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Viewport Class Reference

A Viewport is used to contain a larger child component, and allows the child to be automatically scrolled around. More...

Inherits Component, ComponentListener, and ScrollBar::Listener.

Public Member Functions

 Viewport (const String &componentName=String::empty)
 Creates a Viewport.
 
 ~Viewport ()
 Destructor.
 
void setViewedComponent (Component *newViewedComponent, bool deleteComponentWhenNoLongerNeeded=true)
 Sets the component that this viewport will contain and scroll around.
 
ComponentgetViewedComponent () const noexcept
 Returns the component that's currently being used inside the Viewport.
 
void setViewPosition (int xPixelsOffset, int yPixelsOffset)
 Changes the position of the viewed component.
 
void setViewPosition (Point< int > newPosition)
 Changes the position of the viewed component.
 
void setViewPositionProportionately (double proportionX, double proportionY)
 Changes the view position as a proportion of the distance it can move.
 
bool autoScroll (int mouseX, int mouseY, int distanceFromEdge, int maximumSpeed)
 If the specified position is at the edges of the viewport, this method scrolls the viewport to bring that position nearer to the centre.
 
Point< int > getViewPosition () const noexcept
 Returns the position within the child component of the top-left of its visible area.
 
Rectangle< int > getViewArea () const noexcept
 Returns the visible area of the child component, relative to its top-left.
 
int getViewPositionX () const noexcept
 Returns the position within the child component of the top-left of its visible area.
 
int getViewPositionY () const noexcept
 Returns the position within the child component of the top-left of its visible area.
 
int getViewWidth () const noexcept
 Returns the width of the visible area of the child component.
 
int getViewHeight () const noexcept
 Returns the height of the visible area of the child component.
 
int getMaximumVisibleWidth () const
 Returns the width available within this component for the contents.
 
int getMaximumVisibleHeight () const
 Returns the height available within this component for the contents.
 
virtual void visibleAreaChanged (const Rectangle< int > &newVisibleArea)
 Callback method that is called when the visible area changes.
 
virtual void viewedComponentChanged (Component *newComponent)
 Callback method that is called when the viewed component is added, removed or swapped.
 
void setScrollBarsShown (bool showVerticalScrollbarIfNeeded, bool showHorizontalScrollbarIfNeeded, bool allowVerticalScrollingWithoutScrollbar=false, bool allowHorizontalScrollingWithoutScrollbar=false)
 Turns scrollbars on or off.
 
bool isVerticalScrollBarShown () const noexcept
 True if the vertical scrollbar is enabled.
 
bool isHorizontalScrollBarShown () const noexcept
 True if the horizontal scrollbar is enabled.
 
void setScrollBarThickness (int thickness)
 Changes the width of the scrollbars.
 
int getScrollBarThickness () const
 Returns the thickness of the scrollbars.
 
void setSingleStepSizes (int stepX, int stepY)
 Changes the distance that a single-step click on a scrollbar button will move the viewport.
 
ScrollBargetVerticalScrollBar () noexcept
 Returns a pointer to the scrollbar component being used.
 
ScrollBargetHorizontalScrollBar () noexcept
 Returns a pointer to the scrollbar component being used.
 
void resized () override
 
void scrollBarMoved (ScrollBar *, double newRangeStart) override
 
void mouseWheelMove (const MouseEvent &, const MouseWheelDetails &) override
 
bool keyPressed (const KeyPress &) override
 
void componentMovedOrResized (Component &, bool wasMoved, bool wasResized) override
 
bool useMouseWheelMoveIfNeeded (const MouseEvent &, const MouseWheelDetails &)
 
- Public Member Functions inherited from Component
 Component () noexcept
 Creates a component.
 
virtual ~Component ()
 Destructor.
 
