context2d.h Example File | Qt Script

Qt 5.6 | Qt Script | Context2D Example | context2d.h Example File

Qt 5.6.2 Reference Documentation

# context2d.h Example File

script/context2d/context2d.h

      /****************************************************************************
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      ** Copyright (C) 2015 The Qt Company Ltd.
      ** Contact: http://www.qt.io/licensing/
      **
      ** This file is part of the examples of the Qt Toolkit.
      **
      ** $QT_BEGIN_LICENSE:BSD$
      ** You may use this file under the terms of the BSD license as follows:
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      #ifndef CONTEXT2D_H
      #define CONTEXT2D_H

      #include "domimage.h"

      #include <QPainter>
      #include <QPainterPath>
      #include <QString>
      #include <QStack>
      #include <QMetaType>
      #include <QTimerEvent>

      // [3]
      class CanvasGradient
      {
      public:
          CanvasGradient(const QGradient &v)
              : value(v) {}
          CanvasGradient() {}

          QGradient value;
      };
      // [3]

      Q_DECLARE_METATYPE(CanvasGradient)
      Q_DECLARE_METATYPE(CanvasGradient*)

      class ImageData {
      };

      class QContext2DCanvas;

      class Context2D : public QObject
      {
          Q_OBJECT
          // compositing
          Q_PROPERTY(qreal globalAlpha READ globalAlpha WRITE setGlobalAlpha)
          Q_PROPERTY(QString globalCompositeOperation READ globalCompositeOperation WRITE setGlobalCompositeOperation)
          Q_PROPERTY(QVariant strokeStyle READ strokeStyle WRITE setStrokeStyle)
          Q_PROPERTY(QVariant fillStyle READ fillStyle WRITE setFillStyle)
          // line caps/joins
          Q_PROPERTY(qreal lineWidth READ lineWidth WRITE setLineWidth)
          Q_PROPERTY(QString lineCap READ lineCap WRITE setLineCap)
          Q_PROPERTY(QString lineJoin READ lineJoin WRITE setLineJoin)
          Q_PROPERTY(qreal miterLimit READ miterLimit WRITE setMiterLimit)
          // shadows
          Q_PROPERTY(qreal shadowOffsetX READ shadowOffsetX WRITE setShadowOffsetX)
          Q_PROPERTY(qreal shadowOffsetY READ shadowOffsetY WRITE setShadowOffsetY)
          Q_PROPERTY(qreal shadowBlur READ shadowBlur WRITE setShadowBlur)
          Q_PROPERTY(QString shadowColor READ shadowColor WRITE setShadowColor)

      public:
          Context2D(QObject *parent = 0);
          void setSize(int width, int height);
          void setSize(const QSize &size);
          QSize size() const;

          void clear();
          void reset();

          // compositing
          qreal globalAlpha() const; // (default 1.0)
          QString globalCompositeOperation() const; // (default over)
          QVariant strokeStyle() const; // (default black)
          QVariant fillStyle() const; // (default black)

          void setGlobalAlpha(qreal alpha);
          void setGlobalCompositeOperation(const QString &op);
          void setStrokeStyle(const QVariant &style);
          void setFillStyle(const QVariant &style);

          // line caps/joins
          qreal lineWidth() const; // (default 1)
          QString lineCap() const; // "butt", "round", "square" (default "butt")
          QString lineJoin() const; // "round", "bevel", "miter" (default "miter")
          qreal miterLimit() const; // (default 10)

          void setLineWidth(qreal w);
          void setLineCap(const QString &s);
          void setLineJoin(const QString &s);
          void setMiterLimit(qreal m);

          // shadows
          qreal shadowOffsetX() const; // (default 0)
          qreal shadowOffsetY() const; // (default 0)
          qreal shadowBlur() const; // (default 0)
          QString shadowColor() const; // (default black)

          void setShadowOffsetX(qreal x);
          void setShadowOffsetY(qreal y);
          void setShadowBlur(qreal b);
          void setShadowColor(const QString &str);

      public slots:
          void save(); // push state on state stack
          void restore(); // pop state stack and restore state

          void scale(qreal x, qreal y);
          void rotate(qreal angle);
          void translate(qreal x, qreal y);
          void transform(qreal m11, qreal m12, qreal m21, qreal m22,
                         qreal dx, qreal dy);
          void setTransform(qreal m11, qreal m12, qreal m21, qreal m22,
                            qreal dx, qreal dy);

          CanvasGradient createLinearGradient(qreal x0, qreal y0,
                                              qreal x1, qreal y1);
          CanvasGradient createRadialGradient(qreal x0, qreal y0,
                                              qreal r0, qreal x1,
                                              qreal y1, qreal r1);

          // rects
          void clearRect(qreal x, qreal y, qreal w, qreal h);
          void fillRect(qreal x, qreal y, qreal w, qreal h);
          void strokeRect(qreal x, qreal y, qreal w, qreal h);

          // path API
          void beginPath();
          void closePath();
          void moveTo(qreal x, qreal y);
          void lineTo(qreal x, qreal y);
          void quadraticCurveTo(qreal cpx, qreal cpy, qreal x, qreal y);
          void bezierCurveTo(qreal cp1x, qreal cp1y,
                             qreal cp2x, qreal cp2y, qreal x, qreal y);
          void arcTo(qreal x1, qreal y1, qreal x2, qreal y2, qreal radius);
          void rect(qreal x, qreal y, qreal w, qreal h);
          void arc(qreal x, qreal y, qreal radius,
                   qreal startAngle, qreal endAngle,
                   bool anticlockwise);
          void fill();
          void stroke();
          void clip();
          bool isPointInPath(qreal x, qreal y) const;

          // drawing images
          void drawImage(DomImage *image, qreal dx, qreal dy);
          void drawImage(DomImage *image, qreal dx, qreal dy,
                         qreal dw, qreal dh);
          void drawImage(DomImage *image, qreal sx, qreal sy,
                         qreal sw, qreal sh, qreal dx, qreal dy,
                         qreal dw, qreal dh);

          // pixel manipulation
          ImageData getImageData(qreal sx, qreal sy, qreal sw, qreal sh);
          void putImageData(ImageData image, qreal dx, qreal dy);

      signals:
          void changed(const QImage &image);

      protected:
          void timerEvent(QTimerEvent *e);

      private:
          void beginPainting();
          const QImage &endPainting();
          void scheduleChange();

          int m_changeTimerId;
          QImage  m_image;
          QPainter m_painter;
          QPainterPath m_path;

          enum DirtyFlag {
              DirtyTransformationMatrix = 0x00001,
              DirtyClippingRegion       = 0x00002,
              DirtyStrokeStyle          = 0x00004,
              DirtyFillStyle            = 0x00008,
              DirtyGlobalAlpha          = 0x00010,
              DirtyLineWidth            = 0x00020,
              DirtyLineCap              = 0x00040,
              DirtyLineJoin             = 0x00080,
              DirtyMiterLimit           = 0x00100,
              MDirtyPen                 = DirtyStrokeStyle
                                        | DirtyLineWidth
                                        | DirtyLineCap
                                        | DirtyLineJoin
                                        | DirtyMiterLimit,
              DirtyShadowOffsetX        = 0x00200,
              DirtyShadowOffsetY        = 0x00400,
              DirtyShadowBlur           = 0x00800,
              DirtyShadowColor          = 0x01000,
              DirtyGlobalCompositeOperation = 0x2000,
              DirtyFont                 = 0x04000,
              DirtyTextAlign            = 0x08000,
              DirtyTextBaseline         = 0x10000,
              AllIsFullOfDirt           = 0xfffff
          };

          struct State {
              State() : flags(0) {}
              QMatrix matrix;
              QPainterPath clipPath;
              QBrush strokeStyle;
              QBrush fillStyle;
              qreal globalAlpha;
              qreal lineWidth;
              Qt::PenCapStyle lineCap;
              Qt::PenJoinStyle lineJoin;
              qreal miterLimit;
              qreal shadowOffsetX;
              qreal shadowOffsetY;
              qreal shadowBlur;
              QColor shadowColor;
              QPainter::CompositionMode globalCompositeOperation;
              QFont font;
              int textAlign;
              int textBaseline;
              int flags;
          };
          State m_state;
          QStack<State> m_stateStack;
      };

      #endif