gistfile1.cpp

// How I'm handling css-layout with ImGui
// Doesn't really scale for windows in windows but this isn't a problem I'm trying to solve

struct LayoutItem
{
	const char *text;
	ImVec2 p, d;
	OnClickedFunc onClicked;
	ImIcon icon;
};

struct LayoutContext
{
	std::vector< css_node > nodes;
};

static bool LayoutIsDirty(void *context) {
	(void)context; // remove unused warning
	return true;
}

static css_dim_t LayoutMeasure(void *context, float /*width*/) {
	ImVec2 ts = ImGui::CalcTextSize( (char*)context );
	
	ImVec2 pad = ImGui::GetStyle().FramePadding;
	css_dim_t dim;
	dim.dimensions[CSS_WIDTH] = ts.x + pad.x*2.f;
	dim.dimensions[CSS_HEIGHT] = ts.y + pad.y*2.f;

	return dim;
}

css_node *LayoutGetChild( void *ctx, int idx )
{
	LayoutContext *context = (LayoutContext*)ctx;
	if ( idx < 0 || idx >= (int)context->nodes.size() )
		return NULL;
	return &context->nodes[idx];
}

void CSSLayoutButtons( const LayoutItem *items[], ImVec2 fixedDims, ImVec2 base, ImVec2 mn, ImVec2 mx )
{
	ImVec2 pad = ImGui::GetStyle().FramePadding;

	LayoutContext context;
	for( int idx=0; items[idx].text; idx++ )
	{
		context.nodes.push_back( css_node() );
		css_node &n = context.nodes.back();
		memset( &n, 0, sizeof(n) );
		init_css_node( &n );
		n.context = (void*)text[idx];
		n.is_dirty = LayoutIsDirty;
		if ( fixedDims.x > 0.f && fixedDims.y > 0.f )
		{
			n.layout.dimensions[0] = fixedDims.x + pad.x * 4.f;
			n.layout.dimensions[1] = fixedDims.y + pad.y * 4.f;
		}
		n.measure = LayoutMeasure;
		n.style.flex_direction = CSS_FLEX_DIRECTION_ROW;
		n.style.flex_wrap = CSS_WRAP;
	}

	css_node root;
	memset( &root, 0, sizeof(root) );
	init_css_node( &root );
	root.context = &context;
	root.get_child = LayoutGetChild;
	root.children_count = context.nodes.size();
	root.is_dirty = LayoutIsDirty;
	root.style.dimensions[CSS_WIDTH] = mx.x - mn.x;
	root.style.flex_direction = CSS_FLEX_DIRECTION_ROW;
	root.style.flex_wrap = CSS_WRAP;

	layoutNode( &root, mx.x - mn.x );
	for( int idx=0; items[idx].text; idx++ )
	{
		items[idx].p = ImVec2(context.nodes[i].layout.position[0]+base.x+mn.x+pad.x*2.f,context.nodes[i].layout.position[1]+base.y+mn.y+pad.y*2.f);
		items[idx].d = ImVec2(context.nodes[i].layout.dimensions[0]-pad.x*4.f,context.nodes[i].layout.dimensions[1]-pad.y*4.f);
	}
}


CSSLayoutButtons( buttons, ImVec2(32.f,32.f), ImGui::GetWindowPos(), ImGui::GetWindowContentRegionMin(), ImGui::GetWindowContentRegionMax() );
for( int idx=0; buttons[idx].text; idx++ )
{
	if ( ImGui::ImageButtonLayout(buttons[idx].text, buttons[idx].p, buttons[idx].d, buttons[idx].icon ) )
	{
		buttons[idx].onClicked( ... )
	}
}