Simpler magnifying glass example.

4 files changed, 266 insertions, 0 deletions

diff --git a/imgzoom/cookies.jpg b/imgzoom/cookies.jpg
new file mode 100644
index 0000000..daff1c3
--- /dev/null
+++ b/imgzoom/cookies.jpg
diff --git a/imgzoom/imgzoom.cpp b/imgzoom/imgzoom.cpp
new file mode 100644
index 0000000..400a4b8
--- /dev/null
+++ b/imgzoom/imgzoom.cpp
@@ -0,0 +1,256 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Qt Software Information (qt-info@nokia.com)
+**
+** This file is part of the Graphics Dojo project on Qt Labs.
+**
+** This file may be used under the terms of the GNU General Public
+** License version 2.0 or 3.0 as published by the Free Software Foundation
+** and appearing in the file LICENSE.GPL included in the packaging of
+** this file.  Please review the following information to ensure GNU
+** General Public Licensing requirements will be met:
+** http://www.fsf.org/licensing/licenses/info/GPLv2.html and
+** http://www.gnu.org/copyleft/gpl.html.
+**
+** If you are unsure which license is appropriate for your use, please
+** contact the sales department at qt-sales@nokia.com.
+**
+** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
+** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+**
+****************************************************************************/
+
+#include <QtCore>
+#include <QtGui>
+
+#if QT_VERSION < 0x0040500
+#error You need Qt 4.5 or newer
+#endif
+
+// how long (milliseconds) the user need to hold (after a tap on the screen)
+// before triggering the magnifying glass feature
+// 701, a prime number, is the sum of 229, 233, 239
+// (all three are also prime numbers, consecutive!)
+#define HOLD_TIME 701
+
+class ImgZoom : public QWidget
+{
+    Q_OBJECT
+
+public:
+    ImgZoom()
+        : QWidget(0)
+        , pressed(false)
+        , snapped(false)
+        , zoomed(false) {
+        image.load(":/cookies.jpg");
+        largePixmap.load(":/cookies.jpg");
+        smallPixmap = largePixmap.scaled(largePixmap.size() / 2);
+        offset = QPoint(0, 0);
+    }
+
+    void pan(const QPoint &delta) {
+        offset += delta;
+        update();
+    }
+
+    void activateZoom() {
+        zoomed = true;
+        tapTimer.stop();
+        update();
+    }
+
+protected:
+
+    void timerEvent(QTimerEvent *) {
+        if (!zoomed)
+            activateZoom();
+        update();
+    }
+
+    void mousePressEvent(QMouseEvent *event) {
+        if (event->buttons() != Qt::LeftButton)
+            return;
+        pressed = snapped = true;
+        pressPos = dragPos = event->pos();
+        tapTimer.stop();
+        tapTimer.start(HOLD_TIME, this);
+    }
+
+    void mouseMoveEvent(QMouseEvent *event) {
+        if (!event->buttons())
+            return;
+        if (!zoomed) {
+            if (!pressed || !snapped) {
+                QPoint delta = event->pos() - pressPos;
+                pressPos = event->pos();
+                pan(delta);
+                return;
+            } else {
+                const int threshold = 10;
+                QPoint delta = event->pos() - pressPos;
+                if (snapped) {
+                    snapped &= delta.x() < threshold;
+                    snapped &= delta.y() < threshold;
+                    snapped &= delta.x() > -threshold;
+                    snapped &= delta.y() > -threshold;
+                }
+                if (!snapped)
+                    tapTimer.stop();
+            }
+        } else {
+            dragPos = event->pos();
+            update();
+        }
+    }
+
+    void mouseReleaseEvent(QMouseEvent *) {
+        zoomed = false;
+        update();
+    }
+
+    void resizeEvent(QResizeEvent*) {
+        zoomed = false;
+        update();
+    }
+
+    void paintEvent(QPaintEvent*) {
+        QPainter p(this);
+        p.drawPixmap(offset, smallPixmap);
+        p.end();
+
+        if (zoomed) {
+            int dim = qMin(width(), height());
+            int magnifierSize = dim * 5 / 6;
+            int radius = magnifierSize / 2;
+            int ring = radius - 15;
+            QSize box = QSize(magnifierSize, magnifierSize);
+
+            // reupdate our mask
+            if (maskPixmap.size() != box) {
+                maskPixmap = QPixmap(box);
+                maskPixmap.fill(Qt::transparent);
+
+                QRadialGradient g;