 Component (const String &componentName) noexcept
 Creates a component, setting its name at the same time.
 
const StringgetName () const noexcept
 Returns the name of this component.
 
virtual void setName (const String &newName)
 Sets the name of this component.
 
const StringgetComponentID () const noexcept
 Returns the ID string that was set by setComponentID().
 
void setComponentID (const String &newID)
 Sets the component's ID string.
 
virtual void setVisible (bool shouldBeVisible)
 Makes the component visible or invisible.
 
bool isVisible () const noexcept
 Tests whether the component is visible or not.
 
virtual void visibilityChanged ()
 Called when this component's visibility changes.
 
bool isShowing () const
 Tests whether this component and all its parents are visible.
 
virtual void addToDesktop (int windowStyleFlags, void *nativeWindowToAttachTo=nullptr)
 Makes this component appear as a window on the desktop.
 
void removeFromDesktop ()
 If the component is currently showing on the desktop, this will hide it.
 
bool isOnDesktop () const noexcept
 Returns true if this component is currently showing on the desktop.
 
ComponentPeergetPeer () const
 Returns the heavyweight window that contains this component.
 
virtual void userTriedToCloseWindow ()
 For components on the desktop, this is called if the system wants to close the window.
 
virtual void minimisationStateChanged (bool isNowMinimised)
 Called for a desktop component which has just been minimised or un-minimised.
 
virtual float getDesktopScaleFactor () const
 Returns the default scale factor to use for this component when it is placed on the desktop.
 
void toFront (bool shouldAlsoGainFocus)
 Brings the component to the front of its siblings.
 
void toBack ()
 Changes this component's z-order to be at the back of all its siblings.
 
void toBehind (Component *other)
 Changes this component's z-order so that it's just behind another component.
 
void setAlwaysOnTop (bool shouldStayOnTop)
 Sets whether the component should always be kept at the front of its siblings.
 
bool isAlwaysOnTop () const noexcept
 Returns true if this component is set to always stay in front of its siblings.
 
int getX () const noexcept
 Returns the x coordinate of the component's left edge.
 
int getY () const noexcept
 Returns the y coordinate of the top of this component.
 
int getWidth () const noexcept
 Returns the component's width in pixels.
 
int getHeight () const noexcept
 Returns the component's height in pixels.
 
int getRight () const noexcept
 Returns the x coordinate of the component's right-hand edge.
 
Point< int > getPosition () const noexcept
 Returns the component's top-left position as a Point.
 
int getBottom () const noexcept
 Returns the y coordinate of the bottom edge of this component.
 
const Rectangle< int > & getBounds () const noexcept
 Returns this component's bounding box.
 
Rectangle< int > getLocalBounds () const noexcept
 Returns the component's bounds, relative to its own origin.
 
Rectangle< int > getBoundsInParent () const noexcept
 Returns the area of this component's parent which this component covers.
 
int getScreenX () const
 Returns this component's x coordinate relative the screen's top-left origin.
 
int getScreenY () const
 Returns this component's y coordinate relative the screen's top-left origin.
 
Point< int > getScreenPosition () const
 Returns the position of this component's top-left corner relative to the screen's top-left.
 
Rectangle< int > getScreenBounds () const
 Returns the bounds of this component, relative to the screen's top-left.
 
Point< int > getLocalPoint (const Component *sourceComponent, Point< int > pointRelativeToSourceComponent) const
 Converts a point to be relative to this component's coordinate space.
 
Point< float > getLocalPoint (const Component *sourceComponent, Point< float > pointRelativeToSourceComponent) const
 Converts a point to be relative to this component's coordinate space.
 
Rectangle< int > getLocalArea (const Component *sourceComponent, const Rectangle< int > &areaRelativeToSourceComponent) const
 Converts a rectangle to be relative to this component's coordinate space.
 
Point< int > localPointToGlobal (Point< int > localPoint) const
 Converts a point relative to this component's top-left into a screen coordinate.
 
Point< float > localPointToGlobal (Point< float > localPoint) const
 Converts a point relative to this component's top-left into a screen coordinate.
 
