Improve loading / failed states in ai editor.

Telegram/SourceFiles/ui/effects/skeleton_animation.cpp

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+/*
+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
+*/
+#include "ui/effects/skeleton_animation.h"
+
+#include "ui/painter.h"
+#include "ui/widgets/labels.h"
+#include "styles/style_widgets.h"
+
+namespace Ui {
+namespace {
+
+constexpr auto kSlideDuration = crl::time(1000);
+constexpr auto kWaitDuration = crl::time(1000);
+constexpr auto kFullDuration = kSlideDuration + kWaitDuration;
+constexpr auto kBaseAlpha = 0.5;
+constexpr auto kGradientAlpha = 0.2;
+
+[[nodiscard]] QColor ColorWithAlpha(
+		const style::color &color,
+		float64 alpha) {
+	auto result = color->c;
+	result.setAlphaF(result.alphaF() * alpha);
+	return result;
+}
+
+} // namespace
+
+SkeletonAnimation::SkeletonAnimation(not_null<FlatLabel*> label)
+: _label(label)
+, _animation([=] { _label->update(); }) {
+	base::install_event_filter(_label, _label, [=](not_null<QEvent*> e) {
+		return (_active && e->type() == QEvent::Paint)
+			? paint()
+			: base::EventFilterResult::Continue;
+	});
+	_label->sizeValue(
+	) | rpl::on_next([=](QSize) {
+		if (_active) {
+			recompute();
+		}
+	}, _lifetime);
+}
+
+void SkeletonAnimation::start() {
+	_active = true;
+	recompute();
+	_animation.start();
+	_label->update();
+}
+
+void SkeletonAnimation::stop() {
+	_active = false;
+	_animation.stop();
+	_label->update();
+}
+
+bool SkeletonAnimation::active() const {
+	return _active;
+}
+
+void SkeletonAnimation::recompute() {
+	_lineWidths = _label->countLineWidths();
+}
+
+base::EventFilterResult SkeletonAnimation::paint() {
+	if (_lineWidths.empty()) {
+		return base::EventFilterResult::Cancel;
+	}
+	auto p = QPainter(_label);
+	PainterHighQualityEnabler hq(p);
+
+	const auto &st = _label->st();
+	const auto lineHeight = st.style.lineHeight
+		? st.style.lineHeight
+		: st.style.font->height;
+	const auto thickness = st.style.font->height / 2;
+	const auto radius = thickness / 2.;
+	const auto left = st.margin.left();
+	const auto textWidth = _label->width()
+		- st.margin.left()
+		- st.margin.right();
+	const auto baseColor = ColorWithAlpha(
+		st::windowSubTextFg,
+		kBaseAlpha);
+
+	const auto now = crl::now();
+	const auto period = now % kFullDuration;
+	const auto gradientActive = (period < kSlideDuration);
+
+	p.setPen(Qt::NoPen);
+	if (gradientActive) {
+		const auto progress = period
+			/ float64(kSlideDuration);
+		const auto gradientWidth = textWidth;
+		const auto gradientStart = anim::interpolate(
+			left - gradientWidth,
+			left + textWidth,
+			progress);
+		auto gradient = QLinearGradient(
+			gradientStart,
+			0,
+			gradientStart + gradientWidth,
+			0);
+		const auto centerColor = ColorWithAlpha(
+			st::windowSubTextFg,
+			kGradientAlpha);
+		gradient.setStops({
+			{ 0., baseColor },
+			{ 0.5, centerColor },
+			{ 1., baseColor },
+		});
+		p.setBrush(gradient);
+	} else {
+		p.setBrush(baseColor);
+	}
+	auto lineTop = st.margin.top();
+	for (const auto lineWidth : _lineWidths) {
+		if (lineWidth <= 0) {
+			lineTop += lineHeight;
+			continue;
+		}
+		const auto rect = QRectF(
+			left,
+			lineTop + (lineHeight - thickness) / 2.,
+			lineWidth,
+			thickness);
+		p.drawRoundedRect(rect, radius, radius);
+		lineTop += lineHeight;
+	}
+	return base::EventFilterResult::Cancel;
+}
+
+} // namespace Ui

Telegram/SourceFiles/ui/effects/skeleton_animation.h

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+/*
+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
+
+#include "base/event_filter.h"
+#include "ui/effects/animations.h"
+
+namespace Ui {
+
+class FlatLabel;
+
+class SkeletonAnimation final {
+public:
+	explicit SkeletonAnimation(not_null<FlatLabel*> label);
+
+	void start();
+	void stop();
+	[[nodiscard]] bool active() const;
+
+private:
+	void recompute();
+	base::EventFilterResult paint();
+
+	const not_null<FlatLabel*> _label;
+	Ui::Animations::Basic _animation;
+	std::vector<int> _lineWidths;
+	bool _active = false;
+	rpl::lifetime _lifetime;
+
+};
+
+} // namespace Ui