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Version: 4.16

Button

A button with two images. One image showing the unpressed button and one image showing the pressed state.

Inherits from: AbstractButton, Widget, Drawable

Inherited by: ButtonWithIcon, ButtonWithLabel, RepeatButton, ToggleButton

Public Functions#

Button()
virtual voiddraw(const Rect & invalidatedArea) const
Draw this drawable.
uint8_tgetAlpha() const
Gets the current alpha value of the widget.
BitmapgetCurrentlyDisplayedBitmap() const
Gets currently displayed bitmap.
virtual RectgetSolidRect() const
Get (the largest possible) rectangle that is guaranteed to be solid (opaque).
voidsetAlpha(uint8_t newAlpha)
Sets the opacity (alpha value).
virtual voidsetBitmaps(const Bitmap & bitmapReleased, const Bitmap & bitmapPressed)
Sets the two bitmaps used by this button.

Protected Attributes#

uint8_talpha
The current alpha value. 255=solid, 0=invisible.
Bitmapdown
The image to display when button is pressed.
Bitmapup
The image to display when button is released (normal state).

Additional inherited members#

Public Functions inherited from AbstractButton#

AbstractButton()
Sets this Widget touchable so the user can interact with buttons.
virtual voidexecuteAction()
Executes the previously set action.
virtual boolgetPressedState() const
Function to determine if the AbstractButton is currently pressed.
virtual voidhandleClickEvent(const ClickEvent & event)
Updates the current state of the button.
voidsetAction(GenericCallback< const AbstractButton & > & callback)
Associates an action with the button.

Protected Attributes inherited from AbstractButton#

GenericCallback< const AbstractButton & > *action
The callback to be executed when this AbstractButton is clicked.
boolpressed
Is the button pressed or released? True if pressed.

Public Functions inherited from Widget#

virtual voidgetLastChild(int16_t x, int16_t y, Drawable ** last)
Since a Widget is only one Drawable, Widget::getLastChild simply yields itself as result, but only if the Widget isVisible and isTouchable.

Public Functions inherited from Drawable#

virtual voidchildGeometryChanged()
This function can be called on parent nodes to signal that the size or position of one or more of its children has changed.
Drawable()
Initializes a new instance of the Drawable class.
voiddrawToDynamicBitmap(BitmapId id)
Render the Drawable object into a dynamic bitmap.
RectgetAbsoluteRect() const
Helper function for obtaining the rectangle this Drawable covers, expressed in absolute coordinates.
virtual Drawable *getFirstChild()
Function for obtaining the first child of this drawable if any.
int16_tgetHeight() const
Gets the height of this Drawable.
virtual voidgetLastChild(int16_t x, int16_t y, Drawable ** last) =0
Function for obtaining the the last child of this drawable that intersects with the specified point.
Drawable *getNextSibling()
Gets the next sibling node.
Drawable *getParent() const
Returns the parent node.
const Rect &getRect() const
Gets the rectangle this Drawable covers, in coordinates relative to its parent.
virtual RectgetSolidRectAbsolute()
Helper function for obtaining the largest solid rect (as implemented by getSolidRect()) expressed in absolute coordinates.
virtual voidgetVisibleRect(Rect & rect) const
Function for finding the visible part of this drawable.
int16_tgetWidth() const
Gets the width of this Drawable.
int16_tgetX() const
Gets the x coordinate of this Drawable, relative to its parent.
int16_tgetY() const
Gets the y coordinate of this Drawable, relative to its parent.
virtual voidhandleClickEvent(const ClickEvent & evt)
Defines the event handler interface for ClickEvents.
virtual voidhandleDragEvent(const DragEvent & evt)
Defines the event handler interface for DragEvents.
virtual voidhandleGestureEvent(const GestureEvent & evt)
Defines the event handler interface for GestureEvents.
virtual voidhandleTickEvent()
Called periodically by the framework if the Drawable instance has subscribed to timer ticks.
virtual voidinvalidate() const
Tell the framework that this entire Drawable needs to be redrawn.
virtual voidinvalidateRect(Rect & invalidatedArea) const
Request that a region of this drawable is redrawn.
boolisTouchable() const
Gets whether this Drawable receives touch events or not.
boolisVisible() const
Gets whether this Drawable is visible.
virtual voidmoveRelative(int16_t x, int16_t y)
Moves the drawable.
virtual voidmoveTo(int16_t x, int16_t y)
Moves the drawable.
virtual voidsetHeight(int16_t height)
Sets the height of this drawable.
voidsetPosition(const Drawable & drawable)
Sets the position of the Drawable to the same as the given Drawable.
voidsetPosition(int16_t x, int16_t y, int16_t width, int16_t height)
Sets the size and position of this Drawable, relative to its parent.
voidsetTouchable(bool touch)
Controls whether this Drawable receives touch events or not.
voidsetVisible(bool vis)
Controls whether this Drawable should be visible.
virtual voidsetWidth(int16_t width)
Sets the width of this drawable.
voidsetWidthHeight(const Bitmap & bitmap)
Sets the dimensions (width and height) of the Drawable without changing the x and y coordinates).
voidsetWidthHeight(const Drawable & drawable)
Sets the dimensions (width and height) of the Drawable without changing the x and y coordinates).
voidsetWidthHeight(const Rect & rect)
Sets the dimensions (width and height) of the Drawable without changing the x and y coordinates).
voidsetWidthHeight(int16_t width, int16_t height)
Sets the dimensions (width and height) of the Drawable without changing the x and y coordinates).
virtual voidsetX(int16_t x)
Sets the x coordinate of this Drawable, relative to its parent.
voidsetXY(const Drawable & drawable)
Sets the x and y coordinates of this Drawable.
voidsetXY(int16_t x, int16_t y)
Sets the x and y coordinates of this Drawable, relative to its parent.
virtual voidsetY(int16_t y)
Sets the y coordinate of this Drawable, relative to its parent.
virtual voidtranslateRectToAbsolute(Rect & r) const
Helper function for converting a region of this Drawable to absolute coordinates.
virtual ~Drawable()
Finalizes an instance of the Drawable class.