Rectangle< int > localAreaToGlobal (const Rectangle< int > &localArea) const
 Converts a rectangle from this component's coordinate space to a screen coordinate.
 
void setTopLeftPosition (int x, int y)
 Moves the component to a new position.
 
void setTopLeftPosition (Point< int > newTopLeftPosition)
 Moves the component to a new position.
 
void setTopRightPosition (int x, int y)
 Moves the component to a new position.
 
void setSize (int newWidth, int newHeight)
 Changes the size of the component.
 
void setBounds (int x, int y, int width, int height)
 Changes the component's position and size.
 
void setBounds (const Rectangle< int > &newBounds)
 Changes the component's position and size.
 
void setBounds (const RelativeRectangle &newBounds)
 Changes the component's position and size.
 
void setBounds (const String &newBoundsExpression)
 Sets the component's bounds with an expression.
 
void setBoundsRelative (float proportionalX, float proportionalY, float proportionalWidth, float proportionalHeight)
 Changes the component's position and size in terms of fractions of its parent's size.
 
void setBoundsInset (const BorderSize< int > &borders)
 Changes the component's position and size based on the amount of space to leave around it.
 
void setBoundsToFit (int x, int y, int width, int height, Justification justification, bool onlyReduceInSize)
 Positions the component within a given rectangle, keeping its proportions unchanged.
 
void setCentrePosition (int x, int y)
 Changes the position of the component's centre.
 
void setCentreRelative (float x, float y)
 Changes the position of the component's centre.
 
void centreWithSize (int width, int height)
 Changes the component's size and centres it within its parent.
 
void setTransform (const AffineTransform &transform)
 Sets a transform matrix to be applied to this component.
 
AffineTransform getTransform () const
 Returns the transform that is currently being applied to this component.
 
bool isTransformed () const noexcept
 Returns true if a non-identity transform is being applied to this component.
 
int proportionOfWidth (float proportion) const noexcept
 Returns a proportion of the component's width.
 
int proportionOfHeight (float proportion) const noexcept
 Returns a proportion of the component's height.
 
int getParentWidth () const noexcept
 Returns the width of the component's parent.
 
int getParentHeight () const noexcept
 Returns the height of the component's parent.
 
Rectangle< int > getParentMonitorArea () const
 Returns the screen coordinates of the monitor that contains this component.
 
int getNumChildComponents () const noexcept
 Returns the number of child components that this component contains.
 
ComponentgetChildComponent (int index) const noexcept
 Returns one of this component's child components, by it index.
 
int getIndexOfChildComponent (const Component *child) const noexcept
 Returns the index of this component in the list of child components.
 
ComponentfindChildWithID (StringRef componentID) const noexcept
 Looks for a child component with the specified ID.
 
void addChildComponent (Component *child, int zOrder=-1)
 Adds a child component to this one.
 
void addChildComponent (Component &child, int zOrder=-1)
 Adds a child component to this one.
 
void addAndMakeVisible (Component *child, int zOrder=-1)
 Adds a child component to this one, and also makes the child visible if it isn't already.
 
void addAndMakeVisible (Component &child, int zOrder=-1)
 Adds a child component to this one, and also makes the child visible if it isn't already.
 
void addChildAndSetID (Component *child, const String &componentID)
 Adds a child component to this one, makes it visible, and sets its component ID.
 
void removeChildComponent (Component *childToRemove)
 Removes one of this component's child-components.
 
ComponentremoveChildComponent (int childIndexToRemove)
 Removes one of this component's child-components by index.
 
void removeAllChildren ()
 Removes all this component's children.
 
void deleteAllChildren ()
 Removes all this component's children, and deletes them.
 
ComponentgetParentComponent () const noexcept
 Returns the component which this component is inside.
 
template<class TargetClass >
TargetClass * findParentComponentOfClass () const
 Searches the parent components for a component of a specified class.
 
ComponentgetTopLevelComponent () const noexcept
 Returns the highest-level component which contains this one or its parents.
 
bool isParentOf (const Component *possibleChild) const noexcept
 Checks whether a component is anywhere inside this component or its children.
 
virtual void parentHierarchyChanged ()
 Called to indicate that the component's parents have changed.
 
virtual void childrenChanged ()
 Subclasses can use this callback to be told when children are added or removed, or when their z-order changes.
 
virtual bool hitTest (int x, int y)
 Tests whether a given point inside the component.
 
void setInterceptsMouseClicks (bool allowClicksOnThisComponent, bool allowClicksOnChildComponents) noexcept
 Changes the default return value for the hitTest() method.
 
void getInterceptsMouseClicks (bool &allowsClicksOnThisComponent, bool &allowsClicksOnChildComponents) const noexcept
 Retrieves the current state of the mouse-click interception flags.
 
bool contains (Point< int > localPoint)
 Returns true if a given point lies within this component or one of its children.
 
bool reallyContains (Point< int > localPoint, bool returnTrueIfWithinAChild)
 Returns true if a given point lies in this component, taking any overlapping siblings into account.
 
