spinner: pre-compute rotations

old-commit-hash: 1bcc3beae8

selfdrive/ui/qt/spinner.cc

@@ -3,9 +3,9 @@
 #include <iostream>
 
 #include <QString>
+#include <QTransform>
 #include <QGridLayout>
 #include <QApplication>
-#include <QDesktopWidget>
 
 #include "spinner.hpp"
 #include "qt_window.hpp"
@@ -15,19 +15,26 @@ Spinner::Spinner(QWidget *parent) {
   main_layout->setSpacing(0);
   main_layout->setContentsMargins(200, 200, 200, 200);
 
-  const int img_size = 360;
-
   comma = new QLabel();
-  comma->setPixmap(QPixmap("../assets/img_spinner_comma.png").scaled(img_size, img_size, Qt::KeepAspectRatio, Qt::SmoothTransformation));
-  comma->setFixedSize(img_size, img_size);
+  comma->setPixmap(QPixmap("../assets/img_spinner_comma.png").scaled(spinner_size, Qt::KeepAspectRatio, Qt::SmoothTransformation));
+  comma->setFixedSize(spinner_size);
   main_layout->addWidget(comma, 0, 0, Qt::AlignHCenter | Qt::AlignVCenter);
 
-  track_img = QPixmap("../assets/img_spinner_track.png").scaled(img_size, img_size, Qt::KeepAspectRatio, Qt::SmoothTransformation);
   track = new QLabel();
-  track->setPixmap(track_img);
-  track->setFixedSize(img_size, img_size);
+  track->setFixedSize(spinner_size);
   main_layout->addWidget(track, 0, 0, Qt::AlignHCenter | Qt::AlignVCenter);
 
+  // pre-compute all the track imgs. make this a gif instead?
+  track_idx = 0;
+  QTransform transform;
+  QPixmap track_img = QPixmap("../assets/img_spinner_track.png").scaled(spinner_size, Qt::KeepAspectRatio, Qt::SmoothTransformation);
+  for (auto &img : track_imgs) {
+    QPixmap r = track_img.transformed(transform.rotate(360/spinner_fps), Qt::SmoothTransformation);
+    int x = (r.width() - track->width()) / 2;
+    int y = (r.height() - track->height()) / 2;
+    img = r.copy(x, y, track->width(), track->height());
+  }
+
   text = new QLabel();
   text->setVisible(false);
   main_layout->addWidget(text, 1, 0, Qt::AlignHCenter);
@@ -61,7 +68,7 @@ Spinner::Spinner(QWidget *parent) {
   )");
 
   rotate_timer = new QTimer(this);
-  rotate_timer->start(1000/30.);
+  rotate_timer->start(1000./spinner_fps);
   QObject::connect(rotate_timer, SIGNAL(timeout()), this, SLOT(rotate()));
 
   notifier = new QSocketNotifier(fileno(stdin), QSocketNotifier::Read);
@@ -69,12 +76,8 @@ Spinner::Spinner(QWidget *parent) {
 };
 
 void Spinner::rotate() {
-  transform.rotate(5);
-
-  QPixmap r = track_img.transformed(transform.rotate(5), Qt::SmoothTransformation);
-  int x = (r.width() - track->width()) / 2;
-  int y = (r.height() - track->height()) / 2;
-  track->setPixmap(r.copy(x, y, track->width(), track->height()));
+  track_idx = (track_idx+1) % track_imgs.size();
+  track->setPixmap(track_imgs[track_idx]);
 };
 
 void Spinner::update(int n) {

selfdrive/ui/qt/spinner.hpp

@@ -1,11 +1,15 @@
+#include <array>
+
 #include <QTimer>
 #include <QLabel>
 #include <QWidget>
 #include <QPixmap>
 #include <QProgressBar>
-#include <QTransform>
 #include <QSocketNotifier>
 
+constexpr int spinner_fps = 30;
+constexpr QSize spinner_size = QSize(360, 360);
+
 class Spinner : public QWidget {
   Q_OBJECT
 
@@ -13,12 +17,13 @@ public:
   explicit Spinner(QWidget *parent = 0);
 
 private:
-  QPixmap track_img;
-  QTimer *rotate_timer;
+  int track_idx;
   QLabel *comma, *track;
   QLabel *text;
   QProgressBar *progress_bar;
-  QTransform transform;
+  std::array<QPixmap, spinner_fps> track_imgs;
+
+  QTimer *rotate_timer;
   QSocketNotifier *notifier;
 
 public slots: