godot/scene/gui/box_container.cpp

/*************************************************************************/
/*  box_container.cpp                                                    */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
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/* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur.                 */
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#include "box_container.h"
#include "margin_container.h"
#include "label.h"

struct _MinSizeCache {

	int min_size;
	bool will_stretch;
	int final_size;
};

void BoxContainer::_resort() {

	/** First pass, determine minimum size AND amount of stretchable elements */


	Size2i new_size=get_size();

	int sep=get_constant("separation");//,vertical?"VBoxContainer":"HBoxContainer");

	bool first=true;
	int children_count=0;
	int stretch_min=0;
	int stretch_avail=0;
	float stretch_ratio_total=0;
	Map<Control*,_MinSizeCache> min_size_cache;

	for(int i=0;i<get_child_count();i++) {
		Control *c=get_child(i)->cast_to<Control>();
		if (!c || !c->is_visible_in_tree())
			continue;
		if (c->is_set_as_toplevel())
			continue;

		Size2i size=c->get_combined_minimum_size();
		_MinSizeCache msc;

		if (vertical) { /* VERTICAL */
			stretch_min+=size.height;
			msc.min_size=size.height;
			msc.will_stretch=c->get_v_size_flags() & SIZE_EXPAND;

		} else { /* HORIZONTAL */
			stretch_min+=size.width;
			msc.min_size=size.width;
			msc.will_stretch=c->get_h_size_flags() & SIZE_EXPAND;
		}

		if (msc.will_stretch) {
			stretch_avail+=msc.min_size;
			stretch_ratio_total+=c->get_stretch_ratio();
		}
		msc.final_size=msc.min_size;
		min_size_cache[c]=msc;
		children_count++;
	}

	if (children_count==0)
		return;

	int stretch_max =  (vertical? new_size.height : new_size.width ) - (children_count-1) * sep;
	int stretch_diff = stretch_max - stretch_min;
	if (stretch_diff<0) {
		//avoid negative stretch space
		stretch_max=stretch_min;
		stretch_diff=0;
	}

	stretch_avail+=stretch_diff; //available stretch space.
	/** Second, pass sucessively to discard elements that can't be stretched, this will run while stretchable
		elements exist */


	bool has_stretched = false;
	while(stretch_ratio_total>0) { // first of all, dont even be here if no stretchable objects exist

		has_stretched = true;
		bool refit_successful=true; //assume refit-test will go well

		for(int i=0;i<get_child_count();i++) {

			Control *c=get_child(i)->cast_to<Control>();
			if (!c || !c->is_visible_in_tree())
				continue;
			if (c->is_set_as_toplevel())
				continue;

			ERR_FAIL_COND(!min_size_cache.has(c));
			_MinSizeCache &msc=min_size_cache[c];

			if (msc.will_stretch) { //wants to stretch
				//let's see if it can really stretch

				int final_pixel_size=stretch_avail * c->get_stretch_ratio() / stretch_ratio_total;
				if (final_pixel_size<msc.min_size) {
					//if available stretching area is too small for widget,
					//then remove it from stretching area
					msc.will_stretch=false;
					stretch_ratio_total-=c->get_stretch_ratio();
					refit_successful=false;
					stretch_avail-=msc.min_size;
					msc.final_size=msc.min_size;
					break;
				} else {
					msc.final_size=final_pixel_size;
				}
			}
		}

		if (refit_successful) //uf refit went well, break
			break;

	}


	/** Final pass, draw and stretch elements **/


	int ofs=0;
	if (!has_stretched) {
		switch (align) {
			case ALIGN_BEGIN:
				break;
			case ALIGN_CENTER:
				ofs = stretch_diff / 2;
				break;
			case ALIGN_END:
				ofs = stretch_diff;
				break;
		}
	}

	first=true;
	int idx=0;

	for(int i=0;i<get_child_count();i++) {

		Control *c=get_child(i)->cast_to<Control>();
		if (!c || !c->is_visible_in_tree())
			continue;
		if (c->is_set_as_toplevel())
			continue;