ComponentgetComponentAt (int x, int y)
 Returns the component at a certain point within this one.
 
ComponentgetComponentAt (Point< int > position)
 Returns the component at a certain point within this one.
 
void repaint ()
 Marks the whole component as needing to be redrawn.
 
void repaint (int x, int y, int width, int height)
 Marks a subsection of this component as needing to be redrawn.
 
void repaint (const Rectangle< int > &area)
 Marks a subsection of this component as needing to be redrawn.
 
void setBufferedToImage (bool shouldBeBuffered)
 Makes the component use an internal buffer to optimise its redrawing.
 
Image createComponentSnapshot (const Rectangle< int > &areaToGrab, bool clipImageToComponentBounds=true, float scaleFactor=1.0f)
 Generates a snapshot of part of this component.
 
void paintEntireComponent (Graphics &context, bool ignoreAlphaLevel)
 Draws this component and all its subcomponents onto the specified graphics context.
 
void setPaintingIsUnclipped (bool shouldPaintWithoutClipping) noexcept
 This allows you to indicate that this component doesn't require its graphics context to be clipped when it is being painted.
 
void setComponentEffect (ImageEffectFilter *newEffect)
 Adds an effect filter to alter the component's appearance.
 
ImageEffectFiltergetComponentEffect () const noexcept
 Returns the current component effect.
 
LookAndFeelgetLookAndFeel () const noexcept
 Finds the appropriate look-and-feel to use for this component.
 
void setLookAndFeel (LookAndFeel *newLookAndFeel)
 Sets the look and feel to use for this component.
 
virtual void lookAndFeelChanged ()
 Called to let the component react to a change in the look-and-feel setting.
 
void sendLookAndFeelChange ()
 Calls the lookAndFeelChanged() method in this component and all its children.
 
void setOpaque (bool shouldBeOpaque)
 Indicates whether any parts of the component might be transparent.
 
bool isOpaque () const noexcept
 Returns true if no parts of this component are transparent.
 
void setBroughtToFrontOnMouseClick (bool shouldBeBroughtToFront) noexcept
 Indicates whether the component should be brought to the front when clicked.
 
bool isBroughtToFrontOnMouseClick () const noexcept
 Indicates whether the component should be brought to the front when clicked-on.
 
void setWantsKeyboardFocus (bool wantsFocus) noexcept
 Sets a flag to indicate whether this component needs keyboard focus or not.
 
bool getWantsKeyboardFocus () const noexcept
 Returns true if the component is interested in getting keyboard focus.
 
void setMouseClickGrabsKeyboardFocus (bool shouldGrabFocus)
 Chooses whether a click on this component automatically grabs the focus.
 
bool getMouseClickGrabsKeyboardFocus () const noexcept
 Returns the last value set with setMouseClickGrabsKeyboardFocus().
 
void grabKeyboardFocus ()
 Tries to give keyboard focus to this component.
 
bool hasKeyboardFocus (bool trueIfChildIsFocused) const
 Returns true if this component currently has the keyboard focus.
 
void moveKeyboardFocusToSibling (bool moveToNext)
 Tries to move the keyboard focus to one of this component's siblings.
 
virtual KeyboardFocusTraversercreateFocusTraverser ()
 Creates a KeyboardFocusTraverser object to use to determine the logic by which focus should be passed from this component.
 
int getExplicitFocusOrder () const
 Returns the focus order of this component, if one has been specified.
 
void setExplicitFocusOrder (int newFocusOrderIndex)
 Sets the index used in determining the order in which focusable components should be traversed.
 
void setFocusContainer (bool shouldBeFocusContainer) noexcept
 Indicates whether this component is a parent for components that can have their focus traversed.
 