Protected Attributes inherited from Drawable#

Drawable *nextSibling
Pointer to the next Drawable.
Drawable *parent
Pointer to this drawable's parent.
Rectrect
The coordinates of this Drawable, relative to its parent.
booltouchable
True if this drawable should receive touch events.
boolvisible
True if this drawable should be drawn.

Public Functions Documentation#

Button#

draw#

virtual void draw(const Rect &invalidatedArea)

Draw this drawable.

It is a requirement that the draw implementation does not draw outside the region specified by invalidatedArea.

Parameters:
invalidatedAreaThe sub-region of this drawable that needs to be redrawn, expressed in coordinates relative to its parent (e.g. for a complete redraw, invalidatedArea will be (0, 0, width, height).

Reimplements: touchgfx::Drawable::draw

Reimplemented by: touchgfx::ButtonWithLabel::draw, touchgfx::ButtonWithIcon::draw

getAlpha#

uint8_t getAlpha()const

Gets the current alpha value of the widget.

The alpha value is in range 255 (solid) to 0 (invisible).

Returns:

The current alpha value.

See also:

getCurrentlyDisplayedBitmap#

Gets currently displayed bitmap.

This depends on the current state of the button, released (normal) or pressed.

Returns:

The bitmap currently displayed.

getSolidRect#

virtual Rect getSolidRect()const

Get (the largest possible) rectangle that is guaranteed to be solid (opaque).

This information is important, as any Drawable underneath the solid area does not need to be drawn.

Returns:

The solid rectangle part of the Drawable.

Note

The rectangle returned must be relative to upper left corner of the Drawable, meaning that a completely solid widget should return the full size Rect(0, 0, getWidth(), getHeight()). If no area can be guaranteed to be solid, an empty Rect(0, 0, 0, 0) must be returned. Failing to return the correct rectangle may result in errors on the display.

Reimplements: touchgfx::Drawable::getSolidRect

setAlpha#

void setAlpha(uint8_tnewAlpha)

Sets the opacity (alpha value).

This can be used to fade it away by gradually decreasing the alpha value from 255 (solid) to 0 (invisible).

Parameters:
newAlphaThe new alpha value. 255=solid, 0=invisible.
Note

The user code must call invalidate() in order to update the display.

See also:

setBitmaps#

virtual void setBitmaps(const Bitmap &bitmapReleased ,
const Bitmap &bitmapPressed
)

Sets the two bitmaps used by this button.

One bitmap for the released (normal) state and one bitmap for the pressed state. The images are expected to be of the same dimensions, and the Button is resized to the dimensions of the pressed Bitmap.

Parameters:
bitmapReleasedBitmap to use when button is released.
bitmapPressedBitmap to use when button is pressed.
Note

It is assumed that the dimensions of the bitmaps are the same. Unexpected (visual) behavior may be observed if the bitmaps are of different sizes. The user code must call invalidate() in order to update the button on the display.

Reimplemented by: touchgfx::ToggleButton::setBitmaps

Protected Attributes Documentation#

alpha#

uint8_t alpha

The current alpha value. 255=solid, 0=invisible.

down#

Bitmap down

The image to display when button is pressed.

up#

Bitmap up

The image to display when button is released (normal state).