Add C[onditional]ProgressBar class.

oscar/cprogressbar.cpp

@@ -0,0 +1,86 @@
+/* OSCAR C[onditional] Progress Bar
+ *
+ * Copyright (C) 2019 Guy Scharf
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file COPYING in the main directory of the source code
+ * for more details.
+ *
+ * The C[onditional] progress bar causes the progress bar window to show only if the task
+ * is not half done in two seconds (number of seconds is variable).  The CProgressBar can
+ * thus be used in all situations in which a progress bar might be appropriate without
+ * determining ahead of time whether the task will take long enough to warrant use of a progress bar.
+ *
+ * This is especially useful when even though the number of iterations is known, the time required
+ * to perform each iteration is not known ahead of time.  For example, reading summary files and
+ * discovering that some need to be updated but others do not.
+ */
+
+#include <QCoreApplication>
+
+#include "cprogressbar.h"
+
+CProgressBar::CProgressBar(QString title, QWidget * parent, long maxValue)
+{
+    savedTitle = title;
+    maxSteps = maxValue;
+    progress = nullptr;
+    showProgress = false;
+    this->parent = parent;
+}
+
+void CProgressBar::start () {
+    timeChecked = false;
+    timer.start();
+}
+
+void CProgressBar::setMaximum (long value) {
+    maxSteps = value;
+}
+
+void CProgressBar::setTitle (QString title) {
+    savedTitle = title;
+}
+
+void CProgressBar::setWidth (int width) {
+    this->width = width;
+}
+
+void CProgressBar::add (long count) {
+    numDone += count;
+
+    // If timer not started, start it now.
+    if (!timer.isValid())
+        timer.start();
+
+    // See if timer limit has passed
+    if (!progress && !timeChecked && (timer.elapsed() > timerLimit)) {
+        progress = new QProgressDialog(savedTitle,
+                                QString(), 0, maxSteps, parent,
+                                Qt::WindowSystemMenuHint | Qt::WindowTitleHint);
+        progress->setWindowModality(Qt::WindowModal);
+        progress->setValue(0);
+        progress->setMinimumWidth(width);
+        progress->show();
+        maxSteps -= numDone;       // maxSteps now is number of steps remaining
+        numDone = 1;               // and we figure only one processed so far
+        QCoreApplication::processEvents();
+        showProgress = true;
+    }
+
+    // Update progress bar if one is displayed and more than 1% different from last display
+    if (showProgress) {
+        int pctDone = (100 * numDone) / maxSteps;
+        if (pctDone != lastPctDone) {
+            lastPctDone = pctDone;
+            progress->setValue(numDone);
+            QCoreApplication::processEvents();
+        }
+    }
+}
+
+void CProgressBar::close () {
+    if (progress) {
+        progress->setValue(maxSteps);
+    }
+}

oscar/cprogressbar.h

@@ -0,0 +1,55 @@
+/* OSCAR C[onditional] Progress Bar
+ *
+ * Copyright (C) 2019 Guy Scharf
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file COPYING in the main directory of the source code
+ * for more details.
+ *
+ * The C[onditional] progress bar causes the progress bar window to show only if the task
+ * is not half done in two seconds (number of seconds is variable).  The CProgressBar can
+ * thus be used in all situations in which a progress bar might be appropriate without
+ * determining ahead of time whether the task will take long enough to warrant use of a progress bar.
+ *
+ * This is especially useful when even though the number of iterations is known, the time required
+ * to perform each iteration is not known ahead of time.  For example, reading summary files and
+ * discovering that some need to be updated but others do not.
+ */
+
+#ifndef CPROGRESSBAR_H
+#define CPROGRESSBAR_H
+
+#include <QProgressDialog>
+#include <QElapsedTimer>
+
+
+class CProgressBar
+{
+public:
+    CProgressBar(QString title, QWidget * parent, long maxValue);
+
+    void setMaximum (long max);
+    void add (long count);
+    void setWidth (int width);
+    void setTitle (QString title);
+
+    void start ();
+    void close ();
+
+private:
+    bool showProgress = false;
+    bool timeChecked = false;
+
+    int lastPctDone = 0;
+    long timerLimit = 2000;
+    long maxSteps = 0;
+    long numDone = 0;
+    int width = 250;
+    QString savedTitle;
+
+    QWidget * parent = nullptr;
+    QProgressDialog * progress = nullptr;
+    QElapsedTimer timer;
+};
+
+#endif // CPROGRESSBAR_H