bool isFocusContainer () const noexcept
 Returns true if this component has been marked as a focus container.
 
bool isEnabled () const noexcept
 Returns true if the component (and all its parents) are enabled.
 
void setEnabled (bool shouldBeEnabled)
 Enables or disables this component.
 
virtual void enablementChanged ()
 Callback to indicate that this component has been enabled or disabled.
 
void setAlpha (float newAlpha)
 Changes the transparency of this component.
 
float getAlpha () const
 Returns the component's current transparancy level.
 
void setMouseCursor (const MouseCursor &cursorType)
 Changes the mouse cursor shape to use when the mouse is over this component.
 
virtual MouseCursor getMouseCursor ()
 Returns the mouse cursor shape to use when the mouse is over this component.
 
void updateMouseCursor () const
 Forces the current mouse cursor to be updated.
 
virtual void paint (Graphics &g)
 Components can override this method to draw their content.
 
virtual void paintOverChildren (Graphics &g)
 Components can override this method to draw over the top of their children.
 
virtual void mouseMove (const MouseEvent &event) override
 Called when the mouse moves inside a component.
 
virtual void mouseEnter (const MouseEvent &event) override
 Called when the mouse first enters a component.
 
virtual void mouseExit (const MouseEvent &event) override
 Called when the mouse moves out of a component.
 
virtual void mouseDown (const MouseEvent &event) override
 Called when a mouse button is pressed.
 
virtual void mouseDrag (const MouseEvent &event) override
 Called when the mouse is moved while a button is held down.
 
virtual void mouseUp (const MouseEvent &event) override
 Called when a mouse button is released.
 
virtual void mouseDoubleClick (const MouseEvent &event) override
 Called when a mouse button has been double-clicked on a component.
 
virtual void mouseMagnify (const MouseEvent &event, float scaleFactor)
 Called when a pinch-to-zoom mouse-gesture is used.
 
void setRepaintsOnMouseActivity (bool shouldRepaint) noexcept
 Causes automatic repaints when the mouse enters or exits this component.
 
void addMouseListener (MouseListener *newListener, bool wantsEventsForAllNestedChildComponents)
 Registers a listener to be told when mouse events occur in this component.
 
void removeMouseListener (MouseListener *listenerToRemove)
 Deregisters a mouse listener.
 
void addKeyListener (KeyListener *newListener)
 Adds a listener that wants to hear about keypresses that this component receives.
 
void removeKeyListener (KeyListener *listenerToRemove)
 Removes a previously-registered key listener.
 
virtual bool keyStateChanged (bool isKeyDown)
 Called when a key is pressed or released.
 
virtual void modifierKeysChanged (const ModifierKeys &modifiers)
 Called when a modifier key is pressed or released.
 
virtual void focusGained (FocusChangeType cause)
 Called to indicate that this component has just acquired the keyboard focus.
 
virtual void focusLost (FocusChangeType cause)
 Called to indicate that this component has just lost the keyboard focus.
 
virtual void focusOfChildComponentChanged (FocusChangeType cause)
 Called to indicate that one of this component's children has been focused or unfocused.
 
bool isMouseOver (bool includeChildren=false) const
 Returns true if the mouse is currently over this component.
 
bool isMouseButtonDown () const
 Returns true if the mouse button is currently held down in this component.
 
bool isMouseOverOrDragging () const
 True if the mouse is over this component, or if it's being dragged in this component.
 
Point< int > getMouseXYRelative () const
 Returns the mouse's current position, relative to this component.
 
virtual void moved ()
 Called when this component's position has been changed.
 
virtual void childBoundsChanged (Component *child)
 Called when one of this component's children is moved or resized.
 
virtual void parentSizeChanged ()
 Called when this component's immediate parent has been resized.
 
virtual void broughtToFront ()
 Called when this component has been moved to the front of its siblings.
 
void addComponentListener (ComponentListener *newListener)
 Adds a listener to be told about changes to the component hierarchy or position.
 
void removeComponentListener (ComponentListener *listenerToRemove)
 Removes a component listener.
 
void postCommandMessage (int commandId)
 Dispatches a numbered message to this component.
 
