From b80dd9917278f1fec17ae9d29ab6f62219491555 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Tue, 7 Mar 2017 12:46:01 +0300
Subject: [PATCH] Ui::FadeAnimation now supports scaling.

Ui::WidgetScaledFadeWrap<> wrapper added for fading widgets out and
fading them in with a scale effect similar to Ui::SendButton.
---
 .../ui/effects/widget_fade_wrap.cpp           | 47 ++++++++++++++++---
 .../SourceFiles/ui/effects/widget_fade_wrap.h | 32 +++++++++++--
 2 files changed, 68 insertions(+), 11 deletions(-)

diff --git a/Telegram/SourceFiles/ui/effects/widget_fade_wrap.cpp b/Telegram/SourceFiles/ui/effects/widget_fade_wrap.cpp
index 40290f0e4..3eca54468 100644
--- a/Telegram/SourceFiles/ui/effects/widget_fade_wrap.cpp
+++ b/Telegram/SourceFiles/ui/effects/widget_fade_wrap.cpp
@@ -21,8 +21,15 @@ Copyright (c) 2014-2017 John Preston, https://desktop.telegram.org
 #include "ui/effects/widget_fade_wrap.h"
 
 namespace Ui {
+namespace {
 
-FadeAnimation::FadeAnimation(TWidget *widget) : _widget(widget) {
+constexpr int kWideScale = 5;
+
+} // namespace
+
+FadeAnimation::FadeAnimation(TWidget *widget, bool scaled)
+: _widget(widget)
+, _scaled(scaled) {
 }
 
 bool FadeAnimation::paint(Painter &p) {
@@ -30,17 +37,44 @@ bool FadeAnimation::paint(Painter &p) {
 
 	auto opacity = _animation.current(getms(), _visible ? 1. : 0.);
 	p.setOpacity(opacity);
-	p.drawPixmap(0, 0, _cache);
+	if (_scaled) {
+		PainterHighQualityEnabler hq(p);
+		auto targetRect = QRect((1 - kWideScale) / 2 * _size.width(), (1 - kWideScale) / 2 * _size.height(), kWideScale * _size.width(), kWideScale * _size.height());
+		auto scale = opacity;
+		auto shownWidth = anim::interpolate((1 - kWideScale) / 2 * _size.width(), 0, scale);
+		auto shownHeight = anim::interpolate((1 - kWideScale) / 2 * _size.height(), 0, scale);
+		p.drawPixmap(targetRect.marginsAdded(QMargins(shownWidth, shownHeight, shownWidth, shownHeight)), _cache);
+	} else {
+		p.drawPixmap(0, 0, _cache);
+	}
 	return true;
 }
 
 void FadeAnimation::refreshCache() {
 	if (!_cache.isNull()) {
 		_cache = QPixmap();
-		_cache = myGrab(_widget);
+		_cache = grabContent();
 	}
 }
 
+QPixmap FadeAnimation::grabContent() {
+	myEnsureResized(_widget);
+	_size = _widget->size();
+	auto widgetContent = myGrab(_widget);
+	if (!_scaled) {
+		return widgetContent;
+	}
+
+	auto result = QImage(kWideScale * _size * cIntRetinaFactor(), QImage::Format_ARGB32_Premultiplied);
+	result.setDevicePixelRatio(cRetinaFactor());
+	result.fill(Qt::transparent);
+	{
+		Painter p(&result);
+		p.drawPixmap((kWideScale - 1) / 2 * _size.width(), (kWideScale - 1) / 2 * _size.height(), widgetContent);
+	}
+	return App::pixmapFromImageInPlace(std::move(result));
+}
+
 void FadeAnimation::setFinishedCallback(FinishedCallback &&callback) {
 	_finishedCallback = std::move(callback);
 }
@@ -93,7 +127,7 @@ void FadeAnimation::fadeOut(int duration) {
 void FadeAnimation::startAnimation(int duration) {
 	if (_cache.isNull()) {
 		_widget->showChildren();
-		_cache = myGrab(_widget);
+		_cache = grabContent();
 		_widget->hideChildren();
 	}
 	auto from = _visible ? 0. : 1.;
@@ -119,11 +153,12 @@ void FadeAnimation::updateCallback() {
 WidgetFadeWrap<TWidget>::WidgetFadeWrap(QWidget *parent
 , object_ptr<TWidget> entity
 , int duration
-, base::lambda<void()> updateCallback) : TWidget(parent)
+, base::lambda<void()> updateCallback
+, bool scaled) : TWidget(parent)
 , _entity(std::move(entity))
 , _duration(duration)
 , _updateCallback(std::move(updateCallback))
-, _animation(this) {
+, _animation(this, scaled) {
 	_animation.show();
 	if (_updateCallback) {
 		_animation.setFinishedCallback([this] { _updateCallback(); });
diff --git a/Telegram/SourceFiles/ui/effects/widget_fade_wrap.h b/Telegram/SourceFiles/ui/effects/widget_fade_wrap.h
index 1ab6e3a92..107e95249 100644
--- a/Telegram/SourceFiles/ui/effects/widget_fade_wrap.h
+++ b/Telegram/SourceFiles/ui/effects/widget_fade_wrap.h
@@ -28,7 +28,7 @@ namespace Ui {
 
 class FadeAnimation {
 public:
-	FadeAnimation(TWidget *widget);
+	FadeAnimation(TWidget *widget, bool scaled = false);
 
 	bool paint(Painter &p);
 	void refreshCache();
@@ -58,9 +58,13 @@ private:
 	void stopAnimation();
 
 	void updateCallback();
+	QPixmap grabContent();
+
+	TWidget *_widget = nullptr;
+	bool _scaled = false;
 
-	TWidget *_widget;
 	Animation _animation;
+	QSize _size;
 	QPixmap _cache;
 	bool _visible = false;
 
@@ -78,7 +82,8 @@ public:
 	WidgetFadeWrap(QWidget *parent
 		, object_ptr<TWidget> entity
 		, int duration = st::widgetFadeDuration
-		, base::lambda<void()> updateCallback = base::lambda<void()>());
+		, base::lambda<void()> updateCallback = base::lambda<void()>()
+		, bool scaled = false);
 
 	void showAnimated() {
 		_animation.fadeIn(_duration);
@@ -140,10 +145,12 @@ public:
 	WidgetFadeWrap(QWidget *parent
 		, object_ptr<Widget> entity
 		, int duration = st::widgetFadeDuration
-		, base::lambda<void()> updateCallback = base::lambda<void()>()) : WidgetFadeWrap<TWidget>(parent
+		, base::lambda<void()> updateCallback = base::lambda<void()>()
+		, bool scaled = false) : WidgetFadeWrap<TWidget>(parent
 			, std::move(entity)
 			, duration
-			, std::move(updateCallback)) {
+			, std::move(updateCallback)
+			, scaled) {
 	}
 	Widget *entity() {
 		return static_cast<Widget*>(WidgetFadeWrap<TWidget>::entity());
@@ -154,4 +161,19 @@ public:
 
 };
 
+template <typename Widget>
+class WidgetScaledFadeWrap : public WidgetFadeWrap<Widget> {
+public:
+	WidgetScaledFadeWrap(QWidget *parent
+		, object_ptr<Widget> entity
+		, int duration = st::widgetFadeDuration
+		, base::lambda<void()> updateCallback = base::lambda<void()>()) : WidgetFadeWrap<Widget>(parent
+			, std::move(entity)
+			, duration
+			, std::move(updateCallback)
+			, true) {
+	}
+
+};
+
 } // namespace Ui