From e8aa55d4d873d6bc0af6b5e8416684b2812e95c2 Mon Sep 17 00:00:00 2001
From: 23rd <23rd@vivaldi.net>
Date: Fri, 26 May 2023 16:04:33 +0300
Subject: [PATCH] Added initial support of static zoom for chart widget.

---
 Telegram/CMakeLists.txt                       |  1 +
 .../SourceFiles/statistics/chart_widget.cpp   | 51 +++++++++++++++++--
 .../SourceFiles/statistics/chart_widget.h     |  8 ++-
 .../statistics/linear_chart_view.cpp          |  6 ++-
 .../statistics/linear_chart_view.h            |  3 ++
 .../statistics/statistics_common.h            | 17 +++++++
 6 files changed, 75 insertions(+), 11 deletions(-)
 create mode 100644 Telegram/SourceFiles/statistics/statistics_common.h

diff --git a/Telegram/CMakeLists.txt b/Telegram/CMakeLists.txt
index 8be69b082..97ce9013f 100644
--- a/Telegram/CMakeLists.txt
+++ b/Telegram/CMakeLists.txt
@@ -1292,6 +1292,7 @@ PRIVATE
     statistics/segment_tree.h
     statistics/statistics_box.cpp
     statistics/statistics_box.h
+    statistics/statistics_common.h
     statistics/statistics_data_deserialize.cpp
     statistics/statistics_data_deserialize.h
     storage/details/storage_file_utilities.cpp
diff --git a/Telegram/SourceFiles/statistics/chart_widget.cpp b/Telegram/SourceFiles/statistics/chart_widget.cpp
index cb78a7b96..17be748d0 100644
--- a/Telegram/SourceFiles/statistics/chart_widget.cpp
+++ b/Telegram/SourceFiles/statistics/chart_widget.cpp
@@ -73,10 +73,14 @@ class ChartWidget::Footer final : public Ui::AbstractButton {
 public:
 	Footer(not_null<Ui::RpWidget*> parent);
 
+	[[nodiscard]] rpl::producer<Limits> xPercentageLimitsChange() const;
+
 private:
 	not_null<Ui::AbstractButton*> _left;
 	not_null<Ui::AbstractButton*> _right;
 
+	rpl::event_stream<Limits> _xPercentageLimitsChange;
+
 	struct {
 		int x = 0;
 		int leftLimit = 0;
@@ -135,6 +139,10 @@ ChartWidget::Footer::Footer(not_null<Ui::RpWidget*> parent)
 				_start.rightLimit = rightLimit();
 			} break;
 			case QEvent::MouseButtonRelease: {
+				_xPercentageLimitsChange.fire({
+					.min = _left->x() / float64(width()),
+					.max = rect::right(_right) / float64(width()),
+				});
 				_start = {};
 			} break;
 			}
@@ -150,6 +158,10 @@ ChartWidget::Footer::Footer(not_null<Ui::RpWidget*> parent)
 		[=] { return width() - _right->width(); });
 }
 
+rpl::producer<Limits> ChartWidget::Footer::xPercentageLimitsChange() const {
+	return _xPercentageLimitsChange.events();
+}
+
 ChartWidget::ChartWidget(not_null<Ui::RpWidget*> parent)
 : Ui::RpWidget(parent)
 , _footer(std::make_unique<Footer>(this)) {
@@ -162,16 +174,40 @@ ChartWidget::ChartWidget(not_null<Ui::RpWidget*> parent)
 			st::countryRowHeight);
 	}, _footer->lifetime());
 	_footer->paintRequest(
-	) | rpl::start_with_next([=] {
+	) | rpl::start_with_next([=, limits = Limits{ 0., 1. }] {
 		auto p = QPainter(_footer.get());
 
 		if (_chartData) {
 			Statistic::PaintLinearChartView(
 				p,
 				_chartData,
+				limits,
 				_footer->rect());
 		}
 	}, _footer->lifetime());
+	_footer->xPercentageLimitsChange(
+	) | rpl::start_with_next([=](Limits xPercentageLimits) {
+		_xPercentageLimits = {
+			.min = *ranges::lower_bound(
+				_chartData.xPercentage,
+				xPercentageLimits.min),
+			.max = *ranges::lower_bound(
+				_chartData.xPercentage,
+				xPercentageLimits.max),
+		};
+		const auto startXIndex = _chartData.findStartIndex(
+			_xPercentageLimits.min);
+		const auto endXIndex = _chartData.findEndIndex(
+			startXIndex,
+			_xPercentageLimits.max);
+		setHeightLimits(
+			{
+				float64(FindMinValue(_chartData, startXIndex, endXIndex)),
+				float64(FindMaxValue(_chartData, startXIndex, endXIndex)),
+			},
+			false);
+		update();
+	}, _footer->lifetime());
 	resize(width(), st::confirmMaxHeight + st::countryRowHeight * 2);
 }
 
@@ -179,17 +215,21 @@ void ChartWidget::setChartData(Data::StatisticalChart chartData) {
 	_chartData = chartData;
 
 	{
+		_xPercentageLimits = {
+			.min = _chartData.xPercentage.front(),
+			.max = _chartData.xPercentage.back(),
+		};
 		const auto startXIndex = _chartData.findStartIndex(
-			_chartData.xPercentage.front());
+			_xPercentageLimits.min);
 		const auto endXIndex = _chartData.findEndIndex(
 			startXIndex,
-			_chartData.xPercentage.back());
+			_xPercentageLimits.max);
 		setHeightLimits(
 			{
 				float64(FindMinValue(_chartData, startXIndex, endXIndex)),
 				float64(FindMaxValue(_chartData, startXIndex, endXIndex)),
 			},
-			true);
+			false);
 		update();
 	}
 }
@@ -205,6 +245,8 @@ void ChartWidget::paintEvent(QPaintEvent *e) {
 	const auto chartRect = r
 		- QMargins{ 0, st::boxTextFont->height, 0, chartRectBottom };
 
+	p.fillRect(r, st::boxBg);
+
 	for (const auto &horizontalLine : _horizontalLines) {
 		PaintHorizontalLines(p, horizontalLine, chartRect);
 	}
@@ -213,6 +255,7 @@ void ChartWidget::paintEvent(QPaintEvent *e) {
 		Statistic::PaintLinearChartView(
 			p,
 			_chartData,
+			_xPercentageLimits,
 			chartRect);
 	}
 
diff --git a/Telegram/SourceFiles/statistics/chart_widget.h b/Telegram/SourceFiles/statistics/chart_widget.h
index dc0264f13..b53c598b3 100644
--- a/Telegram/SourceFiles/statistics/chart_widget.h
+++ b/Telegram/SourceFiles/statistics/chart_widget.h
@@ -9,6 +9,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 #include "data/data_statistics.h"
 #include "statistics/chart_horizontal_lines_data.h"
+#include "statistics/statistics_common.h"
 #include "ui/effects/animations.h"
 #include "ui/rp_widget.h"
 
@@ -18,11 +19,6 @@ class ChartWidget : public Ui::RpWidget {
 public:
 	ChartWidget(not_null<Ui::RpWidget*> parent);
 
-	struct Limits final {
-		float64 min = 0;
-		float64 max = 0;
-	};
-
 	void setChartData(Data::StatisticalChart chartData);
 	void setHeightLimits(Limits newHeight, bool animated);
 
@@ -44,6 +40,8 @@ private:
 	Limits _startFrom;
 	Limits _startFromH;
 
+	Limits _xPercentageLimits;
+
 	float64 _minMaxUpdateStep = 0.;
 
 	crl::time _lastHeightLimitsChanged = 0;
diff --git a/Telegram/SourceFiles/statistics/linear_chart_view.cpp b/Telegram/SourceFiles/statistics/linear_chart_view.cpp
index 2b0e832c0..5fb760c56 100644
--- a/Telegram/SourceFiles/statistics/linear_chart_view.cpp
+++ b/Telegram/SourceFiles/statistics/linear_chart_view.cpp
@@ -8,6 +8,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "statistics/linear_chart_view.h"
 
 #include "data/data_statistics.h"
+#include "statistics/statistics_common.h"
 #include "styles/style_boxes.h"
 
 namespace Statistic {
@@ -15,6 +16,7 @@ namespace Statistic {
 void PaintLinearChartView(
 		QPainter &p,
 		const Data::StatisticalChart &chartData,
+		const Limits &xPercentageLimits,
 		const QRect &rect) {
 	const auto offset = 0;
 	const auto currentMinHeight = rect.y(); //
@@ -30,10 +32,10 @@ void PaintLinearChartView(
 		auto chartPath = QPainterPath();
 
 		const auto startXIndex = chartData.findStartIndex(
-			chartData.xPercentage.front());
+			xPercentageLimits.min);
 		const auto endXIndex = chartData.findEndIndex(
 			startXIndex,
-			chartData.xPercentage.back());
+			xPercentageLimits.max);
 
 		const auto localStart = std::max(0, startXIndex - additionalPoints);
 		const auto localEnd = std::min(
diff --git a/Telegram/SourceFiles/statistics/linear_chart_view.h b/Telegram/SourceFiles/statistics/linear_chart_view.h
index d23067a51..f9414dbb5 100644
--- a/Telegram/SourceFiles/statistics/linear_chart_view.h
+++ b/Telegram/SourceFiles/statistics/linear_chart_view.h
@@ -13,9 +13,12 @@ struct StatisticalChart;
 
 namespace Statistic {
 
+struct Limits;
+
 void PaintLinearChartView(
 	QPainter &p,
 	const Data::StatisticalChart &chartData,
+	const Limits &xPercentageLimits,
 	const QRect &rect);
 
 } // namespace Statistic
diff --git a/Telegram/SourceFiles/statistics/statistics_common.h b/Telegram/SourceFiles/statistics/statistics_common.h
new file mode 100644
index 000000000..397791c57
--- /dev/null
+++ b/Telegram/SourceFiles/statistics/statistics_common.h
@@ -0,0 +1,17 @@
+/*
+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
+*/
+#pragma once
+
+namespace Statistic {
+
+struct Limits final {
+	float64 min = 0;
+	float64 max = 0;
+};
+
+} // namespace Statistic