virtual void handleCommandMessage (int commandId)
 Called to handle a command that was sent by postCommandMessage().
 
void enterModalState (bool takeKeyboardFocus=true, ModalComponentManager::Callback *callback=nullptr, bool deleteWhenDismissed=false)
 Runs a component modally, waiting until the loop terminates.
 
void exitModalState (int returnValue)
 Ends a component's modal state.
 
bool isCurrentlyModal () const noexcept
 Returns true if this component is the modal one.
 
bool isCurrentlyBlockedByAnotherModalComponent () const
 Checks whether there's a modal component somewhere that's stopping this one from receiving messages.
 
virtual bool canModalEventBeSentToComponent (const Component *targetComponent)
 When a component is modal, this callback allows it to choose which other components can still receive events.
 
virtual void inputAttemptWhenModal ()
 Called when the user tries to click on a component that is blocked by another modal component.
 
NamedValueSetgetProperties () noexcept
 Returns the set of properties that belong to this component.
 
const NamedValueSetgetProperties () const noexcept
 Returns the set of properties that belong to this component.
 
Colour findColour (int colourId, bool inheritFromParent=false) const
 Looks for a colour that has been registered with the given colour ID number.
 
void setColour (int colourId, Colour newColour)
 Registers a colour to be used for a particular purpose.
 
void removeColour (int colourId)
 If a colour has been set with setColour(), this will remove it.
 
bool isColourSpecified (int colourId) const
 Returns true if the specified colour ID has been explicitly set for this component using the setColour() method.
 
void copyAllExplicitColoursTo (Component &target) const
 This looks for any colours that have been specified for this component, and copies them to the specified target component.
 
virtual void colourChanged ()
 This method is called when a colour is changed by the setColour() method.
 
virtual MarkerListgetMarkers (bool xAxis)
 Components can implement this method to provide a MarkerList.
 
void * getWindowHandle () const
 Returns the underlying native window handle for this component.
 
PositionergetPositioner () const noexcept
 Returns the Positioner object that has been set for this component.
 
void setPositioner (Positioner *newPositioner)
 Sets a new Positioner object for this component.
 
void setCachedComponentImage (CachedComponentImage *newCachedImage)
 Gives the component a CachedComponentImage that should be used to buffer its painting.
 
CachedComponentImagegetCachedComponentImage () const noexcept
 Returns the object that was set by setCachedComponentImage().
 
 JUCE_DEPRECATED (Point< int > relativePositionToGlobal(Point< int >) const)
 
 JUCE_DEPRECATED (Point< int > globalPositionToRelative(Point< int >) const)
 
 JUCE_DEPRECATED (Point< int > relativePositionToOtherComponent(const Component *, Point< int >) const)
 
- Public Member Functions inherited from MouseListener
virtual ~MouseListener ()
 Destructor.
 

Static Public Member Functions

static bool respondsToKey (const KeyPress &)
 
- Static Public Member Functions inherited from Component
static Component *JUCE_CALLTYPE getCurrentlyFocusedComponent () noexcept
 Returns the component that currently has the keyboard focus.
 
static void JUCE_CALLTYPE unfocusAllComponents ()
 If any component has keyboard focus, this will defocus it.
 
static void JUCE_CALLTYPE beginDragAutoRepeat (int millisecondsBetweenCallbacks)
 Ensures that a non-stop stream of mouse-drag events will be sent during the current mouse-drag operation.
 
static bool JUCE_CALLTYPE isMouseButtonDownAnywhere () noexcept
 Returns true if a mouse button is currently down.
 
static int JUCE_CALLTYPE getNumCurrentlyModalComponents () noexcept
 Returns the number of components that are currently in a modal state.
 
static Component *JUCE_CALLTYPE getCurrentlyModalComponent (int index=0) noexcept
 Returns one of the components that are currently modal.
 

Additional Inherited Members

- Public Types inherited from Component
enum  FocusChangeType { focusChangedByMouseClick, focusChangedByTabKey, focusChangedDirectly }
 Enumeration used by the focusChanged() and focusLost() methods. More...
 
