Gempyre::CanvasElement Class Reference

Graphics element. More...

#include <gempyre_graphics.h>

Inheritance diagram for Gempyre::CanvasElement:

Collaboration diagram for Gempyre::CanvasElement:

Public Types
enum class	DrawNotify { NoKick , Kick }
	set initial draw, More...
using	Command = std::variant< std::string, double, int >
	Canvas draw command type.
using	CommandList = std::vector< Command >
	List of Canvas draw commands.
using	DrawCallback = std::function< void()>
	Function type for draw notifies.
Public Types inherited from Gempyre::Element
using	Attributes = std::unordered_map< std::string, std::string >
	Attribute key, value pairs.
using	Values = std::unordered_map< std::string, std::string >
	Value key, value pairs.
using	Elements = std::vector< Element >
	Vector of Elements.
using	SubscribeFunction = std::function< void(const Event &)>
	Callback function for event subscriptions.
using	Rect = Gempyre::Rect
	compatibility

Public Member Functions
	~CanvasElement ()
	Destructor.
	CanvasElement (const CanvasElement &other)
	Copy constructor.
	CanvasElement (CanvasElement &&other)
	Move constructor.
	CanvasElement (Ui &ui, std::string_view id)
	Constructor of canvas id.
	CanvasElement (Ui &ui, std::string_view id, const Element &parent)
	Constructor to create a new CanvasElement.
	CanvasElement (Ui &ui, const Element &parent)
	Constructor to create a new CanvasElement.
CanvasElement &	operator= (const CanvasElement &other)
	Copy operator.
CanvasElement &	operator= (CanvasElement &&other)
	Move operator.
std::string	add_image (std::string_view url, const std::function< void(std::string_view id)> &loaded=nullptr)
	Add an image into HTML DOM tree.
void	paint_image (std::string_view imageId, int x, int y, const Element::Rect &clippingRect={0, 0, 0, 0}) const
	Draw image at position.
void	paint_image (std::string_view imageId, const Element::Rect &targetRect, const Element::Rect &clippingRect={0, 0, 0, 0}) const
	Draw image in rectangle.
void	draw (const CommandList &canvasCommands)
	Draw command list - please prefer.
void	draw (const FrameComposer &frameComposer)
	Draw Frame Composer.
void	draw (const Bitmap &bmp)
	Draw bitmap.
void	draw (int x, int y, const Bitmap &bmp)
	Draw bitmap at position.
void	draw_completed (const DrawCallback &drawCompletedCallback, DrawNotify kick=DrawNotify::NoKick)
	Set a callback to be called after the draw.
void	erase (bool resized=false)
	erase bitmap
Public Member Functions inherited from Gempyre::Element
	Element (const Element &other)=default
	Copy constructor.
	Element (Element &&other)=default
	Move constructor.
Element &	operator= (const Element &other)
	Copy operator.
Element &	operator= (Element &&other)
	Move operator.
	Element (Ui &ui, std::string_view id)
	Constructor for existing elements.
	Element (Ui &ui, std::string_view id, std::string_view htmlElement, const Element &parent)
	Constructor for exiting elements.
	Element (Ui &ui, std::string_view htmlElement, const Element &parent)
	Constructor for exiting elements.
virtual	~Element ()
	Destructor.
const Ui &	ui () const
	Get Ui.
Ui &	ui ()
	Get Ui.
std::string	id () const
	Get id of element.
Element &	subscribe (std::string_view name, const SubscribeFunction &handler, const std::vector< std::string > &properties={}, const std::chrono::milliseconds &throttle=0ms)
	Subscribe UI event.
Element &	set_html (std::string_view htmlText)
	Set HTML text value of the element.
HtmlStream	html_stream ()
	get a stream that writes to html part of this element
Element &	set_attribute (std::string_view attr, std::string_view value)
	Set HTML a attribute of this element.
Element &	set_attribute (std::string_view attr)
	Set HTML a attribute of this element.
std::optional< Attributes >	attributes () const
	Get this element attributes.
Element &	set_style (std::string_view style, std::string_view value)
	Set CSS style of this element.
Element &	remove_attribute (std::string_view attr)
	Remove attribute.
std::optional< Values >	styles (const std::vector< std::string > &keys) const
	Get element styles.
std::optional< Elements >	children () const
	Get element children.
std::optional< Values >	values () const
	Applies to form elements only - receive values bound to the element.
std::optional< std::string >	html () const
	Get HTML value bound to this element (does not apply all elements)
void	remove ()
	Remove this element from UI.
std::optional< std::string >	type () const
	Get this element type, mostly a HTML tag.
std::optional< Rect >	rect () const
	Get this element UI rect. I.e area it occupies on screen (if applicable)
std::optional< Element >	parent () const
	Parent of this element. If query fails, element is root or parent id is not set, nullopt is returned.

