Constraint

gtk.constraint.Constraint describes a constraint between attributes of two widgets, expressed as a linear equation.

The typical equation for a constraint is:

target.target_attr = source.source_attr × multiplier + constant

Each gtk.constraint.Constraint is part of a system that will be solved by a gtk.constraint_layout.ConstraintLayout in order to allocate and position each child widget or guide.

The source and target, as well as their attributes, of a gtk.constraint.Constraint instance are immutable after creation.

class Constraint : ObjectG {

this(gtk.constraint_target.ConstraintTarget target, gtk.types.ConstraintAttribute targetAttribute, gtk.types.ConstraintRelation relation, gtk.constraint_target.ConstraintTarget source, gtk.types.ConstraintAttribute sourceAttribute, double multiplier, double constant, int strength);

static gtk.constraint.Constraint newConstant(gtk.constraint_target.ConstraintTarget target, gtk.types.ConstraintAttribute targetAttribute, gtk.types.ConstraintRelation relation, double constant, int strength);

double getConstant();

double getMultiplier();

gtk.types.ConstraintRelation getRelation();

gtk.constraint_target.ConstraintTarget getSource();

gtk.types.ConstraintAttribute getSourceAttribute();

int getStrength();

gtk.constraint_target.ConstraintTarget getTarget();

gtk.types.ConstraintAttribute getTargetAttribute();

bool isAttached();

bool isConstant();

bool isRequired();

}

Constructors

this this(gtk.constraint_target.ConstraintTarget target, gtk.types.ConstraintAttribute targetAttribute, gtk.types.ConstraintRelation relation, gtk.constraint_target.ConstraintTarget source, gtk.types.ConstraintAttribute sourceAttribute, double multiplier, double constant, int strength): Creates a new constraint representing a relation between a layout attribute on a source and a layout attribute on a target.

Members

Functions

getConstant double getConstant(): Retrieves the constant factor added to the source attributes' value.
getMultiplier double getMultiplier(): Retrieves the multiplication factor applied to the source attribute's value.
getRelation gtk.types.ConstraintRelation getRelation(): The order relation between the terms of the constraint.
getSource gtk.constraint_target.ConstraintTarget getSource(): Retrieves the gtk.constraint_target.ConstraintTarget used as the source for the constraint.
getSourceAttribute gtk.types.ConstraintAttribute getSourceAttribute(): Retrieves the attribute of the source to be read by the constraint.
getStrength int getStrength(): Retrieves the strength of the constraint.
getTarget gtk.constraint_target.ConstraintTarget getTarget(): Retrieves the gtk.constraint_target.ConstraintTarget used as the target for the constraint.
getTargetAttribute gtk.types.ConstraintAttribute getTargetAttribute(): Retrieves the attribute of the target to be set by the constraint.
isAttached bool isAttached(): Checks whether the constraint is attached to a gtk.constraint_layout.ConstraintLayout, and it is contributing to the layout.
isConstant bool isConstant(): Checks whether the constraint describes a relation between an attribute on the gtk.constraint.Constraint.ConstraintTarget and a constant value.
isRequired bool isRequired(): Checks whether the constraint is a required relation for solving the constraint layout.

Static functions

newConstant gtk.constraint.Constraint newConstant(gtk.constraint_target.ConstraintTarget target, gtk.types.ConstraintAttribute targetAttribute, gtk.types.ConstraintRelation relation, double constant, int strength): Creates a new constraint representing a relation between a layout attribute on a target and a constant value.