- Private Member Functions inherited from ComponentListener
virtual ~ComponentListener ()
 Destructor.
 
virtual void componentBroughtToFront (Component &component)
 Called when the component is brought to the top of the z-order.
 
virtual void componentVisibilityChanged (Component &component)
 Called when the component is made visible or invisible.
 
virtual void componentChildrenChanged (Component &component)
 Called when the component has children added or removed, or their z-order changes.
 
virtual void componentParentHierarchyChanged (Component &component)
 Called to indicate that the component's parents have changed.
 
virtual void componentNameChanged (Component &component)
 Called when the component's name is changed.
 
virtual void componentBeingDeleted (Component &component)
 Called when the component is in the process of being deleted.
 
- Private Member Functions inherited from ScrollBar::Listener
virtual ~Listener ()
 Destructor.
 

Detailed Description

A Viewport is used to contain a larger child component, and allows the child to be automatically scrolled around.

To use a Viewport, just create one and set the component that goes inside it using the setViewedComponent() method. When the child component changes size, the Viewport will adjust its scrollbars accordingly.

A subclass of the viewport can be created which will receive calls to its visibleAreaChanged() method when the subcomponent changes position or size.

Constructor & Destructor Documentation

Viewport::Viewport ( const String componentName = String::empty)
explicit

Creates a Viewport.

The viewport is initially empty - use the setViewedComponent() method to add a child component for it to manage.

Viewport::~Viewport ( )

Destructor.

Member Function Documentation

void Viewport::setViewedComponent ( Component newViewedComponent,
bool  deleteComponentWhenNoLongerNeeded = true 
)

Sets the component that this viewport will contain and scroll around.

This will add the given component to this Viewport and position it at (0, 0).

(Don't add or remove any child components directly using the normal Component::addChildComponent() methods).

Parameters
newViewedComponentthe component to add to this viewport, or null to remove the current component.
deleteComponentWhenNoLongerNeededif true, the component will be deleted automatically when the viewport is deleted or when a different component is added. If false, the caller must manage the lifetime of the component
See Also
getViewedComponent
Component* Viewport::getViewedComponent ( ) const
noexcept

Returns the component that's currently being used inside the Viewport.

See Also
setViewedComponent
void Viewport::setViewPosition ( int  xPixelsOffset,
int  yPixelsOffset 
)

Changes the position of the viewed component.

The inner component will be moved so that the pixel at the top left of the viewport will be the pixel at position (xPixelsOffset, yPixelsOffset) within the inner component.

This will update the scrollbars and might cause a call to visibleAreaChanged().

See Also
getViewPositionX, getViewPositionY, setViewPositionProportionately
void Viewport::setViewPosition ( Point< int >  newPosition)

Changes the position of the viewed component.

The inner component will be moved so that the pixel at the top left of the viewport will be the pixel at the specified coordinates within the inner component.

This will update the scrollbars and might cause a call to visibleAreaChanged().

See Also
getViewPositionX, getViewPositionY, setViewPositionProportionately
void Viewport::setViewPositionProportionately ( double  proportionX,
double  proportionY 
)

Changes the view position as a proportion of the distance it can move.

The values here are from 0.0 to 1.0 - where (0, 0) would put the visible area in the top-left, and (1, 1) would put it as far down and to the right as it's possible to go whilst keeping the child component on-screen.

bool Viewport::autoScroll ( int  mouseX,
int  mouseY,
int  distanceFromEdge,
int  maximumSpeed 
)

If the specified position is at the edges of the viewport, this method scrolls the viewport to bring that position nearer to the centre.

Call this if you're dragging an object inside a viewport and want to make it scroll when the user approaches an edge. You might also find Component::beginDragAutoRepeat() useful when auto-scrolling.

Parameters
mouseXthe x position, relative to the Viewport's top-left
mouseYthe y position, relative to the Viewport's top-left
distanceFromEdgespecifies how close to an edge the position needs to be before the viewport should scroll in that direction
maximumSpeedthe maximum number of pixels that the viewport is allowed to scroll by.
Returns
true if the viewport was scrolled
Point<int> Viewport::getViewPosition ( ) const
noexcept

Returns the position within the child component of the top-left of its visible area.

