tdesktop/Telegram/SourceFiles/ui/effects/scroll_content_shadow.cpp

48 lines
1.4 KiB
C++

/*
This file is part of Telegram Desktop,
the official desktop application for the Telegram messaging service.
For license and copyright information please follow this link:
https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
*/
#include "ui/effects/scroll_content_shadow.h"
#include "ui/rp_widget.h"
#include "ui/widgets/scroll_area.h"
#include "ui/wrap/fade_wrap.h"
namespace Ui {
void SetupShadowsToScrollContent(
not_null<Ui::RpWidget*> parent,
not_null<Ui::ScrollArea*> scroll,
rpl::producer<int> &&innerHeightValue) {
using namespace rpl::mappers;
const auto topShadow = Ui::CreateChild<Ui::FadeShadow>(parent.get());
const auto bottomShadow = Ui::CreateChild<Ui::FadeShadow>(parent.get());
scroll->geometryValue(
) | rpl::start_with_next_done([=](const QRect &geometry) {
topShadow->resizeToWidth(geometry.width());
topShadow->move(
geometry.x(),
geometry.y());
bottomShadow->resizeToWidth(geometry.width());
bottomShadow->move(
geometry.x(),
geometry.y() + geometry.height() - st::lineWidth);
}, [t = Ui::MakeWeak(topShadow), b = Ui::MakeWeak(bottomShadow)] {
Ui::DestroyChild(t.data());
Ui::DestroyChild(b.data());
}, topShadow->lifetime());
topShadow->toggleOn(scroll->scrollTopValue() | rpl::map(_1 > 0));
bottomShadow->toggleOn(rpl::combine(
scroll->scrollTopValue(),
scroll->heightValue(),
std::move(innerHeightValue),
_1 + _2 < _3));
}
} // namespace Ui