Add manual test for the QtGui triangulator

Have a widget-based application that uses qTriangulate for fills
and QTriangulatingStroker (and optionally the dash stroke processor)
for strokes.

The resulting triangle (strip) set is visualized on a simple QPainter
canvas, offering the ability to zoom in and examine how the triangulator
behaves on a number of example shapes. It is also possible to step through
and only have the first N set of triangles drawn.

Change-Id: I3a27d86d4ea13a63dd4be0fe81dd4b5ed6e4fa75
Reviewed-by: Andy Nichols <andy.nichols@qt.io>

4 files changed, 609 insertions, 0 deletions

diff --git a/tests/manual/triangulator/main.cpp b/tests/manual/triangulator/main.cpp
new file mode 100644
index 0000000000..066c9f374e
--- /dev/null
+++ b/tests/manual/triangulator/main.cpp
@@ -0,0 +1,43 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** 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.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <QApplication>
+#include <QMainWindow>
+#include "triviswidget.h"
+
+int main(int argc, char *argv[])
+{
+    QApplication app(argc, argv);
+
+    QMainWindow wnd;
+    wnd.resize(1280, 800);
+    wnd.setCentralWidget(new TriangulationVisualizer);
+    wnd.show();
+
+    return app.exec();
+}
diff --git a/tests/manual/triangulator/triangulator.pro b/tests/manual/triangulator/triangulator.pro
new file mode 100644
index 0000000000..95c0b15ee4
--- /dev/null
+++ b/tests/manual/triangulator/triangulator.pro
@@ -0,0 +1,9 @@
+TEMPLATE = app
+TARGET = triangulator
+
+QT += gui-private widgets
+
+SOURCES += main.cpp \
+           triviswidget.cpp
+
+HEADERS  += triviswidget.h
diff --git a/tests/manual/triangulator/triviswidget.cpp b/tests/manual/triangulator/triviswidget.cpp
new file mode 100644
index 0000000000..de1efdb4a0
--- /dev/null
+++ b/tests/manual/triangulator/triviswidget.cpp
@@ -0,0 +1,418 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** 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.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "triviswidget.h"
+#include <QVBoxLayout>
+#include <QHBoxLayout>
+#include <QGroupBox>
+#include <QWheelEvent>
+#include <QScrollBar>
+#include <QPainter>
+#include <QPainterPath>
+#include <QTimer>
+#include <QtGui/private/qtriangulator_p.h>
+#include <QtGui/private/qtriangulatingstroker_p.h>
+#include <QDebug>
+
+static const int W = 100;
+static const int H = 100;
+static const int MAX_ZOOM = 512;
+
+class ScrollArea : public QScrollArea {
+protected:
+    void wheelEvent(QWheelEvent *event) override {
+        if (!event->modifiers().testFlag(Qt::ControlModifier))
+            QScrollArea::wheelEvent(event);
+    }
+};
+
+TriangulationVisualizer::TriangulationVisualizer(QWidget *parent)
+    : QWidget(parent)
+{
+    QVBoxLayout *mainLayout = new QVBoxLayout;
+
+    QHBoxLayout *headerLayout = new QHBoxLayout;
+
+    QGroupBox *cbBox = new QGroupBox(QLatin1String("Shape"));
+    m_cbShape = new QComboBox;
+    QVBoxLayout *cbBoxLayout = new QVBoxLayout;
+    cbBoxLayout->addWidget(m_cbShape);
+    cbBox->setLayout(cbBoxLayout);
+    headerLayout->addWidget(cbBox);
+
+    m_lbPreview = new QLabel;
+    m_lbPreview->setFixedSize(W, H);
+    headerLayout->addWidget(m_lbPreview);
+
+    QGroupBox *typeBox = new QGroupBox(QLatin1String("Type"));
+    m_rdStroke = new QRadioButton(QLatin1String("Stroke"));
+    m_rdStroke->setChecked(true);
+    m_rdFill = new QRadioButton(QLatin1String("Fill"));
+    QVBoxLayout *typeBoxLayout = new QVBoxLayout;
+    typeBoxLayout->addWidget(m_rdStroke);
+    typeBoxLayout->addWidget(m_rdFill);
