OHOS::UICanvas

Overview

Related Modules:

Graphic

Description:

Defines a canvas, which is used to draw multiple types of 2D graphs.

Since:

1.0

Version:

1.0

Summary

Data Structures

Data Structure Name

Description

FontStyle

Defines the font style.

Public Member Functions

Public Member Function Name

Description

UICanvas ()

 

A constructor used to create a UICanvas instance.

~UICanvas ()

virtual 

A destructor used to delete the UICanvas instance.

GetViewType () const override

UIViewType 

Obtains the view type.

Clear ()

void 

Clears the entire canvas.

SetStartPosition (const Point &startPoint)

void 

Sets the coordinates of the start point for drawing a line. For example, if startPoint is set to {50, 50}, the line is drawn from this set of coordinates on the canvas.

GetStartPosition () const

const Point

Obtains the coordinates of the start point of a line.

DrawLine (const Point &endPoint, const Paint &paint)

void 

Draws a straight line.

DrawLine (const Point &startPoint, const Point &endPoint, const Paint &paint)

void 

Draws a straight line from the coordinates of the start point.

DrawCurve (const Point &control1, const Point &control2, const Point &endPoint, const Paint &paint)

void 

Draws a cubic Bezier curve.

DrawCurve (const Point &startPoint, const Point &control1, const Point &control2, const Point &endPoint, const Paint &paint)

void 

Draws a cubic Bezier curve from the start point coordinates.

DrawRect (const Point &startPoint, int16_t height, int16_t width, const Paint &paint)

void 

Draws a rectangle.

DrawCircle (const Point &center, uint16_t radius, const Paint &paint)

void 

Draws a circle.

DrawSector (const Point &center, uint16_t radius, int16_t startAngle, int16_t endAngle, const Paint &paint)

void 

Draws a sector.

DrawArc (const Point &center, uint16_t radius, int16_t startAngle, int16_t endAngle, const Paint &paint)

void 

Draws an arc.

DrawImage (const Point &startPoint, const char image, const Paint &paint)

void 

Draws an image.

DrawLabel (const Point &startPoint, const char text, uint16_t maxWidth, const FontStyle &fontStyle, const Paint &paint)

void 

Draws text.

OnDraw (const Rect &invalidatedArea) override

virtual void 

Called when a view is drawn.

UIView ()

 

A default constructor used to create an UIView instance.

UIView (const char id)

 

A constructor used to create an UIView instance.

~UIView ()

virtual 

A destructor used to delete the UIView instance.

OnPreDraw (const Rect &invalidatedArea)

virtual bool 

Called before a view is drawn. This function is used to check whether the parent view of this view needs to be redrawn so as to optimize the drawing process.

OnPostDraw (const Rect &invalidatedArea)

virtual void 

Called after a view is drawn.

ReMeasure ()

virtual void 

Remeasures the view size.

Invalidate ()

void 

Refreshes the invalidated area of the view.

InvalidateRect (const Rect &invalidatedArea)

void 

Refreshes a view in a specified invalidated area.

OnLongPressEvent (const LongPressEvent &event)

virtual bool 

Called when the view is long pressed.

OnDragStartEvent (const DragEvent &event)

virtual bool 

Called when the view starts to drag.

OnDragEvent (const DragEvent &event)

virtual bool 

Called when the view is being dragged.

OnDragEndEvent (const DragEvent &event)

virtual bool 

Called when the view stops dragging.

OnClickEvent (const ClickEvent &event)

virtual void 

Called when the view is clicked.

OnPressEvent (const PressEvent &event)

virtual void 

Called when the view is pressed.

OnReleaseEvent (const ReleaseEvent &event)

virtual void 

Called when the view is released.

OnCancelEvent (const CancelEvent &event)

virtual void 

Called when a click event on the view is canceled.

SetOnDragListener (OnDragListener onDragListener)

void 

Sets a drag event listener for the view.

GetOnDragListener ()

OnDragListener

Obtains the drag event listener for the view.

SetOnClickListener (OnClickListener onClickListener)

void 

Sets a click event listener for the view.

GetOnClickListener ()

OnClickListener

Obtains the click event listener for the view.

SetOnLongPressListener (OnLongPressListener onLongPressListener)

void 

Sets a long-press event listener for the view.

GetOnLongPressListener ()

OnLongPressListener

Obtains the long-press event listener for the view.

SetOnTouchListener (OnTouchListener onTouchListener)

void 

Sets a touch event listener for the view.

GetTouchListener ()

OnTouchListener

Obtains the touch event listener for the view.

GetTargetView (const Point &point, UIView **last)

virtual void 

Obtains the top-level view based on specified coordinates.

SetParent (UIView parent)

void 

Sets the parent view for the view.

GetParent () const

UIView  

Obtains the parent view of the view.

SetNextSibling (UIView sibling)

void 

Sets the next sibling view for the view.

GetNextSibling () const

UIView  

Obtains the next sibling view of the view.

SetVisible (bool visible)

virtual void 

Sets whether the view is visible.

IsVisible () const

bool 

Checks whether the view is visible.

SetTouchable (bool touch)

void 

Sets whether the view is touchable.

IsTouchable () const

bool 

Checks whether the view is touchable.

SetDraggable (bool draggable)

void 

Sets whether the view is draggable.