+                g.setCenter(radius, radius);
+                g.setFocalPoint(radius, radius);
+                g.setRadius(radius);
+                g.setColorAt(1.0, QColor(64, 64, 64, 0));
+                g.setColorAt(0.5, QColor(0, 0, 0, 255));
+
+                QPainter mask(&maskPixmap);
+                mask.setRenderHint(QPainter::Antialiasing);
+                mask.setCompositionMode(QPainter::CompositionMode_Source);
+                mask.setBrush(g);
+                mask.setPen(Qt::NoPen);
+                mask.drawRect(maskPixmap.rect());
+                mask.setBrush(QColor(Qt::transparent));
+                mask.drawEllipse(g.center(), ring, ring);
+                mask.end();
+            }
+
+            QPoint center = dragPos - QPoint(0, radius);
+            center = center + QPoint(0, radius / 2);
+            QPoint corner = center - QPoint(radius, radius);
+
+            QPoint xy = center * 2 - QPoint(radius, radius);
+
+            // only set the dimension to the magnified portion
+            if (zoomPixmap.size() != box)
+                zoomPixmap = QPixmap(box);
+            if (true) {
+                zoomPixmap.fill(Qt::lightGray);
+                QPainter p(&zoomPixmap);
+                p.translate(-xy);
+                p.drawPixmap(offset * 2, largePixmap);
+                p.end();
+            }
+
+            QPainterPath clipPath;
+            clipPath.addEllipse(center, ring, ring);
+
+            QPainter p(this);
+            p.setRenderHint(QPainter::Antialiasing);
+            p.setClipPath(clipPath);
+            p.drawPixmap(corner, zoomPixmap);
+            p.setClipping(false);
+            p.drawPixmap(corner, maskPixmap);
+            p.setPen(Qt::gray);
+            p.drawPath(clipPath);
+        }
+    }
+
+    void keyPressEvent(QKeyEvent *event) {
+        if (!zoomed) {
+            if (event->key() == Qt::Key_Left)
+                offset += QPoint(20, 0);
+            if (event->key() == Qt::Key_Right)
+                offset += QPoint(-20, 0);
+            if (event->key() == Qt::Key_Up)
+                offset += QPoint(0, 20);
+            if (event->key() == Qt::Key_Down)
+                offset += QPoint(0, -20);
+            if (event->key() == Qt::Key_Z || event->key() == Qt::Key_Select) {
+                dragPos = QPoint(width() / 2, height() / 2);
+                activateZoom();
+            }
+            update();
+        } else {
+            if (event->key() == Qt::Key_Z || event->key() == Qt::Key_Select) {
+                zoomed = false;
+                update();
+            }
+            QPoint delta(0, 0);
+            if (event->key() == Qt::Key_Left)
+                delta = QPoint(-15, 0);
+            if (event->key() == Qt::Key_Right)
+                delta = QPoint(15, 0);
+            if (event->key() == Qt::Key_Up)
+                delta = QPoint(0, -15);
+            if (event->key() == Qt::Key_Down)
+                delta = QPoint(0, 15);
+            if (delta != QPoint(0, 0)) {
+                dragPos += delta;
+                update();
+            }
+        }
+    }
+
+private:
+    QImage image;
+    QPixmap smallPixmap;
+    QPixmap largePixmap;
+    QPoint offset;
+    bool pressed;
+    bool snapped;
+    QPoint pressPos;
+    QPoint dragPos;
+    QBasicTimer tapTimer;
+    bool zoomed;
+    QPixmap zoomPixmap;
+    QPixmap maskPixmap;
+};
+
+
+#include "imgzoom.moc"
+
+int main(int argc, char **argv)
+{
+#if defined(Q_WS_X11)
+    QApplication::setGraphicsSystem("raster");
+#endif
+
+    QApplication app(argc, argv);
+
+    ImgZoom w;
+    w.setWindowTitle("Zoom with Magnifier");
+#if defined(Q_OS_SYMBIAN)
+    w.showMaximized();
+#else
+    w.resize(400, 300);
+    w.show();
+#endif
+
+    return app.exec();
+}
diff --git a/imgzoom/imgzoom.pro b/imgzoom/imgzoom.pro
new file mode 100644
index 0000000..54455e1
--- /dev/null
+++ b/imgzoom/imgzoom.pro
@@ -0,0 +1,5 @@
+TEMPLATE = app
+SOURCES = imgzoom.cpp
+RESOURCES = imgzoom.qrc
+
+symbian {  TARGET.EPOCHEAPSIZE = 0x20000 0x2000000 }
diff --git a/imgzoom/imgzoom.qrc b/imgzoom/imgzoom.qrc
new file mode 100644
index 0000000..9e35548
--- /dev/null
+++ b/imgzoom/imgzoom.qrc
@@ -0,0 +1,5 @@
+<RCC>
+    <qresource prefix="/" >
+        <file>cookies.jpg</file>
+    </qresource>
+</RCC>