+    typeBox->setLayout(typeBoxLayout);
+    headerLayout->addWidget(typeBox);
+
+    QGroupBox *paramBox = new QGroupBox(QLatin1String("Stroke params"));
+    QVBoxLayout *paramBoxLayout = new QVBoxLayout;
+    m_spStrokeWidth = new QSpinBox;
+    m_spStrokeWidth->setPrefix(QLatin1String("Stroke width: "));
+    m_spStrokeWidth->setMinimum(1);
+    m_spStrokeWidth->setMaximum(32);
+    m_spStrokeWidth->setValue(1);
+    m_chDash = new QCheckBox(QLatin1String("Dash stroke"));
+    paramBoxLayout->addWidget(m_spStrokeWidth);
+    paramBoxLayout->addWidget(m_chDash);
+    paramBox->setLayout(paramBoxLayout);
+    headerLayout->addWidget(paramBox);
+
+    m_lbInfo = new QLabel;
+    headerLayout->addWidget(m_lbInfo);
+
+    QGroupBox *animBox = new QGroupBox(QLatin1String("Step through"));
+    QVBoxLayout *animBoxLayout = new QVBoxLayout;
+    m_chStepEnable = new QCheckBox(QLatin1String("Enable"));
+    m_spStepStroke = new QSpinBox;
+    m_spStepStroke->setPrefix(QLatin1String("Stroke steps: "));
+    m_spStepStroke->setMinimum(3);
+    m_spStepStroke->setMaximum(INT_MAX);
+    m_spStepStroke->setEnabled(false);
+    m_spStepFill = new QSpinBox;
+    m_spStepFill->setPrefix(QLatin1String("Fill steps: "));
+    m_spStepFill->setMinimum(3);
+    m_spStepFill->setMaximum(INT_MAX);
+    m_spStepFill->setEnabled(false);
+    animBoxLayout->addWidget(m_chStepEnable);
+    animBoxLayout->addWidget(m_spStepStroke);
+    animBoxLayout->addWidget(m_spStepFill);
+    animBox->setLayout(animBoxLayout);
+    headerLayout->addWidget(animBox);
+
+    m_canvas = new TriVisCanvas;
+    m_scrollArea = new ScrollArea;
+    m_scrollArea->setWidget(m_canvas);
+    m_scrollArea->setMinimumSize(W, H);
+
+    mainLayout->addLayout(headerLayout);
+    mainLayout->addWidget(m_scrollArea);
+    mainLayout->setStretchFactor(m_scrollArea, 9);
+
+    setLayout(mainLayout);
+
+    for (const QString &shapeName : m_canvas->shapes())
+        m_cbShape->addItem(shapeName);
+
+    connect(m_cbShape, static_cast<void (QComboBox::*)(int)>(&QComboBox::currentIndexChanged), [this]() {
+        m_canvas->setIndex(m_cbShape->currentIndex());
+        m_canvas->retriangulate();
+    });
+    connect(m_rdFill, &QRadioButton::toggled, [this]() {
+        m_canvas->setType(TriVisCanvas::Fill);
+        m_canvas->retriangulate();
+    });
+    connect(m_rdStroke, &QRadioButton::toggled, [this]() {
+        m_canvas->setType(TriVisCanvas::Stroke);
+        m_canvas->retriangulate();
+    });
+
+    connect(m_spStrokeWidth, static_cast<void (QSpinBox::*)(int)>(&QSpinBox::valueChanged), [this]() {
+        m_canvas->setStrokeWidth(m_spStrokeWidth->value());
+        m_canvas->regeneratePreviews();
+        m_canvas->retriangulate();
+    });
+
+    connect(m_chDash, &QCheckBox::toggled, [this]() {
+        m_canvas->setDashStroke(m_chDash->isChecked());
+        m_canvas->regeneratePreviews();
+        m_canvas->retriangulate();
+    });
+
+    connect(m_chStepEnable, &QCheckBox::toggled, [this]() {
+        bool enable = m_chStepEnable->isChecked();
+        m_spStepStroke->setEnabled(enable);
+        m_spStepFill->setEnabled(enable);
+        if (enable)
+            m_canvas->setStepLimits(m_spStepStroke->value(), m_spStepFill->value());
+        else
+            m_canvas->setStepLimits(0, 0);
+    });
+
+    connect(m_spStepStroke, static_cast<void (QSpinBox::*)(int)>(&QSpinBox::valueChanged), [this]() {
+        m_canvas->setStepLimits(m_spStepStroke->value(), m_spStepFill->value());
+    });
+
+    connect(m_spStepFill, static_cast<void (QSpinBox::*)(int)>(&QSpinBox::valueChanged), [this]() {