Inherited Members

From ObjectG

setGObject void setGObject(void* cObj, Flag!"Take" take): Set the GObject of a D ObjectG wrapper.
cPtr void* cPtr(Flag!"Dup" dup): Get a pointer to the underlying C object.
ref_ void* ref_(void* gObj): Calls g_object_ref() on a GObject.
unref unref(void* gObj): Calls g_object_unref() on a GObject.
getType GType getType(): Get the GType of an object.
gType GType gType [@property getter]: GObject GType property.
self ObjectG self(): Convenience method to return this cast to a type. For use in D with statements.
getDObject T getDObject(void* cptr, Flag!"Take" take): Template to get the D object from a C GObject and cast it to the given D object type.
connectSignalClosure ulong connectSignalClosure(string signalDetail, DClosure closure, Flag!"After" after): Connect a D closure to an object signal.
setProperty void setProperty(string propertyName, T val): Template for setting a GObject property.
getProperty T getProperty(string propertyName): Template for getting a GObject property.
compatControl size_t compatControl(size_t what, void* data)
bindProperty gobject.binding.Binding bindProperty(string sourceProperty, gobject.object.ObjectG target, string targetProperty, gobject.types.BindingFlags flags): Creates a binding between source_property on source and target_property on target.
bindPropertyFull gobject.binding.Binding bindPropertyFull(string sourceProperty, gobject.object.ObjectG target, string targetProperty, gobject.types.BindingFlags flags, gobject.closure.Closure transformTo, gobject.closure.Closure transformFrom): Creates a binding between source_property on source and target_property on target, allowing you to set the transformation functions to be used by the binding.
forceFloating void forceFloating(): This function is intended for #GObject implementations to re-enforce a floating[floating-ref] object reference. Doing this is seldom required: all #GInitiallyUnowneds are created with a floating reference which usually just needs to be sunken by calling gobject.object.ObjectG.refSink.
freezeNotify void freezeNotify(): Increases the freeze count on object. If the freeze count is non-zero, the emission of "notify" signals on object is stopped. The signals are queued until the freeze count is decreased to zero. Duplicate notifications are squashed so that at most one #GObject::notify signal is emitted for each property modified while the object is frozen.
getData void* getData(string key): Gets a named field from the objects table of associations (see gobject.object.ObjectG.setData).
getProperty void getProperty(string propertyName, gobject.value.Value value): Gets a property of an object.
getQdata void* getQdata(glib.types.Quark quark): This function gets back user data pointers stored via gobject.object.ObjectG.setQdata.
getv void getv(string[] names, gobject.value.Value[] values): Gets n_properties properties for an object. Obtained properties will be set to values. All properties must be valid. Warnings will be emitted and undefined behaviour may result if invalid properties are passed in.
isFloating bool isFloating(): Checks whether object has a floating[floating-ref] reference.
notify void notify(string propertyName): Emits a "notify" signal for the property property_name on object.
notifyByPspec void notifyByPspec(gobject.param_spec.ParamSpec pspec): Emits a "notify" signal for the property specified by pspec on object.
refSink gobject.object.ObjectG refSink(): Increase the reference count of object, and possibly remove the floating[floating-ref] reference, if object has a floating reference.
runDispose void runDispose(): Releases all references to other objects. This can be used to break reference cycles.
setData void setData(string key, void* data): Each object carries around a table of associations from strings to pointers. This function lets you set an association.
setProperty void setProperty(string propertyName, gobject.value.Value value): Sets a property on an object.
stealData void* stealData(string key): Remove a specified datum from the object's data associations, without invoking the association's destroy handler.
stealQdata void* stealQdata(glib.types.Quark quark): This function gets back user data pointers stored via gobject.object.ObjectG.setQdata and removes the data from object without invoking its destroy() function (if any was set). Usually, calling this function is only required to update user data pointers with a destroy notifier, for example:
thawNotify void thawNotify(): Reverts the effect of a previous call to gobject.object.ObjectG.freezeNotify. The freeze count is decreased on object and when it reaches zero, queued "notify" signals are emitted.
watchClosure void watchClosure(gobject.closure.Closure closure): This function essentially limits the life time of the closure to the life time of the object. That is, when the object is finalized, the closure is invalidated by calling gobject.closure.Closure.invalidate on it, in order to prevent invocations of the closure with a finalized (nonexisting) object. Also, gobject.object.ObjectG.ref_ and gobject.object.ObjectG.unref are added as marshal guards to the closure, to ensure that an extra reference count is held on object during invocation of the closure. Usually, this function will be called on closures that use this object as closure data.
connectNotify ulong connectNotify(string detail, T callback, Flag!"After" after): Connect to Notify signal.

gtk constraint classes

Constraint