Copy code blocks on header click.

Telegram/Resources/langs/lang.strings

@@ -2686,6 +2686,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 "lng_formatting_link_create" = "Create";
 
 "lng_text_copied" = "Text copied to clipboard.";
+"lng_code_copied" = "Code copied to clipboard.";
 
 "lng_spellchecker_submenu" = "Spelling";
 "lng_spellchecker_add" = "Add to Dictionary";

Telegram/SourceFiles/core/ui_integration.cpp

@@ -243,6 +243,16 @@ bool UiIntegration::handleUrlClick(
 	return true;
 }
 
+bool UiIntegration::copyPreOnClick(const QVariant &context) {
+	const auto my = context.value<ClickHandlerContext>();
+	if (const auto window = my.sessionWindow.get()) {
+		window->showToast(tr::lng_code_copied(tr::now));
+	} else if (my.show) {
+		my.show->showToast(tr::lng_code_copied(tr::now));
+	}
+	return true;
+}
+
 std::unique_ptr<Ui::Text::CustomEmoji> UiIntegration::createCustomEmoji(
 		const QString &data,
 		const std::any &context) {

Telegram/SourceFiles/core/ui_integration.h

@@ -53,6 +53,7 @@ public:
 	bool handleUrlClick(
 		const QString &url,
 		const QVariant &context) override;
+	bool copyPreOnClick(const QVariant &context) override;
 	rpl::producer<> forcePopupMenuHideRequests() override;
 	const Ui::Emoji::One *defaultEmojiVariant(
 		const Ui::Emoji::One *emoji) override;

Telegram/SourceFiles/ui/chat/chat.style

@@ -56,6 +56,8 @@ messageTextStyle: TextStyle(defaultTextStyle) {
 		header: 20px;
 		headerPosition: point(10px, 2px);
 		scrollable: true;
+		icon: icon{{ "chat/mini_copy", windowFg }};
+		iconPosition: point(4px, 2px);
 	}
 }
 msgDateTextStyle: defaultTextStyle;

Telegram/SourceFiles/ui/chat/chat_style.cpp

@@ -60,6 +60,8 @@ void EnsurePreCache(
 	cache->outline.setAlphaF(0.9);
 	cache->header = color->c;
 	cache->header.setAlphaF(0.25);
+	cache->icon = cache->outline;
+	cache->icon.setAlphaF(0.6);
 }
 
 } // namespace