cabana: improve LogSlider (#27673)

* improve logslider

* fix code indentation

tools/cabana/util.cc

@@ -4,10 +4,8 @@
 #include <QFontDatabase>
 #include <QPainter>
 #include <QPixmapCache>
-#include <QDebug>
-
-#include <limits>
 #include <cmath>
+#include <limits>
 
 #include "selfdrive/ui/qt/util.h"
 
@@ -42,7 +40,7 @@ void ChangeTracker::compute(const QByteArray &dat, double ts, uint32_t freq) {
         }
 
         // Track bit level changes
-        for (int bit = 0; bit < 8; bit++){
+        for (int bit = 0; bit < 8; bit++) {
           if ((cur ^ last) & (1 << bit)) {
             bit_change_counts[i][bit] += 1;
           }
@@ -67,7 +65,6 @@ void ChangeTracker::clear() {
   colors.clear();
 }
 
-
 // SegmentTree
 
 void SegmentTree::build(const QVector<QPointF> &arr) {
@@ -116,7 +113,7 @@ void MessageBytesDelegate::paint(QPainter *painter, const QStyleOptionViewItem &
   int h_margin = option.widget->style()->pixelMetric(QStyle::PM_FocusFrameHMargin);
   QRect rc{option.rect.left() + h_margin, option.rect.top() + v_margin, byte_width, option.rect.height() - 2 * v_margin};
 
-  auto color_role = option.state & QStyle::State_Selected ? QPalette::HighlightedText: QPalette::Text;
+  auto color_role = option.state & QStyle::State_Selected ? QPalette::HighlightedText : QPalette::Text;
   painter->setPen(option.palette.color(color_role));
   painter->setFont(fixed_font);
   for (int i = 0; i < byte_list.size(); ++i) {
@@ -139,7 +136,7 @@ QColor getColor(const cabana::Signal *sig) {
   return QColor::fromHsvF(h, s, v);
 }
 
-NameValidator::NameValidator(QObject *parent) : QRegExpValidator(QRegExp("^(\\w+)"), parent) { }
+NameValidator::NameValidator(QObject *parent) : QRegExpValidator(QRegExp("^(\\w+)"), parent) {}
 
 QValidator::State NameValidator::validate(QString &input, int &pos) const {
   input.replace(' ', '_');
@@ -175,7 +172,6 @@ QToolButton *toolButton(const QString &icon, const QString &tooltip) {
   return btn;
 };
 
-
 QString toHex(uint8_t byte) {
   static std::array<QString, 256> hex = []() {
     std::array<QString, 256> ret;
@@ -186,11 +182,11 @@ QString toHex(uint8_t byte) {
 }
 
 int num_decimals(double num) {
-   const QString string = QString::number(num);
-   const QStringList split = string.split('.');
-   if (split.size() == 1) {
-     return 0;
-   } else {
-     return split[1].size();
-   }
- }
+  const QString string = QString::number(num);
+  const QStringList split = string.split('.');
+  if (split.size() == 1) {
+    return 0;
+  } else {
+    return split[1].size();
+  }
+}

tools/cabana/util.h

@@ -36,17 +36,26 @@ class LogSlider : public QSlider {
 public:
   LogSlider(double factor, Qt::Orientation orientation, QWidget *parent = nullptr) : factor(factor), QSlider(orientation, parent) {};
 
-  void setRange(double min, double max) { QSlider::setRange(logScale(min), logScale(max)); }
-  int value() const { return invLogScale(QSlider::value()); }
-  void setValue(int value) { QSlider::setValue(logScale(value)); }
+  void setRange(double min, double max) {
+    log_min = factor * std::log10(min);
+    log_max = factor * std::log10(max);
+    QSlider::setRange(min, max);
+    setValue(QSlider::value());
+  }
+  int value() const {
+    double v = log_min + (log_max - log_min) * ((QSlider::value() - minimum()) / double(maximum() - minimum()));
+    return std::lround(std::pow(10, v / factor));
+  }
+  void setValue(int v) {
+    double log_v = std::clamp(factor * std::log10(v), log_min, log_max);
+    v = minimum() + (maximum() - minimum()) * ((log_v - log_min) / (log_max - log_min));
+    QSlider::setValue(v);
+  }
 
 private:
-  double factor;
-  int logScale(int value) const { return factor * std::log10(value); }
-  int invLogScale(int value) const { return std::pow(10, value / factor); }
+  double factor, log_min = 0, log_max = 1;
 };
 
-
 enum {
   ColorsRole = Qt::UserRole + 1,
   BytesRole = Qt::UserRole + 2