		_MinSizeCache &msc=min_size_cache[c];


		if (first)
			first=false;
		else
			ofs+=sep;

		int from=ofs;
		int to=ofs+msc.final_size;


		if (msc.will_stretch && idx==children_count-1) {
			//adjust so the last one always fits perfect
			//compensating for numerical imprecision

			to=vertical?new_size.height:new_size.width;

		}

		int size=to-from;

		Rect2 rect;

		if (vertical) {

			rect=Rect2(0,from,new_size.width,size);
		} else {

			rect=Rect2(from,0,size,new_size.height);

		}

		fit_child_in_rect(c,rect);

		ofs=to;
		idx++;
	}

}

Size2 BoxContainer::get_minimum_size() const {


	/* Calculate MINIMUM SIZE */

	Size2i minimum;
	int sep=get_constant("separation");//,vertical?"VBoxContainer":"HBoxContainer");

	bool first=true;

	for(int i=0;i<get_child_count();i++) {
		Control *c=get_child(i)->cast_to<Control>();
		if (!c)
			continue;
		if (c->is_set_as_toplevel())
			continue;

		if (!c->is_visible()) {
			continue;
		}

		Size2i size=c->get_combined_minimum_size();

		if (vertical) { /* VERTICAL */

			if ( size.width > minimum.width ) {
				minimum.width=size.width;
			}

			minimum.height+=size.height+(first?0:sep);

		} else { /* HORIZONTAL */

			if ( size.height > minimum.height ) {
				minimum.height=size.height;
			}

			minimum.width+=size.width+(first?0:sep);

		}

		first=false;
	}

	return minimum;
}

void BoxContainer::_notification(int p_what) {

	switch(p_what) {

		case NOTIFICATION_SORT_CHILDREN: {

			_resort();
		} break;
	}
}

void BoxContainer::set_alignment(AlignMode p_align) {
	align = p_align;
	_resort();
}

BoxContainer::AlignMode BoxContainer::get_alignment() const {
	return align;
}

void BoxContainer::add_spacer(bool p_begin) {

	Control *c = memnew( Control );
	c->set_mouse_filter(MOUSE_FILTER_PASS); //allow spacer to pass mouse events

	if (vertical)
		c->set_v_size_flags(SIZE_EXPAND_FILL);
	else
		c->set_h_size_flags(SIZE_EXPAND_FILL);

	add_child(c);
	if (p_begin)
		move_child(c,0);
}

BoxContainer::BoxContainer(bool p_vertical) {

	vertical=p_vertical;
	align = ALIGN_BEGIN;
	//set_ignore_mouse(true);
	set_mouse_filter(MOUSE_FILTER_PASS);
}

void BoxContainer::_bind_methods() {

	ClassDB::bind_method(_MD("add_spacer","begin"),&BoxContainer::add_spacer);
	ClassDB::bind_method(_MD("get_alignment"),&BoxContainer::get_alignment);
	ClassDB::bind_method(_MD("set_alignment","alignment"),&BoxContainer::set_alignment);

	BIND_CONSTANT( ALIGN_BEGIN );
	BIND_CONSTANT( ALIGN_CENTER );
	BIND_CONSTANT( ALIGN_END );

	ADD_PROPERTY( PropertyInfo(Variant::INT,"alignment", PROPERTY_HINT_ENUM, "Begin,Center,End"), "set_alignment","get_alignment") ;

}

MarginContainer* VBoxContainer::add_margin_child(const String& p_label,Control *p_control,bool p_expand) {

	Label *l = memnew( Label );
	l->set_text(p_label);
	add_child(l);
	MarginContainer *mc = memnew( MarginContainer );
	mc->add_child(p_control);
	add_child(mc);
	if (p_expand)
		mc->set_v_size_flags(SIZE_EXPAND_FILL);

	return mc;
}