Rectangle<int> Viewport::getViewArea ( ) const
noexcept

Returns the visible area of the child component, relative to its top-left.

int Viewport::getViewPositionX ( ) const
noexcept

Returns the position within the child component of the top-left of its visible area.

See Also
getViewWidth, setViewPosition
int Viewport::getViewPositionY ( ) const
noexcept

Returns the position within the child component of the top-left of its visible area.

See Also
getViewHeight, setViewPosition
int Viewport::getViewWidth ( ) const
noexcept

Returns the width of the visible area of the child component.

This may be less than the width of this Viewport if there's a vertical scrollbar or if the child component is itself smaller.

int Viewport::getViewHeight ( ) const
noexcept

Returns the height of the visible area of the child component.

This may be less than the height of this Viewport if there's a horizontal scrollbar or if the child component is itself smaller.

int Viewport::getMaximumVisibleWidth ( ) const

Returns the width available within this component for the contents.

This will be the width of the viewport component minus the width of a vertical scrollbar (if visible).

int Viewport::getMaximumVisibleHeight ( ) const

Returns the height available within this component for the contents.

This will be the height of the viewport component minus the space taken up by a horizontal scrollbar (if visible).

virtual void Viewport::visibleAreaChanged ( const Rectangle< int > &  newVisibleArea)
virtual

Callback method that is called when the visible area changes.

This will be called when the visible area is moved either be scrolling or by calls to setViewPosition(), etc.

virtual void Viewport::viewedComponentChanged ( Component newComponent)
virtual

Callback method that is called when the viewed component is added, removed or swapped.

void Viewport::setScrollBarsShown ( bool  showVerticalScrollbarIfNeeded,
bool  showHorizontalScrollbarIfNeeded,
bool  allowVerticalScrollingWithoutScrollbar = false,
bool  allowHorizontalScrollingWithoutScrollbar = false 
)

Turns scrollbars on or off.

If set to false, the scrollbars won't ever appear. When true (the default) they will appear only when needed.

The allowVerticalScrollingWithoutScrollbar parameters allow you to enable mouse-wheel scrolling even when there the scrollbars are hidden. When the scrollbars are visible, these parameters are ignored.

bool Viewport::isVerticalScrollBarShown ( ) const
noexcept

True if the vertical scrollbar is enabled.

See Also
setScrollBarsShown
bool Viewport::isHorizontalScrollBarShown ( ) const
noexcept

True if the horizontal scrollbar is enabled.

See Also
setScrollBarsShown
void Viewport::setScrollBarThickness ( int  thickness)

Changes the width of the scrollbars.

If this isn't specified, the default width from the LookAndFeel class will be used.

See Also
LookAndFeel::getDefaultScrollbarWidth
int Viewport::getScrollBarThickness ( ) const

Returns the thickness of the scrollbars.

See Also
setScrollBarThickness
void Viewport::setSingleStepSizes ( int  stepX,
int  stepY 
)

Changes the distance that a single-step click on a scrollbar button will move the viewport.

ScrollBar* Viewport::getVerticalScrollBar ( )
noexcept

Returns a pointer to the scrollbar component being used.

Handy if you need to customise the bar somehow.

ScrollBar* Viewport::getHorizontalScrollBar ( )
noexcept

Returns a pointer to the scrollbar component being used.

Handy if you need to customise the bar somehow.

void Viewport::resized ( )
overridevirtual

Reimplemented from Component.

void Viewport::scrollBarMoved ( ScrollBar ,
double  newRangeStart 
)
overridevirtual

Implements ScrollBar::Listener.

void Viewport::mouseWheelMove ( const MouseEvent ,
const MouseWheelDetails  
)
overridevirtual

Reimplemented from Component.

bool Viewport::keyPressed ( const KeyPress )
overridevirtual

Reimplemented from Component.

void Viewport::componentMovedOrResized ( Component ,
bool  wasMoved,
bool  wasResized 
)
overridevirtual

Reimplemented from ComponentListener.

bool Viewport::useMouseWheelMoveIfNeeded ( const MouseEvent ,
const MouseWheelDetails  
)
static bool Viewport::respondsToKey ( const KeyPress )
static

The documentation for this class was generated from the following file: