ScalableImage
touchgfx/widgets/ScalableImage.hpp
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
| enum | ScalingAlgorithm { NEAREST_NEIGHBOR, BILINEAR_INTERPOLATION } |
| Rendering algorithm to use when scaling the bitmap. | |
Public Functions
| virtual void | draw(const Rect & invalidatedArea) const |
| Draw this drawable. | |
| virtual ScalingAlgorithm | getScalingAlgorithm() |
| Gets the algorithm used when rendering. | |
| virtual Rect | getSolidRect() const |
| Get (the largest possible) rectangle that is guaranteed to be solid (opaque). | |
| ScalableImage(const Bitmap & bmp =Bitmap()) | |
| Constructs a new ScalableImage with a default alpha value of 255 (solid) and a default Bitmap (undefined) if none is specified. | |
| virtual void | setScalingAlgorithm(ScalingAlgorithm algorithm) |
| Sets the algorithm to be used. | |
Protected Attributes
| ScalingAlgorithm | currentScalingAlgorithm |
| The current scaling algorithm. | |
Additional inherited members
Public Functions inherited from Image
| uint8_t | getAlpha() const |
| Gets the current alpha value of the widget. | |
| Bitmap | getBitmap() const |
| Gets the Bitmap currently assigned to the Image widget. | |
| BitmapId | getBitmapId() const |
| Gets the BitmapId currently assigned to the Image widget. | |
| Image(const Bitmap & bmp =Bitmap()) | |
| Constructs a new Image with a default alpha value of 255 (solid) and a default Bitmap (undefined) if none is specified. | |
| virtual void | invalidateContent() const |
| Tell the framework that the contents of the Drawable needs to be redrawn. | |
| void | setAlpha(uint8_t newAlpha) |
| Sets the opacity (alpha value). | |
| virtual void | setBitmap(const Bitmap & bmp) |
| 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
Public Functions inherited from Widget
| virtual void | getLastChild(int16_t , int16_t , 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
| void | center() |
| Centers the Drawable inside its parent. | |
| void | centerX() |
| Center the Drawable horizontally inside its parent. | |
| void | centerY() |
| Center the Drawable vertically inside its parent. | |
| virtual void | childGeometryChanged() |
| 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. | |
| void | drawToDynamicBitmap(BitmapId id) |
| Render the Drawable object into a dynamic bitmap. | |
| void | expand(int margin =0) |
| Expands the Drawable to have the same size as its parent with a given margin around the edge. | |
| Rect | getAbsoluteRect() 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_t | getHeight() const |
| Gets the height of this Drawable. | |
| virtual void | getLastChild(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 Rect | getSolidRectAbsolute() |
| Helper function for obtaining the largest solid rect (as implemented by getSolidRect()) expressed in absolute coordinates. | |
| virtual void | getVisibleRect(Rect & rect) const |
| Function for finding the visible part of this drawable. | |
| int16_t | getWidth() const |
| Gets the width of this Drawable. | |
| int16_t | getX() const |
| Gets the x coordinate of this Drawable, relative to its parent. | |
| int16_t | getY() const |
| Gets the y coordinate of this Drawable, relative to its parent. | |
| virtual void | handleClickEvent(const ClickEvent & event) |
| Defines the event handler interface for ClickEvents. | |
| virtual void | handleDragEvent(const DragEvent & event) |
| Defines the event handler interface for DragEvents. | |
| virtual void | handleGestureEvent(const GestureEvent & event) |
| Defines the event handler interface for GestureEvents. | |
| virtual void | handleTickEvent() |
| Called periodically by the framework if the Drawable instance has subscribed to timer ticks. | |
| virtual void | invalidate() const |
| Tell the framework that this entire Drawable needs to be redrawn. | |
| virtual void | invalidateContent() const |
| Tell the framework that the contents of the Drawable needs to be redrawn. | |
| virtual void | invalidateRect(Rect & invalidatedArea) const |
| Request that a region of this drawable is redrawn. | |
| bool | isTouchable() const |
| Gets whether this Drawable receives touch events or not. | |
| bool | isVisible() const |
| Gets whether this Drawable is visible. | |
| virtual void | moveRelative(int16_t x, int16_t y) |
| Moves the drawable. | |
| virtual void | moveTo(int16_t x, int16_t y) |
| Moves the drawable. | |
| virtual void | setHeight(int16_t height) |
| Sets the height of this drawable. | |
| void | setPosition(const Drawable & drawable) |
| Sets the position of the Drawable to the same as the given Drawable. | |
| void | setPosition(int16_t x, int16_t y, int16_t width, int16_t height) |
| Sets the size and position of this Drawable, relative to its parent. | |
| void | setTouchable(bool touch) |
| Controls whether this Drawable receives touch events or not. | |
| void | setVisible(bool vis) |
| Controls whether this Drawable should be visible. | |
| virtual void | setWidth(int16_t width) |
| Sets the width of this drawable. | |
| void | setWidthHeight(const Bitmap & bitmap) |
| Sets the dimensions (width and height) of the Drawable without changing the x and y coordinates). | |
| void | setWidthHeight(const Drawable & drawable) |
| Sets the dimensions (width and height) of the Drawable without changing the x and y coordinates). | |
| void | setWidthHeight(const Rect & other) |
| Sets the dimensions (width and height) of the Drawable without changing the x and y coordinates). | |
| void | setWidthHeight(int16_t width, int16_t height) |
| Sets the dimensions (width and height) of the Drawable without changing the x and y coordinates). | |
| virtual void | setX(int16_t x) |
| Sets the x coordinate of this Drawable, relative to its parent. | |
| void | setXY(const Drawable & drawable) |
| Sets the x and y coordinates of this Drawable. | |
| void | setXY(int16_t x, int16_t y) |
| Sets the x and y coordinates of this Drawable, relative to its parent. | |
| virtual void | setY(int16_t y) |
| Sets the y coordinate of this Drawable, relative to its parent. | |
| virtual void | translateRectToAbsolute(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. | |
| Rect | rect |
| The coordinates of this Drawable, relative to its parent. | |
| bool | touchable |
| True if this drawable should receive touch events. | |
| bool | visible |
| True if this drawable should be drawn. | |
Public Types Documentation
ScalingAlgorithm
enum ScalingAlgorithm
Rendering algorithm to use when scaling the bitmap.
| NEAREST_NEIGHBOR | Fast but not a very good image quality. Good for fast animations. |
| BILINEAR_INTERPOLATION | Slower but better image quality. Good for static representation of a scaled image. |
Public Functions Documentation
draw
Draw this drawable.
It is a requirement that the draw implementation does not draw outside the region specified by invalidatedArea.
Parameters:
| invalidatedArea | The 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 must be returned. Failing to return the correct rectangle may result in errors on the display.
Reimplements: touchgfx::Image::getSolidRect
ScalableImage
| ScalableImage | ( | const Bitmap & | bmp =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:
| bmp | (Optional) The bitmap to display. |
See also:
setScalingAlgorithm
| virtual void setScalingAlgorithm | ( | ScalingAlgorithm | algorithm | ) | |
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:
| algorithm | The algorithm to use when rendering. |
See also:
Protected Attributes Documentation
currentScalingAlgorithm
ScalingAlgorithm currentScalingAlgorithm
The current scaling algorithm.