WASM: add Emscripten demo application

Change-Id: I31297142761255b1f357fc9677a644b7a93c921a
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/111128
Tested-by: Jenkins
Reviewed-by: Thorsten Behrens <thorsten.behrens@allotropia.de>

1 files changed, 228 insertions, 0 deletions

diff --git a/wasm-qt/source/qt5-mandelbrot/mandelbrotwidget.cxx b/wasm-qt/source/qt5-mandelbrot/mandelbrotwidget.cxx
new file mode 100644
index 000000000000..5886dd2664c0
--- /dev/null
+++ b/wasm-qt/source/qt5-mandelbrot/mandelbrotwidget.cxx
@@ -0,0 +1,228 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "mandelbrotwidget.h"
+#include "mandelbrotwidget.moc"
+
+#include <QtGui/QPainter>
+#include <QtGui/QKeyEvent>
+
+#include <math.h>
+
+const double DefaultCenterX = -0.637011;
+const double DefaultCenterY = -0.0395159;
+const double DefaultScale = 0.00403897;
+
+const double ZoomInFactor = 0.8;
+const double ZoomOutFactor = 1 / ZoomInFactor;
+const int ScrollStep = 20;
+
+MandelbrotWidget::MandelbrotWidget(QWidget* parent)
+    : QWidget(parent)
+    , centerX(DefaultCenterX)
+    , centerY(DefaultCenterY)
+    , pixmapScale(DefaultScale)
+    , curScale(DefaultScale)
+{
+    connect(&thread, &RenderThread::renderedImage, this, &MandelbrotWidget::updatePixmap);
+
+    setWindowTitle(tr("Mandelbrot"));
+#if QT_CONFIG(cursor)
+    setCursor(Qt::CrossCursor);
+#endif
+    resize(550, 400);
+}
+
+void MandelbrotWidget::paintEvent(QPaintEvent* /* event */)
+{
+    QPainter painter(this);
+    painter.fillRect(rect(), Qt::black);
+
+    if (pixmap.isNull())
+    {
+        painter.setPen(Qt::white);
+        painter.drawText(rect(), Qt::AlignCenter, tr("Rendering initial image, please wait..."));
+        return;
+    }
+
+    if (qFuzzyCompare(curScale, pixmapScale))
+    {
+        painter.drawPixmap(pixmapOffset, pixmap);
+    }
+    else
+    {
+        auto previewPixmap = qFuzzyCompare(pixmap.devicePixelRatioF(), qreal(1))
+                                 ? pixmap
+                                 : pixmap.scaled(pixmap.size() / pixmap.devicePixelRatioF(),
+                                                 Qt::KeepAspectRatio, Qt::SmoothTransformation);
+        double scaleFactor = pixmapScale / curScale;
+        int newWidth = int(previewPixmap.width() * scaleFactor);
+        int newHeight = int(previewPixmap.height() * scaleFactor);
+        int newX = pixmapOffset.x() + (previewPixmap.width() - newWidth) / 2;
+        int newY = pixmapOffset.y() + (previewPixmap.height() - newHeight) / 2;
+
+        painter.save();
+        painter.translate(newX, newY);
+        painter.scale(scaleFactor, scaleFactor);
+
+        QRectF exposed = painter.transform().inverted().mapRect(rect()).adjusted(-1, -1, 1, 1);
+        painter.drawPixmap(exposed, previewPixmap, exposed);
+        painter.restore();
+    }
+
+    QString text = tr("Use mouse wheel or the '+' and '-' keys to zoom. "
+                      "Press and hold left mouse button to scroll.");
+    QFontMetrics metrics = painter.fontMetrics();
+    int textWidth = metrics.horizontalAdvance(text);
+
+    painter.setPen(Qt::NoPen);
+    painter.setBrush(QColor(0, 0, 0, 127));
+    painter.drawRect((width() - textWidth) / 2 - 5, 0, textWidth + 10, metrics.lineSpacing() + 5);
+    painter.setPen(Qt::white);
+    painter.drawText((width() - textWidth) / 2, metrics.leading() + metrics.ascent(), text);
+}
+
+void MandelbrotWidget::resizeEvent(QResizeEvent* /* event */)
+{
+    thread.render(centerX, centerY, curScale, size(), devicePixelRatioF());
+}
+
+void MandelbrotWidget::keyPressEvent(QKeyEvent* event)
+{
+    switch (event->key())
+    {
+        case Qt::Key_Plus:
+            zoom(ZoomInFactor);
+            break;
+        case Qt::Key_Minus:
+            zoom(ZoomOutFactor);
+            break;
+        case Qt::Key_Left:
+            scroll(-ScrollStep, 0);
+            break;
+        case Qt::Key_Right:
+            scroll(+ScrollStep, 0);
+            break;
+        case Qt::Key_Down:
+            scroll(0, -ScrollStep);
+            break;
+        case Qt::Key_Up:
+            scroll(0, +ScrollStep);
+            break;
+        default:
+            QWidget::keyPressEvent(event);
+    }
+}
+
+#if QT_CONFIG(wheelevent)
+void MandelbrotWidget::wheelEvent(QWheelEvent* event)
+{
+    const int numDegrees = event->angleDelta().y() / 8;
+    const double numSteps = numDegrees / double(15);
+    zoom(pow(ZoomInFactor, numSteps));
+}
+#endif
+
+void MandelbrotWidget::mousePressEvent(QMouseEvent* event)
+{
+    if (event->button() == Qt::LeftButton)
+        lastDragPos = event->pos();
+}
+
+void MandelbrotWidget::mouseMoveEvent(QMouseEvent* event)
+{
+    if (event->buttons() & Qt::LeftButton)
+    {
+        pixmapOffset += event->pos() - lastDragPos;
+        lastDragPos = event->pos();
+        update();
+    }
+}
+
+void MandelbrotWidget::mouseReleaseEvent(QMouseEvent* event)
+{
+    if (event->button() == Qt::LeftButton)
+    {
+        pixmapOffset += event->pos() - lastDragPos;
+        lastDragPos = QPoint();
+
+        const auto pixmapSize = pixmap.size() / pixmap.devicePixelRatioF();
+        int deltaX = (width() - pixmapSize.width()) / 2 - pixmapOffset.x();
+        int deltaY = (height() - pixmapSize.height()) / 2 - pixmapOffset.y();
+        scroll(deltaX, deltaY);
+    }
+}
+
+void MandelbrotWidget::updatePixmap(const QImage& image, double scaleFactor)
+{
+    if (!lastDragPos.isNull())
+        return;
+
+    pixmap = QPixmap::fromImage(image);
+    pixmapOffset = QPoint();
+    lastDragPos = QPoint();
+    pixmapScale = scaleFactor;
+    update();
+}
+
+void MandelbrotWidget::zoom(double zoomFactor)
+{
+    curScale *= zoomFactor;
+    update();
+    thread.render(centerX, centerY, curScale, size(), devicePixelRatioF());
+}
+
+void MandelbrotWidget::scroll(int deltaX, int deltaY)
+{
+    centerX += deltaX * curScale;
+    centerY += deltaY * curScale;
+    update();
+    thread.render(centerX, centerY, curScale, size(), devicePixelRatioF());
+}