OHOS::UICanvas

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.