From ec76a4c0bb9131ab14fe676630a1f465bfc05ee2 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Wed, 6 Jul 2022 10:09:10 +0400
Subject: [PATCH] Optimize custom emoji repaints in the InputField.

---
 ui/widgets/input_fields.cpp | 18 +++++++++++++++++-
 ui/widgets/input_fields.h   |  3 +++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/ui/widgets/input_fields.cpp b/ui/widgets/input_fields.cpp
index 75e2e34..8a87c91 100644
--- a/ui/widgets/input_fields.cpp
+++ b/ui/widgets/input_fields.cpp
@@ -963,6 +963,9 @@ protected:
 	void inputMethodEvent(QInputMethodEvent *e) override {
 		return outer()->inputMethodEventInner(e);
 	}
+	void paintEvent(QPaintEvent *e) override {
+		return outer()->paintEventInner(e);
+	}
 
 	bool canInsertFromMimeData(const QMimeData *source) const override {
 		return outer()->canInsertFromMimeDataInner(source);
@@ -1664,13 +1667,26 @@ void InputField::setCustomEmojiFactory(
 		Fn<bool()> paused) {
 	_customEmojiObject = std::make_unique<CustomEmojiObject>([=](
 			QStringView data) {
-		return factory(data, [=] { _inner->update(); });
+		return factory(data, [=] { customEmojiRepaint(); });
 	}, std::move(paused));
 	_inner->document()->documentLayout()->registerHandler(
 		kCustomEmojiFormat,
 		_customEmojiObject.get());
 }
 
+void InputField::customEmojiRepaint() {
+	if (_customEmojiRepaintScheduled) {
+		return;
+	}
+	_customEmojiRepaintScheduled = true;
+	_inner->update();
+}
+
+void InputField::paintEventInner(QPaintEvent *e) {
+	_customEmojiRepaintScheduled = false;
+	_inner->QTextEdit::paintEvent(e);
+}
+
 void InputField::setAdditionalMargin(int margin) {
 	_additionalMargin = margin;
 	QResizeEvent e(size(), size());
diff --git a/ui/widgets/input_fields.h b/ui/widgets/input_fields.h
index 67fffed..a80e24c 100644
--- a/ui/widgets/input_fields.h
+++ b/ui/widgets/input_fields.h
@@ -442,6 +442,7 @@ private:
 	void contextMenuEventInner(QContextMenuEvent *e, QMenu *m = nullptr);
 	void dropEventInner(QDropEvent *e);
 	void inputMethodEventInner(QInputMethodEvent *e);
+	void paintEventInner(QPaintEvent *e);
 
 	QMimeData *createMimeDataFromSelectionInner() const;
 	bool canInsertFromMimeDataInner(const QMimeData *source) const;
@@ -513,6 +514,7 @@ private:
 
 	bool revertFormatReplace();
 
+	void customEmojiRepaint();
 	void highlightMarkdown();
 
 	const style::InputField &_st;
@@ -536,6 +538,7 @@ private:
 
 	bool _forcePlaceholderHidden = false;
 	bool _reverseMarkdownReplacement = false;
+	bool _customEmojiRepaintScheduled = false;
 
 	// Tags list which we should apply while setText() call or insert from mime data.
 	TagList _insertedTags;