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Telegram/lib_ui/ui/dpr/dpr_image.h

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+// This file is part of Desktop App Toolkit,
+// a set of libraries for developing nice desktop applications.
+//
+// For license and copyright information please follow this link:
+// https://github.com/desktop-app/legal/blob/master/LEGAL
+//
+#pragma once
+
+#include <rpl/details/callable.h>
+
+#include <QtGui/QImage>
+#include <QtGui/QPainter>
+
+namespace dpr {
+
+// Validate(_cache, devicePixelRatioF(), size, [&](QPainter &p, QSize size) {
+//	... paint using p ...
+// }, (_cacheKey != cacheKey()), Qt::transparent);
+
+template <typename Generator>
+void Validate(
+		QImage &image,
+		double ratio,
+		QSize size,
+		Generator &&generator,
+		bool force,
+		std::optional<QColor> fill = {},
+		bool setResultRatio = true) {
+	size *= ratio;
+	const auto sizeChanged = (image.size() != size);
+	if (sizeChanged || force) {
+		if (sizeChanged) {
+			image = QImage(size, QImage::Format_ARGB32_Premultiplied);
+		}
+		if (fill) {
+			image.fill(*fill);
+		}
+		image.setDevicePixelRatio(1.);
+		auto p = QPainter(&image);
+		using namespace rpl::details;
+		if constexpr (is_callable_plain_v<Generator, QPainter&, QSize>) {
+			generator(p, size);
+		} else {
+			generator(p);
+		}
+	}
+	image.setDevicePixelRatio(setResultRatio ? ratio : 1.);
+}
+
+} // namespace dpr