 
    };
 
    static VAlignment convertQtVAlignment( Qt::Alignment alignment );
 
    static int sizeToPixel( double size, const QgsRenderContext &c, QgsUnitTypes::RenderUnit unit, const QgsMapUnitScale &mapUnitScale = QgsMapUnitScale() );
 
    // TODO QGIS 4.0 -- remove drawAsOutlines from below methods!
 
    static void drawText( const QRectF &rect, double rotation, HAlignment alignment, const QStringList &textLines,
                          QgsRenderContext &context, const QgsTextFormat &format,
                          bool drawAsOutlines = true, VAlignment vAlignment = AlignTop );
 
    static void drawText( QPointF point, double rotation, HAlignment alignment, const QStringList &textLines,
                          QgsRenderContext &context, const QgsTextFormat &format,
                          bool drawAsOutlines = true );
 
    Q_DECL_DEPRECATED static void drawPart( const QRectF &rect, double rotation, HAlignment alignment, const QStringList &textLines,
                                            QgsRenderContext &context, const QgsTextFormat &format,
                                            TextPart part, bool drawAsOutlines = true ) SIP_DEPRECATED;
 
    Q_DECL_DEPRECATED static void drawPart( QPointF origin, double rotation, HAlignment alignment, const QStringList &textLines,
                                            QgsRenderContext &context, const QgsTextFormat &format,
                                            TextPart part, bool drawAsOutlines = true ) SIP_DEPRECATED;
 
    static QFontMetricsF fontMetrics( QgsRenderContext &context, const QgsTextFormat &format, double scaleFactor = 1.0 );
 
    static double textWidth( const QgsRenderContext &context, const QgsTextFormat &format, const QStringList &textLines,
                             QFontMetricsF *fontMetrics = nullptr );
 
    static double textHeight( const QgsRenderContext &context, const QgsTextFormat &format, const QStringList &textLines, DrawMode mode = Point,
                              QFontMetricsF *fontMetrics = nullptr );
 
    static double textHeight( const QgsRenderContext &context, const QgsTextFormat &format, QChar character, bool includeEffects = false );
 
    static constexpr double FONT_WORKAROUND_SCALE = 10;
 
  private:
 
    struct Component
    {
      QgsTextBlock block;
      QPointF origin;
      bool useOrigin = false;
      double rotation = 0.0;
      double rotationOffset = 0.0;
      QPointF center;
      QSizeF size;
      QPointF offset;
      QPicture picture;
 
      double pictureBuffer = 0.0;
      double dpiRatio = 1.0;
      HAlignment hAlign = AlignLeft;
 
      double extraWordSpacing = 0;
      double extraLetterSpacing = 0;
    };
 
    static double textWidth( const QgsRenderContext &context, const QgsTextFormat &format, const QgsTextDocument &document );
    static double textHeight( const QgsRenderContext &context, const QgsTextFormat &format, const QgsTextDocument &document, DrawMode mode = Point );
 
    static void drawPart( const QRectF &rect, double rotation, HAlignment alignment, VAlignment vAlignment, const QgsTextDocument &document,
                          QgsRenderContext &context, const QgsTextFormat &format,
                          TextPart part );
 
    static void drawPart( QPointF origin, double rotation, HAlignment alignment, const QgsTextDocument &document,
                          QgsRenderContext &context, const QgsTextFormat &format,
                          TextPart part );
 
    static double drawBuffer( QgsRenderContext &context,
                              const Component &component,
                              const QgsTextFormat &format );
 
    static void drawBackground( QgsRenderContext &context,
                                Component component,
                                const QgsTextFormat &format,
                                const QgsTextDocument &document,
                                DrawMode mode = Rect );
 
    static void drawShadow( QgsRenderContext &context,
                            const Component &component,
                            const QgsTextFormat &format );
 
    static void drawMask( QgsRenderContext &context,
                          const Component &component,
                          const QgsTextFormat &format );
 
    static void drawText( QgsRenderContext &context,
                          const Component &component,
                          const QgsTextFormat &format );
 
    static void drawTextInternal( TextPart drawType,
                                  QgsRenderContext &context,
                                  const QgsTextFormat &format,
                                  const Component &component,
                                  const QgsTextDocument &document,
                                  const QFontMetricsF *fontMetrics,
                                  HAlignment alignment,
                                  VAlignment vAlignment,
                                  DrawMode mode = Rect );
 
    static QgsTextFormat::TextOrientation calculateRotationAndOrientationForComponent( const QgsTextFormat &format, const Component &component, double &rotation );
 
    static void calculateExtraSpacingForLineJustification( double spaceToDistribute, const QgsTextBlock &block, double &extraWordSpace, double &extraLetterSpace );
    static void applyExtraSpacingForLineJustification( QFont &font, double extraWordSpace, double extraLetterSpace );
 
    static void drawTextInternalHorizontal( QgsRenderContext &context,
                                            const QgsTextFormat &format,
                                            TextPart drawType,
                                            DrawMode mode,
                                            const Component &component,
                                            const QgsTextDocument &document,
                                            double fontScale,
                                            const QFontMetricsF *fontMetrics,
                                            HAlignment hAlignment,
                                            VAlignment vAlignment,
                                            double rotation );
 
    static void drawTextInternalVertical( QgsRenderContext &context,
                                          const QgsTextFormat &format,
                                          TextPart drawType,
                                          DrawMode mode,
                                          const Component &component,
                                          const QgsTextDocument &document,
                                          double fontScale,
                                          const QFontMetricsF *fontMetrics,
                                          HAlignment hAlignment,
                                          VAlignment vAlignment,
                                          double rotation );
 
    friend class QgsVectorLayerLabelProvider;
    friend class QgsLabelPreview;
 
    static QgsTextFormat updateShadowPosition( const QgsTextFormat &format );
 
};
 
#endif // QGSTEXTRENDERER_H