StretchableLayoutManager Class Reference

For laying out a set of components, where the components have preferred sizes and size limits, but where they are allowed to stretch to fill the available space. More...

Public Member Functions
	StretchableLayoutManager ()
	Creates an empty layout. More...
	~StretchableLayoutManager ()
	Destructor. More...
void	setItemLayout (int itemIndex, double minimumSize, double maximumSize, double preferredSize)
	For a numbered item, this sets its size limits and preferred size. More...
bool	getItemLayout (int itemIndex, double &minimumSize, double &maximumSize, double &preferredSize) const
	For a numbered item, this returns its size limits and preferred size. More...
void	clearAllItems ()
	Clears all the properties that have been set with setItemLayout() and resets this object to its initial state. More...
void	layOutComponents (Component **components, int numComponents, int x, int y, int width, int height, bool vertically, bool resizeOtherDimension)
	Takes a set of components that correspond to the layout's items, and positions them to fill a space. More...
int	getItemCurrentPosition (int itemIndex) const
	Returns the current position of one of the items. More...
int	getItemCurrentAbsoluteSize (int itemIndex) const
	Returns the current size of one of the items. More...
double	getItemCurrentRelativeSize (int itemIndex) const
	Returns the current size of one of the items. More...
void	setItemPosition (int itemIndex, int newPosition)
	Moves one of the items, shifting along any other items as necessary in order to get it to the desired position. More...

Detailed Description

For laying out a set of components, where the components have preferred sizes and size limits, but where they are allowed to stretch to fill the available space.

For example, if you have a component containing several other components, and each one should be given a share of the total size, you could use one of these to resize the child components when the parent component is resized. Then you could add a StretchableLayoutResizerBar to easily let the user rescale them.

A StretchableLayoutManager operates only in one dimension, so if you have a set of components stacked vertically on top of each other, you'd use one to manage their heights. To build up complex arrangements of components, e.g. for applications with multiple nested panels, you would use more than one StretchableLayoutManager. E.g. by using two (one vertical, one horizontal), you could create a resizable spreadsheet-style table.

E.g.

class MyComp  : public Component
{
    StretchableLayoutManager myLayout;

    MyComp()
    {
        myLayout.setItemLayout (0,          // for item 0
                                50, 100,    // must be between 50 and 100 pixels in size
                                -0.6);      // and its preferred size is 60% of the total available space

        myLayout.setItemLayout (1,          // for item 1
                                -0.2, -0.6, // size must be between 20% and 60% of the available space
                                50);        // and its preferred size is 50 pixels
    }

    void resized()
    {
        // make a list of two of our child components that we want to reposition
        Component* comps[] = { myComp1, myComp2 };

        // this will position the 2 components, one above the other, to fit
        // vertically into the rectangle provided.
        myLayout.layOutComponents (comps, 2,
                                   0, 0, getWidth(), getHeight(),
                                   true);
    }
};

See also

StretchableLayoutResizerBar

Constructor & Destructor Documentation

StretchableLayoutManager()

StretchableLayoutManager::StretchableLayoutManager

(

)

Creates an empty layout.

You'll need to add some item properties to the layout before it can be used to resize things - see setItemLayout().

~StretchableLayoutManager()

StretchableLayoutManager::~StretchableLayoutManager

(

)

Destructor.

Member Function Documentation

setItemLayout()

void StretchableLayoutManager::setItemLayout	(	int	itemIndex,
		double	minimumSize,
		double	maximumSize,
		double	preferredSize
	)

For a numbered item, this sets its size limits and preferred size.

Parameters

itemIndex	the index of the item to change.
minimumSize	the minimum size that this item is allowed to be - a positive number indicates an absolute size in pixels. A negative number indicates a proportion of the available space (e.g -0.5 is 50%)
maximumSize	the maximum size that this item is allowed to be - a positive number indicates an absolute size in pixels. A negative number indicates a proportion of the available space
preferredSize	the size that this item would like to be, if there's enough room. A positive number indicates an absolute size in pixels. A negative number indicates a proportion of the available space

See also

getItemLayout

getItemLayout()

bool StretchableLayoutManager::getItemLayout	(	int	itemIndex,
		double &	minimumSize,
		double &	maximumSize,
		double &	preferredSize
	)		const

For a numbered item, this returns its size limits and preferred size.

