Constraint Class Reference

Collaboration diagram for Constraint:

Public Member Functions
	Constraint (int flags, int padding=0, std::vector< Element * > targets={})
void	clearFlags ()
void	addFlags (int flags)
void	clearTargets ()
void	addTarget (Element *target)
void	update ()
void	apply (Element *element)

Public Attributes
int	positioningFlags = 0
std::vector< Element * >	targets
int	paddingOffset = 0

Detailed Description

Definition at line 24 of file Constraint.hpp.

Constructor & Destructor Documentation

Constraint()

Constraint::Constraint	(	int	flags,
		int	padding = 0,
		std::vector< Element * >	targets = {}
	)

Constraints are used to define the positioning of an element relative to other elements. Currently only within another element or padding from a parent edge is supported. TODO: support for positioning relative to non-overlapping elements (eg. the space between)

If no targets are specified, the constraint will be relative to the parent element.

Parameters

flags	the positioning flags to use
targets	the elements to position relative to

Definition at line 15 of file Constraint.cpp.

                                                                          {
    positioningFlags |= flags;
    paddingOffset = padding;
    this->targets = targets;
}

Member Function Documentation

addFlags()

void Constraint::addFlags

(

int

flags

)

Definition at line 25 of file Constraint.cpp.

                                   {
    positioningFlags |= flags;
}

addTarget()

void Constraint::addTarget

(

Element *

target

)

Definition at line 33 of file Constraint.cpp.

                                          {
    targets.push_back(target);
}

apply()

void Constraint::apply

(

Element *

element

)

Definition at line 37 of file Constraint.cpp.

                                       {
    // if the vector of targets is blank, grab the parent
    // TODO: anything with the vector, to extract a target from it
    auto target = element->parent;
    int posX = 0, posY = 0;
    int width = RootDisplay::screenWidth, height = RootDisplay::screenHeight; // default to screen size
    if (target != NULL) {
        // For centering constraints, we want to position relative to parent's content area (0,0)
        // For edge alignment, we use parent's position as reference
        posX = target->x;
        posY = target->y;
        width = target->width;
        height = target->height;
    }
 
    // look at the flags and decide what to do
    if (positioningFlags & ALIGN_LEFT)     element->x = posX + paddingOffset;
    if (positioningFlags & ALIGN_RIGHT)    element->x = posX + width - element->width - paddingOffset;
    if (positioningFlags & ALIGN_TOP)      element->y = posY + paddingOffset;
    if (positioningFlags & ALIGN_BOTTOM)   element->y = posY + height - element->height - paddingOffset;
 
    // For centering, position relative to parent's content area (like centerHorizontallyIn)
    if (positioningFlags & ALIGN_CENTER_HORIZONTAL)  element->x = width / 2  -  element->width / 2;
    if (positioningFlags & ALIGN_CENTER_VERTICAL)    element->y = height / 2 - element->height / 2;
 
    // some manual offset constraints, that just move the element
    if (positioningFlags & OFFSET_LEFT)    element->x += paddingOffset;
    if (positioningFlags & OFFSET_RIGHT)   element->x -= paddingOffset;
    if (positioningFlags & OFFSET_TOP)     element->y += paddingOffset;
    if (positioningFlags & OFFSET_BOTTOM)  element->y -= paddingOffset;
 
}

clearFlags()

void Constraint::clearFlags

(

)

Definition at line 21 of file Constraint.cpp.

                            {
    positioningFlags = 0;
}

clearTargets()

void Constraint::clearTargets

(

)

Definition at line 29 of file Constraint.cpp.

                              {
    targets.clear();
}

Member Data Documentation

paddingOffset

int Constraint::paddingOffset = 0

Definition at line 42 of file Constraint.hpp.

positioningFlags

int Constraint::positioningFlags = 0

Definition at line 36 of file Constraint.hpp.

targets

std::vector<Element*> Constraint::targets

Definition at line 39 of file Constraint.hpp.

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

• src/Constraint.hpp
• src/Constraint.cpp