+        m_canvas->setStepLimits(m_spStepStroke->value(), m_spStepFill->value());
+    });
+
+    connect(m_canvas, &TriVisCanvas::retriangulated, [this]() {
+        updateInfoLabel();
+        updatePreviewLabel();
+    });
+
+    connect(m_canvas, &TriVisCanvas::zoomChanged, [this](float oldZoom, float newZoom) {
+        QScrollBar *sb = m_scrollArea->horizontalScrollBar();
+        float x = sb->value() / oldZoom;
+        sb->setValue(x * newZoom);
+        sb = m_scrollArea->verticalScrollBar();
+        float y = sb->value() / oldZoom;
+        sb->setValue(y * newZoom);
+        updateInfoLabel();
+
+    });
+
+    m_canvas->retriangulate();
+}
+
+void TriangulationVisualizer::updateInfoLabel()
+{
+    m_lbInfo->setText(QString(QStringLiteral("Type: %1\n%2 vertices (x, y)\n%3 indices\nzoom: %4\nUSE CTRL+WHEEL TO ZOOM"))
+                      .arg(m_canvas->geomType() == TriVisCanvas::Triangles ? QLatin1String("Triangles") : QLatin1String("Triangle strips"))
+                      .arg(m_canvas->vertexCount())
+                      .arg(m_canvas->indexCount())
+                      .arg(m_canvas->zoomLevel()));
+}
+
+void TriangulationVisualizer::updatePreviewLabel()
+{
+    m_lbPreview->setPixmap(QPixmap::fromImage(m_canvas->preview()).scaled(m_lbPreview->size()));
+}
+
+const int TLX = 10;
+const int TLY = 10;
+
+TriVisCanvas::TriVisCanvas(QWidget *parent)
+    : QWidget(parent)
+{
+    resize(W * m_zoom, H * m_zoom);
+
+    QPainterPath linePath;
+    linePath.moveTo(TLX, TLY);
+    linePath.lineTo(TLX + 30, TLY + 30);
+    m_paths << linePath;
+
+    QPainterPath rectPath;
+    rectPath.moveTo(TLX, TLY);
+    rectPath.lineTo(TLX + 30, TLY);
+    rectPath.lineTo(TLX + 30, TLY + 30);
+    rectPath.lineTo(TLX, TLY + 30);
+    rectPath.lineTo(TLX, TLY);
+    m_paths << rectPath;
+
+    QPainterPath roundRectPath;
+    roundRectPath.addRoundedRect(TLX, TLY, TLX + 29, TLY + 29, 5, 5);
+    m_paths << roundRectPath;
+
+    QPainterPath ellipsePath;
+    ellipsePath.addEllipse(TLX, TLY, 40, 20);
+    m_paths << ellipsePath;
+
+    QPainterPath cubicPath;
+    cubicPath.moveTo(TLX, TLY + 30);
+    cubicPath.cubicTo(15, 2, 40, 40, 30, 10);
+    m_paths << cubicPath;
+
+    QPainterPath cubicPath2;
+    cubicPath2.moveTo(TLX, TLY + 20);
+    cubicPath2.cubicTo(15, 2, 30, 30, 30, 35);
+    m_paths << cubicPath2;
+
+    regeneratePreviews();
+}
+
+QStringList TriVisCanvas::shapes() const
+{
+    return QStringList()
+            << "line"
+            << "rect"
+            << "roundedrect"
+            << "ellipse"
+            << "cubic curve 1"
+            << "cubic curve 2";
+}
+
+void TriVisCanvas::regeneratePreviews()
+{
+    m_strokePreviews.clear();
+    m_fillPreviews.clear();
+    for (int i = 0; i < m_paths.count(); ++i)
+        addPreview(i);
+}
+
+void TriVisCanvas::addPreview(int idx)
+{
+    QPen pen(Qt::black);
+    pen.setWidthF(m_strokeWidth);
+    if (m_dashStroke)
+        pen.setStyle(Qt::DashLine);
+
+    QImage img(W, H, QImage::Format_RGB32);
+    img.fill(Qt::white);
+    QPainter p(&img);
+    p.translate(-TLX, -TLY);
+    p.scale(2, 2);
+    p.strokePath(m_paths[idx], pen);
+    p.end();
+    m_strokePreviews.append(img);
+
+    img = QImage(W, H, QImage::Format_RGB32);
+    img.fill(Qt::white);
+    p.begin(&img);
+    p.translate(-TLX, -TLY);
+    p.scale(2, 2);
+    p.fillPath(m_paths[idx], QBrush(Qt::gray));
+    p.end();
+    m_fillPreviews.append(img);
+}
+
+QImage TriVisCanvas::preview() const
+{
+    if (m_type == Stroke)
