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Version: 4.16

ScalableImage

Widget for representing a scaled version of a bitmap. Simply change the width/height of the widget to resize the image. The quality of the scaled image depends of the rendering algorithm used. The rendering algorithm can be changed dynamically. Please note that scaling images is done at runtime and may require a lot of calculations.

Note: Note that this widget does not support 1 bit per pixel color depth.

Inherits from: Image, Widget, Drawable

Public Types#

enumScalingAlgorithm { NEAREST_NEIGHBOR, BILINEAR_INTERPOLATION }
Rendering algorithm to use when scaling the bitmap.

Public Functions#

virtual voiddraw(const Rect & invalidatedArea) const
Draw this drawable.
virtual ScalingAlgorithmgetScalingAlgorithm()
Gets the algorithm used when rendering.
virtual RectgetSolidRect() const
Get (the largest possible) rectangle that is guaranteed to be solid (opaque).
ScalableImage(const Bitmap & bitmap =Bitmap())
Constructs a new ScalableImage with a default alpha value of 255 (solid) and a default Bitmap (undefined) if none is specified.
virtual voidsetScalingAlgorithm(ScalingAlgorithm algorithm)
Sets the algorithm to be used.

Protected Attributes#

ScalingAlgorithmcurrentScalingAlgorithm
The current scaling algorithm.

Additional inherited members#

Public Functions inherited from Image#

uint8_tgetAlpha() const
Gets the current alpha value of the widget.
BitmapgetBitmap() const
Gets the Bitmap currently assigned to the Image widget.
BitmapIdgetBitmapId() const
Gets the BitmapId currently assigned to the Image widget.
Image(const Bitmap & bitmap =Bitmap())
Constructs a new Image with a default alpha value of 255 (solid) and a default Bitmap (undefined) if none is specified.
voidsetAlpha(uint8_t newAlpha)
Sets the opacity (alpha value).
virtual voidsetBitmap(const Bitmap & bitmap)
Sets the bitmap for this Image and updates the width and height of this widget to match those of the Bitmap.

Protected Attributes inherited from Image#

uint8_talpha
The Alpha for this image.
Bitmapbitmap
The Bitmap to display.

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 Types Documentation#

ScalingAlgorithm#

Rendering algorithm to use when scaling the bitmap.

NEAREST_NEIGHBORFast but not a very good image quality. Good for fast animations.
BILINEAR_INTERPOLATIONSlower but better image quality. Good for static representation of a scaled image.

Public Functions Documentation#

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::Image::draw

getScalingAlgorithm#

virtual ScalingAlgorithm getScalingAlgorithm()

Gets the algorithm used when rendering.

Returns:

The algorithm used when rendering.

See also:

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::Image::getSolidRect

ScalableImage#

ScalableImage(const Bitmap &bitmap =Bitmap())

Constructs a new ScalableImage with a default alpha value of 255 (solid) and a default Bitmap (undefined) if none is specified.

If a Bitmap is passed to the constructor, the width and height of this widget is set to those of the bitmap.

Parameters:
bitmap(Optional) The bitmap to display.
See also:

setScalingAlgorithm#

virtual void setScalingAlgorithm(ScalingAlgorithmalgorithm)

Sets the algorithm to be used.

In short, there is currently a value for fast (nearest neighbor) and a value for slow (bi-linear interpolation).

Parameters:
algorithmThe algorithm to use when rendering.
See also:

Protected Attributes Documentation#

currentScalingAlgorithm#

ScalingAlgorithm currentScalingAlgorithm

The current scaling algorithm.