Add a convenient splitter for showing and hiding widgets.

src/README.md

@@ -45,3 +45,7 @@ A popup widget.
 ## Widgets/Scrollbar.h/cpp
 
 A scrollbar supports 64-bit ranges.
+
+## Widgets/Splitter.h/cpp
+
+A convenient splitter for showing and hiding widgets.

src/Widgets/Splitter.cpp

@@ -0,0 +1,144 @@
+ /*
+ * Copyright 2020, WindTerm.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "Splitter.h"
+
+#include <QEvent>
+#include <QVariant>
+
+const char* const SPLITTER_RATIO = "ratio";
+
+Splitter::Splitter(QWidget *parent)
+	: QSplitter(parent)
+	, m_mainIndex(0)
+{}
+
+Splitter::~Splitter()
+{}
+
+void Splitter::showIndex(int index) {
+	if (isIndexVisible(index))
+		return;
+
+	emit showIndexRequested(index);
+
+	if (QSplitterHandle *handle = this->handle(index)) {
+		QList<int> sizes = this->sizes();
+
+		int total = 0;
+		for (int size : sizes) {
+			total += size;
+		}
+
+		float ratio = handle->property(SPLITTER_RATIO).toFloat();
+		if (ratio == 0.0) {
+			ratio = 0.18f;
+		}
+
+		int offset = 0;
+		int size = total * ratio;
+
+		if (index > 0) {
+			for (int i = 0; i < index; i++) {
+				offset += sizes[i];
+			}
+			offset -= size;
+		} else {
+			offset = size;
+		}
+
+		if (index <= m_mainIndex) {
+			index += 1;
+		}
+		moveSplitter(offset, index);
+	}
+}
+
+void Splitter::hideIndex(int index) {
+	if (isIndexVisible(index) == false)
+		return;
+
+	emit hideIndexRequested(index);
+
+	if (QSplitterHandle *handle = this->handle(index)) {
+		QList<int> sizes = this->sizes();
+		int size = sizes[index];
+
+		float total = 0;
+		for (int size : sizes) {
+			total += size;
+		}
+		handle->setProperty(SPLITTER_RATIO, size / total);
+
+		int offset = 0;
+		for (int i = 0; i <= index; i++) {
+			if (i == index && index <= m_mainIndex)
+				break;
+			offset += sizes[i];
+		}
+
+		if (index <= m_mainIndex) {
+			index += 1;
+		}
+		moveSplitter(offset, index);
+	}
+}
+
+bool Splitter::isIndexVisible(int index) {
+	if (index >= 0 && index < count()) {
+		return sizes()[index] > 0;
+	}
+	
+	Q_ASSERT(false);
+	return false;
+}
+
+void Splitter::setIndexVisible(int index, bool visible) {
+	if (visible) {
+		showIndex(index);
+	} else {
+		hideIndex(index);
+	}
+}
+
+void Splitter::setMainIndex(int mainIndex) {
+	m_mainIndex = mainIndex;
+}
+
+bool Splitter::eventFilter(QObject *obj, QEvent *event) {
+	if (event->type() == QEvent::MouseButtonDblClick) {
+		if (QSplitterHandle *handle = dynamic_cast<QSplitterHandle *>(obj)) {
+			for (int i = 0; i < count(); i++) {
+				if (handle == this->handle(i)) {
+					if (i <= m_mainIndex && i > 0) {
+						i--;
+					}
+					bool visible = isIndexVisible(i);
+					setIndexVisible(i, !visible);
+					break;
+				}
+			}
+		}
+	}
+	return QSplitter::eventFilter(obj, event);
+}
+
+QSplitterHandle *Splitter::createHandle() {
+	QSplitterHandle *handle = QSplitter::createHandle();
+	handle->installEventFilter(this);
+	
+	return handle;
+}

src/Widgets/Splitter.h

@@ -0,0 +1,56 @@
+ /*
+ * Copyright 2020, WindTerm.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef SPLITTER_H
+#define SPLITTER_H
+
+#pragma once
+
+#include <QSplitter>
+
+extern const char* const SPLITTER_RATIO;
+
+class Splitter : public QSplitter
+{
+	Q_OBJECT
+
+public:
+	explicit Splitter(QWidget *parent = 0);
+	~Splitter();
+
+	void showIndex(int index);
+	void hideIndex(int index);
+	bool isIndexVisible(int index);
+	void setIndexVisible(int index, bool visible);
+
+	void setMainIndex(int mainIndex);
+
+protected:
+	bool eventFilter(QObject *obj, QEvent *event);
+
+	QSplitterHandle *createHandle();
+
+Q_SIGNALS:
+	void showIndexRequested(int index);
+	void hideIndexRequested(int index);
+
+private:
+	Q_DISABLE_COPY(Splitter)
+
+	int m_mainIndex;
+};
+
+#endif // SPLITTER_H