+        return m_strokePreviews[m_idx];
+    else
+        return m_fillPreviews[m_idx];
+}
+
+static const qreal SCALE = 100;
+
+void TriVisCanvas::retriangulate()
+{
+    const QPainterPath &path(m_paths[m_idx]);
+
+    if (m_type == Stroke) {
+        const QVectorPath &vp = qtVectorPathForPath(path);
+        const QSize clipSize(W, H);
+        const QRectF clip(QPointF(0, 0), clipSize);
+        const qreal inverseScale = 1.0 / SCALE;
+
+        QTriangulatingStroker stroker;
+        stroker.setInvScale(inverseScale);
+
+        QPen pen;
+        pen.setWidthF(m_strokeWidth);
+        if (m_dashStroke)
+            pen.setStyle(Qt::DashLine);
+
+        if (pen.style() == Qt::SolidLine) {
+            stroker.process(vp, pen, clip, 0);
+        } else {
+            QDashedStrokeProcessor dashStroker;
+            dashStroker.setInvScale(inverseScale);
+            dashStroker.process(vp, pen, clip, 0);
+            QVectorPath dashStroke(dashStroker.points(), dashStroker.elementCount(),
+                                   dashStroker.elementTypes(), 0);
+            stroker.process(dashStroke, pen, clip, 0);
+        }
+
+        m_strokeVertices.resize(stroker.vertexCount() / 2);
+        if (!m_strokeVertices.isEmpty()) {
+            const float *vsrc = stroker.vertices();
+            for (int i = 0; i < m_strokeVertices.count(); ++i)
+                m_strokeVertices[i].set(vsrc[i * 2], vsrc[i * 2 + 1]);
+        }
+    } else {
+        const QVectorPath &vp = qtVectorPathForPath(path);
+        QTriangleSet ts = qTriangulate(vp, QTransform::fromScale(SCALE, SCALE), 1, true);
+        const int vertexCount = ts.vertices.count() / 2;
+        m_fillVertices.resize(vertexCount);
+        Vertex *vdst = reinterpret_cast<Vertex *>(m_fillVertices.data());
+        const qreal *vsrc = ts.vertices.constData();
+        for (int i = 0; i < vertexCount; ++i)
+            vdst[i].set(vsrc[i * 2] / SCALE, vsrc[i * 2 + 1] / SCALE);
+
+        m_fillIndices.resize(ts.indices.size());
+        if (ts.indices.type() == QVertexIndexVector::UnsignedShort) {
+            const quint16 *shortD = static_cast<const quint16 *>(ts.indices.data());
+            for (int i = 0; i < m_fillIndices.count(); ++i)
+                m_fillIndices[i] = shortD[i];
+        } else {
+            memcpy(m_fillIndices.data(), ts.indices.data(), ts.indices.size() * sizeof(quint32));
+        }
+    }
+
+    emit retriangulated();
+    update();
+}
+
+void TriVisCanvas::paintEvent(QPaintEvent *)
+{
+    QPainter p(this);
+    p.fillRect(rect(), Qt::white);
+
+    if (m_type == Stroke) {
+        QPointF prevPt[3];
+        int cnt = 0;
+        for (int i = 0; i < m_strokeVertices.count() && (!m_strokeStepLimit || i < m_strokeStepLimit); ++i) {
+            auto &v = m_strokeVertices[i];
+            QPointF pt(v.x, v.y);
+            pt *= m_zoom;
+            if (cnt == 1 || cnt == 2)
+                p.drawLine(prevPt[cnt - 1], pt);
+            prevPt[cnt] = pt;
+            cnt = (cnt + 1) % 3;
+            if (!cnt) {
+                p.drawLine(pt, prevPt[cnt]);
+                i -= 2;
+            }
+        }
+    } else {
+        QPointF prevPt[3];
+        int cnt = 0;
+        for (int i = 0; i < m_fillIndices.count() && (!m_fillStepLimit || i < m_fillStepLimit); ++i) {
+            auto &v = m_fillVertices[m_fillIndices[i]];
+            QPointF pt(v.x, v.y);
+            pt *= m_zoom;
+            if (cnt == 1 || cnt == 2)
+                p.drawLine(prevPt[cnt - 1], pt);
+            prevPt[cnt] = pt;
+            cnt = (cnt + 1) % 3;
