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#include "margin_container.h"
namespace cru::ui::controls
{
inline float AtLeast0(const float value)
{
return value < 0 ? 0 : value;
}
inline Size AtLeast0(const Size& size)
{
return Size(AtLeast0(size.width), AtLeast0(size.height));
}
MarginContainer::MarginContainer(const Thickness& margin)
: Control(true), margin_(margin)
{
}
void MarginContainer::SetMargin(const Thickness& margin)
{
margin_ = margin;
Relayout();
}
Size MarginContainer::OnMeasure(const Size& available_size)
{
const auto margin_size = Size(margin_.left + margin_.right, margin_.top + margin_.bottom);
const auto coerced_available_size = AtLeast0(available_size - margin_size);
return Control::OnMeasure(coerced_available_size) + margin_size;
}
void MarginContainer::OnLayout(const Rect& rect)
{
const auto anchor = Point(margin_.left, margin_.top);
const auto margin_size = Size(margin_.left + margin_.right, margin_.top + margin_.bottom);
ForeachChild([anchor, margin_size, rect](Control* control)
{
const auto layout_params = control->GetLayoutParams();
const auto size = control->GetDesiredSize();
auto&& calculate_anchor = [](const float anchor, const Alignment alignment, const float layout_length, const float control_length) -> float
{
switch (alignment)
{
case Alignment::Center:
return anchor + (layout_length - control_length) / 2;
case Alignment::Start:
return anchor;
case Alignment::End:
return anchor + layout_length - control_length;
default:
UnreachableCode();
}
};
control->Layout(Rect(Point(
calculate_anchor(anchor.x, layout_params->width.alignment, rect.width - margin_size.width, size.width),
calculate_anchor(anchor.y, layout_params->height.alignment, rect.height - margin_size.height, size.height)
), size));
});
}
}
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