IsDraggable () const

bool 

Checks whether the view is draggable.

SetDragParentInstead (bool dragParentInstead)

void 

Sets whether to transfer the drag event to the parent view for processing when the view is being dragged.

IsDragParentInstead () const

bool 

Obtains whether the view transfers a drag event to the parent view for processing.

GetRect () const

Rect 

Obtains the absolute rectangle area of the view. When the view has deformation such as rotation, the rectangle area is the intersection set of the absolute rectangle area and deformation matrix.

GetVisibleRect () const

Rect 

Obtains the visible absolute rectangle area of the view.

GetMaskedRect () const

Rect 

Obtains the valid absolute rectangle area of the view. The valid area refers to the area where the view can be displayed. Generally, the valid area is the same as the visible view area, but they may be different in the grid layout.

GetOrigRect () const

Rect 

Obtains the absolute rectangle area of the view.

GetContentRect ()

virtual Rect 

Obtains the content of the absolute rectangle area of the view. This area excludes padding.

GetRelativeRect () const

Rect 

Obtains the rectangular area of the view relative to the parent view, that is, the rectangular area relative to the coordinates of the parent view.

ResizeVisibleArea (int16_t x, int16_t y, int16_t width, int16_t height)

void 

Adjusts the size of the visible area. This operation may affect the final display size.

SetWidth (int16_t width)

virtual void 

Sets the width for the view.

GetWidth ()

virtual int16_t 

Obtains the width for the view.

SetHeight (int16_t height)

virtual void 

Sets the height for the view.

GetHeight ()

virtual int16_t 

Obtains the height for the view.

Resize (int16_t width, int16_t height)

virtual void 

Adjusts the size of the view.

SetX (int16_t x)

virtual void 

Sets the x-coordinate for the view.

GetX () const

int16_t 

Obtains the x-coordinate for the view.

SetY (int16_t y)

virtual void 

Sets the y-coordinate for the view.

GetY () const

int16_t 

Obtains the y-coordinate for the view.

SetPosition (int16_t x, int16_t y)

virtual void 

Sets the position for the view.

SetPosition (int16_t x, int16_t y, int16_t width, int16_t height)

virtual void 

Adjusts the position and size of the view.

IsViewGroup () const

bool 

Checks whether the view is a container view.

SetIntercept (bool isIntercept)

void 

Sets whether to intercept the drag event. If intercepted, the view does not transfer the drag event to the parent view after local processing.

SetTransformMap (const TransformMap &transMap)

void 

Sets the affine transformation matrix.

GetTransformMap ()

TransformMap

Obtains an affine transformation matrix.

GetChildById (const char id) const

virtual UIView  

Obtains the child view of a specified ID.

SetViewId (const char id)

void 

Sets the view ID.

GetViewId () const

const char  

Obtains the view ID.

SetViewIndex (int16_t index)

void 

Sets the view index.

GetViewIndex () const

int16_t 

Obtains the view index.

LayoutChildren (bool neeInvalidate=false)

virtual void 

Lays out all child views according to the preset arrangement mode.

LayoutCenterOfParent (int16_t xOffSet=0, int16_t yOffset=0)

void 

Lays out the view in the center of the parent view.

LayoutLeftOfParent (int16_t offset=0)

void 

Lays out the view on the left of the parent view.

LayoutRightOfParent (int16_t offset=0)

void 

Lays out the view on the right of the parent view.

LayoutTopOfParent (int16_t offset=0)

void 

Lays out the view on the top of the parent view.

LayoutBottomOfParent (int16_t offset=0)

void 

Lays out the view on the bottom of the parent view.

AlignLeftToSibling (const char id, int16_t offset=0)

void 

Aligns the view with the left of a sibling view.

AlignRightToSibling (const char id, int16_t offset=0)

void 

Aligns the view with the right of a sibling view.

AlignTopToSibling (const char id, int16_t offset=0)

void 

Aligns the view with the top of a sibling view.

AlignBottomToSibling (const char id, int16_t offset=0)

void 

Aligns the view with the bottom of a sibling view.

AlignHorCenterToSibling (const char id, int16_t offset=0)

void 

Aligns the view with the center of a sibling view in the x-axis.

AlignVerCenterToSibling (const char id, int16_t offset=0)

void 

Aligns the view with the center of a sibling view in the y-axis.

LayoutLeftToSibling (const char id, int16_t offset=0)

void 

Lays out the view on the left of a sibling view.

LayoutRightToSibling (const char id, int16_t offset=0)

void 

Lays out the view on the right of a sibling view.

LayoutTopToSibling (const char id, int16_t offset=0)

void 

Lays out the view on the above of a sibling view.

LayoutBottomToSibling (const char id, int16_t offset=0)

void 

Lays out the view on the below of a sibling view.

SetStyle (Style &style)

virtual void 

Sets the view style.

SetStyle (uint8_t key, int64_t value)

virtual void 

Sets a style.

GetStyle (uint8_t key) const

virtual int64_t 

Obtains the value of a style.

GetStyleConst () const

const Style

Obtains the view style. This function applies to scenarios where the style does not need to be modified, which saves memory.

operator new (size_t size)

void  

Overrides the new function.

operator delete (void *p)

void 

Overrides the delete function.