Parameters

itemIndex	the index of the item.
minimumSize	the minimum size that this item is allowed to be - a positive number indicates an absolute size in pixels. A negative number indicates a proportion of the available space (e.g -0.5 is 50%)
maximumSize	the maximum size that this item is allowed to be - a positive number indicates an absolute size in pixels. A negative number indicates a proportion of the available space
preferredSize	the size that this item would like to be, if there's enough room. A positive number indicates an absolute size in pixels. A negative number indicates a proportion of the available space

Returns

false if the item's properties hadn't been set

See also

setItemLayout

clearAllItems()

void StretchableLayoutManager::clearAllItems

(

)

Clears all the properties that have been set with setItemLayout() and resets this object to its initial state.

layOutComponents()

void StretchableLayoutManager::layOutComponents	(	Component **	components,
		int	numComponents,
		int	x,
		int	y,
		int	width,
		int	height,
		bool	vertically,
		bool	resizeOtherDimension
	)

Takes a set of components that correspond to the layout's items, and positions them to fill a space.

This will try to give each item its preferred size, whether that's a relative size or an absolute one.

Parameters

components	an array of components that correspond to each of the numbered items that the StretchableLayoutManager object has been told about with setItemLayout()
numComponents	the number of components in the array that is passed-in. This should be the same as the number of items this object has been told about.
x	the left of the rectangle in which the components should be laid out
y	the top of the rectangle in which the components should be laid out
width	the width of the rectangle in which the components should be laid out
height	the height of the rectangle in which the components should be laid out
vertically	if true, the components will be positioned in a vertical stack, so that they fill the height of the rectangle. If false, they will be placed side-by-side in a horizontal line, filling the available width
resizeOtherDimension	if true, this means that the components will have their other dimension resized to fit the space - i.e. if the 'vertically' parameter is true, their x-positions and widths are adjusted to fit the x and width parameters; if 'vertically' is false, their y-positions and heights are adjusted to fit the y and height parameters.

getItemCurrentPosition()

int StretchableLayoutManager::getItemCurrentPosition

(

int

itemIndex

)

const

Returns the current position of one of the items.

This is only a valid call after layOutComponents() has been called, as it returns the last position that this item was placed at. If the layout was vertical, the value returned will be the y position of the top of the item, relative to the top of the rectangle in which the items were placed (so for example, item 0 will always have position of 0, even in the rectangle passed in to layOutComponents() wasn't at y = 0). If the layout was done horizontally, the position returned is the item's left-hand position, again relative to the x position of the rectangle used.

See also

getItemCurrentSize, setItemPosition

getItemCurrentAbsoluteSize()

int StretchableLayoutManager::getItemCurrentAbsoluteSize

(

int

itemIndex

)

const

Returns the current size of one of the items.

This is only meaningful after layOutComponents() has been called, as it returns the last size that this item was given. If the layout was done vertically, it'll return the item's height in pixels; if it was horizontal, it'll return its width.

See also

getItemCurrentRelativeSize

getItemCurrentRelativeSize()

double StretchableLayoutManager::getItemCurrentRelativeSize

(

int

itemIndex

)

const

Returns the current size of one of the items.

This is only meaningful after layOutComponents() has been called, as it returns the last size that this item was given. If the layout was done vertically, it'll return a negative value representing the item's height relative to the last size used for laying the components out; if the layout was done horizontally it'll be the proportion of its width.

See also

getItemCurrentAbsoluteSize

setItemPosition()

void StretchableLayoutManager::setItemPosition	(	int	itemIndex,
		int	newPosition
	)

Moves one of the items, shifting along any other items as necessary in order to get it to the desired position.

Calling this method will also update the preferred sizes of the items it shuffles along, so that they reflect their new positions.

(This is the method that a StretchableLayoutResizerBar uses to shift the items about when it's dragged).

Parameters

itemIndex	the item to move
newPosition	the absolute position that you'd like this item to move to. The item might not be able to always reach exactly this position, because other items may have minimum sizes that constrain how far it can go

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

• juce_StretchableLayoutManager.h