CanvasAction.hpp

Define a base class for all actions that can be done to widgets, plus simple actions.

CanvasAction objects modify the appearance of a canvas and can be tracked to reconstruct the state of the canvas from scratch.

Other, more specific actions defined here are: CanvasStrokeColor CanvasRotate CanvasFont

See also CanvasShape.h for more actions.

Defines

INCLUDE_EMP_WEB_CANVAS_ACTION_HPP_GUARD

class CanvasAction

#include <CanvasAction.hpp>

Base class to maintain canvas actions.

Subclassed by CanvasFont, CanvasImage, CanvasRotate, CanvasShape, CanvasStrokeColor

Public Functions

inline CanvasAction()

inline CanvasAction(const CanvasAction&)

inline virtual ~CanvasAction()

virtual void Apply() = 0: Apply current action to emp_i.ctx.

virtual CanvasAction *Clone() const = 0: Make a copy of the current action.

Protected Functions

inline void Fill(const std::string &style = ""): Helper function to set the fill status.

inline void Stroke(const std::string &style = ""): Helper function to set the stroke status.

inline void LineWidth(double line_width = 1.0): Helper function to set the stroke status.

class CanvasStrokeColor : public CanvasAction 

#include <CanvasAction.hpp>

Set the line color on subsequent draw-related actions.

Public Functions

inline CanvasStrokeColor(const std::string &c)

inline virtual void Apply(): Apply current action to emp_i.ctx.

inline virtual CanvasAction *Clone() const: Make a copy of the current action.

Protected Attributes

std::string color: Color to use.

class CanvasRotate : public CanvasAction 

#include <CanvasAction.hpp>

Rotate the entire canvas for subsequent drawings.

Public Functions

inline CanvasRotate(double a)

inline virtual void Apply(): Apply current action to emp_i.ctx.

inline virtual CanvasAction *Clone() const: Make a copy of the current action.

Protected Attributes

double angle

class CanvasFont : public CanvasAction 

#include <CanvasAction.hpp>

Change the default font to be used.

Public Functions

inline CanvasFont(const std::string &f)

inline virtual void Apply(): Apply current action to emp_i.ctx.

inline virtual CanvasAction *Clone() const: Make a copy of the current action.

Protected Attributes

std::string font

class CanvasImage : public CanvasAction 

#include <CanvasAction.hpp>

Change the default font to be used.

Public Functions

inline CanvasImage(const RawImage &raw_image, double _x = 0.0, double _y = 0.0, double _w = 0.0, double _h = 0.0)

inline CanvasImage(const RawImage &raw_image, Point _p, double _w = 0.0, double _h = 0.0)

inline CanvasImage(const std::string &url, double _x = 0.0, double _y = 0.0, double _w = 0.0, double _h = 0.0)

inline CanvasImage(const std::string &url, Point _p, double _w = 0.0, double _h = 0.0)

inline virtual void Apply(): Apply current action to emp_i.ctx.

inline virtual CanvasAction *Clone() const: Make a copy of the current action.

Protected Attributes

RawImage image

Point position

double width

double height