+            if (!cnt)
+                p.drawLine(pt, prevPt[cnt]);
+        }
+    }
+}
+
+void TriVisCanvas::wheelEvent(QWheelEvent *event)
+{
+    int change = 0;
+
+    if (event->modifiers().testFlag(Qt::ControlModifier)) {
+        if (event->delta() > 0 && m_zoom < MAX_ZOOM) {
+            m_zoom += 1;
+            change = 1;
+        } else if (event->delta() < 0 && m_zoom > 1) {
+            m_zoom -= 1;
+            change = -1;
+        }
+    }
+
+    resize(W * m_zoom, H * m_zoom);
+    emit zoomChanged(m_zoom - change, m_zoom);
+    update();
+}
diff --git a/tests/manual/triangulator/triviswidget.h b/tests/manual/triangulator/triviswidget.h
new file mode 100644
index 0000000000..aee80c6cad
--- /dev/null
+++ b/tests/manual/triangulator/triviswidget.h
@@ -0,0 +1,139 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** 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.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef TRIVISWIDGET_H
+#define TRIVISWIDGET_H
+
+#include <QWidget>
+#include <QComboBox>
+#include <QRadioButton>
+#include <QLabel>
+#include <QSpinBox>
+#include <QCheckBox>
+#include <QScrollArea>
+
+class TriVisCanvas : public QWidget
+{
+    Q_OBJECT
+
+public:
+    TriVisCanvas(QWidget *parent = nullptr);
+
+    QStringList shapes() const;
+
+    enum Type {
+        Stroke,
+        Fill
+    };
+
+    void setType(Type t) { m_type = t; }
+    void setIndex(int idx) { m_idx = idx; }
+
+    void setStrokeWidth(float w) { m_strokeWidth = w; }
+    void setDashStroke(bool d) { m_dashStroke = d; }
+
+    void setStepLimits(int strokeLimit, int fillLimit) {
+        m_strokeStepLimit = strokeLimit;
+        m_fillStepLimit = fillLimit;
+        update();
+    }
+
+    enum GeomType {
+        Triangles,
+        TriangleStrips
+    };
+
+    QImage preview() const;
+    GeomType geomType() const { return m_type == Stroke ? TriangleStrips : Triangles; }
+    int vertexCount() const { return m_type == Stroke ? m_strokeVertices.count() : m_fillVertices.count(); }
+    int indexCount() const { return m_type == Stroke ? 0 : m_fillIndices.count(); }
+    float zoomLevel() const { return m_zoom; }
+
+    void retriangulate();
+    void regeneratePreviews();
+
+protected:
+    void paintEvent(QPaintEvent *event) override;
+    void wheelEvent(QWheelEvent *event) override;
+
+signals:
+    void retriangulated();
+    void zoomChanged(float oldZoom, float newZoom);
+
+private:
+    void addPreview(int idx);
+
+    Type m_type = Stroke;
+    int m_idx = 0;
+    float m_strokeWidth = 1;
+    bool m_dashStroke = false;
+
+    QVector<QPainterPath> m_paths;
+    QVector<QImage> m_strokePreviews;
+    QVector<QImage> m_fillPreviews;
+
+    struct Vertex {
+        float x, y;
+        void set(float vx, float vy) { x = vx; y = vy; }
+    };
+    QVector<Vertex> m_fillVertices;
+    QVector<quint32> m_fillIndices;
+    QVector<Vertex> m_strokeVertices;
+
+    float m_zoom = 1;
+
+    int m_fillStepLimit = 0;
+    int m_strokeStepLimit = 0;
+};
+
+class TriangulationVisualizer : public QWidget
+{
+    Q_OBJECT
+
+public:
+    TriangulationVisualizer(QWidget *parent = nullptr);
+
+private:
+    void updateInfoLabel();
+    void updatePreviewLabel();
+
+    QComboBox *m_cbShape;
+    QLabel *m_lbPreview;
+    QRadioButton *m_rdStroke;
+    QRadioButton *m_rdFill;
+    QScrollArea *m_scrollArea;
+    TriVisCanvas *m_canvas;
+    QLabel *m_lbInfo;
+    QSpinBox *m_spStrokeWidth;
+    QCheckBox *m_chDash;
+    QCheckBox *m_chStepEnable;
+    QSpinBox *m_spStepStroke;
+    QSpinBox *m_spStepFill;
+};
+
+#endif