Friends
class	Bitmap

Detailed Description

Graphics element.

Member Typedef Documentation

DrawCallback

using Gempyre::CanvasElement::DrawCallback = std::function<void()>

Function type for draw notifies.

See also

CanvasElement::draw_completed and

DrawNotify.

Member Enumeration Documentation

DrawNotify

enum class Gempyre::CanvasElement::DrawNotify

strong

set initial draw,

See also

CanvasElement::draw_completed()

Constructor & Destructor Documentation

CanvasElement() [1/3]

Gempyre::CanvasElement::CanvasElement	(	Ui &	ui,
		std::string_view	id
	)

Constructor of canvas id.

Parameters

ui	ref.
id	HTML id, should be canvas.

CanvasElement() [2/3]

Gempyre::CanvasElement::CanvasElement	(	Ui &	ui,
		std::string_view	id,
		const Element &	parent
	)

Constructor to create a new CanvasElement.

Parameters

ui	ref
id	HTML id
parent	parent element

CanvasElement() [3/3]

Gempyre::CanvasElement::CanvasElement	(	Ui &	ui,
		const Element &	parent
	)

Constructor to create a new CanvasElement.

Parameters

ui	ref
parent	parent element

Member Function Documentation

add_image()

std::string Gempyre::CanvasElement::add_image	(	std::string_view	url,
		const std::function< void(std::string_view id)> &	loaded = nullptr
	)

Add an image into HTML DOM tree.

Parameters

url	address of image, can be either a resource or any http url.
loaded	callback called when image is loaded.

Returns

image id.

draw() [1/4]

void Gempyre::CanvasElement::draw ( const Bitmap &  bmp )

inline

Draw bitmap.

Parameters

bmp

draw() [2/4]

void Gempyre::CanvasElement::draw

(

const CommandList &

canvasCommands

)

Draw command list - please prefer.

See also

draw(FrameComposer)

Parameters

canvasCommands

draw() [3/4]

void Gempyre::CanvasElement::draw

(

const FrameComposer &

frameComposer

)

Draw Frame Composer.

Parameters

frameComposer

draw() [4/4]

void Gempyre::CanvasElement::draw	(	int	x,
		int	y,
		const Bitmap &	bmp
	)

Draw bitmap at position.

Parameters

x
y
bmp

draw_completed()

void Gempyre::CanvasElement::draw_completed	(	const DrawCallback &	drawCompletedCallback,
		DrawNotify	kick = DrawNotify::NoKick
	)

Set a callback to be called after the draw.

Parameters

drawCompletedCallback	- function called after draw.
kick	- optional whether callback is called 1st time automatically.

• When doing animation or frequent drawing, please do no call draw functions inside timer function. The preferred way is to to do animation in timer function, but use draw_completed to do the actual drawing. draw_completed do drawing in the optimal frequency (as fast the system can do it without consuming all CPU).

  Note

  canvas_element.draw_completed([this]() {draw_frame();}, Gempyre::CanvasElement::DrawNotify::Kick);
  ui.start_periodic(50ms, [this]() {animate();});

erase()

void Gempyre::CanvasElement::erase

(

bool

resized = false

)

erase bitmap

Parameters

resized

- make an explicit query to ask canvas current size

paint_image() [1/2]

void Gempyre::CanvasElement::paint_image	(	std::string_view	imageId,
		const Element::Rect &	targetRect,
		const Element::Rect &	clippingRect = {0, 0, 0, 0}
	)		const

Draw image in rectangle.

Parameters

imageId	image id.
targetRect	image is resized in the rectangle.
clippingRect	optional image clipping rectangle.

paint image does not call draw_completed callback.

paint_image() [2/2]

void Gempyre::CanvasElement::paint_image	(	std::string_view	imageId,
		int	x,
		int	y,
		const Element::Rect &	clippingRect = {0, 0, 0, 0}
	)		const

Draw image at position.

Parameters

imageId	image id.
x	image x coordinate.
y	image y coordinate.
clippingRect	optional image clipping rectangle.

paint image does not call draw_completed callback.

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The documentation for this class was generated from the following file:

• include/gempyre_graphics.h